Direct and indirect genetic and fine-scale location effects on breeding date in song sparrows.

PubMed

Germain, Ryan R; Wolak, Matthew E; Arcese, Peter; Losdat, Sylvain; Reid, Jane M

2016-11-01

Quantifying direct and indirect genetic effects of interacting females and males on variation in jointly expressed life-history traits is central to predicting microevolutionary dynamics. However, accurately estimating sex-specific additive genetic variances in such traits remains difficult in wild populations, especially if related individuals inhabit similar fine-scale environments. Breeding date is a key life-history trait that responds to environmental phenology and mediates individual and population responses to environmental change. However, no studies have estimated female (direct) and male (indirect) additive genetic and inbreeding effects on breeding date, and estimated the cross-sex genetic correlation, while simultaneously accounting for fine-scale environmental effects of breeding locations, impeding prediction of microevolutionary dynamics. We fitted animal models to 38 years of song sparrow (Melospiza melodia) phenology and pedigree data to estimate sex-specific additive genetic variances in breeding date, and the cross-sex genetic correlation, thereby estimating the total additive genetic variance while simultaneously estimating sex-specific inbreeding depression. We further fitted three forms of spatial animal model to explicitly estimate variance in breeding date attributable to breeding location, overlap among breeding locations and spatial autocorrelation. We thereby quantified fine-scale location variances in breeding date and quantified the degree to which estimating such variances affected the estimated additive genetic variances. The non-spatial animal model estimated nonzero female and male additive genetic variances in breeding date (sex-specific heritabilities: 0·07 and 0·02, respectively) and a strong, positive cross-sex genetic correlation (0·99), creating substantial total additive genetic variance (0·18). Breeding date varied with female, but not male inbreeding coefficient, revealing direct, but not indirect, inbreeding depression. All three spatial animal models estimated small location variance in breeding date, but because relatedness and breeding location were virtually uncorrelated, modelling location variance did not alter the estimated additive genetic variances. Our results show that sex-specific additive genetic effects on breeding date can be strongly positively correlated, which would affect any predicted rates of microevolutionary change in response to sexually antagonistic or congruent selection. Further, we show that inbreeding effects on breeding date can also be sex specific and that genetic effects can exceed phenotypic variation stemming from fine-scale location-based variation within a wild population. © 2016 The Authors. Journal of Animal Ecology © 2016 British Ecological Society.

New perspectives on evolutionary medicine: the relevance of microevolution for human health and disease

PubMed Central

2013-01-01

Evolutionary medicine (EM) is a growing field focusing on the evolutionary basis of human diseases and their changes through time. To date, the majority of EM studies have used pure theories of hominin macroevolution to explain the present-day state of human health. Here, we propose a different approach by addressing more empirical and health-oriented research concerning past, current and future microevolutionary changes of human structure, functions and pathologies. Studying generation-to-generation changes of human morphology that occurred in historical times, and still occur in present-day populations under the forces of evolution, helps to explain medical conditions and warns clinicians that their current practices may influence future humans. Also, analyzing historic tissue specimens such as mummies is crucial in order to address the molecular evolution of pathogens, of the human genome, and their coadaptations. PMID:23627943

Evolutionary toxicology: Meta-analysis of evolutionary events in response to chemical stressors.

PubMed

M Oziolor, Elias; De Schamphelaere, Karel; Matson, Cole W

2016-12-01

The regulatory decision-making process regarding chemical safety is most often informed by evidence based on ecotoxicity tests that consider growth, reproduction and survival as end-points, which can be quantitatively linked to short-term population outcomes. Changes in these end-points resulting from chemical exposure can cause alterations in micro-evolutionary forces (mutation, drift, selection and gene flow) that control the genetic composition of populations. With multi-generation exposures, anthropogenic contamination can lead to a population with an altered genetic composition, which may respond differently to future stressors. These evolutionary changes are rarely discussed in regulatory or risk assessment frameworks, but the growing body of literature that documents their existence suggests that these important population-level impacts should be considered. In this meta-analysis we have compared existing contamination levels of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) that have been documented to be associated with evolutionary changes in resident aquatic organisms to regulatory benchmarks for these contaminants. The original intent of this project was to perform a meta-analysis on evolutionary events associated with PCB and PAH contamination. However, this effort was hindered by a lack of consistency in congener selection for "total" PCB or PAH measurements. We expanded this manuscript to include a discussion of methods used to determine PCB and PAH total contamination in addition to comparing regulatory guidelines and contamination that has caused evolutionary effects. Micro-evolutionary responses often lead populations onto unique and unpredictable trajectories. Therefore, to better understand the risk of population-wide alterations occurring, we need to improve comparisons of chemical contamination between affected locations. In this manuscript we offer several possibilities to unify chemical comparisons for PCBs and PAHs that would improve comparability among evolutionary toxicology investigations, and with regulatory guidelines. In addition, we identify studies documenting evolutionary change in the presence of PCB and PAH contamination levels below applicable regulatory benchmarks.

Do arms races punctuate evolutionary stasis? Unified insights from phylogeny, phylogeography and microevolutionary processes.

PubMed

Toju, Hirokazu; Sota, Teiji

2009-09-01

One of the major controversies in evolutionary biology concerns the processes underlying macroevolutionary patterns in which prolonged stasis is disrupted by rapid, short-term evolution that leads species to new adaptive zones. Recent advances in the understanding of contemporary evolution have suggested that such rapid evolution can occur in the wild as a result of environmental changes. Here, we examined a novel hypothesis that evolutionary stasis is punctuated by co-evolutionary arms races, which continuously alter adaptive peaks and landscapes. Based on the phylogeny of long-mouthed weevils in the genus Curculio, likelihood ratio tests showed that the macroevolutionary pattern of the weevils coincides with the punctuational evolution model. A coalescent analysis of a species, Curculio camelliae, the mouthpart of which has diverged considerably among populations because of an arms race with its host plant, further suggested that major evolutionary shifts had occurred within 7000 generations. Through a microevolutionary analysis of the species, we also found that natural selection acting through co-evolutionary interactions is potentially strong enough to drive rapid evolutionary shifts between adaptive zones. Overall, we posit that co-evolution is an important factor driving the history of organismal evolution.

Micro-evolutionary implications of allozymic and morphometric variations in sealworms Pseudoterranova sp. (Ascaridoidea: Anisakidae) among sympatric hosts from the southeastern Pacific Ocean.

PubMed

George-Nascimento, M; Llanos, A

1995-10-01

We found significant morphometric and electrophoretic differences between sealworm larvae collected from four sympatric fish host species off the central coast of Chile. The South American sea lion, Otaria byronia, is a suitable host and most likely the only definitive host species in the study area. Morphological patterns of caudal papillae in adult males collected from sea lions and electrophoretic evidence from larvae and adults substantiate our conclusion that they belong to just one, new species yet to be described. The genetic and morphometric differences found between sealworm larvae from sympatric fish hosts may be due to selective pressures arising from the internal environment of the intermediate hosts, although they may serve only for passing sequential filters along the life cycle. The discussion deals with the roles that definitive and intermediate hosts may play in the micro-evolutionary processes of sealworms.

Building v/s Exploring Models: Comparing Learning of Evolutionary Processes through Agent-based Modeling

NASA Astrophysics Data System (ADS)

Wagh, Aditi

Two strands of work motivate the three studies in this dissertation. Evolutionary change can be viewed as a computational complex system in which a small set of rules operating at the individual level result in different population level outcomes under different conditions. Extensive research has documented students' difficulties with learning about evolutionary change (Rosengren et al., 2012), particularly in terms of levels slippage (Wilensky & Resnick, 1999). Second, though building and using computational models is becoming increasingly common in K-12 science education, we know little about how these two modalities compare. This dissertation adopts agent-based modeling as a representational system to compare these modalities in the conceptual context of micro-evolutionary processes. Drawing on interviews, Study 1 examines middle-school students' productive ways of reasoning about micro-evolutionary processes to find that the specific framing of traits plays a key role in whether slippage explanations are cued. Study 2, which was conducted in 2 schools with about 150 students, forms the crux of the dissertation. It compares learning processes and outcomes when students build their own models or explore a pre-built model. Analysis of Camtasia videos of student pairs reveals that builders' and explorers' ways of accessing rules, and sense-making of observed trends are of a different character. Builders notice rules through available blocks-based primitives, often bypassing their enactment while explorers attend to rules primarily through the enactment. Moreover, builders' sense-making of observed trends is more rule-driven while explorers' is more enactment-driven. Pre and posttests reveal that builders manifest a greater facility with accessing rules, providing explanations manifesting targeted assembly. Explorers use rules to construct explanations manifesting non-targeted assembly. Interviews reveal varying degrees of shifts away from slippage in both modalities, with students who built models not incorporating slippage explanations in responses. Study 3 compares these modalities with a control using traditional activities. Pre and posttests reveal that the two modalities manifested greater facility with accessing and assembling rules than the control. The dissertation offers implications for the design of learning environments for evolutionary change, design of the two modalities based on their strengths and weaknesses, and teacher training for the same.

Microevolutionary dynamics of a macroevolutionary key innovation in a Lepidopteran herbivore

PubMed Central

2010-01-01

Background A molecular population genetics understanding is central to the study of ecological and evolutionary functional genomics. Population genetics identifies genetic variation and its distribution within and among populations, it reveals the demographic history of the populations studied, and can provide indirect insights into historical selection dynamics. Here we use this approach to examine the demographic and selective dynamics acting of a candidate gene involved in plant-insect interactions. Previous work documents the macroevolutionary and historical ecological importance of the nitrile-specifier protein (Nsp), which facilitated the host shift of Pieridae butterflies onto Brassicales host plants ~80 Myr ago. Results Here we assess the microevolutionary dynamics of the Nsp gene by studying the within and among-population variation at Nsp and reference genes in the butterfly Pieris rapae (Small Cabbage White). Nsp exhibits unexpectedly high amounts of amino acid polymorphism, unequally distributed across the gene. The vast majority of genetic variation exists within populations, with little to no genetic differentiation among four populations on two continents. A comparison of synonymous and nonsynonymous substitutions in 70 randomly chosen genes among P. rapae and its close relative Pieris brassicae (Large Cabbage White) finds Nsp to have a significantly relaxed functional constraint compared to housekeeping genes. We find strong evidence for a recent population expansion and no role for strong purifying or directional selection upon the Nsp gene. Conclusions The microevolutionary dynamics of the Nsp gene in P. rapae are dominated by recent population expansion and variation in functional constraint across the repeated domains of the Nsp gene. While the high amounts of amino acid diversity suggest there may be significant functional differences among allelic variants segregating within populations, indirect tests of selection could not conclusively identify a signature of historical selection. The importance of using this information for planning future studies of potential performance and fitness consequences of the observed variation is discussed. PMID:20181249

Climate change and timing of avian breeding and migration: evolutionary versus plastic changes

PubMed Central

Charmantier, Anne; Gienapp, Phillip

2014-01-01

There are multiple observations around the globe showing that in many avian species, both the timing of migration and breeding have advanced, due to warmer springs. Here, we review the literature to disentangle the actions of evolutionary changes in response to selection induced by climate change versus changes due to individual plasticity, that is, the capacity of an individual to adjust its phenology to environmental variables. Within the abundant literature on climate change effects on bird phenology, only a small fraction of studies are based on individual data, yet individual data are required to quantify the relative importance of plastic versus evolutionary responses. While plasticity seems common and often adaptive, no study so far has provided direct evidence for an evolutionary response of bird phenology to current climate change. This assessment leads us to notice the alarming lack of tests for microevolutionary changes in bird phenology in response to climate change, in contrast with the abundant claims on this issue. In short, at present we cannot draw reliable conclusions on the processes underlying the observed patterns of advanced phenology in birds. Rapid improvements in techniques for gathering and analysing individual data offer exciting possibilities that should encourage research activity to fill this knowledge gap. PMID:24454545

Mechanisms and microevolutionary consequences of social homogamy in a 19th-century Italian community.

PubMed

Manfredini, Matteo

2009-02-01

Abstract Choosing a spouse has always been an event subjected to strong social control. Consideration of socioprofessional elements is therefore necessary for an in-depth understanding of the microevolutionary consequences of marriage. Thus in this paper I explore the extent and causes of reproduction isolation between different socioprofessional groups of a 19th-century Italian community, Casalguidi. Various features of mate choice pattern were investigated by means of individual-level data. The results show that Casalguidi was a community with strong socioeconomic internal boundaries, in which social belonging mattered much more than geographic provenience. The bourgeoisie showed such a high degree of social homogamy that it was almost reproductively isolated. Much more openness and less isolation was found between the two categories of farm laborers and sharecroppers, and day laborers.

Geographically pervasive effects of urban noise on frequency and syllable rate of songs and calls in silvereyes (Zosterops lateralis).

PubMed

Potvin, Dominique A; Parris, Kirsten M; Mulder, Raoul A

2011-08-22

Recent studies in the Northern Hemisphere have shown that songbirds living in noisy urban environments sing at higher frequencies than their rural counterparts. However, several aspects of this phenomenon remain poorly understood. These include the geographical scale over which such patterns occur (most studies have compared local populations), and whether they involve phenotypic plasticity or microevolutionary change. We conducted a field study of silvereye (Zosterops lateralis) vocalizations over more than 1 million km(2) of urban and rural south-eastern Australia, and compared possible effects of urban noise on songs (which are learned) and contact calls (which are innate). Across 14 paired urban and rural populations, silvereyes consistently sang both songs and contact calls at higher frequencies in urban environments. Syllable rate (syllables per second) decreased in urban environments, consistent with the hypothesis that reflective structures degrade song and encourage longer intervals between syllables. This comprehensive study is, to our knowledge, the first to demonstrate varied adaptations of urban bird vocalizations over a vast geographical area, and to provide insight into the mechanism responsible for these changes.

Rapid Gene Turnover as a Significant Source of Genetic Variation in a Recently Seeded Population of a Healthcare-Associated Pathogen

PubMed Central

Graña-Miraglia, Lucía; Lozano, Luis F.; Velázquez, Consuelo; Volkow-Fernández, Patricia; Pérez-Oseguera, Ángeles; Cevallos, Miguel A.; Castillo-Ramírez, Santiago

2017-01-01

Genome sequencing has been useful to gain an understanding of bacterial evolution. It has been used for studying the phylogeography and/or the impact of mutation and recombination on bacterial populations. However, it has rarely been used to study gene turnover at microevolutionary scales. Here, we sequenced Mexican strains of the human pathogen Acinetobacter baumannii sampled from the same locale over a 3 year period to obtain insights into the microevolutionary dynamics of gene content variability. We found that the Mexican A. baumannii population was recently founded and has been emerging due to a rapid clonal expansion. Furthermore, we noticed that on average the Mexican strains differed from each other by over 300 genes and, notably, this gene content variation has accrued more frequently and faster than the accumulation of mutations. Moreover, due to its rapid pace, gene content variation reflects the phylogeny only at very short periods of time. Additionally, we found that the external branches of the phylogeny had almost 100 more genes than the internal branches. All in all, these results show that rapid gene turnover has been of paramount importance in producing genetic variation within this population and demonstrate the utility of genome sequencing to study alternative forms of genetic variation. PMID:28979253

Rapid Gene Turnover as a Significant Source of Genetic Variation in a Recently Seeded Population of a Healthcare-Associated Pathogen.

PubMed

Graña-Miraglia, Lucía; Lozano, Luis F; Velázquez, Consuelo; Volkow-Fernández, Patricia; Pérez-Oseguera, Ángeles; Cevallos, Miguel A; Castillo-Ramírez, Santiago

2017-01-01

Genome sequencing has been useful to gain an understanding of bacterial evolution. It has been used for studying the phylogeography and/or the impact of mutation and recombination on bacterial populations. However, it has rarely been used to study gene turnover at microevolutionary scales. Here, we sequenced Mexican strains of the human pathogen Acinetobacter baumannii sampled from the same locale over a 3 year period to obtain insights into the microevolutionary dynamics of gene content variability. We found that the Mexican A. baumannii population was recently founded and has been emerging due to a rapid clonal expansion. Furthermore, we noticed that on average the Mexican strains differed from each other by over 300 genes and, notably, this gene content variation has accrued more frequently and faster than the accumulation of mutations. Moreover, due to its rapid pace, gene content variation reflects the phylogeny only at very short periods of time. Additionally, we found that the external branches of the phylogeny had almost 100 more genes than the internal branches. All in all, these results show that rapid gene turnover has been of paramount importance in producing genetic variation within this population and demonstrate the utility of genome sequencing to study alternative forms of genetic variation.

Evolution of body size in the woodrat over the past 25,000 years of climate change

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, F.A.; Brown, J.H.; Betancourt, J.L.

1995-12-22

Microevolutionary changes in the body size of the bushy-tailed woodrat (Neotoma cinerea) since the last glacial maximum were estimated from measurements of fecal pellets preserved in paleomiddens from the Great Basin and Colorado Plateau of the United States. The changes closely track regional temperature fluctuations simulated by the Community Climate Model of the National Center for Atmospheric Research and also those estimated from deuterium isotope ratios of plant cellulose recovered from paleomiddens. Body size decreased during periods of climatic warming, as predicted from Bergmann`s rule and from physiological responses to temperature stress. Fossil woodrat middens, by providing detailed temporal sequencesmore » of body sizes from many locations, permit precise quantification of responses to climatic change that have occurred in the past and may occur in the future. 24 refs., 3 figs.« less

Rapid evolution of cis-regulatory sequences via local point mutations

NASA Technical Reports Server (NTRS)

Stone, J. R.; Wray, G. A.

2001-01-01

Although the evolution of protein-coding sequences within genomes is well understood, the same cannot be said of the cis-regulatory regions that control transcription. Yet, changes in gene expression are likely to constitute an important component of phenotypic evolution. We simulated the evolution of new transcription factor binding sites via local point mutations. The results indicate that new binding sites appear and become fixed within populations on microevolutionary timescales under an assumption of neutral evolution. Even combinations of two new binding sites evolve very quickly. We predict that local point mutations continually generate considerable genetic variation that is capable of altering gene expression.

What triggers the rising of an intraspecific biodiversity hotspot? Hints from the agile frog.

PubMed

Canestrelli, Daniele; Bisconti, Roberta; Sacco, Florinda; Nascetti, Giuseppe

2014-05-23

Hotspots of genetic diversity are regions of utmost importance for species survival and conservation, and their intimate link with the geographic location of glacial refugia has been well established. Nonetheless, the microevolutionary processes underlying the generation of hotspots in such regions have only recently become a fervent field of research. We investigated the phylogeographic and population genetic structure of the agile frog, Rana dalmatina, within its putative refugium in peninsular Italy. We found this region to harbour far more diversity, phylogeographic structure, and lineages of ancient origin than that by the rest of the species' range in Europe. This pattern appeared to be well explained by climate-driven microevolutionary processes that occurred during both glacial and interglacial epochs. Therefore, the inferred evolutionary history of R. dalmatina in Italy supports a view of glacial refugia as 'factories' rather than as repositories of genetic diversity, with significant implications for conservation strategies for hotspots.

How fisheries management can benefit from genomics?

PubMed

Valenzuela-Quiñonez, Fausto

2016-09-01

Fisheries genomics is an emerging field that advocates the application of genomic tools to address questions in fisheries management. Genomic approaches bring a new paradigm for fisheries management by making it possible to integrate adaptive diversity to understand fundamental aspects of fisheries resources. Hence, this review is focused on the relevance of genomic approaches to solve fisheries-specific questions. Particularly the detection of adaptive diversity (outlier loci) provides unprecedented opportunity to understand bio-complexity, increased power to trace processed sample origin to allow enforcement and the potential to understand the genetic basis of micro-evolutionary effects of fisheries-induced evolution and climate change. The understanding of adaptive diversity patterns will be the cornerstone of the future links between fisheries and genomics. These studies will help stakeholders anticipate the potential effects of fishing or climate change on the resilience of fisheries stocks; consequently, in the near future, fisheries sciences might integrate evolutionary principles with fisheries management. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Robustness and flexibility in nematode vulva development.

PubMed

Félix, Marie-Anne; Barkoulas, Michalis

2012-04-01

The Caenorhabditis elegans vulva has served as a paradigm for how conserved developmental pathways, such as EGF-Ras-MAPK, Notch and Wnt signaling, participate in networks driving animal organogenesis. Here, we discuss an emerging direction in the field, which places vulva research in a quantitative and microevolutionary framework. The final vulval cell fate pattern is known to be robust to change, but only recently has the variation of vulval traits been measured under stochastic, environmental or genetic variation. Whereas the resulting cell fate pattern is invariant among rhabditid nematodes, recent studies indicate that the developmental system has accumulated cryptic variation, even among wild C. elegans isolates. Quantitative differences in the signaling network have emerged through experiments and modeling as the driving force behind cryptic variation in Caenorhabditis species. On a wider evolutionary scale, the establishment of new model species has informed about the presence of qualitative variation in vulval signaling pathways. Copyright © 2012 Elsevier Ltd. All rights reserved.

Genome-wide single nucleotide polymorphisms (SNPs) for a model invasive ascidian Botryllus schlosseri.

PubMed

Gao, Yangchun; Li, Shiguo; Zhan, Aibin

2018-04-01

Invasive species cause huge damages to ecology, environment and economy globally. The comprehensive understanding of invasion mechanisms, particularly genetic bases of micro-evolutionary processes responsible for invasion success, is essential for reducing potential damages caused by invasive species. The golden star tunicate, Botryllus schlosseri, has become a model species in invasion biology, mainly owing to its high invasiveness nature and small well-sequenced genome. However, the genome-wide genetic markers have not been well developed in this highly invasive species, thus limiting the comprehensive understanding of genetic mechanisms of invasion success. Using restriction site-associated DNA (RAD) tag sequencing, here we developed a high-quality resource of 14,119 out of 158,821 SNPs for B. schlosseri. These SNPs were relatively evenly distributed at each chromosome. SNP annotations showed that the majority of SNPs (63.20%) were located at intergenic regions, and 21.51% and 14.58% were located at introns and exons, respectively. In addition, the potential use of the developed SNPs for population genomics studies was primarily assessed, such as the estimate of observed heterozygosity (H O ), expected heterozygosity (H E ), nucleotide diversity (π), Wright's inbreeding coefficient (F IS ) and effective population size (Ne). Our developed SNP resource would provide future studies the genome-wide genetic markers for genetic and genomic investigations, such as genetic bases of micro-evolutionary processes responsible for invasion success.

[Macro- and microevolution as related to the problem of origin and global expansion of the plague pathogen Yersinia pestis].

PubMed

Suntsov, V V; Suntsova, N I

2008-01-01

The ratio of macro- and microevolutionary processes is considered with reference to the ecological scenario of the origin of the plague pathogen and its subsequent natural and anthropogenic global expansion. The macroevolutionary transformation of the ancestral pseudotuberculosis microbe clone into the initial plague microbe Yersinia pestis tarbagani occurred in Central Asia at the end of the Late Pleistocene by a "vertical" Darwinian way in an inadaptive heterothermal continual intermediate environment--the Mongolian marmot Marmota sibirica-flea Oropsylla silantiewi system--via a sequence of unstable and currently extinct intermediate forms. Its natural geographic expansion on the "oil spot" principle in the postglacial time led to the microevolutionary formation of 20-30 hostal subspecies circulating in populations of the background species of burrowing rodents and pikas in arid areas of Eurasia. The intercontinental spread of the "marmot" and "rat" pathogen subspecies in the past few centuries has been exclusively anthropogenic, with the involvement of synanthropic (ship) rats.

What triggers the rising of an intraspecific biodiversity hotspot? Hints from the agile frog

PubMed Central

Canestrelli, Daniele; Bisconti, Roberta; Sacco, Florinda; Nascetti, Giuseppe

2014-01-01

Hotspots of genetic diversity are regions of utmost importance for species survival and conservation, and their intimate link with the geographic location of glacial refugia has been well established. Nonetheless, the microevolutionary processes underlying the generation of hotspots in such regions have only recently become a fervent field of research. We investigated the phylogeographic and population genetic structure of the agile frog, Rana dalmatina, within its putative refugium in peninsular Italy. We found this region to harbour far more diversity, phylogeographic structure, and lineages of ancient origin than that by the rest of the species' range in Europe. This pattern appeared to be well explained by climate-driven microevolutionary processes that occurred during both glacial and interglacial epochs. Therefore, the inferred evolutionary history of R. dalmatina in Italy supports a view of glacial refugia as ‘factories' rather than as repositories of genetic diversity, with significant implications for conservation strategies for hotspots. PMID:24853644

Diversification of the vacAs1m1 and vacAs2m2 Strains of Helicobacter pylori in Meriones unguiculatus

PubMed Central

Mendoza-Elizalde, Sandra; Arteaga-Resendiz, Nancy K.; Valencia-Mayoral, Pedro; Luna, Raúl C.; Moreno-Espinosa, Sarbelio; Arenas-Huertero, Francisco; Zúñiga, Gerardo; Velázquez-Guadarrama, Norma

2016-01-01

The bacterium Helicobacter pylori exhibits great genetic diversity, and the pathogenic roles of its virulence factors have been widely studied. However, the evolutionary dynamics of H. pylori strains during stomach colonization are not well-characterized. Here, we analyzed the microevolutionary dynamics of the toxigenic strain vacAs1m1, the non-toxigenic strain vacAs2m2, and a combination of both strains in an animal model over time. Meriones unguiculatus were inoculated with the following bacteria: group 1-toxigenic strain vacAs1m1/cagA+/cagE+/babA2+; ST181, group 2-non-toxigenic strain vacAs2m2/cagA+/cagE+/babA2+; ST2901, and group 3-both strains. The gerbils were euthanized at different time points (3, 6, 12, and 18 months). In group 1, genetic alterations were observed at 6 and 12 months. With the combination of both strains, group 3 also exhibited genetic alterations at 3 and 18 months; moreover, a chimera, vacA m1-m2, was detected. Additionally, four new sequence types (STs) were reported in the PubMLST database for H. pylori. Synonymous and non-synonymous mutations were analyzed and associated with alterations in amino acids. Microevolutionary analysis of the STs (PHYLOViZ) identified in each group revealed many mutational changes in the toxigenic (vacAs1m1) and non-toxigenic (vacAs2m2) strains. Phylogenetic assessments (eBURST) did not reveal clonal complexes. Our findings indicate that the toxigenic strain, vacAs1m1, and a combination of toxigenic and non-toxigenic strains acquired genetic material by recombination. The allelic combination, vacAs2m1, displayed the best adaptation in the animal model over time, and a chimera, m1-m2, was also identified, which confirmed previous reports. PMID:27877163

Diversification of the vacAs1m1 and vacAs2m2 Strains of Helicobacter pylori in Meriones unguiculatus.

PubMed

Mendoza-Elizalde, Sandra; Arteaga-Resendiz, Nancy K; Valencia-Mayoral, Pedro; Luna, Raúl C; Moreno-Espinosa, Sarbelio; Arenas-Huertero, Francisco; Zúñiga, Gerardo; Velázquez-Guadarrama, Norma

2016-01-01

The bacterium Helicobacter pylori exhibits great genetic diversity, and the pathogenic roles of its virulence factors have been widely studied. However, the evolutionary dynamics of H. pylori strains during stomach colonization are not well-characterized. Here, we analyzed the microevolutionary dynamics of the toxigenic strain vacAs1m1 , the non-toxigenic strain vacAs2m2 , and a combination of both strains in an animal model over time. Meriones unguiculatus were inoculated with the following bacteria: group 1-toxigenic strain vacAs1m1/cagA+/cagE+/babA2+ ; ST181, group 2-non-toxigenic strain vacAs2m2/cagA+/cagE+/babA2+ ; ST2901, and group 3-both strains. The gerbils were euthanized at different time points (3, 6, 12, and 18 months). In group 1, genetic alterations were observed at 6 and 12 months. With the combination of both strains, group 3 also exhibited genetic alterations at 3 and 18 months; moreover, a chimera, vacA m1-m2 , was detected. Additionally, four new sequence types (STs) were reported in the PubMLST database for H. pylori . Synonymous and non-synonymous mutations were analyzed and associated with alterations in amino acids. Microevolutionary analysis of the STs (PHYLOViZ) identified in each group revealed many mutational changes in the toxigenic ( vacAs1m1 ) and non-toxigenic ( vacAs2m2 ) strains. Phylogenetic assessments (eBURST) did not reveal clonal complexes. Our findings indicate that the toxigenic strain, vacAs1m1 , and a combination of toxigenic and non-toxigenic strains acquired genetic material by recombination. The allelic combination, vacAs2m1 , displayed the best adaptation in the animal model over time, and a chimera, m1-m2 , was also identified, which confirmed previous reports.

Darwin's Missing Link--A Novel Paradigm for Evolution Education

ERIC Educational Resources Information Center

Catley, Kefyn M.

2006-01-01

Microevolutionary mechanisms are taught almost exclusively in our schools, to the detriment of those mechanisms that allow us to understand the larger picture--macroevolution. The results are demonstrable; as a result of the strong emphasis on micro processes in evolution education, students and teachers still have poor understanding of the…

Metabolic rate covaries with fitness and the pace of the life history in the field

PubMed Central

Pettersen, Amanda K.; White, Craig R.; Marshall, Dustin J.

2016-01-01

Metabolic rate reflects the ‘pace of life’ in every organism. Metabolic rate is related to an organism's capacity for essential maintenance, growth and reproduction—all of which interact to affect fitness. Although thousands of measurements of metabolic rate have been made, the microevolutionary forces that shape metabolic rate remain poorly resolved. The relationship between metabolic rate and components of fitness are often inconsistent, possibly because these fitness components incompletely map to actual fitness and often negatively covary with each other. Here we measure metabolic rate across ontogeny and monitor its effects on actual fitness (lifetime reproductive output) for a marine bryozoan in the field. We also measure key components of fitness throughout the entire life history including growth rate, longevity and age at the onset of reproduction. We found that correlational selection favours individuals with higher metabolic rates in one stage and lower metabolic rates in the other—individuals with similar metabolic rates in each developmental stage displayed the lowest fitness. Furthermore, individuals with the lowest metabolic rates lived for longer and reproduced more, but they also grew more slowly and took longer to reproduce initially. That metabolic rate is related to the pace of the life history in nature has long been suggested by macroevolutionary patterns but this study reveals the microevolutionary processes that probably generated these patterns. PMID:27226476

Transmission bottlenecks and RNAi collectively influence tick-borne flavivirus evolution.

PubMed

Grubaugh, Nathan D; Rückert, Claudia; Armstrong, Philip M; Bransfield, Angela; Anderson, John F; Ebel, Gregory D; Brackney, Doug E

2016-07-01

Arthropod-borne RNA viruses exist within hosts as heterogeneous populations of viral variants and, as a result, possess great genetic plasticity. Understanding the micro-evolutionary forces shaping these viruses can provide insights into how they emerge, adapt, and persist in new and changing ecological niches. While considerable attention has been directed toward studying the population dynamics of mosquito-borne viruses, little is known about tick-borne virus populations. Therefore, using a mouse and Ixodes scapularis tick transmission model, we examined Powassan virus (POWV; Flaviviridae, Flavivirus ) populations in and between both the vertebrate host and arthropod vector. We found that genetic bottlenecks, RNAi-mediated diversification, and selective constraints collectively influence POWV evolution. Together, our data provide a mechanistic explanation for the slow, long-term evolutionary trends of POWV, and suggest that all arthropod-borne viruses encounter similar selective pressures at the molecular level (i.e. RNAi), yet evolve much differently due to their unique rates and modes of transmission.

Anthropogenic fire drives the evolution of seed traits

PubMed Central

Gómez-González, Susana; Torres-Díaz, Cristian; Bustos-Schindler, Carlos; Gianoli, Ernesto

2011-01-01

Fire is a major disturbance affecting ecosystems worldwide. Phylogenetic studies have shown that the evolution of seed persistence (fire resistance) is associated with fire frequency or severity. However, the existence of specific seed traits resulting from natural selection mediated by fire remains a key question in plant evolution. We evaluated the role of fire in the evolution of seed traits from a microevolutionary perspective, using as a study system a native forb from the Chilean matorral, where fire is a novel, anthropogenic disturbance. We show that anthropogenic fires are shaping the evolution of seed traits such as pubescence and shape. Among-population variation in seed pubescence, shape, and pericarp thickness was strongly associated with fire frequency, and within a population, fire selected those plants with more pubescent seeds, thicker pericarps, and less rounded seeds. Seed pubescence and shape were shown to be heritable traits. Our findings provide insights into the understanding of the evolution of seed traits in fire-prone environments and demonstrate that human-made fires can be driving evolutionary changes in plant species from ecosystems where fires do not occur naturally. PMID:22065739

Anthropogenic fire drives the evolution of seed traits.

PubMed

Gómez-González, Susana; Torres-Díaz, Cristian; Bustos-Schindler, Carlos; Gianoli, Ernesto

2011-11-15

Fire is a major disturbance affecting ecosystems worldwide. Phylogenetic studies have shown that the evolution of seed persistence (fire resistance) is associated with fire frequency or severity. However, the existence of specific seed traits resulting from natural selection mediated by fire remains a key question in plant evolution. We evaluated the role of fire in the evolution of seed traits from a microevolutionary perspective, using as a study system a native forb from the Chilean matorral, where fire is a novel, anthropogenic disturbance. We show that anthropogenic fires are shaping the evolution of seed traits such as pubescence and shape. Among-population variation in seed pubescence, shape, and pericarp thickness was strongly associated with fire frequency, and within a population, fire selected those plants with more pubescent seeds, thicker pericarps, and less rounded seeds. Seed pubescence and shape were shown to be heritable traits. Our findings provide insights into the understanding of the evolution of seed traits in fire-prone environments and demonstrate that human-made fires can be driving evolutionary changes in plant species from ecosystems where fires do not occur naturally.

Evolutionary developmental genetics of fruit morphological variation within the Solanaceae

PubMed Central

Wang, Li; Li, Jing; Zhao, Jing; He, Chaoying

2015-01-01

Morphological variations of fruits such as shape and size, and color are a result of adaptive evolution. The evolution of morphological novelties is particularly intriguing. An understanding of these evolutionary processes calls for the elucidation of the developmental and genetic mechanisms that result in particular fruit morphological characteristics, which determine seed dispersal. The genetic and developmental basis for fruit morphological variation was established at a microevolutionary time scale. Here, we summarize the progress on the evolutionary developmental genetics of fruit size, shape and color in the Solanaceae. Studies suggest that the recruitment of a pre-existing gene and subsequent modification of its interaction and regulatory networks are frequently involved in the evolution of morphological diversity. The basic mechanisms underlying changes in plant morphology are alterations in gene expression and/or gene function. We also deliberate on the future direction in evolutionary developmental genetics of fruit morphological variation such as fruit type. These studies will provide insights into plant developmental processes and will help to improve the productivity and fruit quality of crops. PMID:25918515

Testing for biases in selection on avian reproductive traits and partitioning direct and indirect selection using quantitative genetic models.

PubMed

Reed, Thomas E; Gienapp, Phillip; Visser, Marcel E

2016-10-01

Key life history traits such as breeding time and clutch size are frequently both heritable and under directional selection, yet many studies fail to document microevolutionary responses. One general explanation is that selection estimates are biased by the omission of correlated traits that have causal effects on fitness, but few valid tests of this exist. Here, we show, using a quantitative genetic framework and six decades of life-history data on two free-living populations of great tits Parus major, that selection estimates for egg-laying date and clutch size are relatively unbiased. Predicted responses to selection based on the Robertson-Price Identity were similar to those based on the multivariate breeder's equation (MVBE), indicating that unmeasured covarying traits were not missing from the analysis. Changing patterns of phenotypic selection on these traits (for laying date, linked to climate change) therefore reflect changing selection on breeding values, and genetic constraints appear not to limit their independent evolution. Quantitative genetic analysis of correlational data from pedigreed populations can be a valuable complement to experimental approaches to help identify whether apparent associations between traits and fitness are biased by missing traits, and to parse the roles of direct versus indirect selection across a range of environments. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

High-Throughput DNA sequencing of ancient wood.

PubMed

Wagner, Stefanie; Lagane, Frédéric; Seguin-Orlando, Andaine; Schubert, Mikkel; Leroy, Thibault; Guichoux, Erwan; Chancerel, Emilie; Bech-Hebelstrup, Inger; Bernard, Vincent; Billard, Cyrille; Billaud, Yves; Bolliger, Matthias; Croutsch, Christophe; Čufar, Katarina; Eynaud, Frédérique; Heussner, Karl Uwe; Köninger, Joachim; Langenegger, Fabien; Leroy, Frédéric; Lima, Christine; Martinelli, Nicoletta; Momber, Garry; Billamboz, André; Nelle, Oliver; Palomo, Antoni; Piqué, Raquel; Ramstein, Marianne; Schweichel, Roswitha; Stäuble, Harald; Tegel, Willy; Terradas, Xavier; Verdin, Florence; Plomion, Christophe; Kremer, Antoine; Orlando, Ludovic

2018-03-01

Reconstructing the colonization and demographic dynamics that gave rise to extant forests is essential to forecasts of forest responses to environmental changes. Classical approaches to map how population of trees changed through space and time largely rely on pollen distribution patterns, with only a limited number of studies exploiting DNA molecules preserved in wooden tree archaeological and subfossil remains. Here, we advance such analyses by applying high-throughput (HTS) DNA sequencing to wood archaeological and subfossil material for the first time, using a comprehensive sample of 167 European white oak waterlogged remains spanning a large temporal (from 550 to 9,800 years) and geographical range across Europe. The successful characterization of the endogenous DNA and exogenous microbial DNA of 140 (~83%) samples helped the identification of environmental conditions favouring long-term DNA preservation in wood remains, and started to unveil the first trends in the DNA decay process in wood material. Additionally, the maternally inherited chloroplast haplotypes of 21 samples from three periods of forest human-induced use (Neolithic, Bronze Age and Middle Ages) were found to be consistent with those of modern populations growing in the same geographic areas. Our work paves the way for further studies aiming at using ancient DNA preserved in wood to reconstruct the micro-evolutionary response of trees to climate change and human forest management. © 2018 John Wiley & Sons Ltd.

Signatures of microevolutionary processes in phylogenetic patterns.

PubMed

Costa, Carolina L N; Lemos-Costa, Paula; Marquitti, Flavia M D; Fernandes, Lucas D; Ramos, Marlon F; Schneider, David M; Martins, Ayana B; Aguiar, Marcus A M

2018-06-23

Phylogenetic trees are representations of evolutionary relationships among species and contain signatures of the processes responsible for the speciation events they display. Inferring processes from tree properties, however, is challenging. To address this problem we analysed a spatially-explicit model of speciation where genome size and mating range can be controlled. We simulated parapatric and sympatric (narrow and wide mating range, respectively) radiations and constructed their phylogenetic trees, computing structural properties such as tree balance and speed of diversification. We showed that parapatric and sympatric speciation are well separated by these structural tree properties. Balanced trees with constant rates of diversification only originate in sympatry and genome size affected both the balance and the speed of diversification of the simulated trees. Comparison with empirical data showed that most of the evolutionary radiations considered to have developed in parapatry or sympatry are in good agreement with model predictions. Even though additional forces other than spatial restriction of gene flow, genome size, and genetic incompatibilities, do play a role in the evolution of species formation, the microevolutionary processes modeled here capture signatures of the diversification pattern of evolutionary radiations, regarding the symmetry and speed of diversification of lineages.

DNA barcodes reveal microevolutionary signals in fire response trait in two legume genera

PubMed Central

Bello, Abubakar; Daru, Barnabas H.; Stirton, Charles H.; Chimphango, Samson B. M.; van der Bank, Michelle; Maurin, Olivier; Muasya, A. Muthama

2015-01-01

Large-scale DNA barcoding provides a new technique for species identification and evaluation of relationships across various levels (populations and species) and may reveal fundamental processes in recently diverged species. Here, we analysed DNA sequence variation in the recently diverged legumes from the Psoraleeae (Fabaceae) occurring in the Cape Floristic Region (CFR) of southern Africa to test the utility of DNA barcodes in species identification and discrimination. We further explored the phylogenetic signal on fire response trait (reseeding and resprouting) at species and generic levels. We showed that Psoraleoid legumes of the CFR exhibit a barcoding gap yielding the combination of matK and rbcLa (matK + rbcLa) data set as a better barcode than single regions. We found a high score (100 %) of correct identification of individuals to their respective genera but a very low score (<50 %) in identifying them to species. We found a considerable match (54 %) between genetic species and morphologically delimited species. We also found that different lineages showed a weak but significant phylogenetic conservatism in their response to fire as reseeders or resprouters, with more clustering of resprouters than would be expected by chance. These novel microevolutionary patterns might be acting continuously over time to produce multi-scale regularities of biodiversity. This study provides the first insight into the DNA barcoding campaign of land plants in species identification and detection of the phylogenetic signal in recently diverged lineages of the CFR. PMID:26507570

Multivariate selection and intersexual genetic constraints in a wild bird population.

PubMed

Poissant, J; Morrissey, M B; Gosler, A G; Slate, J; Sheldon, B C

2016-10-01

When selection differs between the sexes for traits that are genetically correlated between the sexes, there is potential for the effect of selection in one sex to be altered by indirect selection in the other sex, a situation commonly referred to as intralocus sexual conflict (ISC). While potentially common, ISC has rarely been studied in wild populations. Here, we studied ISC over a set of morphological traits (wing length, tarsus length, bill depth and bill length) in a wild population of great tits (Parus major) from Wytham Woods, UK. Specifically, we quantified the microevolutionary impacts of ISC by combining intra- and intersex additive genetic (co)variances and sex-specific selection estimates in a multivariate framework. Large genetic correlations between homologous male and female traits combined with evidence for sex-specific multivariate survival selection suggested that ISC could play an appreciable role in the evolution of this population. Together, multivariate sex-specific selection and additive genetic (co)variance for the traits considered accounted for additive genetic variance in fitness that was uncorrelated between the sexes (cross-sex genetic correlation = -0.003, 95% CI = -0.83, 0.83). Gender load, defined as the reduction in a population's rate of adaptation due to sex-specific effects, was estimated at 50% (95% CI = 13%, 86%). This study provides novel insights into the evolution of sexual dimorphism in wild populations and illustrates how quantitative genetics and selection analyses can be combined in a multivariate framework to quantify the microevolutionary impacts of ISC. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

Immunogenetics of the Elephant Seal

NASA Technical Reports Server (NTRS)

Garza, John Carlos

1999-01-01

The goals of this cooperative agreement fall into three categories: 1) A basic description of Immunogenetic variation in the northern elephant seal genome; 2) A basic genetic map of the northern elephant seal genome; 3). Microevolutionary forces in the northern elephant seal genome. The results described in this report were acquired using funds from this cooperative agreement together with funds from a National Science Foundation Dissertation Improvement Grant.

Microevolution Analysis of Bacillus coahuilensis Unveils Differences in Phosphorus Acquisition Strategies and Their Regulation.

PubMed

Gómez-Lunar, Zulema; Hernández-González, Ismael; Rodríguez-Torres, María-Dolores; Souza, Valeria; Olmedo-Álvarez, Gabriela

2016-01-01

Bacterial genomes undergo numerous events of gene losses and gains that generate genome variability among strains of the same species (microevolution). Our aim was to compare the genomes and relevant phenotypes of three Bacillus coahuilensis strains from two oligotrophic hydrological systems in the Cuatro Ciénegas Basin (México), to unveil the environmental challenges that this species cope with, and the microevolutionary differences in these genotypes. Since the strains were isolated from a low P environment, we placed emphasis on the search of different phosphorus acquisition strategies. The three B. coahuilensis strains exhibited similar numbers of coding DNA sequences, of which 82% (2,893) constituted the core genome, and 18% corresponded to accessory genes. Most of the genes in this last group were associated with mobile genetic elements (MGEs) or were annotated as hypothetical proteins. Ten percent of the pangenome consisted of strain-specific genes. Alignment of the three B. coahuilensis genomes indicated a high level of synteny and revealed the presence of several genomic islands. Unexpectedly, one of these islands contained genes that encode the 2-keto-3-deoxymannooctulosonic acid (Kdo) biosynthesis enzymes, a feature associated to cell walls of Gram-negative bacteria. Some microevolutionary changes were clearly associated with MGEs. Our analysis revealed inconsistencies between phenotype and genotype, which we suggest result from the impossibility to map regulatory features to genome analysis. Experimental results revealed variability in the types and numbers of auxotrophies between the strains that could not consistently be explained by in silico metabolic models. Several intraspecific differences in preferences for carbohydrate and phosphorus utilization were observed. Regarding phosphorus recycling, scavenging, and storage, variations were found between the three genomes. The three strains exhibited differences regarding alkaline phosphatase that revealed that in addition to gene gain and loss, regulation adjustment of gene expression also has contributed to the intraspecific diversity of B. coahuilensis.

Ecological opportunity and predator–prey interactions: linking eco-evolutionary processes and diversification in adaptive radiations

PubMed Central

2018-01-01

Much of life's diversity has arisen through ecological opportunity and adaptive radiations, but the mechanistic underpinning of such diversification is not fully understood. Competition and predation can affect adaptive radiations, but contrasting theoretical and empirical results show that they can both promote and interrupt diversification. A mechanistic understanding of the link between microevolutionary processes and macroevolutionary patterns is thus needed, especially in trophic communities. Here, we use a trait-based eco-evolutionary model to investigate the mechanisms linking competition, predation and adaptive radiations. By combining available micro-evolutionary theory and simulations of adaptive radiations we show that intraspecific competition is crucial for diversification as it induces disruptive selection, in particular in early phases of radiation. The diversification rate is however decreased in later phases owing to interspecific competition as niche availability, and population sizes are decreased. We provide new insight into how predation tends to have a negative effect on prey diversification through decreased population sizes, decreased disruptive selection and through the exclusion of prey from parts of niche space. The seemingly disparate effects of competition and predation on adaptive radiations, listed in the literature, may thus be acting and interacting in the same adaptive radiation at different relative strength as the radiation progresses. PMID:29514970

Rapid contemporary evolution and clonal food web dynamics

PubMed Central

Jones, Laura E.; Becks, Lutz; Ellner, Stephen P.; Hairston, Nelson G.; Yoshida, Takehito; Fussmann, Gregor F.

2009-01-01

Character evolution that affects ecological community interactions often occurs contemporaneously with temporal changes in population size, potentially altering the very nature of those dynamics. Such eco-evolutionary processes may be most readily explored in systems with short generations and simple genetics. Asexual and cyclically parthenogenetic organisms such as microalgae, cladocerans and rotifers, which frequently dominate freshwater plankton communities, meet these requirements. Multiple clonal lines can coexist within each species over extended periods, until either fixation occurs or a sexual phase reshuffles the genetic material. When clones differ in traits affecting interspecific interactions, within-species clonal dynamics can have major effects on the population dynamics. We first consider a simple predator–prey system with two prey genotypes, parametrized with data from a well-studied experimental system, and explore how the extent of differences in defence against predation within the prey population determine dynamic stability versus instability of the system. We then explore how increased potential for evolution affects the community dynamics in a more general community model with multiple predator and multiple prey genotypes. These examples illustrate how microevolutionary ‘details’ that enhance or limit the potential for heritable phenotypic change can have significant effects on contemporaneous community-level dynamics and the persistence and coexistence of species. PMID:19414472

Innovative empirical approaches for inferring climate-warming impacts on plants in remote areas.

PubMed

De Frenne, Pieter

2015-02-01

The prediction of the effects of climate warming on plant communities across the globe has become a major focus of ecology, evolution and biodiversity conservation. However, many of the frequently used empirical approaches for inferring how warming affects vegetation have been criticized for decades. In addition, methods that require no electricity may be preferred because of constraints of active warming, e.g. in remote areas. Efforts to overcome the limitations of earlier methods are currently under development, but these approaches have yet to be systematically evaluated side by side. Here, an overview of the benefits and limitations of a selection of innovative empirical techniques to study temperature effects on plants is presented, with a focus on practicality in relatively remote areas without an electric power supply. I focus on methods for: ecosystem aboveground and belowground warming; a fuller exploitation of spatial temperature variation; and long-term monitoring of plant ecological and microevolutionary changes in response to warming. An evaluation of the described methodological set-ups in a synthetic framework along six axes (associated with the consistency of temperature differences, disturbance, costs, confounding factors, spatial scale and versatility) highlights their potential usefulness and power. Hence, further developments of new approaches to empirically assess warming effects on plants can critically stimulate progress in climate-change biology.

The red queen in the corn: agricultural weeds as models of rapid adaptive evolution.

PubMed

Vigueira, C C; Olsen, K M; Caicedo, A L

2013-04-01

Weeds are among the greatest pests of agriculture, causing billions of dollars in crop losses each year. As crop field management practices have changed over the past 12 000 years, weeds have adapted in turn to evade human removal. This evolutionary change can be startlingly rapid, making weeds an appealing system to study evolutionary processes that occur over short periods of time. An understanding of how weeds originate and adapt is needed for successful management; however, relatively little emphasis has been placed on genetically characterizing these systems. Here, we review the current literature on agricultural weed origins and their mechanisms of adaptation. Where possible, we have included examples that have been genetically well characterized. Evidence for three possible, non-mutually exclusive weed origins (from wild species, crop-wild hybrids or directly from crops) is discussed with respect to what is known about the microevolutionary signatures that result from these processes. We also discuss what is known about the genetic basis of adaptive traits in weeds and the range of genetic mechanisms that are responsible. With a better understanding of genetic mechanisms underlying adaptation in weedy species, we can address the more general process of adaptive evolution and what can be expected as we continue to apply selective pressures in agroecosystems around the world.

The red queen in the corn: agricultural weeds as models of rapid adaptive evolution

PubMed Central

Vigueira, C C; Olsen, K M; Caicedo, A L

2013-01-01

Weeds are among the greatest pests of agriculture, causing billions of dollars in crop losses each year. As crop field management practices have changed over the past 12 000 years, weeds have adapted in turn to evade human removal. This evolutionary change can be startlingly rapid, making weeds an appealing system to study evolutionary processes that occur over short periods of time. An understanding of how weeds originate and adapt is needed for successful management; however, relatively little emphasis has been placed on genetically characterizing these systems. Here, we review the current literature on agricultural weed origins and their mechanisms of adaptation. Where possible, we have included examples that have been genetically well characterized. Evidence for three possible, non-mutually exclusive weed origins (from wild species, crop-wild hybrids or directly from crops) is discussed with respect to what is known about the microevolutionary signatures that result from these processes. We also discuss what is known about the genetic basis of adaptive traits in weeds and the range of genetic mechanisms that are responsible. With a better understanding of genetic mechanisms underlying adaptation in weedy species, we can address the more general process of adaptive evolution and what can be expected as we continue to apply selective pressures in agroecosystems around the world. PMID:23188175

Long-term in situ persistence of biodiversity in tropical sky islands revealed by landscape genomics.

PubMed

Mastretta-Yanes, Alicia; Xue, Alexander T; Moreno-Letelier, Alejandra; Jorgensen, Tove H; Alvarez, Nadir; Piñero, Daniel; Emerson, Brent C

2018-01-01

Tropical mountains are areas of high species richness and endemism. Two historical phenomena may have contributed to this: (i) fragmentation and isolation of habitats may have promoted the genetic differentiation of populations and increased the possibility of allopatric divergence and speciation and (ii) the mountain areas may have allowed long-term population persistence during global climate fluctuations. These two phenomena have been studied using either species occurrence data or estimating species divergence times. However, only few studies have used intraspecific genetic data to analyse the mechanisms by which endemism may emerge at the microevolutionary scale. Here, we use landscape analysis of genomic SNP data sampled from two high-elevation plant species from an archipelago of tropical sky islands (the Trans-Mexican Volcanic Belt) to test for population genetic differentiation, synchronous demographic changes and habitat persistence. We show that genetic differentiation can be explained by the degree of glacial habitat connectivity among mountains and that mountains have facilitated the persistence of populations throughout glacial/interglacial cycles. Our results support the ongoing role of tropical mountains as cradles for biodiversity by uncovering cryptic differentiation and limits to gene flow. © 2017 John Wiley & Sons Ltd.

Sexual selection predicts advancement of avian spring migration in response to climate change.

PubMed

Spottiswoode, Claire N; Tøttrup, Anders P; Coppack, Timothy

2006-12-22

Global warming has led to earlier spring arrival of migratory birds, but the extent of this advancement varies greatly among species, and it remains uncertain to what degree these changes are phenotypically plastic responses or microevolutionary adaptations to changing environmental conditions. We suggest that sexual selection could help to understand this variation, since early spring arrival of males is favoured by female choice. Climate change could weaken the strength of natural selection opposing sexual selection for early migration, which would predict greatest advancement in species with stronger female choice. We test this hypothesis comparatively by investigating the degree of long-term change in spring passage at two ringing stations in northern Europe in relation to a synthetic estimate of the strength of female choice, composed of degree of extra-pair paternity, relative testes size and degree of sexually dichromatic plumage colouration. We found that species with a stronger index of sexual selection have indeed advanced their date of spring passage to a greater extent. This relationship was stronger for the changes in the median passage date of the whole population than for changes in the timing of first-arriving individuals, suggesting that selection has not only acted on protandrous males. These results suggest that sexual selection may have an impact on the responses of organisms to climate change, and knowledge of a species' mating system might help to inform attempts at predicting these.

The role of habitat choice in micro-evolutionary dynamics: An experimental study on the Mediterranean killifish Aphanius fasciatus (Cyprinodontidae).

PubMed

Angeletti, Dario; Sebbio, Claudia; Carlini, Alessandro; Strinati, Claudia; Nascetti, Giuseppe; Carere, Claudio; Cimmaruta, Roberta

2017-12-01

Habitat choice is defined as a nonrandom distribution of genotypes in different microhabitats. Therefore, it could exert a great impact on the genetic variance of natural populations by promoting genetic divergence, local adaptation, and may even lead to sympatric speciation. Despite this potential role in micro- and macro-evolutionary processes, there is little empirical evidence that the various genotypes within a population may differ in habitat choice-related behaviors. Here, we tested whether habitat choice may have contributed to genetic divergence within a local population of the Mediterranean killifish Aphanius fasciatus , which emerged between groups inhabiting microhabitats with different oxygen concentrations during previous field studies. In a first experiment, we studied the distribution of individuals in conditions of hypoxia and normoxia to test whether they had a different ability to shy away from a hypoxic environment; in a second experiment, we analyzed the individual behavior of fish separately in the two conditions, to verify whether they showed peculiar behavioral responses linked to a possible differential distribution. We then analyzed the six allozyme loci, whose allelic and genotypic frequencies were significantly divergent in the previous studies. In the first test, we found that the distribution of the two homozygote genotypes of the glucose-6-phosphate isomerase-1 locus (GPI-1) was significantly different between the hypoxic and the normoxic conditions. During the second test, all individuals were more active in hypoxic conditions, but the two GPI-1 homozygotes showed a significant difference in time spent performing surface breathing, which was consistent with their distribution observed in the first experiment. These results provide evidence that individual behavioral traits, related to genetic features, may lead to a nonrandom distribution of genotypes in heterogeneous although contiguous microhabitats and, consequently, that habitat choice can play a significant role in driving the micro-evolutionary dynamics of this species.

Microevolutionary analyses of Pythium insidiosum isolates of Brazil and Thailand based on exo-1,3-β-glucanase gene.

PubMed

Ribeiro, Tatiana Corrêa; Weiblen, Carla; de Azevedo, Maria Isabel; de Avila Botton, Sônia; Robe, Lizandra Jaqueline; Pereira, Daniela Isabel Brayer; Monteiro, Danieli Urach; Lorensetti, Douglas Miotto; Santurio, Janio Morais

2017-03-01

Pythium insidiosum is an important oomycete due to its ability to infect humans and animals. It causes pythiosis, a disease of difficult treatment that occurs more frequently in humans in Thailand and in horses in Brazil. Since cell-wall components are frequently related to host shifts, we decided here to use sequences from the exo-1,3-β-glucanase gene (exo1), which encodes an immunodominant protein putatively involved in cell wall remodeling, to investigate the microevolutionary relationships of Brazilian and Thai isolates of P. insidiosum. After neutrality ratification, the phylogenetic analyses performed through Maximum parsimony (MP), Neighbor-joining (NJ), Maximum likelihood (ML), and Bayesian analysis (BA) strongly supported Thai isolates being paraphyletic in relation to those from Brazil. The structure recovered by these analyses, as well as by Spatial Analysis of Molecular Variance (SAMOVA), suggests the subdivision of P. insidiosum into three clades or population groups, which are able to explain almost 81% of the variation encountered for exo1. Moreover, the two identified Thai clades were almost as strongly differentiated between each other, as they were from the Brazilian clade, suggesting an ancient Asian subdivision. The derived positioning in the phylogenetic tree, linked to the lower diversity values and the recent expansion signs detected for the Brazilian clade, further support this clade as derived in relation to the Asian populations. Thus, although some patterns presented here are compatible with those recovered with different molecular markers, exo1 was revealed to be a good marker for studying evolution in Pythium, providing robust and strongly supported results with regard to the patterns of origin and diversification of P. insidiosum. Copyright © 2016 Elsevier B.V. All rights reserved.

Evolution of a predator-induced, nonlinear reaction norm.

PubMed

Carter, Mauricio J; Lind, Martin I; Dennis, Stuart R; Hentley, William; Beckerman, Andrew P

2017-08-30

Inducible, anti-predator traits are a classic example of phenotypic plasticity. Their evolutionary dynamics depend on their genetic basis, the historical pattern of predation risk that populations have experienced and current selection gradients. When populations experience predators with contrasting hunting strategies and size preferences, theory suggests contrasting micro-evolutionary responses to selection. Daphnia pulex is an ideal species to explore the micro-evolutionary response of anti-predator traits because they face heterogeneous predation regimes, sometimes experiencing only invertebrate midge predators and other times experiencing vertebrate fish and invertebrate midge predators. We explored plausible patterns of adaptive evolution of a predator-induced morphological reaction norm. We combined estimates of selection gradients that characterize the various habitats that D. pulex experiences with detail on the quantitative genetic architecture of inducible morphological defences. Our data reveal a fine scale description of daphnid defensive reaction norms, and a strong covariance between the sensitivity to cues and the maximum response to cues. By analysing the response of the reaction norm to plausible, predator-specific selection gradients, we show how in the context of this covariance, micro-evolution may be more uniform than predicted from size-selective predation theory. Our results show how covariance between the sensitivity to cues and the maximum response to cues for morphological defence can shape the evolutionary trajectory of predator-induced defences in D. pulex . © 2017 The Authors.

Micro-evolution due to pollution: possible consequences for ecosystem responses to toxic stress.

PubMed

Medina, Matías H; Correa, Juan A; Barata, Carlos

2007-05-01

Polluting events can change community structure and ecosystem functioning. Selection of genetically inherited tolerance on exposed populations, here referred as micro-evolution due to pollution, has been recognized as one of the causes of these changes. However, there is a gap between studies addressing this process and those assessing effects at higher levels of biological organization. In this review we attempt to address these evolutionary considerations into the ecological risk assessment (ERA) of polluting events and to trigger the discussion about the consequences of this process for the ecosystem response to toxic stress. We provide clear evidence that pollution drives micro-evolutionary processes in several species. When this process occurs, populations inhabiting environments that become polluted may persist. However, due to the existence of ecological costs derived from the loss of genetic variability, negative pleiotropy with fitness traits and/or from physiological alterations, micro-evolution due to pollution may alter different properties of the affected populations. Despite the existence of empirical evidence showing that safety margins currently applied in the ERA process may account for pollution-induced genetic changes in tolerance, information regarding long-term ecological consequences at higher levels of biological organization due to ecological costs is not explicitly considered in these procedures. In relation to this, we present four testable hypotheses considering that micro-evolution due to pollution acts upon the variability of functional response traits of the exposed populations and generates changes on their functional effect traits, therefore, modifying the way species exploit their ecological niches and participate in the overall ecosystem functioning.

The Ecology and Evolution of Cancer: The Ultra-Microevolutionary Process.

PubMed

Wu, Chung-I; Wang, Hurng-Yi; Ling, Shaoping; Lu, Xuemei

2016-11-23

Although tumorigenesis has been accepted as an evolutionary process ( 20 , 102 ), many forces may operate differently in cancers than in organisms, as they evolve at vastly different time scales. Among such forces, natural selection, here defined as differential cellular proliferation among distinct somatic cell genotypes, is particularly interesting because its action might be thwarted in multicellular organisms ( 20 , 29 ). In this review, selection is analyzed in two stages of cancer evolution: Stage I is the evolution between tumors and normal tissues, and Stage II is the evolution within tumors. The Cancer Genome Atlas (TCGA) data show a low degree of convergent evolution in Stage I, where genetic changes are not extensively shared among cases. An equally important, albeit much less highlighted, discovery using TCGA data is that there is almost no net selection in cancer evolution. Both positive and negative selection are evident but they neatly cancel each other out, rendering total selection ineffective in the absence of recombination. The efficacy of selection is even lower in Stage II, where neutral (non-Darwinian) evolution is increasingly supported by high-density sampling studies ( 81 , 123 ). Because natural selection is not a strong deterministic force, cancers usually evolve divergently even in similar tissue environments.

[Landscape and ecological genomics].

PubMed

Tetushkin, E Ia

2013-10-01

Landscape genomics is the modern version of landscape genetics, a discipline that arose approximately 10 years ago as a combination of population genetics, landscape ecology, and spatial statistics. It studies the effects of environmental variables on gene flow and other microevolutionary processes that determine genetic connectivity and variations in populations. In contrast to population genetics, it operates at the level of individual specimens rather than at the level of population samples. Another important difference between landscape genetics and genomics and population genetics is that, in the former, the analysis of gene flow and local adaptations takes quantitative account of landforms and features of the matrix, i.e., hostile spaces that separate species habitats. Landscape genomics is a part of population ecogenomics, which, along with community genomics, is a major part of ecological genomics. One of the principal purposes of landscape genomics is the identification and differentiation of various genome-wide and locus-specific effects. The approaches and computation tools developed for combined analysis of genomic and landscape variables make it possible to detect adaptation-related genome fragments, which facilitates the planning of conservation efforts and the prediction of species' fate in response to expected changes in the environment.

Pollinator-driven ecological speciation in plants: new evidence and future perspectives

PubMed Central

Van der Niet, Timotheüs; Peakall, Rod; Johnson, Steven D.

2014-01-01

Background The hypothesis that pollinators have been important drivers of angiosperm diversity dates back to Darwin, and remains an important research topic today. Mounting evidence indicates that pollinators have the potential to drive diversification at several different stages of the evolutionary process. Microevolutionary studies have provided evidence for pollinator-mediated floral adaptation, while macroevolutionary evidence supports a general pattern of pollinator-driven diversification of angiosperms. However, the overarching issue of whether, and how, shifts in pollination system drive plant speciation represents a critical gap in knowledge. Bridging this gap is crucial to fully understand whether pollinator-driven microevolution accounts for the observed macroevolutionary patterns. Testable predictions about pollinator-driven speciation can be derived from the theory of ecological speciation, according to which adaptation (microevolution) and speciation (macroevolution) are directly linked. This theory is a particularly suitable framework for evaluating evidence for the processes underlying shifts in pollination systems and their potential consequences for the evolution of reproductive isolation and speciation. Scope This Viewpoint paper focuses on evidence for the four components of ecological speciation in the context of plant-pollinator interactions, namely (1) the role of pollinators as selective agents, (2) floral trait divergence, including the evolution of ‘pollination ecotypes‘, (3) the geographical context of selection on floral traits, and (4) the role of pollinators in the evolution of reproductive isolation. This Viewpoint also serves as the introduction to a Special Issue on Pollinator-Driven Speciation in Plants. The 13 papers in this Special Issue range from microevolutionary studies of ecotypes to macroevolutionary studies of historical ecological shifts, and span a wide range of geographical areas and plant families. These studies further illustrate innovative experimental approaches, and they employ modern tools in genetics and floral trait quantification. Future advances to the field require better quantification of selection through male fitness and pollinator isolation, for instance by exploiting next-generation sequencing technologies. By combining these new tools with strategically chosen study systems, and smart experimental design, we predict that examples of pollinator-driven speciation will be among the most widespread and compelling of all cases of ecological speciation. PMID:24418954

Origins of multicellular evolvability in snowflake yeast

PubMed Central

Ratcliff, William C.; Fankhauser, Johnathon D.; Rogers, David W.; Greig, Duncan; Travisano, Michael

2015-01-01

Complex life has arisen through a series of ‘major transitions’ in which collectives of formerly autonomous individuals evolve into a single, integrated organism. A key step in this process is the origin of higher-level evolvability, but little is known about how higher-level entities originate and gain the capacity to evolve as an individual. Here we report a single mutation that not only creates a new level of biological organization, but also potentiates higher-level evolvability. Disrupting the transcription factor ACE2 in Saccharomyces cerevisiae prevents mother–daughter cell separation, generating multicellular ‘snowflake’ yeast. Snowflake yeast develop through deterministic rules that produce geometrically defined clusters that preclude genetic conflict and display a high broad-sense heritability for multicellular traits; as a result they are preadapted to multicellular adaptation. This work demonstrates that simple microevolutionary changes can have profound macroevolutionary consequences, and suggests that the formation of clonally developing clusters may often be the first step to multicellularity. PMID:25600558

[Requirements imposed on model objects in microevolutionary investigations].

PubMed

Mina, M V

2015-01-01

Extrapolation of results of investigations of a model object is justified only within the limits of a set of objects that have essential properties in common with the modal object. Which properties are essential depends on the aim of a study. Similarity of objects emerged in the process of their independent evolution does not prove similarity of ways and mechanisms of their evolution. If the objects differ in their essential properties then extrapolation of results of investigation of an object on another one is risky because it may lead to wrong decisions and, moreover, to the loss of interest to alternative hypotheses. Positions formulated above are considered with the reference to species flocks of fishes, large African Barbus in particular.

The phenetic structure of Aedes albopictus.

PubMed

Morales Vargas, Ronald Enrique; Phumala-Morales, Noppawan; Tsunoda, Takashi; Apiwathnasorn, Chamnan; Dujardin, Jean-Pierre

2013-01-01

The large and recent migrations of the main vector of the Chikungunya virus, Aedes albopictus, raise questions about the epidemiological impact of possible microevolutionary changes in new territories. Quantitative traits are suitable to detect such changes as induced by environmental adaptations, local competition and founder effects. Using landmark-based geometric morphometrics, we compared the size and shape of 22 populations (1572 females) of Ae. albopictus. The collection sites covered five countries around the world, with special emphasis on Asia, which is assumed to be the origin of the vector. Some collections came from places where an important epidemic outbreak of Chikungunya has recently occurred. Quantitative comparisons were based on 18 anatomical landmarks on the wing. To contrast geographic and possible interspecific shape variation, close species were introduced in the sample, namely five Aedes riversi and nine Ae. flavopictus from Japan. The three species had similar size, but they were clearly separated by shape. Within Ae. albopictus, there was general agreement on size variation with the available climatic data. Shape variation was less related to climatic data than to either geography or a known itinerary of past territorial expansion. Thus, two main clusters were distinguished by wing shape variation: the first one composed of the Southeast Asian sample, the second one grouping Japan, Florida, Hawaii and the Reunion Island samples. The Southeast Asian countries, assumed to be at the origin of the geographic expansion of the mosquito, had similar wings and constituted a distinct group where localities clustered into northern and southern localities. Contrasting with this homogeneous group, very distant localities such as United States (US) and Japan shared a common shape pattern. The US Ae. albopictus samples (Hawaii and Florida) were indeed very similar to the Japanese samples, with Florida behaving exactly like a northern Japanese locality, close to Tokyo and Yokohama. Shape proximity among these distant areas could be explained by a common and relatively recent ancestor, as generally suggested in the literature. The three Reunion Island samples conformed a group external to the Southeast Asian countries, loosely connected to the remaining localities. Thus, areas where recent epidemics took place, the Reunion Island and the southernmost localities of Thailand, did not cluster together, but represented separate groups. In sum, the size of the wing was apparently under the influence of climatic factors, while its shape could contribute information on species and geographic differences. Apparent departures from expectations based on geography were explained by known past and present migratory routes. These patterns of shape variation were compatible with genetic drift, suggesting microevolutionary changes probably induced by the expansion of the Ae. albopictus mosquito. Copyright © 2012 Elsevier B.V. All rights reserved.

Comparative Genomics of Mycobacteria: Some Answers, Yet More New Questions

PubMed Central

Behr, Marcel A.

2015-01-01

Comparative genomic studies permit a genus-level perspective on the distinction between environmental mycobacteria and Mycobacterium tuberculosis, as well as a species-level assessment of genetic variability within M. tuberculosis. Both of these strata of evolutionary analysis serve to generate hypotheses regarding the genomic basis of M. tuberculosis virulence. In contrasting lessons from macroevolutionary study and microevolutionary study, one can form predictions about which segments of the genome are likely to be essential for or dispensable for the pathogenesis of tuberculosis. Although some of these predictions have been experimentally verified, notable exceptions challenge the direct link between these virulence factors and the capacity of M. tuberculosis to successfully cause disease and propagate between human hosts. These unexpected findings serve as the stimulus for further studies, using genomic comparisons and other approaches, to better define the remarkable success of this recalcitrant pathogen. PMID:25395374

The initial tolerance to sub-lethal Cd exposure is the same among ten naïve pond populations of Daphnia magna, but their micro-evolutionary potential to develop resistance is very different.

PubMed

Messiaen, Marlies; Janssen, Colin Roger; De Meester, Luc; De Schamphelaere, Karel André Clara

2013-11-15

Genetic variation complicates predictions of both the initial tolerance and the long-term (micro-evolutionary) response of natural Daphnia populations to chemical stressors from results of standard single-clone laboratory ecotoxicity tests. In order to investigate possible solutions to this problem, we aimed to compare the initial sub-lethal tolerance to Cd of 10 naïve natural pond populations of Daphnia magna as well as their evolutionary potential to develop increased resistance. We did so by measuring reproductive performance of 120 clones, i.e. 12 clones hatched from the recent dormant egg bank of each of 10 populations, both in absence (Cd-free control) and presence of 4.4 μg Cd/L. We show that the initial tolerance, defined as the reproductive performance of individuals of the first generation exposed to Cd relative to that in a Cd-free control was not significantly different among the 10 studied pond populations and averaged 0.82 ± 0.04 over these populations. Moreover, these populations' initial tolerances were also not significantly different from the mean initial tolerance of 0.87 ± 0.08 at 4.0 μg Cd/L measured for a group of 7 often-used laboratory clones, collected from a range of European ecotoxicity testing laboratories. This indicates that the initial response of naïve natural pond populations to sub-lethal Cd can be relatively accurately predicted from ecotoxicity test data from only a handful of laboratory clones. We then used estimates of broad-sense heritability of Cd tolerance (H(2)) - based on the same dataset - as a proxy of these populations' capacities to evolutionarily respond to Cd in terms of the development of increased resistance, which is here defined as the increase with time of the frequency of clones with a higher Cd tolerance in the population (accompanied with an increase of mean Cd-tolerance of the population above the initial tolerance). We show that the populations' estimated H(2) values of Cd-tolerance cover almost the entire theoretically possible range, ranging from not significantly different from zero (for five populations) to between 0.48 and 0.81 (for the five other populations). This indicates that, unlike the initial tolerance to Cd, the (long-term) micro-evolutionary response to Cd may be very different among natural pond populations. Therefore, we conclude that it may be very difficult to predict the long-term response of an unstudied population to chemical stress from tolerance data on a sample of other populations. It is therefore suggested that new methods for forecasting long-term responses should be explored, such as the development of predictive models based on the combination of population-genomic and tolerance time-series data. Copyright © 2013 Elsevier B.V. All rights reserved.

Nuclear mtDNA pseudogenes as a source of new variants of mitochondrial genes: A case study of Siberian rubythroat Luscinia calliope (muscicapidae, aves).

PubMed

Spiridonova, L N; Red'kin, Ya A; Valchuk, O P

2016-01-01

First evidence for the presence of copies of mitochondrial cytochrome b gene of the subspecies group Luscinia calliope anadyrensis-L. c. camtschatkensis in the nuclear genome of nominative L. c. calliope was obtained, which indirectly indicates the nuclear origin of the subspecies-specific mitochondrial haplotypes in Siberian rubythroat. This fact clarifies the appearance of mitochondrial haplotypes of eastern subspecies by exchange between the homologous regions of the nuclear and mitochondrial genomes followed by fixation by the founder effect. This is the first study to propose a mechanism of DNA fragment exchange between the nucleus and mitochondria (intergenomic recombination) and to show the role of nuclear copies of mtDNA as a source of new taxon-specific mitochondrial haplotypes, which implies their involvement in the microevolutionary processes and morphogenesis.

Unravelling the effects of gene flow and selection in highly connected populations of the silver-lip pearl oyster (Pinctada maxima).

PubMed

Nayfa, Maria G; Zenger, Kyall R

2016-08-01

Many marine organisms often display weak levels of population genetic structuring as a result of both environmental characteristics (e.g., ocean currents) and life history traits (e.g., widely dispersed planktonic larval stages) maintaining high levels of gene flow. This can lead to the assumption that these organisms can be managed as a single stock based on high levels of population connectivity. However, this neglects to account for other micro-evolutionary forces such as selection, which also shape these populations. This study utilizes 1130 genome-wide SNP loci to unravel the effects of gene flow and selection shaping three highly connected populations of the silver-lip pearl oyster (Pinctada maxima) in the ecologically and economically important Indo-Pacific region (Aru, Bali, and West Papua). Twenty-two loci under directional selection were identified amongst the populations, providing further supporting evidence of strong local adaptation (i.e., G×E effects) among populations in this region. Global Fst values for directional outliers (0.348) were up to eight times greater than for neutral markers (0.043). Pairwise Fst comparisons between Aru and Bali revealed the largest directional differences (0.488), while Bali and West Papua had the least (0.062). Unrooted neighbour-joining (NJ) distance trees and genetic diversity indices of directional outliers revealed that individuals from Bali and West Papua had reduced allelic variation (MAFavg=0.144, Ho=0.238 and MAFavg=0.232, Ho=0.369, respectively) compared to Aru (MAFavg=0.292, Ho=0.412). This indicates that directional selection is most likely acting upon genetic variation within the Bali and West Papua populations. NJ distance trees, discriminant analysis of principal components, and Fst analyses of directional outliers revealed two divergent groups ("Bali/West Papua"; "Aru") that had previously gone unrecognized. This study not only illustrates that relatively strong local adaptive forces are occurring despite high gene flow, but identifies the populations that are most likely experiencing selection. Additionally, this study highlights the need to understand all micro-evolutionary forces acting on populations when resolving stock structure. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Baculovirus phylogeny and evolution.

PubMed

Herniou, Elisabeth A; Jehle, Johannes A

2007-10-01

The family Baculoviridae represents one of the largest and most diverse groups of viruses and a unique model for studying the forces driving the evolution and biodiversity of double-stranded DNA viruses with large genomes. With the advent of comparative genomics, the phylogenetic relationships of baculoviruses have been put on solid bases. This, as well as improved bioinformatic approaches, has provided a detailed picture of baculovirus phylogeny and evolution. According to the present knowledge, baculoviruses can be classified into at least four evolutionary lineages: the most ancestral dipteran nucleopolyhedroviruses, the hymenopteran nucleopolyhedroviruses and the lepidopteran nucleopolyhedroviruses and granuloviruses. Despite the growing understanding of baculovirus phylogeny and macro-evolution, our knowledge of the micro-evolutionary processes within baculovirus species and virus populations is still limited. Here we present the state of the art on baculovirus phylogeny and evolution.

Genetic diversity of a late prehispanic group of the Quebrada de Humahuaca, northwestern Argentina.

PubMed

Mendisco, Fanny; Keyser, Christine; Seldes, Veronica; Rivolta, Clara; Mercolli, Pablo; Cruz, Pablo; Nielsen, Axel E; Crubezy, Eric; Ludes, Bertrand

2014-09-01

This palaeogenetic study focused on the analysis of a late prehispanic Argentinean group from the Humahuaca valley, with the main aim of reconstructing its (micro)evolutionary history. The Humahuaca valley, a natural passageway from the eastern plains to the highlands, was the living environment of Andean societies whose cultural but especially biological diversity is still poorly understood. We analyzed the DNA extracted from 39 individuals who populated this upper valley during the Regional Development period (RDP) (between the 11th and 15th centuries CE), to determine their maternal and paternal genetic ancestry. Some mitochondrial and Y-chromosomal haplotypes specific to the Andean region are consistent with an origin in the highlands of Central Andes. On the other hand, a significant genetic affinity with contemporary admixed communities of the Chaco area was detected. Expectedly, recent demographic events, such as the expansion of the Inca Empire or the European colonization, have changed the original mitochondrial gene pool of the ancient Humahuaca Valley community. Finally, we identified a particular geographical organization of the prehispanic populations of Northwestern Argentina. Our results suggest that the communities of the region were divided between two different spheres of interaction, which is consistent with assumptions made by means of craniometric traits. © 2014 John Wiley & Sons Ltd/University College London.

Radiative evolution of polyploid races of the Iberian carnation Dianthus broteri (Caryophyllaceae).

PubMed

Balao, Francisco; Valente, Luis M; Vargas, Pablo; Herrera, Javier; Talavera, Salvador

2010-07-01

*The micro-evolutionary mechanisms that drive large-scale radiations are not completely understood, partly because of a shortage of population-level studies aimed at identifying putative causes of rapid evolutionary change. The Dianthus broteri complex, representing the largest polyploid series known to date for any species in the genus (2x, 4x, 6x and 12x cytotypes), belongs to a lineage that was recently found to have diversified at unusually rapid rates. *We used a combination of genome sequencing (internal transcribed spacer (ITS), plus chloroplast DNA (cpDNA) regions trnH-psbA, psbA-trnK and trnK-matK) and amplified fragment length polymorphism (AFLP) fingerprinting in 25 populations to infer the evolutionary history of extant polyploid races. *The haplotype, ribotype and AFLP reconstructions showed a star-shaped arrangement suggesting a pattern of radiative evolution. The major, widespread haplotype occurred at all ploidy levels, whereas 20 minor haplotypes were restricted to single populations and cytotypes. In addition, AFLP analyses retrieved well-supported cytogeographic groups: six clades were clearly differentiated in terms of ploidy level and geography. Molecular data indicate that gene flow among different cytotypes is rare or nonexistent. *Our study supports a scenario of rapid diversification in carnations in which autopolyploidy and allopolyploidy, in interaction with geography and/or isolation, have played prominent roles.

Microevolution of Serial Clinical Isolates of Cryptococcus neoformans var. grubii and C. gattii

PubMed Central

Farrer, Rhys A.; Giamberardino, Charles; Sakthikumar, Sharadha; Jones, Alexander; Yang, Timothy; Tenor, Jennifer L.; Wagih, Omar; Van Wyk, Marelize; Govender, Nelesh P.; Mitchell, Thomas G.; Litvintseva, Anastasia P.

2017-01-01

ABSTRACT The pathogenic species of Cryptococcus are a major cause of mortality owing to severe infections in immunocompromised as well as immunocompetent individuals. Although antifungal treatment is usually effective, many patients relapse after treatment, and in such cases, comparative analyses of the genomes of incident and relapse isolates may reveal evidence of determinative, microevolutionary changes within the host. Here, we analyzed serial isolates cultured from cerebrospinal fluid specimens of 18 South African patients with recurrent cryptococcal meningitis. The time between collection of the incident isolates and collection of the relapse isolates ranged from 124 days to 290 days, and the analyses revealed that, during this period within the patients, the isolates underwent several genetic and phenotypic changes. Considering the vast genetic diversity of cryptococcal isolates in sub-Saharan Africa, it was not surprising to find that the relapse isolates had acquired different genetic and correlative phenotypic changes. They exhibited various mechanisms for enhancing virulence, such as growth at 39°C, adaptation to stress, and capsule production; a remarkable amplification of ERG11 at the native and unlinked locus may provide stable resistance to fluconazole. Our data provide a deeper understanding of the microevolution of Cryptococcus species under pressure from antifungal chemotherapy and host immune responses. This investigation clearly suggests a promising strategy to identify novel targets for improved diagnosis, therapy, and prognosis. PMID:28270580

Hybrid zone studies: An interdisciplinary approach for the analysis of evolutionary processes

USGS Publications Warehouse

Scribner, Kim T.

1994-01-01

There has been considerable debate in the ecological and evolutionary literature over the relative importance and rate by which microevolutionary processes operating at the population level result in separation and differentiation of lineages and populations, and ultimately in speciation. Our understanding of evolutionary processes have need greatly enhances through the study of hybridization and hybrid zones. Indeed, hybrid zones have been described as “natural laboratories” (Barton, N. H., and G .M. Hewitt, 189. Adaptation, speciation, and hybrid zones. Nature 341:497-503) or as “windows on the evolutionary processes” (Harrison, R. G. 1990. Hybrid zones: windows on the evolutionary process. Oxford Surveys in Evolutionary Biology 7:69-128). Hybrid zones greatly facilitate analyses of evolutionary dynamics because differences in factors such as mating preference, fertility, and viability are likely to be magnified, making the consequences easier to document over short periods of time.

Microsatellite markers for the Pilosella alpicola group (Hieraciinae, Asteraceae) and their cross-amplification in other Hieraciinae genera.

PubMed

Vít, Petr; Šingliarová, Barbora; Zozomová-Lihová, Judita; Marhold, Karol; Krak, Karol

2015-08-01

Microsatellite markers were developed for the Pilosella alpicola group (Asteraceae), comprising four closely related species distributed in subalpine areas of Europe. These species are believed to have diverged recently, but display contrasting cytogeographic patterns and variation in breeding systems, representing a promising model system for studying plant speciation, adaptation, and recent polyploidization. We developed 17 microsatellite markers for the P. alpicola group using 454 sequencing. Sixteen markers were polymorphic, with the number of alleles per locus ranging from seven to 16 and observed and expected heterozygosity ranging from 0.45 to 0.84 and 0.72 to 0.92, respectively. Ten and five loci amplified in the related species, P. echioides and P. officinarum, respectively, but only two in Andryala and one in Hieracium s. str. The developed microsatellite markers have high potential to become useful tools to study microevolutionary processes in the P. alpicola group and related Pilosella species.

Between “design” and “bricolage”: Genetic networks, levels of selection, and adaptive evolution

PubMed Central

Wilkins, Adam S.

2007-01-01

The extent to which “developmental constraints” in complex organisms restrict evolutionary directions remains contentious. Yet, other forms of internal constraint, which have received less attention, may also exist. It will be argued here that a set of partial constraints below the level of phenotypes, those involving genes and molecules, influences and channels the set of possible evolutionary trajectories. At the top-most organizational level there are the genetic network modules, whose operations directly underlie complex morphological traits. The properties of these network modules, however, have themselves been set by the evolutionary history of the component genes and their interactions. Characterization of the components, structures, and operational dynamics of specific genetic networks should lead to a better understanding not only of the morphological traits they underlie but of the biases that influence the directions of evolutionary change. Furthermore, such knowledge may permit assessment of the relative degrees of probability of short evolutionary trajectories, those on the microevolutionary scale. In effect, a “network perspective” may help transform evolutionary biology into a scientific enterprise with greater predictive capability than it has hitherto possessed. PMID:17494754

Between "design" and "bricolage": genetic networks, levels of selection, and adaptive evolution.

PubMed

Wilkins, Adam S

2007-05-15

The extent to which "developmental constraints" in complex organisms restrict evolutionary directions remains contentious. Yet, other forms of internal constraint, which have received less attention, may also exist. It will be argued here that a set of partial constraints below the level of phenotypes, those involving genes and molecules, influences and channels the set of possible evolutionary trajectories. At the top-most organizational level there are the genetic network modules, whose operations directly underlie complex morphological traits. The properties of these network modules, however, have themselves been set by the evolutionary history of the component genes and their interactions. Characterization of the components, structures, and operational dynamics of specific genetic networks should lead to a better understanding not only of the morphological traits they underlie but of the biases that influence the directions of evolutionary change. Furthermore, such knowledge may permit assessment of the relative degrees of probability of short evolutionary trajectories, those on the microevolutionary scale. In effect, a "network perspective" may help transform evolutionary biology into a scientific enterprise with greater predictive capability than it has hitherto possessed.

Evidence for modular evolution in a long-tailed pterosaur with a pterodactyloid skull.

PubMed

Lü, Junchang; Unwin, David M; Jin, Xingsheng; Liu, Yongqing; Ji, Qiang

2010-02-07

The fossil record is a unique source of evidence for important evolutionary phenomena such as transitions between major clades. Frustratingly, relevant fossils are still comparatively rare, most transitions have yet to be documented in detail and the mechanisms that underpin such events, typified by rapid large scale changes and for which microevolutionary processes seem insufficient, are still unclear. A new pterosaur (Mesozoic flying reptile) from the Middle Jurassic of China, Darwinopterus modularis gen. et sp. nov., provides the first insights into a prominent, but poorly understood transition between basal, predominantly long-tailed pterosaurs and the more derived, exclusively short-tailed pterodactyloids. Darwinopterus exhibits a remarkable 'modular' combination of characters: the skull and neck are typically pterodactyloid, exhibiting numerous derived character states, while the remainder of the skeleton is almost completely plesiomorphic and identical to that of basal pterosaurs. This pattern supports the idea that modules, tightly integrated complexes of characters with discrete, semi-independent and temporally persistent histories, were the principal focus of natural selection and played a leading role in evolutionary transitions.

Craniofacial divergence and ongoing adaptation via the hedgehog pathway.

PubMed

Roberts, Reade B; Hu, Yinan; Albertson, R Craig; Kocher, Thomas D

2011-08-09

Adaptive variation in craniofacial structure contributes to resource specialization and speciation, but the genetic loci that underlie craniofacial adaptation remain unknown. Here we show that alleles of the hedgehog pathway receptor Patched1 (Ptch1) gene are responsible for adaptive variation in the shape of the lower jaw both within and among genera of Lake Malawi cichlid fish. The evolutionarily derived allele of Ptch1 reduces the length of the retroarticular (RA) process of the lower jaw, a change predicted to increase speed of jaw rotation for improved suction-feeding. The alternate allele is associated with a longer RA and a more robustly mineralized jaw, typical of species that use a biting mode of feeding. Genera with the most divergent feeding morphologies are nearly fixed for different Ptch1 alleles, whereas species with intermediate morphologies still segregate variation at Ptch1. Thus, the same alleles that help to define macroevolutionary divergence among genera also contribute to microevolutionary fine-tuning of adaptive traits within some species. Variability of craniofacial morphology mediated by Ptch1 polymorphism has likely contributed to niche partitioning and ecological speciation of these fishes.

Evolution, Diversity, and Taxonomy of the Peronosporaceae, with Focus on the Genus Peronospora.

PubMed

Thines, Marco; Choi, Young-Joon

2016-01-01

Downy mildews are a notorious group of oomycete plant pathogens, causing high economic losses in various crops and ornamentals. The most species-rich genus of oomycetes is the genus Peronospora. This review provides a wide overview of these pathogens, ranging from macro- and micro-evolutionary patterns, their biodiversity and ecology to short overviews for the currently economically most important pathogens and potential emerging diseases. In this overview, the taxonomy of economically relevant species is also discussed, as the application of the correct names and species concepts is a prerequisite for effective quarantine regulations and phytosanitary measures.

On the evolutionary constraint surface of hydra

NASA Technical Reports Server (NTRS)

Slobodkin, L. B.; Dunn, K.

1983-01-01

Food consumption, body size, and budding rate were measured simultaneously in isolated individual hydra of six strains. For each individual hydra the three measurements define a point in the three dimensional space with axes: food consumption, budding rate, and body size. These points lie on a single surface, regardless of species. Floating rate and incidence of sexuality map onto this surface. It is suggested that this surface is an example of a general class of evolutionary constraint surfaces derived from the conjunction of evolutinary theory and the theory of ecological resource budgets. These constraint surfaces correspond to microevolutionary domains.

Multiple Weather Factors Affect Apparent Survival of European Passerine Birds

PubMed Central

Salewski, Volker; Hochachka, Wesley M.; Fiedler, Wolfgang

2013-01-01

Weather affects the demography of animals and thus climate change will cause local changes in demographic rates. In birds numerous studies have correlated demographic factors with weather but few of those examined variation in the impacts of weather in different seasons and, in the case of migrants, in different regions. Using capture-recapture models we correlated weather with apparent survival of seven passerine bird species with different migration strategies to assess the importance of selected facets of weather throughout the year on apparent survival. Contrary to our expectations weather experienced during the breeding season did not affect apparent survival of the target species. However, measures for winter severity were associated with apparent survival of a resident species, two short-distance/partial migrants and a long-distance migrant. Apparent survival of two short distance migrants as well as two long-distance migrants was further correlated with conditions experienced during the non-breeding season in Spain. Conditions in Africa had statistically significant but relatively minor effects on the apparent survival of the two long-distance migrants but also of a presumably short-distance migrant and a short-distance/partial migrant. In general several weather effects independently explained similar amounts of variation in apparent survival for the majority of species and single factors explained only relatively low amounts of temporal variation of apparent survival. Although the directions of the effects on apparent survival mostly met our expectations and there are clear predictions for effects of future climate we caution against simple extrapolations of present conditions to predict future population dynamics. Not only did weather explains limited amounts of variation in apparent survival, but future demographics will likely be affected by changing interspecific interactions, opposing effects of weather in different seasons, and the potential for phenotypic and microevolutionary adaptations. PMID:23593131

Culture History and Population Heterogeneity as Determinants of Bacterial Adaptation: the Adaptomics of a Single Environmental Transition

PubMed Central

Ryall, Ben; Eydallin, Gustavo

2012-01-01

Summary: Diversity in adaptive responses is common within species and populations, especially when the heterogeneity of the frequently large populations found in environments is considered. By focusing on events in a single clonal population undergoing a single transition, we discuss how environmental cues and changes in growth rate initiate a multiplicity of adaptive pathways. Adaptation is a comprehensive process, and stochastic, regulatory, epigenetic, and mutational changes can contribute to fitness and overlap in timing and frequency. We identify culture history as a major determinant of both regulatory adaptations and microevolutionary change. Population history before a transition determines heterogeneities due to errors in translation, stochastic differences in regulation, the presence of aged, damaged, cheating, or dormant cells, and variations in intracellular metabolite or regulator concentrations. It matters whether bacteria come from dense, slow-growing, stressed, or structured states. Genotypic adaptations are history dependent due to variations in mutation supply, contingency gene changes, phase variation, lateral gene transfer, and genome amplifications. Phenotypic adaptations underpin genotypic changes in situations such as stress-induced mutagenesis or prophage induction or in biofilms to give a continuum of adaptive possibilities. Evolutionary selection additionally provides diverse adaptive outcomes in a single transition and generally does not result in single fitter types. The totality of heterogeneities in an adapting population increases the chance that at least some individuals meet immediate or future challenges. However, heterogeneity complicates the adaptomics of single transitions, and we propose that subpopulations will need to be integrated into future population biology and systems biology predictions of bacterial behavior. PMID:22933562

Genomic Comparisons Reveal Microevolutionary Differences in Mycobacterium abscessus Subspecies

PubMed Central

Tan, Joon L.; Ng, Kee P.; Ong, Chia S.; Ngeow, Yun F.

2017-01-01

Mycobacterium abscessus, a rapid-growing non-tuberculous mycobacterium, has been the cause of sporadic and outbreak infections world-wide. The subspecies in M. abscessus complex (M. abscessus, M. massiliense, and M. bolletii) are associated with different biologic and pathogenic characteristics and are known to be among the most frequently isolated opportunistic pathogens from clinical material. To date, the evolutionary forces that could have contributed to these biological and clinical differences are still unclear. We compared genome data from 243 M. abscessus strains downloaded from the NCBI ftp Refseq database to understand how the microevolutionary processes of homologous recombination and positive selection influenced the diversification of the M. abscessus complex at the subspecies level. The three subspecies are clearly separated in the Minimum Spanning Tree. Their MUMi-based genomic distances support the separation of M. massiliense and M. bolletii into two subspecies. Maximum Likelihood analysis through dN/dS (the ratio of number of non-synonymous substitutions per non-synonymous site, to the number of synonymous substitutions per synonymous site) identified distinct genes in each subspecies that could have been affected by positive selection during evolution. The results of genome-wide alignment based on concatenated locally-collinear blocks suggest that (a) recombination has affected the M. abscessus complex more than mutation and positive selection; (b) recombination occurred more frequently in M. massiliense than in the other two subspecies; and (c) the recombined segments in the three subspecies have come from different intra-species and inter-species origins. The results lead to the identification of possible gene sets that could have been responsible for the subspecies-specific features and suggest independent evolution among the three subspecies, with recombination playing a more significant role than positive selection in the diversification among members in this complex. PMID:29109707

Genomic Comparisons Reveal Microevolutionary Differences in Mycobacterium abscessus Subspecies.

PubMed

Tan, Joon L; Ng, Kee P; Ong, Chia S; Ngeow, Yun F

2017-01-01

Mycobacterium abscessus , a rapid-growing non-tuberculous mycobacterium, has been the cause of sporadic and outbreak infections world-wide. The subspecies in M. abscessus complex ( M. abscessus, M. massiliense , and M. bolletii ) are associated with different biologic and pathogenic characteristics and are known to be among the most frequently isolated opportunistic pathogens from clinical material. To date, the evolutionary forces that could have contributed to these biological and clinical differences are still unclear. We compared genome data from 243 M. abscessus strains downloaded from the NCBI ftp Refseq database to understand how the microevolutionary processes of homologous recombination and positive selection influenced the diversification of the M. abscessus complex at the subspecies level. The three subspecies are clearly separated in the Minimum Spanning Tree. Their MUMi-based genomic distances support the separation of M. massiliense and M. bolletii into two subspecies. Maximum Likelihood analysis through dN/dS (the ratio of number of non-synonymous substitutions per non-synonymous site, to the number of synonymous substitutions per synonymous site) identified distinct genes in each subspecies that could have been affected by positive selection during evolution. The results of genome-wide alignment based on concatenated locally-collinear blocks suggest that (a) recombination has affected the M. abscessus complex more than mutation and positive selection; (b) recombination occurred more frequently in M. massiliense than in the other two subspecies; and (c) the recombined segments in the three subspecies have come from different intra-species and inter-species origins. The results lead to the identification of possible gene sets that could have been responsible for the subspecies-specific features and suggest independent evolution among the three subspecies, with recombination playing a more significant role than positive selection in the diversification among members in this complex.

Morphological constraints on changing avian migration phenology.

PubMed

Møller, A P; Rubolini, D; Saino, N

2017-06-01

Many organisms at northern latitudes have responded to climate warming by advancing their spring phenology. Birds are known to show earlier timing of spring migration and reproduction in response to warmer springs. However, species show heterogeneous phenological responses to climate warming, with those that have not advanced or have delayed migration phenology experiencing population declines. Although some traits (such as migration distance) partly explain heterogeneity in phenological responses, the factors affecting interspecies differences in the responsiveness to climate warming have yet to be fully explored. In this comparative study, we investigate whether variation in wing aspect ratio (reflecting relative wing narrowness), an ecomorphological trait that is strongly associated with flight efficiency and migratory behaviour, affects the ability to advance timing of spring migration during 1960-2006 in a set of 80 European migratory bird species. Species with larger aspect ratio (longer and narrower wings) showed smaller advancement of timing of spring migration compared to species with smaller aspect ratio (shorter and wider wings) while controlling for phylogeny, migration distance and other life-history traits. In turn, migration distance positively predicted aspect ratio across species. Hence, species that are better adapted to migration appear to be more constrained in responding phenologically to rapid climate warming by advancing timing of spring migration. Our findings corroborate the idea that aspect ratio is a major evolutionary correlate of migration, and suggest that selection for energetically efficient flights, as reflected by high aspect ratio, may hinder phenotypically plastic/microevolutionary adjustments of migration phenology to ongoing climatic changes. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.

Genomic signature of natural and anthropogenic stress in wild populations of the waterflea Daphnia magna: validation in space, time and experimental evolution.

PubMed

Orsini, Luisa; Spanier, Katina I; DE Meester, Luc

2012-05-01

Natural populations are confronted with multiple selection pressures resulting in a mosaic of environmental stressors at the landscape level. Identifying the genetic underpinning of adaptation to these complex selection environments and assigning causes of natural selection within multidimensional selection regimes in the wild is challenging. The water flea Daphnia is a renowned ecological model system with its well-documented ecology, the possibility to analyse subfossil dormant egg banks and the short generation time allowing an experimental evolution approach. Capitalizing on the strengths of this model system, we here link candidate genome regions to three selection pressures, known to induce micro-evolutionary responses in Daphnia magna: fish predation, parasitism and land use. Using a genome scan approach in space, time and experimental evolution trials, we provide solid evidence of selection at the genome level under well-characterized environmental gradients in the wild and identify candidate genes linked to the three environmental stressors. Our study reveals differential selection at the genome level in Daphnia populations and provides evidence for repeatable patterns of local adaptation in a geographic mosaic of environmental stressors fuelled by standing genetic variation. Our results imply high evolutionary potential of local populations, which is relevant to understand the dynamics of trait changes in natural populations and their impact on community and ecosystem responses through eco-evolutionary feedbacks. © 2012 Blackwell Publishing Ltd.

Selection on parental performance opposes selection for larger body mass in a wild population of blue tits.

PubMed

Thomson, Caroline E; Bayer, Florian; Crouch, Nicholas; Farrell, Samantha; Heap, Elizabeth; Mittell, Elizabeth; Zurita-Cassinello, Mar; Hadfield, Jarrod D

2017-03-01

There is abundant evidence in many taxa for positive directional selection on body size, and yet little evidence for microevolutionary change. In many species, variation in body size is partly determined by the actions of parents, so a proposed explanation for stasis is the presence of a negative genetic correlation between direct and parental effects. Consequently, selecting genes for increased body size would result in a correlated decline in parental effects, reducing body size in the following generation. We show that these arguments implicitly assume that parental care is cost free, and that including a cost alters the predicted genetic architectures needed to explain stasis. Using a large cross-fostered population of blue tits, we estimate direct selection on parental effects for body mass, and show it is negative. Negative selection is consistent with a cost to parental care, mainly acting through a reduction in current fecundity rather than survival. Under these conditions, evolutionary stasis is possible for moderately negative genetic correlations between direct and parental effects. This is in contrast to the implausibly extreme correlations needed when care is assumed to be cost-free. Thus, we highlight the importance of accounting correctly for complete selection acting on traits across generations. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

Birdsong and anthropogenic noise: implications and applications for conservation.

PubMed

Slabbekoorn, Hans; Ripmeester, Erwin A P

2008-01-01

The dramatic increase in human activities all over the world has caused, on an evolutionary time scale, a sudden rise in especially low-pitched noise levels. Ambient noise may be detrimental to birds through direct stress, masking of predator arrival or associated alarm calls, and by interference of acoustic signals in general. Two of the most important functions of avian acoustic signals are territory defence and mate attraction. Both of these functions are hampered when signal efficiency is reduced through rising noise levels, resulting in direct negative fitness consequences. Many bird species are less abundant near highways and studies are becoming available on reduced reproductive success in noisy territories. Urbanization typically leads to homogenization of bird communities over large geographical ranges. We review current evidence for whether and how anthropogenic noise plays a role in these patterns of decline in diversity and density. We also provide details of a case study on great tits (Parus major), a successful urban species. Great tits show features that other species may lack and make them unsuitable for city life. We hypothesize that behavioural plasticity in singing behaviour may allow species more time to adapt to human-altered environments and we address the potential for microevolutionary changes and urban speciation in European blackbirds (Turdus merula). We conclude by providing an overview of mitigating measures available to abate noise levels that are degrading bird breeding areas. Bird conservationists probably gain most by realizing that birds and humans often benefit from the same or only slightly modified measures.

Biodiversity, molecular ecology and phylogeography of marine sponges: patterns, implications and outlooks.

PubMed

Wörheide, Gert; Solé-Cava, Antonio M; Hooper, John N A

2005-04-01

Marine sponges are an ecologically important and highly diverse component of marine benthic communities, found in all the world's oceans, at all depths. Although their commercial potential and evolutionary importance is increasingly recognized, many pivotal aspects of their basic biology remain enigmatic. Knowledge of historical biogeographic affinities and biodiversity patterns is rudimentary, and there are still few data about genetic variation among sponge populations and spatial patterns of this variation. Biodiversity analyses of tropical Australasian sponges revealed spatial trends not universally reflected in the distributions of other marine phyla within the Indo-West Pacific region. At smaller spatial scales sponges frequently form heterogeneous, spatially patchy assemblages, with some empirical evidence suggesting that environmental variables such as light and/or turbidity strongly contribute to local distributions. There are no apparent latitudinal diversity gradients at larger spatial scales but stochastic processes, such as changing current patterns, the presence or absence of major carbonate platforms and historical biogeography, may determine modern day distributions. Studies on Caribbean oceanic reefs have revealed similar patterns, only weakly correlated with environmental factors. However, several questions remain where molecular approaches promise great potential, e.g., concerning connectivity and biogeographic relationships. Studies to date have helped to reveal that sponge populations are genetically highly structured and that historical processes might play an important role in determining such structure. Increasingly sophisticated molecular tools are now being applied, with results contributing significantly to a better understanding of poriferan microevolutionary processes and molecular ecology.

Unprecedented within-species chromosome number cline in the Wood White butterfly Leptidea sinapis and its significance for karyotype evolution and speciation

PubMed Central

2011-01-01

Background Species generally have a fixed number of chromosomes in the cell nuclei while between-species differences are common and often pronounced. These differences could have evolved through multiple speciation events, each involving the fixation of a single chromosomal rearrangement. Alternatively, marked changes in the karyotype may be the consequence of within-species accumulation of multiple chromosomal fissions/fusions, resulting in highly polymorphic systems with the subsequent extinction of intermediate karyomorphs. Although this mechanism of chromosome number evolution is possible in theory, it has not been well documented. Results We present the discovery of exceptional intraspecific variability in the karyotype of the widespread Eurasian butterfly Leptidea sinapis. We show that within this species the diploid chromosome number gradually decreases from 2n = 106 in Spain to 2n = 56 in eastern Kazakhstan, resulting in a 6000 km-wide cline that originated recently (8,500 to 31,000 years ago). Remarkably, intrapopulational chromosome number polymorphism exists, the chromosome number range overlaps between some populations separated by hundreds of kilometers, and chromosomal heterozygotes are abundant. We demonstrate that this karyotypic variability is intraspecific because in L. sinapis a broad geographical distribution is coupled with a homogenous morphological and genetic structure. Conclusions The discovered system represents the first clearly documented case of explosive chromosome number evolution through intraspecific and intrapopulation accumulation of multiple chromosomal changes. Leptidea sinapis may be used as a model system for studying speciation by means of chromosomally-based suppressed recombination mechanisms, as well as clinal speciation, a process that is theoretically possible but difficult to document. The discovered cline seems to represent a narrow time-window of the very first steps of species formation linked to multiple chromosomal changes that have occurred explosively. This case offers a rare opportunity to study this process before drift, dispersal, selection, extinction and speciation erase the traces of microevolutionary events and just leave the final picture of a pronounced interspecific chromosomal difference. PMID:21507222

Bill size variation in northern cardinals associated with anthropogenic drivers across North America.

PubMed

Miller, Colleen R; Latimer, Christopher E; Zuckerberg, Benjamin

2018-05-01

Allen's rule predicts that homeotherms inhabiting cooler climates will have smaller appendages, while those inhabiting warmer climates will have larger appendages relative to body size. Birds' bills tend to be larger at lower latitudes, but few studies have tested whether modern climate change and urbanization affect bill size. Our study explored whether bill size in a wide-ranging bird would be larger in warmer, drier regions and increase with rising temperatures. Furthermore, we predicted that bill size would be larger in densely populated areas, due to urban heat island effects and the higher concentration of supplementary foods. Using measurements from 605 museum specimens, we explored the effects of climate and housing density on northern cardinal bill size over an 85-year period across the Linnaean subspecies' range. We quantified the geographic relationships between bill surface area, housing density, and minimum temperature using linear mixed effect models and geographically weighted regression. We then tested whether bill surface area changed due to housing density and temperature in three subregions (Chicago, IL., Washington, D.C., and Ithaca, NY). Across North America, cardinals occupying drier regions had larger bills, a pattern strongest in males. This relationship was mediated by temperature such that birds in warm, dry areas had larger bills than those in cool, dry areas. Over time, female cardinals' bill size increased with warming temperatures in Washington, D.C., and Ithaca. Bill size was smaller in developed areas of Chicago, but larger in Washington, D.C., while there was no pattern in Ithaca, NY. We found that climate and urbanization were strongly associated with bill size for a wide-ranging bird. These biogeographic relationships were characterized by sex-specific differences, varying relationships with housing density, and geographic variability. It is likely that anthropogenic pressures will continue to influence species, potentially promoting microevolutionary changes over space and time.

The Drosophila flavopilosa species group (Diptera, Drosophilidae)

PubMed Central

Robe, Lizandra J.; De Ré, Francine Cenzi; Ludwig, Adriana; Loreto, Elgion L.S.

2013-01-01

The D. flavopilosa group encompasses an ecologically restricted set of species strictly adapted to hosting flowers of Cestrum (Solanaceae). This group presents potential to be used as a model to the study of different questions regarding ecologically restricted species macro and microevolutionary responses, geographical vs. ecological speciation and intra and interspecific competition. This review aims to revisit and reanalyze the patterns and processes that are subjacent to the interesting ecological and evolutionary properties of these species. Biotic and abiotic niche properties of some species were reanalyzed in face of ecological niche modeling approaches in order to get some insights into their ecological evolution. A test of the potential of DNA-Barcoding provided evidences that this technology may be a way of overcoming difficulties related to cryptic species differentiation. The new focus replenishes the scenario with new questions, presenting a case where neither geographical nor ecological speciation may be as yet suggested. PMID:23459119

Sperm competition and maternal effects differentially influence testis and sperm size in Callosobruchus maculatus.

PubMed

Gay, L; Hosken, D J; Vasudev, R; Tregenza, T; Eady, P E

2009-05-01

The evolutionary factors affecting testis size are well documented, with sperm competition being of major importance. However, the factors affecting sperm length are not well understood; there are no clear theoretical predictions and the empirical evidence is inconsistent. Recently, maternal effects have been implicated in sperm length variation, a finding that may offer insights into its evolution. We investigated potential proximate and microevolutionary factors influencing testis and sperm size in the bruchid beetle Callosobruchus maculatus using a combined approach of an artificial evolution experiment over 90 generations and an environmental effects study. We found that while polyandry seems to select for larger testes, it had no detectable effect on sperm length. Furthermore, population density, a proximate indicator of sperm competition risk, was not significantly associated with sperm length or testis size variation. However, there were strong maternal effects influencing sperm length.

The integrative effects of population density, photoperiod, temperature, and host plant on the induction of alate aphids in Schizaphis graminum.

PubMed

An, Chunju; Fei, Xiaodong; Chen, Wenfeng; Zhao, Zhangwu

2012-04-01

The wheat aphid Schizaphis graminum (Rondani) displays wing dimorphism with both winged and wingless adult morphs. The winged morph is an adaptive microevolutionary response to undesirable environmental conditions, including undesirable population density, photoperiod, temperature, and host plant. Here we studied the integrative effects of population density, photoperiod, temperature, and host plant on the induction of alate aphids in S. graminum. The present results show that these four factors all play roles in inducing alate aphids in S. graminum but population density is the most important under almost all circumstances. In importance, population density is followed by photoperiod, host plant, and temperature, in that order. These results indicate that ambient environmental factors are highly important to stimulation of alate aphids in S. graminum, especially when population density reaches 64 individuals per leaf. © 2012 Wiley Periodicals, Inc.

Gene migration for re-emerging amebiasis in Iran's northwest-Iraq borders: a microevolutionary scale for reflecting epidemiological drift of Entamoeba histolytica metapopulations.

PubMed

Mohammadzadeh, Asad; Spotin, Adel; Mahami-Oskouei, Mahmoud; Haghighi, Ali; Zebardast, Nozhat; Kohansal, Kobra

2017-01-01

In the microevolutionary scales of Entamoeba isolates, the gene migration shows how Entamoeba spp. has epidemiologically drifted among border countries. Five hundred fecal samples were taken from patients suffering gastrointestinal disorders, abdominal pain, and diarrhea at Saggez, northwest Iran located within the border Iraq country. Following parasitological techniques, DNA samples were extracted and amplified by polymerase chain reaction (PCR) of 18S rRNA region to identify Entamoeba infections. To distinguish the Entamoeba spp., a multiplex PCR was conducted. Amplicons were sequenced to reconfirm their heterogeneity traits and phylogenetic analysis. Additionally, Entamoeba histolytica sequences of Iraq were retrieved from GenBank database. The suspected isolates were diagnosed as E. histolytica (2.2 %), Entamoeba moshkovskii (1 %), and Entamoeba dispar (0.4 %). Mixed Entamoeba infections did not detect among isolates. A parsimonious network of the sequence haplotypes displayed star-like features in the overall isolates containing E.h1, E.d2, and E.m3 as the most common haplotypes. According to analysis of molecular variance (AMOVA) test, high partial value of haplotype diversity (0.700 to 0.800) of E. histolytica was shown the total genetic variability within populations while nucleotide diversity was low among Iranian and Iraqi metapopulations. Neutrality indices of the 18S rRNA were shown negative values in E. histolytica populations which indicating significant deviations from neutrality. A pairwise fixation index (F-statistics [Fst]) as a degree of gene flow had a low value for all populations (0.001) while the number of migrants was 2.48. The statistically Fst value indicates that E. histolytica isolates are not genetically differentiated among shared isolates of Iran and Iraq. Occurrence of E.h1 between two regional populations indicates that there is dawn of Entamoeba flow due to transfer of alleles from one population to another population through host mobility and ecological alterations. To evaluate the hypothetical evolutionary scenario, further study is required to analyze Entamoeba spp. in the neighboring Middle East countries.

Genetic perspectives on northern population cycles: bridging the gap between theory and empirical studies.

PubMed

Norén, Karin; Angerbjörn, Anders

2014-05-01

Many key species in northern ecosystems are characterised by high-amplitude cyclic population demography. In 1924, Charles Elton described the ecology and evolution of cyclic populations in a classic paper and, since then, a major focus has been the underlying causes of population cycles. Elton hypothesised that fluctuations reduced population genetic variation and influenced the direction of selection pressures. In concordance with Elton, present theories concern the direct consequences of population cycles for genetic structure due to the processes of genetic drift and selection, but also include feedback models of genetic composition on population dynamics. Most of these theories gained mathematical support during the 1970s and onwards, but due to methodological drawbacks, difficulties in long-term sampling and a complex interplay between microevolutionary processes, clear empirical data allowing the testing of these predictions are still scarce. Current genetic tools allow for estimates of genetic variation and identification of adaptive genomic regions, making this an ideal time to revisit this subject. Herein, we attempt to contribute towards a consensus regarding the enigma described by Elton almost 90 years ago. We present nine predictions covering the direct and genetic feedback consequences of population cycles on genetic variation and population structure, and review the empirical evidence. Generally, empirical support for the predictions was low and scattered, with obvious gaps in the understanding of basic population processes. We conclude that genetic variation in northern cyclic populations generally is high and that the geographic distribution and amount of diversity are usually suggested to be determined by various forms of context- and density-dependent dispersal exceeding the impact of genetic drift. Furthermore, we found few clear signatures of selection determining genetic composition in cyclic populations. Dispersal is assumed to have a strong impact on genetic structuring and we suggest that the signatures of other microevolutionary processes such as genetic drift and selection are weaker and have been over-shadowed by density-dependent dispersal. We emphasise that basic biological and demographical questions still need to be answered and stress the importance of extensive sampling, appropriate choice of tools and the value of standardised protocols. © 2013 The Authors. Biological Reviews © 2013 Cambridge Philosophical Society.

Drought-Adaptation Potential in Fagus sylvatica: Linking Moisture Availability with Genetic Diversity and Dendrochronology

PubMed Central

Pluess, Andrea R.; Weber, Pascale

2012-01-01

Background Microevolution is essential for species persistence especially under anticipated climate change scenarios. Species distribution projection models suggested that the dominant tree species of lowland forests in Switzerland, European beech (Fagus sylvatica L.), might disappear from most areas due to expected longer dry periods. However, if genotypes at the moisture boundary of the species climatic envelope are adapted to lower moisture availability, they can serve as seed source for the continuation of beech forests under changing climates. Methodology/Principal Findings With an AFLP genome scan approach, we studied neutral and potentially adaptive genetic variation in Fagus sylvatica in three regions containing a dry and a mesic site each (n ind. = 241, n markers = 517). We linked this dataset with dendrochronological growth measures and local moisture availabilities based on precipitation and soil characteristics. Genetic diversity decreased slightly at dry sites. Overall genetic differentiation was low (F st = 0.028) and Bayesian cluster analysis grouped all populations together suggesting high (historical) gene flow. The Bayesian outlier analyses indicated 13 markers with three markers differing between all dry and mesic sites and the others between the contrasting sites within individual regions. A total of 41 markers, including seven outlier loci, changed their frequency with local moisture availability. Tree height and median basal growth increments were reduced at dry sites, but marker presence/absence was not related to dendrochronological characteristics. Conclusion and Their Significance The outlier alleles and the makers with changing frequencies in relation to moisture availability indicate microevolutionary processes occurring within short geographic distances. The general genetic similarity among sites suggests that ‘preadaptive’ genes can easily spread across the landscape. Yet, due to the long live span of trees, fostering saplings originating from dry sites and grown within mesic sites might increase resistance of beech forests during the anticipated longer dry periods. PMID:22448260

Drought-adaptation potential in Fagus sylvatica: linking moisture availability with genetic diversity and dendrochronology.

PubMed

Pluess, Andrea R; Weber, Pascale

2012-01-01

Microevolution is essential for species persistence especially under anticipated climate change scenarios. Species distribution projection models suggested that the dominant tree species of lowland forests in Switzerland, European beech (Fagus sylvatica L.), might disappear from most areas due to expected longer dry periods. However, if genotypes at the moisture boundary of the species climatic envelope are adapted to lower moisture availability, they can serve as seed source for the continuation of beech forests under changing climates. With an AFLP genome scan approach, we studied neutral and potentially adaptive genetic variation in Fagus sylvatica in three regions containing a dry and a mesic site each (n(ind.) = 241, n(markers) = 517). We linked this dataset with dendrochronological growth measures and local moisture availabilities based on precipitation and soil characteristics. Genetic diversity decreased slightly at dry sites. Overall genetic differentiation was low (F(st) = 0.028) and Bayesian cluster analysis grouped all populations together suggesting high (historical) gene flow. The Bayesian outlier analyses indicated 13 markers with three markers differing between all dry and mesic sites and the others between the contrasting sites within individual regions. A total of 41 markers, including seven outlier loci, changed their frequency with local moisture availability. Tree height and median basal growth increments were reduced at dry sites, but marker presence/absence was not related to dendrochronological characteristics. CONCLUSION AND THEIR SIGNIFICANCE: The outlier alleles and the makers with changing frequencies in relation to moisture availability indicate microevolutionary processes occurring within short geographic distances. The general genetic similarity among sites suggests that 'preadaptive' genes can easily spread across the landscape. Yet, due to the long live span of trees, fostering saplings originating from dry sites and grown within mesic sites might increase resistance of beech forests during the anticipated longer dry periods.

On joint subtree distributions under two evolutionary models.

PubMed

Wu, Taoyang; Choi, Kwok Pui

2016-04-01

In population and evolutionary biology, hypotheses about micro-evolutionary and macro-evolutionary processes are commonly tested by comparing the shape indices of empirical evolutionary trees with those predicted by neutral models. A key ingredient in this approach is the ability to compute and quantify distributions of various tree shape indices under random models of interest. As a step to meet this challenge, in this paper we investigate the joint distribution of cherries and pitchforks (that is, subtrees with two and three leaves) under two widely used null models: the Yule-Harding-Kingman (YHK) model and the proportional to distinguishable arrangements (PDA) model. Based on two novel recursive formulae, we propose a dynamic approach to numerically compute the exact joint distribution (and hence the marginal distributions) for trees of any size. We also obtained insights into the statistical properties of trees generated under these two models, including a constant correlation between the cherry and the pitchfork distributions under the YHK model, and the log-concavity and unimodality of the cherry distributions under both models. In addition, we show that there exists a unique change point for the cherry distributions between these two models. Copyright © 2015 Elsevier Inc. All rights reserved.

The importance of offshore origination revealed through ophiuroid phylogenomics.

PubMed

Bribiesca-Contreras, Guadalupe; Verbruggen, Heroen; Hugall, Andrew F; O'Hara, Timothy D

2017-07-12

Our knowledge of macro-evolutionary processes in the deep sea is poor, leading to much speculation about whether the deep sea is a source or sink of evolutionary adaptation. Here, we use a phylogenetic approach, on large molecular (688 species, 275 kbp) and distributional datasets (104 513 records) across an entire class of marine invertebrates (Ophiuroidea), to infer rates of bathymetric range shift over time between shallow and deep water biomes. Biome conservation is evident through the phylogeny, with the majority of species in most clades distributed within the same bathome. Despite this, bathymetric shifts have occurred. We inferred from ancestral reconstructions that eurybathic or intermediate distributions across both biomes were a transitional state and direct changes between shallow and deep sea did not occur. The macro-evolutionary pattern of bathome shift appeared to reflect micro-evolutionary processes of bathymetric speciation. Results suggest that most of the oldest clades have a deep-sea origin, but multiple colonization events indicate that the evolution of this group conforms neither to a simple onshore-offshore hypothesis, nor the opposite pattern. Both shallow and deep bathomes have played an important role in generating the current diversity of this major benthic class. © 2017 The Author(s).

Herbivory as an important selective force in the evolution of floral traits and pollinator shifts

PubMed Central

Overson, Rick P.; Raguso, Robert A.; Skogen, Krissa A.

2017-01-01

Abstract Floral trait evolution is frequently attributed to pollinator-mediated selection but herbivores can play a key role in shaping plant reproductive biology. Here we examine the role of florivores in driving floral trait evolution and pollinator shifts in a recently radiated clade of flowering plants, Oenothera sect. Calylophus. We compare florivory by a specialist, internal feeder, Mompha, on closely related hawkmoth- and bee-pollinated species and document variation in damage based on floral traits within sites, species and among species. Our results show that flowers with longer floral tubes and decreased floral flare have increased Mompha damage. Bee-pollinated flowers, which have substantially smaller floral tubes, experience on average 13% less Mompha florivory than do hawkmoth-pollinated flowers. The positive association between tube length and Mompha damage is evident even within sites of some species, suggesting that Mompha can drive trait differentiation at microevolutionary scales. Given that there are at least two independent shifts from hawkmoth to bee pollination in this clade, florivore-mediated selection on floral traits may have played an important role in facilitating morphological changes associated with transitions from hawkmoth to bee pollination. PMID:28011456

Temperature-dependent plasticity of segment number in an arthropod species: the centipede Strigamia maritima.

PubMed

Vedel, Vincent; Chipman, Ariel D; Akam, Michael; Arthur, Wallace

2008-01-01

The evolution of arthropod segment number provides us with a paradox, because, whereas there is more than 20-fold variation in this character overall, most classes and orders of arthropods are composed of species that lack any variation in the number of segments. So, what is the origin of the higher-level variation? The centipede order Geophilomorpha is unusual because, with the exception of one of its families, all species exhibit intraspecific variation in segment number. Hence it provides an opportunity to investigate how segment number may change in a microevolutionary context. Here, we show that segment number can be directly altered by an environmental factor (temperature)-this is the first such demonstration for any arthropod. The direction of the effect is such that higher temperature during embryogenesis produces more segments. This potentially explains an intraspecific cline in the species concerned, Strigamia maritima, but it does not explain how such a cline is translated into the parallel interspecific pattern of lower-latitude species having more segments. Given the plastic nature of the intraspecific variation, its link with interspecific differences may lie in selection acting on developmental reaction norms.

Microevolution in prehistoric Andean populations: chronologic mtDNA variation in the desert valleys of northern Chile.

PubMed

Moraga, Mauricio; Santoro, Calogero M; Standen, Vivien G; Carvallo, Pilar; Rothhammer, Francisco

2005-06-01

Archeological evidence suggests that the iconographic and technological developments that took place in the highlands around Lake Titicaca in the Central Andean region had an influence on the cultural elaborations of the human groups in the valleys and the Pacific coast of northern Chile. In a previous communication, we were able to show, by means of a distance analysis, that a craniofacial differentiation accompanied the process of cultural evolution in the valleys (Rothhammer and Santoro [2001] Lat. Am. Antiq. 12:59-66). Recently, numerous South Amerindian mtDNA studies were published, and more accurate molecular techniques to study ancient mtDNA are available. In view of these recent developments, we decided 1) to study chronological changes of ancient mtDNA haplogroup frequencies in the nearby Lluta, Azapa, and Camarones Valleys, 2) to identify microevolutionary forces responsible for such changes, and 3) to compare ancient mtDNA haplogroup frequencies with previous data in order to validate craniometrical results and to reconstruct the biological history of the prehistoric valley groups in the context of their interaction with culturally more developed highland populations. From a total of 97 samples from 83 individuals, 68 samples (61 individuals) yielded amplifications for the fragments that harbor classical mtDNA markers. The haplogroup distribution among the total sample was as follows: 26.2%, haplogroup A; 34.4%, haplogroup B; 14.8%, haplogroup C; 3.3%, haplogroup D; and 21.3%, other haplogroups. Haplogroup B tended to increase, and haplogroup A to decrease during a 3,900-year time interval. The sequence data are congruent with the haplogroup analysis. In fact, the sequencing of hypervariable region I of 30 prehistoric individuals revealed 43 polymorphic sites. Sequence alignment and subsequent phylogenetic tree construction showed two major clusters associated with the most common restriction haplogroups. Individuals belonging to haplogroups C and D tended to cluster together with nonclassical lineages. 2004 Wiley-Liss, Inc.

Genetic approaches in comparative and evolutionary physiology

PubMed Central

Bridgham, Jamie T.; Kelly, Scott A.; Garland, Theodore

2015-01-01

Whole animal physiological performance is highly polygenic and highly plastic, and the same is generally true for the many subordinate traits that underlie performance capacities. Quantitative genetics, therefore, provides an appropriate framework for the analysis of physiological phenotypes and can be used to infer the microevolutionary processes that have shaped patterns of trait variation within and among species. In cases where specific genes are known to contribute to variation in physiological traits, analyses of intraspecific polymorphism and interspecific divergence can reveal molecular mechanisms of functional evolution and can provide insights into the possible adaptive significance of observed sequence changes. In this review, we explain how the tools and theory of quantitative genetics, population genetics, and molecular evolution can inform our understanding of mechanism and process in physiological evolution. For example, lab-based studies of polygenic inheritance can be integrated with field-based studies of trait variation and survivorship to measure selection in the wild, thereby providing direct insights into the adaptive significance of physiological variation. Analyses of quantitative genetic variation in selection experiments can be used to probe interrelationships among traits and the genetic basis of physiological trade-offs and constraints. We review approaches for characterizing the genetic architecture of physiological traits, including linkage mapping and association mapping, and systems approaches for dissecting intermediary steps in the chain of causation between genotype and phenotype. We also discuss the promise and limitations of population genomic approaches for inferring adaptation at specific loci. We end by highlighting the role of organismal physiology in the functional synthesis of evolutionary biology. PMID:26041111

Genetic approaches in comparative and evolutionary physiology.

PubMed

Storz, Jay F; Bridgham, Jamie T; Kelly, Scott A; Garland, Theodore

2015-08-01

Whole animal physiological performance is highly polygenic and highly plastic, and the same is generally true for the many subordinate traits that underlie performance capacities. Quantitative genetics, therefore, provides an appropriate framework for the analysis of physiological phenotypes and can be used to infer the microevolutionary processes that have shaped patterns of trait variation within and among species. In cases where specific genes are known to contribute to variation in physiological traits, analyses of intraspecific polymorphism and interspecific divergence can reveal molecular mechanisms of functional evolution and can provide insights into the possible adaptive significance of observed sequence changes. In this review, we explain how the tools and theory of quantitative genetics, population genetics, and molecular evolution can inform our understanding of mechanism and process in physiological evolution. For example, lab-based studies of polygenic inheritance can be integrated with field-based studies of trait variation and survivorship to measure selection in the wild, thereby providing direct insights into the adaptive significance of physiological variation. Analyses of quantitative genetic variation in selection experiments can be used to probe interrelationships among traits and the genetic basis of physiological trade-offs and constraints. We review approaches for characterizing the genetic architecture of physiological traits, including linkage mapping and association mapping, and systems approaches for dissecting intermediary steps in the chain of causation between genotype and phenotype. We also discuss the promise and limitations of population genomic approaches for inferring adaptation at specific loci. We end by highlighting the role of organismal physiology in the functional synthesis of evolutionary biology. Copyright © 2015 the American Physiological Society.

Colonisation and Diversification of the Zenaida Dove (Zenaida aurita) in the Antilles: Phylogeography, Contemporary Gene Flow and Morphological Divergence

PubMed Central

Monceau, Karine; Cézilly, Frank; Moreau, Jérôme; Motreuil, Sébastien; Wattier, Rémi

2013-01-01

Caribbean avifaunal biogeography has been mainly studied based on mitochondrial DNA. Here, we investigated both past and recent island differentiation and micro-evolutionary changes in the Zenaida Dove (Zenaida aurita) based on combined information from one mitochondrial (Cytochrome c Oxydase subunit I, COI) and 13 microsatellite markers and four morphological characters. This Caribbean endemic and abundant species has a large distribution, and two subspecies are supposed to occur: Z. a. zenaida in the Greater Antilles (GA) and Z. a. aurita in the Lesser Antilles (LA). Doves were sampled on two GA islands (Puerto Rico and the British Virgin Islands) and six LA islands (Saint Barthélemy, Guadeloupe, Les Saintes, Martinique, Saint Lucia and Barbados). Eleven COI haplotypes were observed that could be assembled in two distinct lineages, with six specific to GA, four to LA, the remaining one occurring in all islands. However, the level of divergence between those two lineages was too moderate to fully corroborate the existence of two subspecies. Colonisation of the studied islands appeared to be a recent process. However, both phenotypic and microsatellite data suggest that differentiation is already under way between all of them, partly associated with the existence of limited gene flow. No isolation by distance was observed. Differentiation for morphological traits was more pronounced than for neutral markers. These results suggest that despite recent colonisation, genetic drift and/or restricted gene flow are promoting differentiation for neutral markers. Variation in selective pressures between islands may explain the observed phenotypic differentiation. PMID:24349217

Molecular Evolution of a Klebsiella pneumoniae ST278 Isolate Harboring blaNDM-7 and Involved in Nosocomial Transmission.

PubMed

Lynch, Tarah; Chen, Liang; Peirano, Gisele; Gregson, Dan B; Church, Deirdre L; Conly, John; Kreiswirth, Barry N; Pitout, Johann D

2016-09-01

During 2013, ST278 Klebsiella pneumoniae with blaNDM-7 was isolated from the urine (KpN01) and rectum (KpN02) of a patient in Calgary, Canada. The same strain (KpN04) was subsequently isolated from another patient in the same unit. Interestingly, a carbapenem-susceptible K. pneumoniae ST278 (KpN06) was obtained 1 month later from the blood of the second patient. Next-generation sequencing (NGS) revealed that the loss of carbapenem-resistance in KpN06 was due to a 5-kb deletion on the blaNDM-7-harboring IncX3 plasmid. In addition, an IncFIB plasmid in KpN06 had a 27-kb deletion that removed genes encoding for heavy metal resistance. Phylogenetic analysis showed that the K. pneumoniae ST278 from patient 2 was likely a descendant of KpN02 and that KpN06 was a close progenitor of an environmental ST278. It is unclear whether KpN06 lost the blaNDM-7 gene in vivo. This study detailed the remarkable plasticity and speed of evolutionary changes in multidrug-resistant K. pneumoniae, demonstrating the highly recombinant nature of this species. It also highlights the ability of NGS to clarify molecular microevolutionary events within antibiotic-resistant organisms. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.

Dynamic selective environments and evolutionary traps in human-dominated landscapes.

PubMed

Rodewald, Amanda D; Shustack, Daniel P; Jones, Todd M

2011-09-01

Human activities can alter selective environments in ways that can reduce the usefulness of certain ornamental traits as honest signals of individual quality and, in some cases, may create evolutionary traps, where rapid changes in selective environments result in maladaptive behavioral decisions. Using the sexually dichromatic, socially monogamous Northern Cardinal (Cardinalis cardinalis) as a model, we hypothesized that urbanization would erode the relationship between plumage coloration and reproductive success. Because the exotic Amur honeysuckle (Lonicera maackii) provides carotenoids, is a preferred habitat attribute, and increases vulnerability to nest predation, we predicted the presence of an evolutionary trap, whereby the brightest males would achieve the lowest reproductive success. Working at 14 forests in Ohio, USA, 2006-2008, we measured plumage color, monitored reproduction, and quantified habitat within territories. In rural landscapes, the brightest males bred earliest in the season and secured more preferred territories; however, annual reproduction declined with plumage brightness. Coloration of urban males was not associated with territory attributes or reproduction. Female redness across all landscapes was negatively related to reproduction. Poor reproductive performance of otherwise higher-quality males probably resulted from preferences for honeysuckle, which reduces annual reproduction when used as a nesting substrate early in the season. In this way, exotic shrubs prompted an evolutionary trap that was avoided in urban forests where anthropogenic resources disassociated male color and reproductive phenology and success. Our study illustrates how modified selective environments in human-dominated landscapes might shape microevolutionary processes in wild bird populations.

Microsatellite Variations of Elite Setaria Varieties Released during Last Six Decades in China.

PubMed

Jia, Guanqing; Liu, Xiaotong; Schnable, James C; Niu, Zhengang; Wang, Chunfang; Li, Yuhui; Wang, Shujun; Wang, Suying; Liu, Jinrong; Guo, Erhu; Zhi, Hui; Diao, Xianmin

2015-01-01

Crop improvement is a multifaceted micro-evolutionary process, involving changes in breeding approaches, planting configurations and consumption preferences of human beings. Recent research has started to identify the specific genes or genomic regions correlate to improved agronomic traits, however, an apparent blank between the genetic structure of crop elite varieties and their improving histories in diverse modern breeding programs is still in existence. Foxtail millet (Setaria italica) was one of the earliest cereal crops to be domesticated and served as a staple crop for early civilizations in China, where it is still widely grown today. In the present trial, a panel of foxtail millet elite varieties, which were released in the last sixty years in different geographical regions of China, was characterized using microsatellite markers (SSRs). A clear separation of two subpopulations corresponding to the two eco-geographical regions of foxtail millet production in China was identified by the dataset, which also indicated that in more recently released elite varieties, large quantities of accessions have been transferred from spring-sowing to summer-sowing ecotypes, likely as a result of breeding response to planting configurations. An association mapping study was conducted to identify loci controlling traits of major agronomic interest. Furthermore, selective sweeps involved in improvement of foxtail millet were identified as multi-diverse minor effect loci controlling different agronomic traits during the long-term improvement of elite varieties. Our results highlight the effect of transition of planting configuration and breeding preference on genetic evolvement of crop species.

Microsatellite Variations of Elite Setaria Varieties Released during Last Six Decades in China

PubMed Central

Schnable, James C.; Niu, Zhengang; Wang, Chunfang; Li, Yuhui; Wang, Shujun; Wang, Suying; Liu, Jinrong; Guo, Erhu; Zhi, Hui; Diao, Xianmin

2015-01-01

Crop improvement is a multifaceted micro-evolutionary process, involving changes in breeding approaches, planting configurations and consumption preferences of human beings. Recent research has started to identify the specific genes or genomic regions correlate to improved agronomic traits, however, an apparent blank between the genetic structure of crop elite varieties and their improving histories in diverse modern breeding programs is still in existence. Foxtail millet (Setaria italica) was one of the earliest cereal crops to be domesticated and served as a staple crop for early civilizations in China, where it is still widely grown today. In the present trial, a panel of foxtail millet elite varieties, which were released in the last sixty years in different geographical regions of China, was characterized using microsatellite markers (SSRs). A clear separation of two subpopulations corresponding to the two eco-geographical regions of foxtail millet production in China was identified by the dataset, which also indicated that in more recently released elite varieties, large quantities of accessions have been transferred from spring-sowing to summer-sowing ecotypes, likely as a result of breeding response to planting configurations. An association mapping study was conducted to identify loci controlling traits of major agronomic interest. Furthermore, selective sweeps involved in improvement of foxtail millet were identified as multi-diverse minor effect loci controlling different agronomic traits during the long-term improvement of elite varieties. Our results highlight the effect of transition of planting configuration and breeding preference on genetic evolvement of crop species. PMID:25932649

Disentangling synergistic climate drivers on the evolution of two species of planktonic foraminifera on regional and global scales

NASA Astrophysics Data System (ADS)

Brombacher, A.; Wilson, P. A.; Bailey, I.; Ezard, T. H. G.

2016-02-01

Evolution is driven by a combination of biotic and abiotic factors. When quantifying the effects of abiotic drivers, evolutionary change is generally described as a response to a single environmental parameter assumed to represent global climate. However, climate is a complex system of many interacting factors and characterized by high regional variability. Therefore, to understand the role of climate in evolutionary change, we need to consider multiple environmental parameters, across local, regional and global scales, as well as their interactions. The deep-sea microfossil record is sufficiently complete that sufficiently continuous multivariate climatic and multivariate trait data can be obtained from the same samples. Here we present morphological records of the planktonic foraminifera species Globoconella puncticulata and Truncorotalia crassaformis over a 500,000-year interval directly preceding the extinction of G. puncticulata (2.41 Ma). Material was collected from five North Atlantic sites (ODP Sites 659 [18° N], 925 [3° N] and 981 [55° N], IODP Site U1313 [41° N] and DSDP Site 606 [37° N]). Test size and shape of over 35,000 individuals were measured and compared to site-specific records of sea surface temperature, primary productivity and marine aeolian dust deposition, as well as to global records of ice volume, ocean circulation and atmospheric CO2, and all two-way interactions. Morphological parameters respond weakly to individual climate parameters. Once interactions among all studied climate parameters were incorporated, abiotic change explained around 35% of the evolutionary variance. Observed covariances between environmental parameters vary strongly with glacial-interglacial cyclicity, implying that the relationships among climate variables and their relative influences on evolutionary change varied through time. This time dependence cautions against unfettered use of dimension reduction techniques, such as principal components analysis, to extract a single, supposedly dominant, proxy. Furthermore species' responses differed between geographic locations, impressing the need to test how interactions among multiple climate variables at different regional settings shape the biotic microevolutionary response to local and global abiotic change.

Contemporary and historic factors influence differently genetic differentiation and diversity in a tropical palm

PubMed Central

da Silva Carvalho, C; Ribeiro, M C; Côrtes, M C; Galetti, M; Collevatti, R G

2015-01-01

Population genetics theory predicts loss in genetic variability because of drift and inbreeding in isolated plant populations; however, it has been argued that long-distance pollination and seed dispersal may be able to maintain gene flow, even in highly fragmented landscapes. We tested how historical effective population size, historical migration and contemporary landscape structure, such as forest cover, patch isolation and matrix resistance, affect genetic variability and differentiation of seedlings in a tropical palm (Euterpe edulis) in a human-modified rainforest. We sampled 16 sites within five landscapes in the Brazilian Atlantic forest and assessed genetic variability and differentiation using eight microsatellite loci. Using a model selection approach, none of the covariates explained the variation observed in inbreeding coefficients among populations. The variation in genetic diversity among sites was best explained by historical effective population size. Allelic richness was best explained by historical effective population size and matrix resistance, whereas genetic differentiation was explained by matrix resistance. Coalescence analysis revealed high historical migration between sites within landscapes and constant historical population sizes, showing that the genetic differentiation is most likely due to recent changes caused by habitat loss and fragmentation. Overall, recent landscape changes have a greater influence on among-population genetic variation than historical gene flow process. As immediate restoration actions in landscapes with low forest amount, the development of more permeable matrices to allow the movement of pollinators and seed dispersers may be an effective strategy to maintain microevolutionary processes. PMID:25873150

Genetic patterns of habitat fragmentation and past climate-change effects in the Mediterranean high-mountain plant Armeria caespitosa (Plumbaginaceae).

PubMed

García-Fernández, Alfredo; Iriondo, Jose M; Escudero, Adrián; Aguilar, Javier Fuertes; Feliner, Gonzalo Nieto

2013-08-01

Mountain plants are among the species most vulnerable to global warming, because of their isolation, narrow geographic distribution, and limited geographic range shifts. Stochastic and selective processes can act on the genome, modulating genetic structure and diversity. Fragmentation and historical processes also have a great influence on current genetic patterns, but the spatial and temporal contexts of these processes are poorly known. We aimed to evaluate the microevolutionary processes that may have taken place in Mediterranean high-mountain plants in response to changing historical environmental conditions. Genetic structure, diversity, and loci under selection were analyzed using AFLP markers in 17 populations distributed over the whole geographic range of Armeria caespitosa, an endemic plant that inhabits isolated mountains (Sierra de Guadarrama, Spain). Differences in altitude, geographic location, and climate conditions were considered in the analyses, because they may play an important role in selective and stochastic processes. Bayesian clustering approaches identified nine genetic groups, although some discrepancies in assignment were found between alternative analyses. Spatially explicit analyses showed a weak relationship between genetic parameters and spatial or environmental distances. However, a large proportion of outlier loci were detected, and some outliers were related to environmental variables. A. caespitosa populations exhibit spatial patterns of genetic structure that cannot be explained by the isolation-by-distance model. Shifts along the altitude gradient in response to Pleistocene climatic oscillations and environmentally mediated selective forces might explain the resulting structure and genetic diversity values found.

Two-generation analysis of pollen flow across a landscape. I. Male gamete heterogeneity among females.

PubMed

Smouse, P E; Dyer, R J; Westfall, R D; Sork, V L

2001-02-01

Gene flow is a key factor in the spatial genetic structure in spatially distributed species. Evolutionary biologists interested in microevolutionary processess and conservation biologists interested in the impact of landscape change require a method that measures the real time process of gene movement. We present a novel two-generation (parent-offspring) approach to the study of genetic structure (TwoGener) that allows us to quantify heterogeneity among the male gamete pools sampled by maternal trees scattered across the landscape and to estimate mean pollination distance and effective neighborhood size. First, we describe the model's elements: genetic distance matrices to estimate intergametic distances, molecular analysis of variance to determine whether pollen profiles differ among mothers, and optimal sampling considerations. Second, we evaluate the model's effectiveness by simulating spatially distributed populations. Spatial heterogeneity in male gametes can be estimated by phiFT, a male gametic analogue of Wright's F(ST) and an inverse function of mean pollination distance. We illustrate TwoGener in cases where the male gamete can be categorically or ambiguously determined. This approach does not require the high level of genetic resolution needed by parentage analysis, but the ambiguous case is vulnerable to bias in the absence of adequate genetic resolution. Finally, we apply TwoGener to an empirical study of Quercus alba in Missouri Ozark forests. We find that phiFT = 0.06, translating into about eight effective pollen donors per female and an effective pollination neighborhood as a circle of radius about 17 m. Effective pollen movement in Q. alba is more restricted than previously realized, even though pollen is capable of moving large distances. This case study illustrates that, with a modest investment in field survey and laboratory analysis, the TwoGener approach permits inferences about landscape-level gene movements.

Environment-dependent microevolution in a Mediterranean pine (Pinus pinaster Aiton).

PubMed

Alía, Ricardo; Chambel, Regina; Notivol, Eduardo; Climent, José; González-Martínez, Santiago C

2014-09-23

A central question for understanding the evolutionary responses of plant species to rapidly changing environments is the assessment of their potential for short-term (in one or a few generations) genetic change. In our study, we consider the case of Pinus pinaster Aiton (maritime pine), a widespread Mediterranean tree, and (i) test, under different experimental conditions (growth chamber and semi-natural), whether higher recruitment in the wild from the most successful mothers is due to better performance of their offspring; and (ii) evaluate genetic change in quantitative traits across generations at two different life stages (mature trees and seedlings) that are known to be under strong selection pressure in forest trees. Genetic control was high for most traits (h2 = 0.137-0.876) under the milder conditions of the growth chamber, but only for ontogenetic change (0.276), total height (0.415) and survival (0.719) under the more stressful semi-natural conditions. Significant phenotypic selection gradients were found in mature trees for traits related to seed quality (germination rate and number of empty seeds). Moreover, female relative reproductive success was significantly correlated with offspring performance for specific leaf area (SLA) in the growth chamber experiment, and stem mass fraction (SMF) in the experiment under semi-natural conditions, two adaptive traits related to abiotic stress-response in pines. Selection gradients based on genetic covariance of seedling traits and responses to selection at this stage involved traits related to biomass allocation (SMF) and growth (as decomposed by a Gompertz model) or delayed ontogenetic change, depending also on the testing environment. Despite the evidence of microevolutionary change in adaptive traits in maritime pine, directional or disruptive changes are difficult to predict due to variable selection at different life stages and environments. At mature-tree stages, higher female effective reproductive success can be explained by differences in their production of offspring (due to seed quality) and, to a lesser extent, by seemingly better adapted seedlings. Selection gradients and responses to selection for seedlings also differed across experimental conditions. The distinct processes involved at the two life stages (mature trees or seedlings) together with environment-specific responses advice caution when predicting likely evolutionary responses to environmental change in Mediterranean forest trees.

Late Neandertals in Southeastern Iberia: Sima de las Palomas del Cabezo Gordo, Murcia, Spain

PubMed Central

Walker, Michael J.; Gibert, Josep; López, Mariano V.; Lombardi, A. Vincent; Pérez-Pérez, Alejandro; Zapata, Josefina; Ortega, Jon; Higham, Thomas; Pike, Alistair; Schwenninger, Jean-Luc; Zilhão, João; Trinkaus, Erik

2008-01-01

Middle Paleolithic fossil human remains from the Sima de las Palomas in southeastern Iberia (dated to ≤43,000–40,000 calendar years before present) present a suite of derived Neandertal and/or retained ancestral morphological features in the mandibular symphysis, mandibular ramus, dental occlusal morphology, and distal hand phalanx. These traits are combined with variation in the mandibular corpus, discrete dental morphology, tooth root lengths, and anterior dental size that indicate a frequency difference with earlier Iberian and more northern European Neandertals. The Palomas Neandertals therefore confirm the late presence of Neandertals associated with the Iberian persistence of the Middle Paleolithic, but suggest microevolutionary processes and/or population contact with contemporaneous modern humans to the north. PMID:19074275

Does ecological specialization transcend scale? Habitat partitioning among individuals and species of Anolis lizards.

PubMed

Kamath, Ambika; Losos, Jonathan B

2017-03-01

Ecological specialization is common across all levels of biological organization, raising the question of whether the evolution of specialization at one scale in a taxon is linked to specialization at other scales. Anolis lizards have diversified repeatedly along axes of habitat use, but it remains unknown if this diversification into habitat use specialists is underlain by individual specialization. From repeated observations of individuals in a population of Anolis sagrei in Florida, we show that the extent of habitat use specialization among individuals is comparable to the extent of specialization in the same traits among ten sympatric Anolis habitat specialist species in Cuba. However, the adaptive correlations between habitat use and morphology commonly seen across species of Anolis were not observed across individuals in the sampled population. Our results therefore suggest that while patterns of ecological specialization can transcend scale, these parallels are the consequence of distinct ecological processes acting at microevolutionary and macroevolutionary scales. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

Ephemeral ecological speciation and the latitudinal biodiversity gradient.

PubMed

Cutter, Asher D; Gray, Jeremy C

2016-10-01

The richness of biodiversity in the tropics compared to high-latitude parts of the world forms one of the most globally conspicuous patterns in biology, and yet few hypotheses aim to explain this phenomenon in terms of explicit microevolutionary mechanisms of speciation and extinction. We link population genetic processes of selection and adaptation to speciation and extinction by way of their interaction with environmental factors to drive global scale macroecological patterns. High-latitude regions are both cradle and grave with respect to species diversification. In particular, we point to a conceptual equivalence of "environmental harshness" and "hard selection" as eco-evolutionary drivers of local adaptation and ecological speciation. By describing how ecological speciation likely occurs more readily at high latitudes, with such nascent species especially prone to extinction by fusion, we derive the ephemeral ecological speciation hypothesis as an integrative mechanistic explanation for latitudinal gradients in species turnover and the net accumulation of biodiversity. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

Pollinators exert natural selection on flower size and floral display in Penstemon digitalis.

PubMed

Parachnowitsch, Amy L; Kessler, André

2010-10-01

• A major gap in our understanding of floral evolution, especially micro-evolutionary processes, is the role of pollinators in generating patterns of natural selection on floral traits. Here we explicitly tested the role of pollinators in selecting floral traits in a herbaceous perennial, Penstemon digitalis. • We manipulated the effect of pollinators on fitness through hand pollinations and compared phenotypic selection in open- and hand-pollinated plants. • Despite the lack of pollen limitation in our population, pollinators mediated selection on floral size and floral display. Hand pollinations removed directional selection for larger flowers and stabilizing selection on flower number, suggesting that pollinators were the agents of selection on both of these traits. • We reviewed studies that measured natural selection on floral traits by biotic agents and generally found stronger signatures of selection imposed by pollinators than by herbivores and co-flowering plant species. © The Authors (2010). Journal compilation © New Phytologist Trust (2010).

Genomic regions controlling shape variation in the first upper molar of the house mouse

PubMed Central

Pantalacci, Sophie; Turner, Leslie M; Steingrimsson, Eirikur; Renaud, Sabrina

2017-01-01

Numerous loci of large effect have been shown to underlie phenotypic variation between species. However, loci with subtle effects are presumably more frequently involved in microevolutionary processes but have rarely been discovered. We explore the genetic basis of shape variation in the first upper molar of hybrid mice between Mus musculus musculus and M. m. domesticus. We performed the first genome-wide association study for molar shape and used 3D surface morphometrics to quantify subtle variation between individuals. We show that many loci of small effect underlie phenotypic variation, and identify five genomic regions associated with tooth shape; one region contained the gene microphthalmia-associated transcription factor Mitf that has previously been associated with tooth malformations. Using a panel of five mutant laboratory strains, we show the effect of the Mitf gene on tooth shape. This is the first report of a gene causing subtle but consistent variation in tooth shape resembling variation in nature. PMID:29091026

A population genetics perspective on the determinants of intra-tumor heterogeneity

PubMed Central

Hu, Zheng; Sun, Ruping; Curtis, Christina

2017-01-01

Cancer results from the acquisition of somatic alterations in a microevolutionary process that typically occurs over many years, much of which is occult. Understanding the evolutionary dynamics that are operative at different stages of progression in individual tumors might inform the earlier detection, diagnosis, and treatment of cancer. Although these processes cannot be directly observed, the resultant spatiotemporal patterns of genetic variation amongst tumor cells encode their evolutionary histories. Such intra-tumor heterogeneity is pervasive not only at the genomic level, but also at the transcriptomic, phenotypic, and cellular levels. Given the implications for precision medicine, the accurate quantification of heterogeneity within and between tumors has become a major focus of current research. In this review, we provide a population genetics perspective on the determinants of intra-tumor heterogeneity and approaches to quantify genetic diversity. We summarize evidence for different modes of evolution based on recent cancer genome sequencing studies and discuss emerging evolutionary strategies to therapeutically exploit tumor heterogeneity. PMID:28274726

Extraordinarily rapid life-history divergence between Cryptasterina sea star species.

PubMed

Puritz, Jonathan B; Keever, Carson C; Addison, Jason A; Byrne, Maria; Hart, Michael W; Grosberg, Richard K; Toonen, Robert J

2012-10-07

Life history plays a critical role in governing microevolutionary processes such as gene flow and adaptation, as well as macroevolutionary processes such speciation. Here, we use multilocus phylogeographic analyses to examine a speciation event involving spectacular life-history differences between sister species of sea stars. Cryptasterina hystera has evolved a suite of derived life-history traits (including internal self-fertilization and brood protection) that differ from its sister species Cryptasterina pentagona, a gonochoric broadcast spawner. We show that these species have only been reproductively isolated for approximately 6000 years (95% highest posterior density of 905-22 628), and that this life-history change may be responsible for dramatic genetic consequences, including low nucleotide diversity, zero heterozygosity and no gene flow. The rapid divergence of these species rules out some mechanisms of isolation such as adaptation to microhabitats in sympatry, or slow divergence by genetic drift during prolonged isolation. We hypothesize that the large phenotypic differences between species relative to the short divergence time suggests that the life-history differences observed may be direct responses to disruptive selection between populations. We speculate that local environmental or demographic differences at the southern range margin are possible mechanisms of selection driving one of the fastest known marine speciation events.

Mosaic evolution and the pattern of transitions in the hominin lineage

PubMed Central

Foley, Robert A.

2016-01-01

Humans are uniquely unique, in terms of the extreme differences between them and other living organisms, and the impact they are having on the biosphere. The evolution of humans can be seen, as has been proposed, as one of the major transitions in evolution, on a par with the origins of multicellular organisms or the eukaryotic cell (Maynard Smith & Szathmáry 1997 Major transitions in evolution). Major transitions require the evolution of greater complexity and the emergence of new evolutionary levels or processes. Does human evolution meet these conditions? I explore the diversity of evidence on the nature of transitions in human evolution. Four levels of transition are proposed—baseline, novel taxa, novel adaptive zones and major transitions—and the pattern of human evolution considered in the light of these. The primary conclusions are that changes in human evolution occur continuously and cumulatively; that novel taxa and the appearance of new adaptations are not clustered very tightly in particular periods, although there are three broad transitional phases (Pliocene, Plio-Pleistocene and later Quaternary). Each phase is distinctive, with the first based on ranging and energetics, the second on technology and niche expansion, and the third on cognition and cultural processes. I discuss whether this constitutes a ‘major transition’ in the context of the evolutionary processes more broadly; the role of behaviour in evolution; and the opportunity provided by the rich genetic, phenotypic (fossil morphology) and behavioural (archaeological) record to examine in detail major transitions and the microevolutionary patterns underlying macroevolutionary change. It is suggested that the evolution of the hominin lineage is consistent with a mosaic pattern of change. This article is part of the themed issue ‘Major transitions in human evolution’. PMID:27298474

Mosaic evolution and the pattern of transitions in the hominin lineage.

PubMed

Foley, Robert A

2016-07-05

Humans are uniquely unique, in terms of the extreme differences between them and other living organisms, and the impact they are having on the biosphere. The evolution of humans can be seen, as has been proposed, as one of the major transitions in evolution, on a par with the origins of multicellular organisms or the eukaryotic cell (Maynard Smith & Szathmáry 1997 Major transitions in evolution). Major transitions require the evolution of greater complexity and the emergence of new evolutionary levels or processes. Does human evolution meet these conditions? I explore the diversity of evidence on the nature of transitions in human evolution. Four levels of transition are proposed-baseline, novel taxa, novel adaptive zones and major transitions-and the pattern of human evolution considered in the light of these. The primary conclusions are that changes in human evolution occur continuously and cumulatively; that novel taxa and the appearance of new adaptations are not clustered very tightly in particular periods, although there are three broad transitional phases (Pliocene, Plio-Pleistocene and later Quaternary). Each phase is distinctive, with the first based on ranging and energetics, the second on technology and niche expansion, and the third on cognition and cultural processes. I discuss whether this constitutes a 'major transition' in the context of the evolutionary processes more broadly; the role of behaviour in evolution; and the opportunity provided by the rich genetic, phenotypic (fossil morphology) and behavioural (archaeological) record to examine in detail major transitions and the microevolutionary patterns underlying macroevolutionary change. It is suggested that the evolution of the hominin lineage is consistent with a mosaic pattern of change.This article is part of the themed issue 'Major transitions in human evolution'. © 2016 The Author(s).

Approaches to Macroevolution: 1. General Concepts and Origin of Variation.

PubMed

Jablonski, David

2017-01-01

Approaches to macroevolution require integration of its two fundamental components, i.e. the origin and the sorting of variation, in a hierarchical framework. Macroevolution occurs in multiple currencies that are only loosely correlated, notably taxonomic diversity, morphological disparity, and functional variety. The origin of variation within this conceptual framework is increasingly understood in developmental terms, with the semi-hierarchical structure of gene regulatory networks (GRNs, used here in a broad sense incorporating not just the genetic circuitry per se but the factors controlling the timing and location of gene expression and repression), the non-linear relation between magnitude of genetic change and the phenotypic results, the evolutionary potential of co-opting existing GRNs, and developmental responsiveness to nongenetic signals (i.e. epigenetics and plasticity), all requiring modification of standard microevolutionary models, and rendering difficult any simple definition of evolutionary novelty. The developmental factors underlying macroevolution create anisotropic probabilities-i.e., an uneven density distribution-of evolutionary change around any given phenotypic starting point, and the potential for coordinated changes among traits that can accommodate change via epigenetic mechanisms. From this standpoint, "punctuated equilibrium" and "phyletic gradualism" simply represent two cells in a matrix of evolutionary models of phenotypic change, and the origin of trends and evolutionary novelty are not simply functions of ecological opportunity. Over long timescales, contingency becomes especially important, and can be viewed in terms of macroevolutionary lags (the temporal separation between the origin of a trait or clade and subsequent diversification); such lags can arise by several mechanisms: as geological or phylogenetic artifacts, or when diversifications require synergistic interactions among traits, or between traits and external events. The temporal and spatial patterns of the origins of evolutionary novelties are a challenge to macroevolutionary theory; individual events can be described retrospectively, but a general model relating development, genetics, and ecology is needed. An accompanying paper (Jablonski in Evol Biol 2017) reviews diversity dynamics and the sorting of variation, with some general conclusions.

Universal scaling in the branching of the tree of life.

PubMed

Herrada, E Alejandro; Tessone, Claudio J; Klemm, Konstantin; Eguíluz, Víctor M; Hernández-García, Emilio; Duarte, Carlos M

2008-07-23

Understanding the patterns and processes of diversification of life in the planet is a key challenge of science. The Tree of Life represents such diversification processes through the evolutionary relationships among the different taxa, and can be extended down to intra-specific relationships. Here we examine the topological properties of a large set of interspecific and intraspecific phylogenies and show that the branching patterns follow allometric rules conserved across the different levels in the Tree of Life, all significantly departing from those expected from the standard null models. The finding of non-random universal patterns of phylogenetic differentiation suggests that similar evolutionary forces drive diversification across the broad range of scales, from macro-evolutionary to micro-evolutionary processes, shaping the diversity of life on the planet.

Exploring neutral and adaptive processes in expanding populations of gilthead sea bream, Sparus aurata L., in the North-East Atlantic.

PubMed

Coscia, I; Vogiatzi, E; Kotoulas, G; Tsigenopoulos, C S; Mariani, S

2012-05-01

Recent studies in empirical population genetics have highlighted the importance of taking into account both neutral and adaptive genetic variation in characterizing microevolutionary dynamics. Here, we explore the genetic population structure and the footprints of selection in four populations of the warm-temperate coastal fish, the gilthead sea bream (Sparus aurata), whose recent northward expansion has been linked to climate change. Samples were collected at four Atlantic locations, including Spain, Portugal, France and the South of Ireland, and genetically assayed using a suite of species-specific markers, including 15 putatively neutral microsatellites and 23 expressed sequence tag-linked markers, as well as a portion of the mitochondrial DNA (mtDNA) control region. Two of the putatively neutral markers, Bld-10 and Ad-10, bore signatures of strong directional selection, particularly in the newly established Irish population, although the potential 'surfing effect' of rare alleles at the edge of the expansion front was also considered. Analyses after the removal of these loci suggest low but significant population structure likely affected by some degree of gene flow counteracting random genetic drift. No signal of historic divergence was detected at mtDNA. BLAST searches conducted with all 38 markers used failed to identify specific genomic regions associated to adaptive functions. However, the availability of genomic resources for this commercially valuable species is rapidly increasing, bringing us closer to the understanding of the interplay between selective and neutral evolutionary forces, shaping population divergence of an expanding species in a heterogeneous milieu.

When new human-modified habitats favour the expansion of an amphibian pioneer species: Evolutionary history of the natterjack toad (Bufo calamita) in a coal basin.

PubMed

Faucher, Leslie; Hénocq, Laura; Vanappelghem, Cédric; Rondel, Stéphanie; Quevillart, Robin; Gallina, Sophie; Godé, Cécile; Jaquiéry, Julie; Arnaud, Jean-François

2017-09-01

Human activities affect microevolutionary dynamics by inducing environmental changes. In particular, land cover conversion and loss of native habitats decrease genetic diversity and jeopardize the adaptive ability of populations. Nonetheless, new anthropogenic habitats can also promote the successful establishment of emblematic pioneer species. We investigated this issue by examining the population genetic features and evolutionary history of the natterjack toad (Bufo [Epidalea] calamita) in northern France, where populations can be found in native coastal habitats and coalfield habitats shaped by European industrial history, along with an additional set of European populations located outside this focal area. We predicted contrasting patterns of genetic structure, with newly settled coalfield populations departing from migration-drift equilibrium. As expected, coalfield populations showed a mosaic of genetically divergent populations with short-range patterns of gene flow, and native coastal populations indicated an equilibrium state with an isolation-by-distance pattern suggestive of postglacial range expansion. However, coalfield populations exhibited (i) high levels of genetic diversity, (ii) no evidence of local inbreeding or reduced effective population size and (iii) multiple maternal mitochondrial lineages, a genetic footprint depicting independent colonization events. Furthermore, approximate Bayesian computations suggested several evolutionary trajectories from ancient isolation in glacial refugia during the Pleistocene, with biogeographical signatures of recent expansion probably confounded by human-mediated mixing of different lineages. From an evolutionary and conservation perspective, this study highlights the ecological value of industrial areas, provided that ongoing regional gene flow is ensured within the existing lineage boundaries. © 2017 John Wiley & Sons Ltd.

DNA Mutations Mediate Microevolution between Host-Adapted Forms of the Pathogenic Fungus Cryptococcus neoformans

PubMed Central

Magditch, Denise A.; Liu, Tong-Bao; Xue, Chaoyang; Idnurm, Alexander

2012-01-01

The disease cryptococcosis, caused by the fungus Cryptococcus neoformans, is acquired directly from environmental exposure rather than transmitted person-to-person. One explanation for the pathogenicity of this species is that interactions with environmental predators select for virulence. However, co-incubation of C. neoformans with amoeba can cause a “switch” from the normal yeast morphology to a pseudohyphal form, enabling fungi to survive exposure to amoeba, yet conversely reducing virulence in mammalian models of cryptococcosis. Like other human pathogenic fungi, C. neoformans is capable of microevolutionary changes that influence the biology of the organism and outcome of the host-pathogen interaction. A yeast-pseudohyphal phenotypic switch also happens under in vitro conditions. Here, we demonstrate that this morphological switch, rather than being under epigenetic control, is controlled by DNA mutation since all pseudohyphal strains bear mutations within genes encoding components of the RAM pathway. High rates of isolation of pseudohyphal strains can be explained by the physical size of RAM pathway genes and a hypermutator phenotype of the strain used in phenotypic switching studies. Reversion to wild type yeast morphology in vitro or within a mammalian host can occur through different mechanisms, with one being counter-acting mutations. Infection of mice with RAM mutants reveals several outcomes: clearance of the infection, asymptomatic maintenance of the strains, or reversion to wild type forms and progression of disease. These findings demonstrate a key role of mutation events in microevolution to modulate the ability of a fungal pathogen to cause disease. PMID:23055925

Evolutionary genomics of animal personality.

PubMed

van Oers, Kees; Mueller, Jakob C

2010-12-27

Research on animal personality can be approached from both a phenotypic and a genetic perspective. While using a phenotypic approach one can measure present selection on personality traits and their combinations. However, this approach cannot reconstruct the historical trajectory that was taken by evolution. Therefore, it is essential for our understanding of the causes and consequences of personality diversity to link phenotypic variation in personality traits with polymorphisms in genomic regions that code for this trait variation. Identifying genes or genome regions that underlie personality traits will open exciting possibilities to study natural selection at the molecular level, gene-gene and gene-environment interactions, pleiotropic effects and how gene expression shapes personality phenotypes. In this paper, we will discuss how genome information revealed by already established approaches and some more recent techniques such as high-throughput sequencing of genomic regions in a large number of individuals can be used to infer micro-evolutionary processes, historical selection and finally the maintenance of personality trait variation. We will do this by reviewing recent advances in molecular genetics of animal personality, but will also use advanced human personality studies as case studies of how molecular information may be used in animal personality research in the near future.

The industrial melanism mutation in British peppered moths is a transposable element.

PubMed

Van't Hof, Arjen E; Campagne, Pascal; Rigden, Daniel J; Yung, Carl J; Lingley, Jessica; Quail, Michael A; Hall, Neil; Darby, Alistair C; Saccheri, Ilik J

2016-06-02

Discovering the mutational events that fuel adaptation to environmental change remains an important challenge for evolutionary biology. The classroom example of a visible evolutionary response is industrial melanism in the peppered moth (Biston betularia): the replacement, during the Industrial Revolution, of the common pale typica form by a previously unknown black (carbonaria) form, driven by the interaction between bird predation and coal pollution. The carbonaria locus has been coarsely localized to a 200-kilobase region, but the specific identity and nature of the sequence difference controlling the carbonaria-typica polymorphism, and the gene it influences, are unknown. Here we show that the mutation event giving rise to industrial melanism in Britain was the insertion of a large, tandemly repeated, transposable element into the first intron of the gene cortex. Statistical inference based on the distribution of recombined carbonaria haplotypes indicates that this transposition event occurred around 1819, consistent with the historical record. We have begun to dissect the mode of action of the carbonaria transposable element by showing that it increases the abundance of a cortex transcript, the protein product of which plays an important role in cell-cycle regulation, during early wing disc development. Our findings fill a substantial knowledge gap in the iconic example of microevolutionary change, adding a further layer of insight into the mechanism of adaptation in response to natural selection. The discovery that the mutation itself is a transposable element will stimulate further debate about the importance of 'jumping genes' as a source of major phenotypic novelty.

The maximum rate of mammal evolution

NASA Astrophysics Data System (ADS)

Evans, Alistair R.; Jones, David; Boyer, Alison G.; Brown, James H.; Costa, Daniel P.; Ernest, S. K. Morgan; Fitzgerald, Erich M. G.; Fortelius, Mikael; Gittleman, John L.; Hamilton, Marcus J.; Harding, Larisa E.; Lintulaakso, Kari; Lyons, S. Kathleen; Okie, Jordan G.; Saarinen, Juha J.; Sibly, Richard M.; Smith, Felisa A.; Stephens, Patrick R.; Theodor, Jessica M.; Uhen, Mark D.

2012-03-01

How fast can a mammal evolve from the size of a mouse to the size of an elephant? Achieving such a large transformation calls for major biological reorganization. Thus, the speed at which this occurs has important implications for extensive faunal changes, including adaptive radiations and recovery from mass extinctions. To quantify the pace of large-scale evolution we developed a metric, clade maximum rate, which represents the maximum evolutionary rate of a trait within a clade. We applied this metric to body mass evolution in mammals over the last 70 million years, during which multiple large evolutionary transitions occurred in oceans and on continents and islands. Our computations suggest that it took a minimum of 1.6, 5.1, and 10 million generations for terrestrial mammal mass to increase 100-, and 1,000-, and 5,000-fold, respectively. Values for whales were down to half the length (i.e., 1.1, 3, and 5 million generations), perhaps due to the reduced mechanical constraints of living in an aquatic environment. When differences in generation time are considered, we find an exponential increase in maximum mammal body mass during the 35 million years following the Cretaceous-Paleogene (K-Pg) extinction event. Our results also indicate a basic asymmetry in macroevolution: very large decreases (such as extreme insular dwarfism) can happen at more than 10 times the rate of increases. Our findings allow more rigorous comparisons of microevolutionary and macroevolutionary patterns and processes.

Genotypic effects of elevated CO[sub 2] on fecundity in an annual weed (wild radish, Raphanus raphanistrum)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Curtis, P.S.; Snow, A.A.

1993-06-01

Rising atmospheric CO[sub 2] levels may lead to microevolutionary change in native plant populations. To test for within-population variation in genetic responses to elevated p(CO[sub 2]), we exposed five paternal sibships of wild radish to ambient and 2X ambient (700 [mu]bar) p(CO[sub 2]) in 3 m open top chambers for an entre growing season. Seeds were planted singly in 2.5 1 pots filled with locally derived, low fertility soil (160 plants per CO[sub 2] treatment). Net CO[sub 2] assimilation increased 25% in vegetative plants and 48% in reproductive plants growing at elevated p(CO[sub 2]). Every flower was hand-pollinated to mimicmore » natural pollination levels. Lifetime fecundity was greater in the elevated CO[sub 2] treatment, but the magnitude of this effect differed dramatically among paternal sibships: seed production increased 13% overall, yet among paternal sibships seed production varied between 0% and 50% more seeds in elevated p(CO[sub 2]) as compared to ambient. Our results suggest that natural selection can occur due to genotypic differences in the CO[sub 2] response. This process should be considered in estimates of long-term effects of elevated p(CO[sub 2]), especially with regard to anticipated increases in primary productivity.« less

Gene networks and developmental context: the importance of understanding complex gene expression patterns in evolution.

PubMed

Signor, Sarah A; Arbeitman, Michelle N; Nuzhdin, Sergey V

2016-05-01

Animal development is the product of distinct components and interactions-genes, regulatory networks, and cells-and it exhibits emergent properties that cannot be inferred from the components in isolation. Often the focus is on the genotype-to-phenotype map, overlooking the process of development that turns one into the other. We propose a move toward micro-evolutionary analysis of development, incorporating new tools that enable cell type resolution and single-cell microscopy. Using the sex determination pathway in Drosophila to illustrate potential avenues of research, we highlight some of the questions that these emerging technologies can address. For example, they provide an unprecedented opportunity to study heterogeneity within cell populations, and the potential to add the dimension of time to gene regulatory network analysis. Challenges still remain in developing methods to analyze this data and to increase the throughput. However this line of research has the potential to bridge the gaps between previously more disparate fields, such as population genetics and development, opening up new avenues of research. © 2016 Wiley Periodicals, Inc.

Ecological, morphological and genetic divergence of sympatric North Atlantic killer whale populations.

PubMed

Foote, Andrew D; Newton, Jason; Piertney, Stuart B; Willerslev, Eske; Gilbert, M Thomas P

2009-12-01

Ecological divergence has a central role in speciation and is therefore an important source of biodiversity. Studying the micro-evolutionary processes of ecological diversification at its early stages provides an opportunity for investigating the causative mechanisms and ecological conditions promoting divergence. Here we use morphological traits, nitrogen stable isotope ratios and tooth wear to characterize two disparate types of North Atlantic killer whale. We find a highly specialist type, which reaches up to 8.5 m in length and a generalist type which reaches up to 6.6 m in length. There is a single fixed genetic difference in the mtDNA control region between these types, indicating integrity of groupings and a shallow divergence. Phylogenetic analysis indicates this divergence is independent of similar ecological divergences in the Pacific and Antarctic. Niche-width in the generalist type is more strongly influenced by between-individual variation rather than within-individual variation in the composition of the diet. This first step to divergent specialization on different ecological resources provides a rare example of the ecological conditions at the early stages of adaptive radiation.

Molecular hyperdiversity and evolution in very large populations.

PubMed

Cutter, Asher D; Jovelin, Richard; Dey, Alivia

2013-04-01

The genomic density of sequence polymorphisms critically affects the sensitivity of inferences about ongoing sequence evolution, function and demographic history. Most animal and plant genomes have relatively low densities of polymorphisms, but some species are hyperdiverse with neutral nucleotide heterozygosity exceeding 5%. Eukaryotes with extremely large populations, mimicking bacterial and viral populations, present novel opportunities for studying molecular evolution in sexually reproducing taxa with complex development. In particular, hyperdiverse species can help answer controversial questions about the evolution of genome complexity, the limits of natural selection, modes of adaptation and subtleties of the mutation process. However, such systems have some inherent complications and here we identify topics in need of theoretical developments. Close relatives of the model organisms Caenorhabditis elegans and Drosophila melanogaster provide known examples of hyperdiverse eukaryotes, encouraging functional dissection of resulting molecular evolutionary patterns. We recommend how best to exploit hyperdiverse populations for analysis, for example, in quantifying the impact of noncrossover recombination in genomes and for determining the identity and micro-evolutionary selective pressures on noncoding regulatory elements. © 2013 Blackwell Publishing Ltd.

Music Evolution in the Laboratory: Cultural Transmission Meets Neurophysiology

PubMed Central

Lumaca, Massimo; Ravignani, Andrea; Baggio, Giosuè

2018-01-01

In recent years, there has been renewed interest in the biological and cultural evolution of music, and specifically in the role played by perceptual and cognitive factors in shaping core features of musical systems, such as melody, harmony, and rhythm. One proposal originates in the language sciences. It holds that aspects of musical systems evolve by adapting gradually, in the course of successive generations, to the structural and functional characteristics of the sensory and memory systems of learners and “users” of music. This hypothesis has found initial support in laboratory experiments on music transmission. In this article, we first review some of the most important theoretical and empirical contributions to the field of music evolution. Next, we identify a major current limitation of these studies, i.e., the lack of direct neural support for the hypothesis of cognitive adaptation. Finally, we discuss a recent experiment in which this issue was addressed by using event-related potentials (ERPs). We suggest that the introduction of neurophysiology in cultural transmission research may provide novel insights on the micro-evolutionary origins of forms of variation observed in cultural systems. PMID:29713263

Music Evolution in the Laboratory: Cultural Transmission Meets Neurophysiology.

PubMed

Lumaca, Massimo; Ravignani, Andrea; Baggio, Giosuè

2018-01-01

In recent years, there has been renewed interest in the biological and cultural evolution of music, and specifically in the role played by perceptual and cognitive factors in shaping core features of musical systems, such as melody, harmony, and rhythm. One proposal originates in the language sciences. It holds that aspects of musical systems evolve by adapting gradually, in the course of successive generations, to the structural and functional characteristics of the sensory and memory systems of learners and "users" of music. This hypothesis has found initial support in laboratory experiments on music transmission. In this article, we first review some of the most important theoretical and empirical contributions to the field of music evolution. Next, we identify a major current limitation of these studies, i.e., the lack of direct neural support for the hypothesis of cognitive adaptation. Finally, we discuss a recent experiment in which this issue was addressed by using event-related potentials (ERPs). We suggest that the introduction of neurophysiology in cultural transmission research may provide novel insights on the micro-evolutionary origins of forms of variation observed in cultural systems.

RAPD variation and population genetic structure of Physalaemus cuvieri (Anura: Leptodactylidae) in Central Brazil.

PubMed

Telles, Mariana Pires de Campos; Bastos, Rogério Pereira; Soares, Thannya Nascimento; Resende, Lucileide Vilela; Diniz-Filho, José Alexandre Felizola

2006-01-01

Studies about the organization of the genetic variability and population structure in natural populations are used either to understand microevolutionary processes or the effects of isolation by human-inducted landscape modifications. In this paper, we analyzed patterns of genetic population structure using 126 RAPD loci scored for 214 individuals of Physalaemus cuvieri, sampled from 18 local populations. Around 97% of these loci were polymorphic. The among-population variation component (Phi(ST)) obtained by AMOVA was equal to 0.101 and theta B obtained using a Bayesian approach for dominant markers was 0.103. Genetic divergence, analyzed by Mantel spatial correlogram, revealed only a short-distance significant correlation between genetic and geographic distances. This is expected if low levels of population differentiation, due to high abundance buffering the effect of stochastic processes, are combined with low spatially restricted gene flow. Although this may be consistent with the current knowledge of species' biology, the spatial distribution of local populations observed in this study also suggest that, at least in part, recent human occupation and habitat fragmentation may also explain part of the interpopulational component of the genetic variation.

Boltzmann, Darwin and Directionality theory

NASA Astrophysics Data System (ADS)

Demetrius, Lloyd A.

2013-09-01

Boltzmann’s statistical thermodynamics is a mathematical theory which relates the macroscopic properties of aggregates of interacting molecules with the laws of their interaction. The theory is based on the concept thermodynamic entropy, a statistical measure of the extent to which energy is spread throughout macroscopic matter. Macroscopic evolution of material aggregates is quantitatively explained in terms of the principle: Thermodynamic entropy increases as the composition of the aggregate changes under molecular collision. Darwin’s theory of evolution is a qualitative theory of the origin of species and the adaptation of populations to their environment. A central concept in the theory is fitness, a qualitative measure of the capacity of an organism to contribute to the ancestry of future generations. Macroscopic evolution of populations of living organisms can be qualitatively explained in terms of a neo-Darwinian principle: Fitness increases as the composition of the population changes under variation and natural selection. Directionality theory is a quantitative model of the Darwinian argument of evolution by variation and selection. This mathematical theory is based on the concept evolutionary entropy, a statistical measure which describes the rate at which an organism appropriates energy from the environment and reinvests this energy into survivorship and reproduction. According to directionality theory, microevolutionary dynamics, that is evolution by mutation and natural selection, can be quantitatively explained in terms of a directionality principle: Evolutionary entropy increases when the resources are diverse and of constant abundance; but decreases when the resource is singular and of variable abundance. This report reviews the analytical and empirical support for directionality theory, and invokes the microevolutionary dynamics of variation and selection to delineate the principles which govern macroevolutionary dynamics of speciation and extinction. We also elucidate the relation between thermodynamic entropy, which pertains to the extent of energy spreading and sharing within inanimate matter, and evolutionary entropy, which refers to the rate of energy appropriation from the environment and allocation within living systems. We show that the entropic principle of thermodynamics is the limit as R→0, M→∞, (where R denote the resource production rate, and M denote population size) of the entropic principle of evolution. We exploit this relation between the thermodynamic and evolutionary tenets to propose a physico-chemical model of the transition from inanimate matter which is under thermodynamic selection, to living systems which are subject to evolutionary selection. Life history variation and the evolution of senescence The evolutionary dynamics of speciation and extinction Evolutionary trends in body size. The origin of sporadic forms of cancer and neurological diseases, and the evolution of cooperation are important recent applications of directionality theory. These applications, which draw from the medical sciences and sociobiology, appeal to methods which lie outside the formalism described in this report. A companion review, Demetrius and Gundlach (submitted for publication), gives an account of these applications.An important aspect of this report pertains to the connection between statistical mechanics and evolutionary theory and its implications towards understanding the processes which underlie the emergence of living systems from inanimate matter-a problem which has recently attracted considerable attention, Morowitz (1992), Eigen (1992), Dyson (2000), Pross (2012).The connection between the two disciplines can be addressed by appealing to certain extremal principles which are considered the mainstay of the respective theories.The extremal principle in statistical mechanics can be stated as follows:

Life-history evolution and the microevolution of intermediary metabolism: activities of lipid-metabolizing enzymes in life-history morphs of a wing-dimorphic cricket.

PubMed

Zera, Anthony J; Zhao, Zhangwu

2003-03-01

Although a considerable amount of information is available on the ecology, genetics, and physiology of life-history traits, much more limited data are available on the biochemical and genetic correlates of life-history variation within species. Specific activities of five enzymes of lipid biosynthesis and two enzymes of amino acid catabolism were compared among lines selected for flight-capable (LW[f]) versus flightless (SW) morphs of the cricket Gryllus firmus. These morphs, which exist in natural populations, differ genetically in ovarian growth (100-400% higher in SW) and aspects of flight capability including the size of wings and flight muscles, and the concentration of triglyceride flight fuel (40% greater in LW[f]). Consistently higher activity of each enzyme in LW(f) versus SW-selected lines, and strong co-segregation between morph and enzyme activity, demonstrated genetically based co-variance between wing morph and enzyme activity. Developmental profiles of enzyme activities strongly paralleled profiles of triglyceride accumulation during adulthood and previous measures of in vivo lipid biosynthesis. These data strongly imply that genetically based elevation in activities of lipogenic enzymes, and enzymes controlling the conversion of amino acids into lipids, is an important cause underlying the elevated accumulation of triglyceride in the LW(f) morph, a key biochemical component of the trade-off between elevated early fecundity and flight capability. Global changes in lipid and amino-acid metabolism appear to have resulted from microevolutionary alteration of regulators of metabolism. Finally, strong genotype x environment (diet) interactions were observed for most enzyme activities. Future progress in understanding the functional causes of life-history evolution requires a more detailed synthesis of the fields of life-history evolution and metabolic biochemistry. Wing polymorphism is a powerful experimental model in such integrative studies.

The genetic profile of susceptibility to infectious diseases in Roman-Period populations from Central Poland.

PubMed

Lewandowska, Magda; Jędrychowska-Dańska, Krystyna; Zamerska, Alicja; Płoszaj, Tomasz; Witas, Henryk W

2017-01-01

For thousands of years human beings have resisted life-threatening pathogens. This ongoing battle is considered to be the major force shaping our gene pool as every micro-evolutionary process provokes specific shifts in the genome, both that of the host and the pathogen. Past populations were more susceptible to changes in allele frequencies not only due to selection pressure, but also as a result of genetic drift, migration and inbreeding. In the present study we have investigated the frequency of five polymorphisms within innate immune-response genes (SLC11A1 D543N, MBL2 G161A, P2RX7 A1513C, IL10 A-1082G, TLR2 -196 to -174 ins/del) related to susceptibility to infections in humans. The DNA of individuals from two early Roman-Period populations of Linowo and Rogowo was analysed. The distribution of three mutations varied significantly when compared to the modern Polish population. The TAFT analysis suggests that the decreased frequency of SLC11A1 D543N in modern Poles as compared to 2nd century Linowo samples is the result of non-stochastic mechanisms, such as purifying or balancing selection. The disparity in frequency of other mutations is most likely the result of genetic drift, an evolutionary force which is remarkably amplified in low-size groups. Together with the F ST analysis, mtDNA haplotypes' distribution and deviation from the Hardy-Weinberg equilibrium, we suggest that the two populations were not interbreeding (despite the close proximity between them), but rather inbreeding, the results of which are particularly pronounced among Rogowo habitants. Copyright © 2016 Elsevier B.V. All rights reserved.

Testing for a genetic response to sexual selection in a wild Drosophila population.

PubMed

Gosden, T P; Thomson, J R; Blows, M W; Schaul, A; Chenoweth, S F

2016-06-01

In accordance with the consensus that sexual selection is responsible for the rapid evolution of display traits on macroevolutionary scales, microevolutionary studies suggest sexual selection is a widespread and often strong form of directional selection in nature. However, empirical evidence for the contemporary evolution of sexually selected traits via sexual rather than natural selection remains weak. In this study, we used a novel application of quantitative genetic breeding designs to test for a genetic response to sexual selection on eight chemical display traits from a field population of the fly, Drosophila serrata. Using our quantitative genetic approach, we were able to detect a genetically based difference in means between groups of males descended from fathers who had either successfully sired offspring or were randomly collected from the same wild population for one of these display traits, the diene (Z,Z)-5,9-C27 : 2 . Our experimental results, in combination with previous laboratory studies on this system, suggest that both natural and sexual selection may be influencing the evolutionary trajectories of these traits in nature, limiting the capacity for a contemporary evolutionary response. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

The Pattern of Genetic Variability in Apomictic Clones of Taraxacum officinale Indicates the Alternation of Asexual and Sexual Histories of Apomicts

PubMed Central

Majeský, Ľuboš; Vašut, Radim J.; Kitner, Miloslav; Trávníček, Bohumil

2012-01-01

Dandelions (genus Taraxacum) comprise a group of sexual diploids and apomictic polyploids with a complicated reticular evolution. Apomixis (clonal reproduction through seeds) in this genus is considered to be obligate, and therefore represent a good model for studying the role of asexual reproduction in microevolutionary processes of apomictic genera. In our study, a total of 187 apomictic individuals composing a set of nine microspecies (sampled across wide geographic area in Europe) were genotyped for six microsatellite loci and for 162 amplified fragment length polymorphism (AFLP) markers. Our results indicated that significant genetic similarity existed within accessions with low numbers of genotypes. Genotypic variability was high among accessions but low within accessions. Clustering methods discriminated individuals into nine groups corresponding to their phenotypes. Furthermore, two groups of apomictic genotypes were observed, which suggests that they had different asexual histories. A matrix compatibility test suggests that most of the variability within accession groups was mutational in origin. However, the presence of recombination was also detected. The accumulation of mutations in asexual clones leads to the establishment of a network of clone mates. However, this study suggests that the clones primarily originated from the hybridisation between sexual and apomicts. PMID:22870257

Elastic, not plastic species: frozen plasticity theory and the origin of adaptive evolution in sexually reproducing organisms.

PubMed

Flegr, Jaroslav

2010-01-13

Darwin's evolutionary theory could easily explain the evolution of adaptive traits (organs and behavioral patterns) in asexual but not in sexual organisms. Two models, the selfish gene theory and frozen plasticity theory were suggested to explain evolution of adaptive traits in sexual organisms in past 30 years. The frozen plasticity theory suggests that sexual species can evolve new adaptations only when their members are genetically uniform, i.e. only after a portion of the population of the original species had split off, balanced on the edge of extinction for several generations, and then undergone rapid expansion. After a short period of time, estimated on the basis of paleontological data to correspond to 1-2% of the duration of the species, polymorphism accumulates in the gene pool due to frequency-dependent selection; and thus, in each generation, new mutations occur in the presence of different alleles and therefore change their selection coefficients from generation to generation. The species ceases to behave in an evolutionarily plastic manner and becomes evolutionarily elastic on a microevolutionary time-scale and evolutionarily frozen on a macroevolutionary time-scale. It then exists in this state until such changes accumulate in the environment that the species becomes extinct. Frozen plasticity theory, which includes the Darwinian model of evolution as a special case--the evolution of species in a plastic state, not only offers plenty of new predictions to be tested, but also provides explanations for a much broader spectrum of known biological phenomena than classic evolutionary theories. This article was reviewed by Rob Knight, Fyodor Kondrashov and Massimo Di Giulio (nominated by David H. Ardell).

Mitochondrial genomes and avian phylogeny: complex characters and resolvability without explosive radiations.

PubMed

Gibb, Gillian C; Kardailsky, Olga; Kimball, Rebecca T; Braun, Edward L; Penny, David

2007-01-01

We improve the taxon sampling for avian phylogeny by analyzing 7 new mitochondrial genomes (a toucan, woodpecker, osprey, forest falcon, American kestrel, heron, and a pelican). This improves inference of the avian tree, and it supports 3 major conclusions. The first is that some birds (including a parrot, a toucan, and an osprey) exhibit a complete duplication of the control region (CR) meaning that there are at least 4 distinct gene orders within birds. However, it appears that there are regions of continued gene conversion between the duplicate CRs, resulting in duplications that can be stable for long evolutionary periods. Because of this stable duplicated state, gene order can eventually either revert to the original order or change to the new gene order. The existence of this stable duplicate state explains how an apparently unlikely event (finding the same novel gene order) can arise multiple times. Although rare genomic changes have theoretical advantages for tree reconstruction, they can be compromised if these apparently rare events have a stable intermediate state. Secondly, the toucan and woodpecker improve the resolution of the 6-way split within Neoaves that has been called an "explosive radiation." An explosive radiation implies that normal microevolutionary events are insufficient to explain the observed macroevolution. By showing the avian tree is, in principle, resolvable, we demonstrate that the radiation of birds is amenable to standard evolutionary analysis. Thirdly, and as expected from theory, additional taxa breaking up long branches stabilize the position of some problematic taxa (like the falcon). In addition, we report that within the birds of prey and allies, we did not find evidence pairing New World vultures with storks or accipitrids (hawks, eagles, and osprey) with Falconids.

Quantitative complete tooth variation among east Asians and Native Americans: developmental biology as a tool for the assessment of human divergence.

PubMed

Shields, E D

1996-01-01

The quantification of total tooth structure derived from X-rays of Vietnamese, Southern Chinese, Mongolians, Western Eskimos, and Peruvian pre-Inca (Huari Empire) populations was used to examine dental divergence and the morphogenetics of change. Multivariate derived distances between the samples helped identify a quasicontinuous web of ethnic groups with two binary clusters ensconced within the web. One cluster was composed of Mongolians, Western Eskimos, and pre-Inca, and the other group consisted of the Southern Chinese and Vietnamese. Mongolians entered the quasicontinuum from a divergent angle (externally influenced) from that of the Southeast Asians. The Chinese and pre-Inca formed the polar samples of the distance superstructure. The pre-Inca sample was the most isolated, its closest neighbor being the Western Eskimos. Univariate and multivariate analyses suggested that the pre-Inca, whose ancestors arrived in America perhaps approximately 30,000 years ago, was the least derived sample. Clearly, microevolutionary change occurred among the samples, but the dental phenotype was resistant to environmental developmental perturbations. An assessment of dental divergence and developmental biology suggested that the overall dental phenotype is a complex multigenic morphological character, and that the observed variation evolved through total genomic drift. The quantified dental phenotype is greater than its highly multigenic algorithm and its development homeostasis is tightly controlled, or canalized, by the deterministic organization of a complex nonlinear epigenetic milieu. The overall dental phenotype quantified here was selectively neutral and a good character to help reconstruct the sequence of human evolution, but if the outlying homeostatic threshold was or will be exceeded in antecedents and descendants, respectively, evolutionary saltation occurs.

Microevolution of Serial Clinical Isolates of Cryptococcus neoformans var. grubii and C. gattii.

PubMed

Chen, Yuan; Farrer, Rhys A; Giamberardino, Charles; Sakthikumar, Sharadha; Jones, Alexander; Yang, Timothy; Tenor, Jennifer L; Wagih, Omar; Van Wyk, Marelize; Govender, Nelesh P; Mitchell, Thomas G; Litvintseva, Anastasia P; Cuomo, Christina A; Perfect, John R

2017-03-07

The pathogenic species of Cryptococcus are a major cause of mortality owing to severe infections in immunocompromised as well as immunocompetent individuals. Although antifungal treatment is usually effective, many patients relapse after treatment, and in such cases, comparative analyses of the genomes of incident and relapse isolates may reveal evidence of determinative, microevolutionary changes within the host. Here, we analyzed serial isolates cultured from cerebrospinal fluid specimens of 18 South African patients with recurrent cryptococcal meningitis. The time between collection of the incident isolates and collection of the relapse isolates ranged from 124 days to 290 days, and the analyses revealed that, during this period within the patients, the isolates underwent several genetic and phenotypic changes. Considering the vast genetic diversity of cryptococcal isolates in sub-Saharan Africa, it was not surprising to find that the relapse isolates had acquired different genetic and correlative phenotypic changes. They exhibited various mechanisms for enhancing virulence, such as growth at 39°C, adaptation to stress, and capsule production; a remarkable amplification of ERG11 at the native and unlinked locus may provide stable resistance to fluconazole. Our data provide a deeper understanding of the microevolution of Cryptococcus species under pressure from antifungal chemotherapy and host immune responses. This investigation clearly suggests a promising strategy to identify novel targets for improved diagnosis, therapy, and prognosis. IMPORTANCE Opportunistic infections caused by species of the pathogenic yeast Cryptococcus lead to chronic meningoencephalitis and continue to ravage thousands of patients with HIV/AIDS. Despite receiving antifungal treatment, over 10% of patients develop recurrent disease. In this study, we collected isolates of Cryptococcus from cerebrospinal fluid specimens of 18 patients at the time of their diagnosis and when they relapsed several months later. We then sequenced and compared the genomic DNAs of each pair of initial and relapse isolates. We also tested the isolates for several key properties related to cryptococcal virulence as well as for their susceptibility to the antifungal drug fluconazole. These analyses revealed that the relapsing isolates manifested multiple genetic and chromosomal changes that affected a variety of genes implicated in the pathogenicity of Cryptococcus or resistance to fluconazole. This application of comparative genomics to serial clinical isolates provides a blueprint for identifying the mechanisms whereby pathogenic microbes adapt within patients to prolong disease. Copyright © 2017 Chen et al.

Assessing Students' Understanding of Macroevolution: Concerns regarding the validity of the MUM

NASA Astrophysics Data System (ADS)

Novick, Laura R.; Catley, Kefyn M.

2012-11-01

In a recent article, Nadelson and Southerland (2010. Development and preliminary evaluation of the Measure of Understanding of Macroevolution: Introducing the MUM. The Journal of Experimental Education, 78, 151-190) reported on their development of a multiple-choice concept inventory intended to assess college students' understanding of macroevolutionary concepts, the Measure of Understanding Macroevolution (MUM). Given that the only existing evolution inventories assess understanding of natural selection, a microevolutionary concept, a valid assessment of students' understanding of macroevolution would be a welcome and necessary addition to the field of science education. Although the conceptual framework underlying Nadelson and Southerland's test is promising, we believe the test has serious shortcomings with respect to validity evidence for the construct being tested. We argue and provide evidence that these problems are serious enough that the MUM should not be used in its current form to measure students' understanding of macroevolution.

Hybridization Reveals the Evolving Genomic Architecture of Speciation

PubMed Central

Kronforst, Marcus R.; Hansen, Matthew E.B.; Crawford, Nicholas G.; Gallant, Jason R.; Zhang, Wei; Kulathinal, Rob J.; Kapan, Durrell D.; Mullen, Sean P.

2014-01-01

SUMMARY The rate at which genomes diverge during speciation is unknown, as are the physical dynamics of the process. Here, we compare full genome sequences of 32 butterflies, representing five species from a hybridizing Heliconius butterfly community, to examine genome-wide patterns of introgression and infer how divergence evolves during the speciation process. Our analyses reveal that initial divergence is restricted to a small fraction of the genome, largely clustered around known wing-patterning genes. Over time, divergence evolves rapidly, due primarily to the origin of new divergent regions. Furthermore, divergent genomic regions display signatures of both selection and adaptive introgression, demonstrating the link between microevolutionary processes acting within species and the origin of species across macroevolutionary timescales. Our results provide a uniquely comprehensive portrait of the evolving species boundary due to the role that hybridization plays in reducing the background accumulation of divergence at neutral sites. PMID:24183670

The pollination niche and its role in the diversification and maintenance of the southern African flora

PubMed Central

Johnson, Steven D.

2010-01-01

The flora of southern Africa has exceptional species richness and endemism, making it an ideal system for studying the patterns and processes of evolutionary diversification. Using a wealth of recent case studies, I examine the evidence for pollinator-driven diversification in this flora. Pollination systems, which represent available niches for ecological diversification, are characterized in southern Africa by a high level of ecological and evolutionary specialization on the part of plants, and, in some cases, by pollinators as well. These systems are asymmetric, with entire plant guilds commonly specialized for a particular pollinator species or functional type, resulting in obvious convergent floral evolution among guild members. Identified modes of plant lineage diversification involving adaptation to pollinators in these guilds include (i) shifts between pollination systems, (ii) divergent use of the same pollinator, (iii) coevolution, (iv) trait tracking, and (v) floral mimicry of different model species. Microevolutionary studies confirm that pollinator shifts can be precipitated when a plant species encounters a novel pollinator fauna on its range margin, and macroevolutionary studies confirm frequent pollinator shifts associated with lineage diversification. As Darwin first noted, evolutionary specialization for particular pollinators, when resulting in ecological dependency, may increase the risk of plant extinction. I thus also consider the evidence that disturbance provokes pollination failure in some southern African plants with specialized pollination systems. PMID:20047876

The pollination niche and its role in the diversification and maintenance of the southern African flora.

PubMed

Johnson, Steven D

2010-02-12

The flora of southern Africa has exceptional species richness and endemism, making it an ideal system for studying the patterns and processes of evolutionary diversification. Using a wealth of recent case studies, I examine the evidence for pollinator-driven diversification in this flora. Pollination systems, which represent available niches for ecological diversification, are characterized in southern Africa by a high level of ecological and evolutionary specialization on the part of plants, and, in some cases, by pollinators as well. These systems are asymmetric, with entire plant guilds commonly specialized for a particular pollinator species or functional type, resulting in obvious convergent floral evolution among guild members. Identified modes of plant lineage diversification involving adaptation to pollinators in these guilds include (i) shifts between pollination systems, (ii) divergent use of the same pollinator, (iii) coevolution, (iv) trait tracking, and (v) floral mimicry of different model species. Microevolutionary studies confirm that pollinator shifts can be precipitated when a plant species encounters a novel pollinator fauna on its range margin, and macroevolutionary studies confirm frequent pollinator shifts associated with lineage diversification. As Darwin first noted, evolutionary specialization for particular pollinators, when resulting in ecological dependency, may increase the risk of plant extinction. I thus also consider the evidence that disturbance provokes pollination failure in some southern African plants with specialized pollination systems.

Environmental Complexity and Biodiversity: The Multi-Layered Evolutionary History of a Log-Dwelling Velvet Worm in Montane Temperate Australia

PubMed Central

Garrick, Ryan C.; Gardner, Michael G.; Tait, Noel N.; Briscoe, David A.; Rowell, David M.; Sunnucks, Paul

2013-01-01

Phylogeographic studies provide a framework for understanding the importance of intrinsic versus extrinsic factors in shaping patterns of biodiversity through identifying past and present microevolutionary processes that contributed to lineage divergence. Here we investigate population structure and diversity of the Onychophoran (velvet worm) Euperipatoides rowelli in southeastern Australian montane forests that were not subject to Pleistocene glaciations, and thus likely retained more forest cover than systems under glaciation. Over a ~100 km transect of structurally-connected forest, we found marked nuclear and mitochondrial (mt) DNA genetic structuring, with spatially-localised groups. Patterns from mtDNA and nuclear data broadly corresponded with previously defined geographic regions, consistent with repeated isolation in refuges during Pleistocene climatic cycling. Nevertheless, some E. rowelli genetic contact zones were displaced relative to hypothesized influential landscape structures, implying more recent processes overlying impacts of past environmental history. Major impacts at different timescales were seen in the phylogenetic relationships among mtDNA sequences, which matched geographic relationships and nuclear data only at recent timescales, indicating historical gene flow and/or incomplete lineage sorting. Five major E. rowelli phylogeographic groups were identified, showing substantial but incomplete reproductive isolation despite continuous habitat. Regional distinctiveness, in the face of lineages abutting within forest habitat, could indicate pre- and/or postzygotic gene flow limitation. A potentially functional phenotypic character, colour pattern variation, reflected the geographic patterns in the molecular data. Spatial-genetic patterns broadly match those in previously-studied, co-occurring low-mobility organisms, despite a variety of life histories. We suggest that for E. rowelli, the complex topography and history of the region has led to interplay among limited dispersal ability, historical responses to environmental change, local adaptation, and some resistance to free admixture at geographic secondary contact, leading to strong genetic structuring at fine spatial scale. PMID:24358365

Drosophila sex combs as a model of evolutionary innovations.

PubMed

Kopp, Artyom

2011-01-01

The diversity of animal and plant forms is shaped by nested evolutionary innovations. Understanding the genetic and molecular changes responsible for these innovations is therefore one of the key goals of evolutionary biology. From the genetic point of view, the origin of novel traits implies the origin of new regulatory pathways to control their development. To understand how these new pathways are assembled in the course of evolution, we need model systems that combine relatively recent innovations with a powerful set of genetic and molecular tools. One such model is provided by the Drosophila sex comb-a male-specific morphological structure that evolved in a relatively small lineage related to the model species D. melanogaster. Our extensive knowledge of sex comb development in D. melanogaster provides the basis for investigating the genetic changes responsible for sex comb origin and diversification. At the same time, sex combs can change on microevolutionary timescales and differ spectacularly among closely related species, providing opportunities for direct genetic analysis and for integrating developmental and population-genetic approaches. Sex comb evolution is associated with the origin of novel interactions between Hox and sex determination genes. Activity of the sex determination pathway was brought under the control of the Hox code to become segment-specific, while Hox gene expression became sexually dimorphic. At the same time, both Hox and sex determination genes were integrated into the intrasegmental spatial patterning network, and acquired new joint downstream targets. Phylogenetic analysis shows that similar sex comb morphologies evolved independently in different lineages. Convergent evolution at the phenotypic level reflects convergent changes in the expression of Hox and sex determination genes, involving both independent gains and losses of regulatory interactions. However, the downstream cell-differentiation programs have diverged between species, and in some lineages, similar adult morphologies are produced by different morphogenetic mechanisms. These features make the sex comb an excellent model for examining not only the genetic changes responsible for its evolution, but also the cellular processes that translate DNA sequence changes into morphological diversity. The origin and diversification of sex combs provides insights into the roles of modularity, cooption, and regulatory changes in evolutionary innovations, and can serve as a model for understanding the origin of the more drastic novelties that define higher order taxa. © 2011 Wiley Periodicals, Inc.

Drosophila Sex Combs as a Model of Evolutionary Innovations

PubMed Central

Kopp, Artyom

2011-01-01

The diversity of animal and plant forms is shaped by nested evolutionary innovations. Understanding the genetic and molecular changes responsible for these innovations is therefore one of the key goals of evolutionary biology. From the genetic point of view, the origin of novel traits implies the origin of new regulatory pathways to control their development. To understand how these new pathways are assembled in the course of evolution, we need model systems that combine relatively recent innovations with a powerful set of genetic and molecular tools. One such model is provided by the Drosophila sex comb – a male-specific morphological structure that evolved in a relatively small lineage related to the model species D. melanogaster. Our extensive knowledge of sex comb development in D. melanogaster provides the basis for investigating the genetic changes responsible for sex comb origin and diversification. At the same time, sex combs can change on microevolutionary timescales and differ spectacularly among closely related species, providing opportunities for direct genetic analysis and for integrating developmental and population-genetic approaches. Sex comb evolution is associated with the origin of novel interactions between HOX and sex determination genes. Activity of the sex determination pathway was brought under the control of the HOX code to become segment-specific, while HOX gene expression became sexually dimorphic. At the same time, both HOX and sex determination genes were integrated into the intrasegmental spatial patterning network, and acquired new joint downstream targets. Phylogenetic analysis shows that similar sex comb morphologies evolved independently in different lineages. Convergent evolution at the phenotypic level reflects convergent changes in the expression of HOX and sex determination genes, involving both independent gains and losses of regulatory interactions. However, the downstream cell differentiation programs have diverged between species, and in some lineages similar adult morphologies are produced by different morphogenetic mechanisms. These features make the sex comb an excellent model for examining not only the genetic changes responsible for its evolution, but also the cellular processes that translate DNA sequence changes into morphological diversity. The origin and diversification of sex combs provides insights into the roles of modularity, cooption, and regulatory changes in evolutionary innovations, and can serve as a model for understanding the origin of the more drastic novelties that define higher-order taxa. PMID:23016935

Genome biogeography reveals the intraspecific spread of adaptive mutations for a complex trait.

PubMed

Olofsson, Jill K; Bianconi, Matheus; Besnard, Guillaume; Dunning, Luke T; Lundgren, Marjorie R; Holota, Helene; Vorontsova, Maria S; Hidalgo, Oriane; Leitch, Ilia J; Nosil, Patrik; Osborne, Colin P; Christin, Pascal-Antoine

2016-12-01

Physiological novelties are often studied at macro-evolutionary scales such that their micro-evolutionary origins remain poorly understood. Here, we test the hypothesis that key components of a complex trait can evolve in isolation and later be combined by gene flow. We use C 4 photosynthesis as a study system, a derived physiology that increases plant productivity in warm, dry conditions. The grass Alloteropsis semialata includes C 4 and non-C 4 genotypes, with some populations using laterally acquired C 4 -adaptive loci, providing an outstanding system to track the spread of novel adaptive mutations. Using genome data from C 4 and non-C 4 A. semialata individuals spanning the species' range, we infer and date past migrations of different parts of the genome. Our results show that photosynthetic types initially diverged in isolated populations, where key C 4 components were acquired. However, rare but recurrent subsequent gene flow allowed the spread of adaptive loci across genetic pools. Indeed, laterally acquired genes for key C 4 functions were rapidly passed between populations with otherwise distinct genomic backgrounds. Thus, our intraspecific study of C 4 -related genomic variation indicates that components of adaptive traits can evolve separately and later be combined through secondary gene flow, leading to the assembly and optimization of evolutionary innovations. © 2016 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

The evolution of labile traits in sex- and age-structured populations.

PubMed

Childs, Dylan Z; Sheldon, Ben C; Rees, Mark

2016-03-01

Many quantitative traits are labile (e.g. somatic growth rate, reproductive timing and investment), varying over the life cycle as a result of behavioural adaptation, developmental processes and plastic responses to the environment. At the population level, selection can alter the distribution of such traits across age classes and among generations. Despite a growing body of theoretical research exploring the evolutionary dynamics of labile traits, a data-driven framework for incorporating such traits into demographic models has not yet been developed. Integral projection models (IPMs) are increasingly being used to understand the interplay between changes in labile characters, life histories and population dynamics. One limitation of the IPM approach is that it relies on phenotypic associations between parents and offspring traits to capture inheritance. However, it is well-established that many different processes may drive these associations, and currently, no clear consensus has emerged on how to model micro-evolutionary dynamics in an IPM framework. We show how to embed quantitative genetic models of inheritance of labile traits into age-structured, two-sex models that resemble standard IPMs. Commonly used statistical tools such as GLMs and their mixed model counterparts can then be used for model parameterization. We illustrate the methodology through development of a simple model of egg-laying date evolution, parameterized using data from a population of Great tits (Parus major). We demonstrate how our framework can be used to project the joint dynamics of species' traits and population density. We then develop a simple extension of the age-structured Price equation (ASPE) for two-sex populations, and apply this to examine the age-specific contributions of different processes to change in the mean phenotype and breeding value. The data-driven framework we outline here has the potential to facilitate greater insight into the nature of selection and its consequences in settings where focal traits vary over the lifetime through ontogeny, behavioural adaptation and phenotypic plasticity, as well as providing a potential bridge between theoretical and empirical studies of labile trait variation. © 2016 The Authors Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.

The Nature and Evolution of Genomic Diversity in the Mycobacterium tuberculosis Complex.

PubMed

Brites, Daniela; Gagneux, Sebastien

2017-01-01

The Mycobacterium tuberculosis Complex (MTBC) consists of a clonal group of several mycobacterial lineages pathogenic to a range of different mammalian hosts. In this chapter, we discuss the origins and the evolutionary forces shaping the genomic diversity of the human-adapted MTBC. Advances in whole-genome sequencing have brought invaluable insights into the macro-evolution of the MTBC, and the biogeographical distribution of the different MTBC lineages, the phylogenetic relationships between these lineages. Moreover, micro-evolutionary processes start to be better understood, including those influencing bacterial mutation rates and those governing the fate of new mutations emerging within patients during treatment. Current genomic and epidemiological evidence reflect the fact that, through ecological specialization, the MTBC affecting humans became an obligate and extremely well-adapted human pathogen. Identifying the adaptive traits of human-adapted MTBC and unraveling the bacterial loci that interact with human genomic variation might help identify new targets for developing better vaccines and designing more effective treatments.

The signal transduction pathways controlling in planta tuberization in potato: an emerging synthesis.

PubMed

Sarkar, Debabrata

2008-01-01

Tuberization is one of the multiple outputs of a single-input phytochrome B sensory system, involving several regulatory genes. Phytochrome B- and GA-mediated photoperiodic perception occurs in the leaf, and then the RNA acts as a systemic signal in the long-distance signaling pathway to initiate tuberization in the subapical region of an underground stolon. There is good evidence that flowering and tuberizing signals might be similar. Is there a cross-talk with an oxidative burst-mediated redox signaling pathway during tuberization? Is the lipoxygenase cascade involved in the formation of the perimedullary tissue in a growing tuber? Do aquaporins regulate cell division, expansion and elongation during stolon growth and tuber induction in potato? Is the adaptive diversity for tuberization under varying photoperiods a micro-evolutionary indicator of differential transduction of cell-to-cell signal molecules under spatial and temporal expression of regulatory genes encoding transcriptional activators? Taking these views into consideration, the review presents an interim synthesis of a signaling network regulating in planta tuberization in potato.

Reticulate evolution in stick insects: the case of Clonopsis (Insecta Phasmida).

PubMed

Milani, Liliana; Ghiselli, Fabrizio; Pellecchia, Marco; Scali, Valerio; Passamonti, Marco

2010-08-25

Phasmids show noteworthy abilities to overcome species-specific reproductive isolation mechanisms, including hybridization, polyploidy, parthenogenesis, hybridogenesis and androgenesis. From an evolutionary standpoint, such tangled reproductive interactions lead to the complex phyletic relationships known as "reticulate evolution". Moroccan stick insects of the genus Clonopsis include one bisexual (C. felicitatis) and two closely related parthenogenetic forms (C. gallica, C. soumiae), which represent a polyploid series in chromosome number, but with apparent diploid karyotypes. Moreover, two Clonopsis strains of ameiotic males have been described, C. androgenes-35 and C. androgenes-53. As a consequence, Clonopsis stick insects may have experienced complex micro-evolutionary events, which we try to disentangle in this study. Mitochondrial cox2 analysis supports a recent divergence of Clonopsis, while AFLPs evidence genetic differentiation not linked to karyotypes, so that parthenogenetic C. gallica and C. soumiae appear to be a mix of strains of polyphyletic origin rather than single parthenogenetic species. Moreover, an admixed hybrid origin seems to be confirmed for C. androgenes. On the whole, Clonopsis is an intriguing case of reticulate evolution. Actually, complex cladogenetic events should be taken into account to explain the observed genetic structure, including diploidization of polyploid karyotypes, possibly coupled with hybridization and androgenesis. We also proposed a "working hypothesis" to account for the observed data, which deserves further studies, but fits the observed data very well.

Concordant morphological and molecular clines in a contact zone of the Common and Spined toad (Bufo bufo and B. spinosus) in the northwest of France.

PubMed

Arntzen, Jan W; Trujillo, Tania; Butôt, Roland; Vrieling, Klaas; Schaap, Onno; Gutiérrez-Rodríguez, Jorge; Martínez-Solano, Iñigo

2016-01-01

Hybrid zones are regions where individuals of two species meet and produce hybrid progeny, and are often regarded as natural laboratories to understand the process of species formation. Two microevolutionary processes can take place in hybrid zones, with opposing effects on population differentiation. Hybridization tends to produce genetic homogenization, reducing species differences, whereas the presence of mechanisms of reproductive isolation result in barriers to gene flow, maintaining or increasing differences between taxa. Here we study a contact zone between two hybridizing toad species, Bufo bufo and B. spinosus , through a combination of molecular (12 polymorphic microsatellites, four nuclear and two mitochondrial SNP markers) and morphological data in a transect in the northwest of France. The results show largely concordant clines across markers, defining a narrow hybrid zone of ca. 30 km wide. Most hybrids in the centre of the contact zone are classified as F 2 or backcrossed individuals, with no individuals assigned to the F 1 hybrid class. We discuss the implications of these results for our understanding of the evolutionary history of these species. We anticipate that the toad contact zone here described will become an important asset in the study of hybrid zone dynamics and evolutionary biology because of its easy access and the abundance of the species involved.

Tideless estuaries in brackish seas as possible freshwater-marine transition zones for bacteria: the case study of the Vistula river estuary.

PubMed

Gołębiewski, Marcin; Całkiewicz, Joanna; Creer, Simon; Piwosz, Kasia

2017-04-01

Most bacteria are found either in marine or fresh waters and transitions between the two habitats are rare, even though freshwater and marine bacteria co-occur in brackish habitats. Estuaries in brackish, tideless seas could be habitats where the transition of freshwater phylotypes to marine conditions occurs. We tested this hypothesis in the Gulf of Gdańsk (Baltic Sea) by comparing bacterial communities from different zones of the estuary, via pyrosequencing of 16S rRNA amplicons. We predicted the existence of a core microbiome (CM, a set of abundant OTUs present in all samples) comprising OTUs consisting of populations specific for particular zones of the estuary. The CMs for the entire studied period consisted of only eight OTUs, and this number was even lower for specific seasons: five in spring, two in summer, and one in autumn and winter. Six of the CM OTUs, and another 21 of the 50 most abundant OTUs consisted of zone-specific populations, plausibly representing micro-evolutionary forces. The presence of up to 15% of freshwater phylotypes from the Vistula River in the brackish Gulf of Gdańsk supported our hypothesis, but high dissimilarity between the bacterial communities suggested that freshwater-marine transitions are rare even in tideless estuaries in brackish seas. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

Postfire response and genetic diversity in Erica coccinea: connecting population dynamics and diversification in a biodiversity hotspot.

PubMed

Segarra-Moragues, José Gabriel; Ojeda, Fernando

2010-12-01

Understanding the processes of biological diversification is a central topic in evolutionary biology. The South African Cape fynbos, one of the major plant biodiversity hotspots out of the tropics, has prompted several hypotheses about the causes of generation and maintenance of biodiversity. Fire has been traditionally invoked as a key element to explain high levels of biodiversity in highly speciose fynbos taxa, such as the genus Erica. In this study, we have implemented a microevolutionary approach to elucidate how plant-response to fire may contribute to explain high levels of diversification in Erica. By using microsatellite markers, we investigated the genetic background of seeder (fire-sensitive) and resprouter (fire-resistant) populations of the fynbos species Erica coccinea. We found higher within-population genetic diversity and higher among-population differentiation in seeder populations and interpreted these higher levels of genetic diversification as a consequence of the comparatively shorter generation times and faster population turnover in the seeder form of this species. Considering that genetic divergence among populations may be seen as the initial step to speciation, the parallelism between these results and the pattern of biodiversity at the genus level offers stimulating insights into understanding causes of speciation of the genus Erica in the Cape fynbos. © 2010 The Author(s). Evolution© 2010 The Society for the Study of Evolution.

Reticulate evolution in stick insects: the case of Clonopsis (Insecta Phasmida)

PubMed Central

2010-01-01

Background Phasmids show noteworthy abilities to overcome species-specific reproductive isolation mechanisms, including hybridization, polyploidy, parthenogenesis, hybridogenesis and androgenesis. From an evolutionary standpoint, such tangled reproductive interactions lead to the complex phyletic relationships known as "reticulate evolution". Moroccan stick insects of the genus Clonopsis include one bisexual (C. felicitatis) and two closely related parthenogenetic forms (C. gallica, C. soumiae), which represent a polyploid series in chromosome number, but with apparent diploid karyotypes. Moreover, two Clonopsis strains of ameiotic males have been described, C. androgenes-35 and C. androgenes-53. As a consequence, Clonopsis stick insects may have experienced complex micro-evolutionary events, which we try to disentangle in this study. Results Mitochondrial cox2 analysis supports a recent divergence of Clonopsis, while AFLPs evidence genetic differentiation not linked to karyotypes, so that parthenogenetic C. gallica and C. soumiae appear to be a mix of strains of polyphyletic origin rather than single parthenogenetic species. Moreover, an admixed hybrid origin seems to be confirmed for C. androgenes. Conclusion On the whole, Clonopsis is an intriguing case of reticulate evolution. Actually, complex cladogenetic events should be taken into account to explain the observed genetic structure, including diploidization of polyploid karyotypes, possibly coupled with hybridization and androgenesis. We also proposed a "working hypothesis" to account for the observed data, which deserves further studies, but fits the observed data very well. PMID:20738851

Influences of introduced plague on North American mammals: Implications from ecology of plague in Asia

USGS Publications Warehouse

Biggins, D.E.; Kosoy, M.Y.

2001-01-01

Intercontinental movements of invasive species continue to modify the world's ecosystems. The plague bacterium (Yersinia pestis) has colonized and altered animal communities worldwide but has received much more attention as a human pathogen. We reviewed studies on the ecology of Y. pestis in ancient foci of central Asia and in western North America, where the bacterium apparently has become established much more recently. Although rodent populations on both continents are affected dramatically by epizootics of plague, the epidemiologically important species of Asia demonstrate resistance in portions of their populations, whereas those of North America are highly susceptible. Individual variation in resistance, which is widespread in Asian rodents and allows a microevolutionary response, has been documented in few North American species of rodents. Plague increases costs of sociality and coloniality in susceptible hosts, increases benefits of disease resistance in general, and increases benefits of adaptability to variable environments for species at higher trophic levels. Prairie dogs (Cynomys) epitomize taxa with high risk to plague because prairie dogs have uniformly low resistance to plague and are highly social. Relationships to plague are poorly understood for many North American rodents, but more than one-half of the species of conservation concern occur within the geographic range of plague.

Large-scale diversification of skull shape in domestic dogs: disparity and modularity.

PubMed

Drake, Abby Grace; Klingenberg, Christian Peter

2010-03-01

Abstract: The variation among domestic dog breeds offers a unique opportunity to study large-scale diversification by microevolutionary mechanisms. We use geometric morphometrics to quantify the diversity of skull shape in 106 breeds of domestic dog, in three wild canid species, and across the order Carnivora. The amount of shape variation among domestic dogs far exceeds that in wild species, and it is comparable to the disparity throughout the Carnivora. The greatest shape distances between dog breeds clearly surpass the maximum divergence between species in the Carnivora. Moreover, domestic dogs occupy a range of novel shapes outside the domain of wild carnivorans. The disparity among companion dogs substantially exceeds that of other classes of breeds, suggesting that relaxed functional demands facilitated diversification. Much of the diversity of dog skull shapes stems from variation between short and elongate skulls and from modularity of the face versus that of the neurocranium. These patterns of integration and modularity apply to variation among individuals and breeds, but they also apply to fluctuating asymmetry, indicating they have a shared developmental basis. These patterns of variation are also found for the wolf and across the Carnivora, suggesting that they existed before the domestication of dogs and are not a result of selective breeding.

Patterns of genetic diversity at the nine forensically approved STR loci in the Indian populations.

PubMed

Dutta, Ranjan; Reddy, B Mohan; Chattopadhyay, P; Kashyap, V K; Sun, Guangyun; Deka, Ranjan

2002-02-01

Genetic diversity at the nine short tandem repeat (STR) loci, which are universally approved and widely used for forensic investigations, has been studied among nine Indian populations with diverse ethnic, linguistic, and geographic backgrounds. The nine STR loci were profiled on 902 individuals using fluorescent detection methods on an ABI377 System, with the aid of an Amp-F1 Profiler Plus Kit. The studied populations include two upper castes, Brahmin and Kayastha; a tribe, Garo, from West Bengal; a Hindu caste, Meitei, with historical links to Bengal Brahmins; a migrant group of Muslims; three tribal groups, Naga, Kuki and Hmar, from Manipur in northeast India; and a middle-ranking caste, Golla, who are seminomadic herders from Andhra Pradesh. Gene diversity analysis suggests that the average heterozygosity is uniformly high (>0.8) in the studied populations, with the coefficient of gene differentiation at 0.050 +/- 0.0054. Both neighbor-joining (NJ) and unweighted pair group method with arithmetic mean (UPGMA) trees based on DA distances bring out distinct clusters that are consistent with ethnic, linguistic, and/or geographic backgrounds of the populations. The fit of the Harpending and Ward model of regression of average heterozygosity on the gene frequency centroid is found to be good, and the observed outliers are consistent with the population structure and history of the studied populations. Our study suggests that the nine STR loci, used so far mostly for forensic investigations, can be used fruitfully for microevolutionary studies as well, and for reconstructing the phylogenetic history of human populations, at least at the local level.

Tempo and mode in the macroevolutionary reconstruction of Darwinism.

PubMed Central

Gould, S J

1994-01-01

Among the several central meanings of Darwinism, his version of Lyellian uniformitarianism--the extrapolationist commitment to viewing causes of small-scale, observable change in modern populations as the complete source, by smooth extension through geological time, of all magnitudes and sequences in evolution--has most contributed to the causal hegemony of microevolution and the assumption that paleontology can document the contingent history of life but cannot act as a domain of novel evolutionary theory. G. G. Simpson tried to combat this view of paleontology as theoretically inert in his classic work, Tempo and Mode in Evolution (1944), with a brilliant argument that the two subjects of his title fall into a unique paleontological domain and that modes (processes and causes) can be inferred from the quantitative study of tempos (pattern). Nonetheless, Simpson did not cash out his insight to paleontology's theoretical benefit because he followed the strict doctrine of the Modern Synthesis. He studied his domain of potential theory and concluded that no actual theory could be found--and that a full account of causes could therefore be located in the microevolutionary realm after all. I argue that Simpson was unduly pessimistic and that modernism's belief in reductionistic unification (the conventional view of Western intellectuals from the 1920s to the 1950s) needs to be supplanted by a postmodernist commitment to pluralism and multiple levels of causation. Macro- and microevolution should not be viewed as opposed, but as truly complementary. I describe the two major domains where a helpful macroevolutionary theory may be sought--unsmooth causal boundaries between levels (as illustrated by punctuated equilibrium and mass extinction) and hierarchical expansion of the theory of natural selection to levels both below (gene and cell-line) and above organisms (demes, species, and clades). Problems remain in operationally defining selection at non-organismic levels (emergent traits vs. emergent fitness approaches, for example) and in specifying the nature and basis of levels, but this subject should be the central focus in formulating a more ample and satisfactory general theory of evolution on extended Darwinian principles. PMID:8041695

Comparability of multiple data types from the Bering Strait region: cranial and dental metrics and nonmetrics, mtDNA, and Y-chromosome DNA.

PubMed

Herrera, Brianne; Hanihara, Tsunehiko; Godde, Kanya

2014-07-01

Different data types have previously been shown to have the same microevolutionary patterns in worldwide data sets. However, peopling of the New World studies have shown a difference in migration paths and timings using multiple types of data, spurring research to understand why this is the case. This study was designed to test the degree of similarity in evolutionary patterns by using cranial and dental metric and nonmetric data, along with Y-chromosome DNA and mtDNA. The populations used included Inuits from Alaska, Canada, Siberia, Greenland, and the Aleutian Islands. For comparability, the populations used for the cranial and molecular data were from similar geographic regions or had a shared population history. Distance, R and kinship matrices were generated for use in running Mantel tests, PROTEST analyses, and Procrustes analyses. A clear patterning was seen, with the craniometric data being most highly correlated to the mtDNA data and the cranial nonmetric data being most highly correlated with the Y-chromosome data, while the phenotypic data were also linked. This patterning is suggestive of a possible male or female inheritance, or the correlated data types are affected by the same or similar evolutionary forces. The results of this study indicate cranial traits have some degree of heritability. Moreover, combining data types leads to a richer knowledge of biological affinity. This understanding is important for bioarchaeological contexts, in particular, peopling of the New World studies where focusing on reconciling the results from comparing multiple data types is necessary to move forward. © 2014 Wiley Periodicals, Inc.

The evolution of test size in the Planktic Foraminifera

NASA Astrophysics Data System (ADS)

Fraass, A.; Huber, B. T.; Kelly, D. C.

2017-12-01

Planktic foraminifera are vital tools for understanding paleoceanography, paleoclimate, and evolution. A dataset of measurements from all planktic foraminiferal species is used here to investigate how their size changes through the late Jurassic to Recent. The mean test size of planktic foraminifera increases in the Cretaceous and the Cenozoic, with substantial drops at the Aptian/Albian boundary, in the Coniacian and Santonian, with the end-Cretaceous extinction, and across the Paleocene/Eocene boundary. The Oligocene contains only a small drop in mean size, which is surprising given the substantial extinction of planktic foraminifera at that boundary. There is a qualitative connection between mean and median size and paleoceanographic events, but several key issues remain before rigorous quantitative interrogation of the dataset can be undertaken. In general, species that originate early in a family's range are smaller than those evolving later, though this is a weak relationship. Individual families do not always conform to that finding, however, and have both increasing and decreasing family age-size relationships. The 'three faunas' concept for foraminiferal evolution fails with respect to mean and median size; each diversification has a unique rate of increase and character. Lastly, through comparison with the Schmidt et al. (2004) population-level test size dataset, the size response to climate in the low-latitudes is at the species-level. In the high-latitude regions, however, the response to climate is at the population level. Thus, methods for uncovering climate responses in planktic foraminifera must be specific to the region. Taxonomic or macroevolutionary responses dominate the tropics and global signals, while the polar regions appear to have a unique, and more microevolutionary response.Schmidt, D., Thierstein, H., Bollmann, J., & Schiebel, R. (2004). Abiotic Forcing of Plankton Evolution in the Cenozoic. Science, 303(5655), 207-210.

Understanding plant reproductive diversity.

PubMed

Barrett, Spencer C H

2010-01-12

Flowering plants display spectacular floral diversity and a bewildering array of reproductive adaptations that promote mating, particularly outbreeding. A striking feature of this diversity is that related species often differ in pollination and mating systems, and intraspecific variation in sexual traits is not unusual, especially among herbaceous plants. This variation provides opportunities for evolutionary biologists to link micro-evolutionary processes to the macro-evolutionary patterns that are evident within lineages. Here, I provide some personal reflections on recent progress in our understanding of the ecology and evolution of plant reproductive diversity. I begin with a brief historical sketch of the major developments in this field and then focus on three of the most significant evolutionary transitions in the reproductive biology of flowering plants: the pathway from outcrossing to predominant self-fertilization, the origin of separate sexes (females and males) from hermaphroditism and the shift from animal pollination to wind pollination. For each evolutionary transition, I consider what we have discovered and some of the problems that still remain unsolved. I conclude by discussing how new approaches might influence future research in plant reproductive biology.

Evolutionary speed limited by water in arid Australia

PubMed Central

Goldie, Xavier; Gillman, Len; Crisp, Mike; Wright, Shane

2010-01-01

The covariation of biodiversity with climate is a fundamental pattern in nature. However, despite the ubiquity of this relationship, a consensus on the ultimate cause remains elusive. The evolutionary speed hypothesis posits direct mechanistic links between ambient temperature, the tempo of micro-evolution and, ultimately, species richness. Previous research has demonstrated faster rates of molecular evolution in warmer climates for a broad range of poikilothermic and homeothermic organisms, in both terrestrial and aquatic environments. In terrestrial systems, species richness increases with both temperature and water availability and the interaction of those terms: productivity. However, the influence of water availability as an independent variable on micro-evolutionary processes has not been examined previously. Here, using methodology that limits the potentially confounding role of cladogenetic and demographic processes, we report, to our knowledge, the first evidence that woody plants living in the arid Australian Outback are evolving more slowly than related species growing at similar latitudes in moist habitats on the mesic continental margins. These results support a modified evolutionary speed explanation for the relationship between the water-energy balance and plant diversity patterns. PMID:20410038

Evolutionary speed limited by water in arid Australia.

PubMed

Goldie, Xavier; Gillman, Len; Crisp, Mike; Wright, Shane

2010-09-07

The covariation of biodiversity with climate is a fundamental pattern in nature. However, despite the ubiquity of this relationship, a consensus on the ultimate cause remains elusive. The evolutionary speed hypothesis posits direct mechanistic links between ambient temperature, the tempo of micro-evolution and, ultimately, species richness. Previous research has demonstrated faster rates of molecular evolution in warmer climates for a broad range of poikilothermic and homeothermic organisms, in both terrestrial and aquatic environments. In terrestrial systems, species richness increases with both temperature and water availability and the interaction of those terms: productivity. However, the influence of water availability as an independent variable on micro-evolutionary processes has not been examined previously. Here, using methodology that limits the potentially confounding role of cladogenetic and demographic processes, we report, to our knowledge, the first evidence that woody plants living in the arid Australian Outback are evolving more slowly than related species growing at similar latitudes in moist habitats on the mesic continental margins. These results support a modified evolutionary speed explanation for the relationship between the water-energy balance and plant diversity patterns.

ATGC database and ATGC-COGs: an updated resource for micro- and macro-evolutionary studies of prokaryotic genomes and protein family annotation

PubMed Central

Kristensen, David M.; Wolf, Yuri I.; Koonin, Eugene V.

2017-01-01

The Alignable Tight Genomic Clusters (ATGCs) database is a collection of closely related bacterial and archaeal genomes that provides several tools to aid research into evolutionary processes in the microbial world. Each ATGC is a taxonomy-independent cluster of 2 or more completely sequenced genomes that meet the objective criteria of a high degree of local gene order (synteny) and a small number of synonymous substitutions in the protein-coding genes. As such, each ATGC is suited for analysis of microevolutionary variations within a cohesive group of organisms (e.g. species), whereas the entire collection of ATGCs is useful for macroevolutionary studies. The ATGC database includes many forms of pre-computed data, in particular ATGC-COGs (Clusters of Orthologous Genes), multiple sequence alignments, a set of ‘index’ orthologs representing the most well-conserved members of each ATGC-COG, the phylogenetic tree of the organisms within each ATGC, etc. Although the ATGC database contains several million proteins from thousands of genomes organized into hundreds of clusters (roughly a 4-fold increase since the last version of the ATGC database), it is now built with completely automated methods and will be regularly updated following new releases of the NCBI RefSeq database. The ATGC database is hosted jointly at the University of Iowa at dmk-brain.ecn.uiowa.edu/ATGC/ and the NCBI at ftp.ncbi.nlm.nih.gov/pub/kristensen/ATGC/atgc_home.html. PMID:28053163

Micro- and Macroevolutionary Trade-Offs in Plant-Feeding Insects.

PubMed

Peterson, Daniel A; Hardy, Nate B; Normark, Benjamin B

2016-12-01

A long-standing hypothesis asserts that plant-feeding insects specialize on particular host plants because of negative interactions (trade-offs) between adaptations to alternative hosts, yet empirical evidence for such trade-offs is scarce. Most studies have looked for microevolutionary performance trade-offs within insect species, but host use could also be constrained by macroevolutionary trade-offs caused by epistasis and historical contingency. Here we used a phylogenetic approach to estimate the micro- and macroevolutionary correlations between use of alternative host-plant taxa within two major orders of plant-feeding insects: Lepidoptera (caterpillars) and Hemiptera (true bugs). Across 1,604 caterpillar species, we found both positive and negative pairwise correlations between use of 11 host-plant orders, with overall network patterns suggesting that different host-use constraints act over micro- and macroevolutionary timescales. In contrast, host-use patterns of 955 true bug species revealed uniformly positive correlations between use of the same 11 host plant orders over both timescales. The lack of consistent patterns across timescales and insect orders indicates that host-use trade-offs are historically contingent rather than universal constraints. Moreover, we observed few negative correlations overall despite the wide taxonomic and ecological diversity of the focal host-plant orders, suggesting that positive interactions between host-use adaptations, not trade-offs, dominate the long-term evolution of host use in plant-feeding insects.

The complete nucleotide sequences of the 5 genetically distinct plastid genomes of Oenothera, subsection Oenothera: II. A microevolutionary view using bioinformatics and formal genetic data.

PubMed

Greiner, Stephan; Wang, Xi; Herrmann, Reinhold G; Rauwolf, Uwe; Mayer, Klaus; Haberer, Georg; Meurer, Jörg

2008-09-01

A unique combination of genetic features and a rich stock of information make the flowering plant genus Oenothera an appealing model to explore the molecular basis of speciation processes including nucleus-organelle coevolution. From representative species, we have recently reported complete nucleotide sequences of the 5 basic and genetically distinguishable plastid chromosomes of subsection Oenothera (I-V). In nature, Oenothera plastid genomes are associated with 6 distinct, either homozygous or heterozygous, diploid nuclear genotypes of the 3 basic genomes A, B, or C. Artificially produced plastome-genome combinations that do not occur naturally often display interspecific plastome-genome incompatibility (PGI). In this study, we compare formal genetic data available from all 30 plastome-genome combinations with sequence differences between the plastomes to uncover potential determinants for interspecific PGI. Consistent with an active role in speciation, a remarkable number of genes have high Ka/Ks ratios. Different from the Solanacean cybrid model Atropa/tobacco, RNA editing seems not to be relevant for PGIs in Oenothera. However, predominantly sequence polymorphisms in intergenic segments are proposed as possible sources for PGI. A single locus, the bidirectional promoter region between psbB and clpP, is suggested to contribute to compartmental PGI in the interspecific AB hybrid containing plastome I (AB-I), consistent with its perturbed photosystem II activity.

Low Genetic Diversity in Wide-Spread Eurasian Liver Fluke Opisthorchis felineus Suggests Special Demographic History of This Trematode Species

PubMed Central

Brusentsov, Ilja I.; Katokhin, Alexey V.; Brusentsova, Irina V.; Shekhovtsov, Sergei V.; Borovikov, Sergei N.; Goncharenko, Grigoriy G.; Lider, Lyudmila A.; Romashov, Boris V.; Rusinek, Olga T.; Shibitov, Samat K.; Suleymanov, Marat M.; Yevtushenko, Andrey V.; Mordvinov, Viatcheslav A.

2013-01-01

Opisthorchis felineus or Siberian liver fluke is a trematode parasite (Opisthorchiidae) that infects the hepato-biliary system of humans and other mammals. Despite its public health significance, this wide-spread Eurasian species is one of the most poorly studied human liver flukes and nothing is known about its population genetic structure and demographic history. In this paper, we attempt to fill this gap for the first time and to explore the genetic diversity in O. felineus populations from Eastern Europe (Ukraine, European part of Russia), Northern Asia (Siberia) and Central Asia (Northern Kazakhstan). Analysis of marker DNA fragments from O. felineus mitochondrial cytochrome c oxidase subunit 1 and 3 (cox1, cox3) and nuclear rDNA internal transcribed spacer 1 (ITS1) sequences revealed that genetic diversity is very low across the large geographic range of this species. Microevolutionary processes in populations of trematodes may well be influenced by their peculiar biology. Nevertheless, we suggest that lack of population genetics structure observed in O. felineus can be primarily explained by the Pleistocene glacial events and subsequent sudden population growth from a very limited group of founders. Rapid range expansion of O. felineus through Asian and European territories after severe bottleneck points to a high dispersal potential of this trematode species. PMID:23634228

Disentangling geographical, biotic, and abiotic drivers of plant diversity in neotropical Ruellia (Acanthaceae).

PubMed

Tripp, Erin A; Tsai, Yi-Hsin Erica

2017-01-01

It has long been hypothesized that biotic interactions are important drivers of biodiversity evolution, yet such interactions have been relatively less studied than abiotic factors owing to the inherent complexity in and the number of types of such interactions. Amongst the most prominent of biotic interactions worldwide are those between plants and pollinators. In the Neotropics, the most biodiverse region on Earth, hummingbird and bee pollination have contributed substantially to plant fitness. Using comparative methods, we test the macroevolutionary consequences of bird and bee pollination within a species rich lineage of flowering plants: Ruellia. We additionally explore impacts of species occupancy of ever-wet rainforests vs. dry ecosystems including cerrado and seasonally dry tropical forests. We compared outcomes based on two different methods of model selection: a traditional approach that utilizes a series of transitive likelihood ratio tests as well as a weighted model averaging approach. Analyses yield evidence for increased net diversification rates among Neotropical Ruellia (compared to Paleotropical lineages) as well as among hummingbird-adapted species. In contrast, we recovered no evidence of higher diversification rates among either bee- or non-bee-adapted lineages and no evidence for higher rates among wet or dry habitat lineages. Understanding fully the factors that have contributed to biases in biodiversity across the planet will ultimately depend upon incorporating knowledge of biotic interactions as well as connecting microevolutionary processes to macroevolutionary patterns.

Disentangling geographical, biotic, and abiotic drivers of plant diversity in neotropical Ruellia (Acanthaceae)

PubMed Central

Tsai, Yi-Hsin Erica

2017-01-01

It has long been hypothesized that biotic interactions are important drivers of biodiversity evolution, yet such interactions have been relatively less studied than abiotic factors owing to the inherent complexity in and the number of types of such interactions. Amongst the most prominent of biotic interactions worldwide are those between plants and pollinators. In the Neotropics, the most biodiverse region on Earth, hummingbird and bee pollination have contributed substantially to plant fitness. Using comparative methods, we test the macroevolutionary consequences of bird and bee pollination within a species rich lineage of flowering plants: Ruellia. We additionally explore impacts of species occupancy of ever-wet rainforests vs. dry ecosystems including cerrado and seasonally dry tropical forests. We compared outcomes based on two different methods of model selection: a traditional approach that utilizes a series of transitive likelihood ratio tests as well as a weighted model averaging approach. Analyses yield evidence for increased net diversification rates among Neotropical Ruellia (compared to Paleotropical lineages) as well as among hummingbird-adapted species. In contrast, we recovered no evidence of higher diversification rates among either bee- or non-bee-adapted lineages and no evidence for higher rates among wet or dry habitat lineages. Understanding fully the factors that have contributed to biases in biodiversity across the planet will ultimately depend upon incorporating knowledge of biotic interactions as well as connecting microevolutionary processes to macroevolutionary patterns. PMID:28472046

Geographic variation in body form of prehistoric Jomon males in the Japanese archipelago: its ecogeographic implications.

PubMed

Fukase, Hitoshi; Wakebe, Tetsuaki; Tsurumoto, Toshiyuki; Saiki, Kazunobu; Fujita, Masaki; Ishida, Hajime

2012-09-01

Diversity of human body size and shape is often biogeographically interpreted in association with climatic conditions. According to Bergmann's and Allen's rules, populations in regions with a cold climate are expected to display an overall larger body and smaller/shorter extremities than those in warm/hot environments. In the present study, the skeletal limb size and proportions of prehistoric Jomon hunter-gatherers, who extensively inhabited subarctic to subtropical areas in the ancient Japanese archipelago, were examined to evaluate whether or not the inter-regional differences follow such ecogeographic patterns. Results showed that the Jomon intralimb proportions including relative distal limb lengths did not differ significantly among five regions from northern Hokkaido to the southern Okinawa Islands. This suggests a limited co-variability of the intralimb proportions with climate, particularly within genealogically close populations. In contrast, femoral head breadth (associated with body mass) and skeletal limb lengths were found to be significantly and positively correlated with latitude, suggesting a north-south geographical cline in the body size. This gradient therefore comprehensively conforms to Bergmann's rule, and may stem from multiple potential factors such as phylogenetic constraints, microevolutionary adaptation to climatic/geographic conditions during the Jomon period, and nutritional and physiological response during ontogeny. Specifically, the remarkably small-bodied Jomon in the Okinawa Islands can also be explained as an adjustment to subtropical and insular environments. Thus, the findings obtained in this study indicate that Jomon people, while maintaining fundamental intralimb proportions, displayed body size variation in concert with ambient surroundings. Copyright © 2012 Wiley Periodicals, Inc.

Ecological divergence and evolutionary transition of resprouting types in Banksia attenuata.

PubMed

He, Tianhua

2014-08-01

Resprouting is a key functional trait that allows plants to survive diverse disturbances. The fitness benefits associated with resprouting include a rapid return to adult growth, early flowering, and setting seed. The resprouting responses observed following fire are varied, as are the ecological outcomes. Understanding the ecological divergence and evolutionary pathways of different resprouting types and how the environment and genetics interact to drive such morphological evolution represents an important, but under-studied, topic. In the present study, microsatellite markers and microevolutionary approaches were used to better understand: (1) whether genetic differentiation is related to morphological divergence among resprouting types and if so, whether there are any specific genetic variations associated with morphological divergence and (2) the evolutionary pathway of the transitions between two resprouting types in Banksia attenuata (epicormic resprouting from aerial stems or branch; resprouting from a underground lignotuber). The results revealed an association between population genetic differentiation and the morphological divergence of postfire resprouting types in B. attenuata. A microsatellite allele has been shown to be associated with epicormic populations. Approximate Bayesian Computation analysis revealed a likely evolutionary transition from epicormic to lignotuberous resprouting in B. attenuata. It is concluded that the postfire resprouting type in B. attenuata is likely determined by the fire's characteristics. The differentiated expression of postfire resprouting types in different environments is likely a consequence of local genetic adaptation. The capacity to shift the postfire resprouting type to adapt to diverse fire regimes is most likely the key factor explaining why B. attenuata is the most widespread member of the Banksia genus.

Genomic variation in macrophage-cultured European porcine reproductive and respiratory syndrome virus Olot/91 revealed using ultra-deep next generation sequencing.

PubMed

Lu, Zen H; Brown, Alexander; Wilson, Alison D; Calvert, Jay G; Balasch, Monica; Fuentes-Utrilla, Pablo; Loecherbach, Julia; Turner, Frances; Talbot, Richard; Archibald, Alan L; Ait-Ali, Tahar

2014-03-04

Porcine Reproductive and Respiratory Syndrome (PRRS) is a disease of major economic impact worldwide. The etiologic agent of this disease is the PRRS virus (PRRSV). Increasing evidence suggest that microevolution within a coexisting quasispecies population can give rise to high sequence heterogeneity in PRRSV. We developed a pipeline based on the ultra-deep next generation sequencing approach to first construct the complete genome of a European PRRSV, strain Olot/9, cultured on macrophages and then capture the rare variants representative of the mixed quasispecies population. Olot/91 differs from the reference Lelystad strain by about 5% and a total of 88 variants, with frequencies as low as 1%, were detected in the mixed population. These variants included 16 non-synonymous variants concentrated in the genes encoding structural and nonstructural proteins; including Glycoprotein 2a and 5. Using an ultra-deep sequencing methodology, the complete genome of Olot/91 was constructed without any prior knowledge of the sequence. Rare variants that constitute minor fractions of the heterogeneous PRRSV population could successfully be detected to allow further exploration of microevolutionary events.

Darwin's missing link - a novel paradigm for evolution education

NASA Astrophysics Data System (ADS)

Catley, Kefyn M.

2006-09-01

Microevolutionary mechanisms are taught almost exclusively in our schools, to the detriment of those mechanisms that allow us to understand the larger picture - macroevolution. The results are demonstrable; as a result of the strong emphasis on micro processes in evolution education, students and teachers still have poor understanding of the processes which operate at the macro level, and virtually no understanding at all of the history of life on our planet. Natural selection has become synonymous with the suite of processes we call evolution. This paper makes the case for a paradigm shift in evolution education, so that both perspectives - micro and macro - are given equal weight. Increasingly, issues of bioethics, human origins, cloning, etc., are being cast in a light that requires an understanding of macroevolution. To deny our students access to this debate is to deny the call for universal science literacy. A methodology from professional practice is proposed that could achieve this goal, and discussed in light of its utility, theoretical underpinnings, and historical legacy. A mandate for research is proposed that focuses on learners' understanding of several challenging macroevolutionary concepts, including species, the formation of higher groups, deep time, and hierarchical thinking.

Sex-specific evolution during the diversification of live-bearing fishes.

PubMed

Culumber, Zachary W; Tobler, Michael

2017-08-01

Natural selection is often assumed to drive parallel functional diversification of the sexes. But males and females exhibit fundamental differences in their biology, and it remains largely unknown how sex differences affect macroevolutionary patterns. On microevolutionary scales, we understand how natural and sexual selection interact to give rise to sex-specific evolution during phenotypic diversification and speciation. Here we show that ignoring sex-specific patterns of functional trait evolution misrepresents the macroevolutionary adaptive landscape and evolutionary rates for 112 species of live-bearing fishes (Poeciliidae). Males and females of the same species evolve in different adaptive landscapes. Major axes of female morphology were correlated with environmental variables but not reproductive investment, while male morphological variation was primarily associated with sexual selection. Despite the importance of both natural and sexual selection in shaping sex-specific phenotypic diversification, species diversification was overwhelmingly associated with ecological divergence. Hence, the inter-predictability of mechanisms of phenotypic and species diversification may be limited in many systems. These results underscore the importance of explicitly addressing sex-specific diversification in empirical and theoretical frameworks of evolutionary radiations to elucidate the roles of different sources of selection and constraint.

Ecological correlates of population genetic structure: a comparative approach using a vertebrate metacommunity.

PubMed

Manier, Mollie K; Arnold, Stevan J

2006-12-07

Identifying ecological factors associated with population genetic differentiation is important for understanding microevolutionary processes and guiding the management of threatened populations. We identified ecological correlates of several population genetic parameters for three interacting species (two garter snakes and an anuran) that occupy a common landscape. Using multiple regression analysis, we found that species interactions were more important in explaining variation in population genetic parameters than habitat and nearest-neighbour characteristics. Effective population size was best explained by census size, while migration was associated with differences in species abundance. In contrast, genetic distance was poorly explained by the ecological correlates that we tested, but geographical distance was prominent in models for all species. We found substantially different population dynamics for the prey species relative to the two predators, characterized by larger effective sizes, lower gene flow and a state of migration-drift equilibrium. We also identified an escarpment formed by a series of block faults that serves as a barrier to dispersal for the predators. Our results suggest that successful landscape-level management should incorporate genetic and ecological data for all relevant species, because even closely associated species can exhibit very different population genetic dynamics on the same landscape.

A Macroevolutionary Perspective on Multiple Sexual Traits in the Phasianidae (Galliformes)

PubMed Central

Kimball, Rebecca T.; Mary, Colette M. St.; Braun, Edward L.

2011-01-01

Traits involved in sexual signaling are ubiquitous among animals. Although a single trait appears sufficient to convey information, many sexually dimorphic species exhibit multiple sexual signals, which may be costly to signalers and receivers. Given that one signal may be enough, there are many microevolutionary hypotheses to explain the evolution of multiple signals. Here we extend these hypotheses to a macroevolutionary scale and compare those predictions to the patterns of gains and losses of sexual dimorphism in pheasants and partridges. Among nine dimorphic characters, including six intersexual signals and three indicators of competitive ability, all exhibited both gains and losses of dimorphism within the group. Although theories of intersexual selection emphasize gain and elaboration, those six characters exhibited greater rates of loss than gain; in contrast, the competitive traits showed a slight bias towards gains. The available models, when examined in a macroevolutionary framework, did not yield unique predictions, making it difficult to distinguish among them. Even with this limitation, when the predictions of these alternative models were compared with the heterogeneous patterns of evolution of dimorphism in phasianids, it is clear that many different selective processes have been involved in the evolution of sexual signals in this group. PMID:21716735

Multivariate genetic architecture of the Anolis dewlap reveals both shared and sex-specific features of a sexually dimorphic ornament.

PubMed

Cox, R M; Costello, R A; Camber, B E; McGlothlin, J W

2017-07-01

Darwin viewed the ornamentation of females as an indirect consequence of sexual selection on males and the transmission of male phenotypes to females via the 'laws of inheritance'. Although a number of studies have supported this view by demonstrating substantial between-sex genetic covariance for ornament expression, the majority of this work has focused on avian plumage. Moreover, few studies have considered the genetic basis of ornaments from a multivariate perspective, which may be crucial for understanding the evolution of sex differences in general, and of complex ornaments in particular. Here, we provide a multivariate, quantitative-genetic analysis of a sexually dimorphic ornament that has figured prominently in studies of sexual selection: the brightly coloured dewlap of Anolis lizards. Using data from a paternal half-sibling breeding experiment in brown anoles (Anolis sagrei), we show that multiple aspects of dewlap size and colour exhibit significant heritability and a genetic variance-covariance structure (G) that is broadly similar in males (G m ) and females (G f ). Whereas sexually monomorphic aspects of the dewlap, such as hue, exhibit significant between-sex genetic correlations (r mf ), sexually dimorphic features, such as area and brightness, exhibit reduced r mf values that do not differ from zero. Using a modified random skewers analysis, we show that the between-sex genetic variance-covariance matrix (B) should not strongly constrain the independent responses of males and females to sexually antagonistic selection. Our microevolutionary analysis is in broad agreement with macroevolutionary perspectives indicating considerable scope for the independent evolution of coloration and ornamentation in males and females. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.

Genetic diversity and differentiation in a wide ranging anadromous fish, American shad (Alosa sapidissima), is correlated with latitude.

PubMed

Hasselman, Daniel J; Ricard, Daniel; Bentzen, Paul

2013-03-01

Studies that span entire species ranges can provide insight into the relative roles of historical contingency and contemporary factors that influence population structure and can reveal patterns of genetic variation that might otherwise go undetected. American shad is a wide ranging anadromous clupeid fish that exhibits variation in demographic histories and reproductive strategies (both semelparity and iteroparity) and provides a unique perspective on the evolutionary processes that govern the genetic architecture of anadromous fishes. Using 13 microsatellite loci, we examined the magnitude and spatial distribution of genetic variation among 33 populations across the species' range to (i) determine whether signals of historical demography persist among contemporary populations and (ii) assess the effect of different reproductive strategies on population structure. Patterns of genetic diversity and differentiation among populations varied widely and reflect the differential influences of historical demography, microevolutionary processes and anthropogenic factors across the species' range. Sequential reductions of diversity with latitude among formerly glaciated rivers are consistent with stepwise postglacial colonization and successive population founder events. Weak differentiation among U.S. iteroparous populations may be a consequence of human-mediated gene flow, while weak differentiation among semelparous populations probably reflects natural gene flow. Evidence for an effect of reproductive strategy on population structure suggests an important role for environmental variation and suggests that the factors that are responsible for shaping American shad life history patterns may also influence population genetic structure. © 2013 Blackwell Publishing Ltd.

Insights into the history of a bacterial group II intron remnant from the genomes of the nitrogen-fixing symbionts Sinorhizobium meliloti and Sinorhizobium medicae.

PubMed

Toro, N; Martínez-Rodríguez, L; Martínez-Abarca, F

2014-10-01

Group II introns are self-splicing catalytic RNAs that act as mobile retroelements. In bacteria, they are thought to be tolerated to some extent because they self-splice and home preferentially to sites outside of functional genes, generally within intergenic regions or in other mobile genetic elements, by mechanisms including the divergence of DNA target specificity to prevent target site saturation. RmInt1 is a mobile group II intron that is widespread in natural populations of Sinorhizobium meliloti and was first described in the GR4 strain. Like other bacterial group II introns, RmInt1 tends to evolve toward an inactive form by fragmentation, with loss of the 3' terminus. We identified genomic evidence of a fragmented intron closely related to RmInt1 buried in the genome of the extant S. meliloti/S. medicae species. By studying this intron, we obtained evidence for the occurrence of intron insertion before the divergence of ancient rhizobial species. This fragmented group II intron has thus existed for a long time and has provided sequence variation, on which selection can act, contributing to diverse genetic rearrangements, and to generate pan-genome divergence after strain differentiation. The data presented here suggest that fragmented group II introns within intergenic regions closed to functionally important neighboring genes may have been microevolutionary forces driving adaptive evolution of these rhizobial species.

Insights into the history of a bacterial group II intron remnant from the genomes of the nitrogen-fixing symbionts Sinorhizobium meliloti and Sinorhizobium medicae

PubMed Central

Toro, N; Martínez-Rodríguez, L; Martínez-Abarca, F

2014-01-01

Group II introns are self-splicing catalytic RNAs that act as mobile retroelements. In bacteria, they are thought to be tolerated to some extent because they self-splice and home preferentially to sites outside of functional genes, generally within intergenic regions or in other mobile genetic elements, by mechanisms including the divergence of DNA target specificity to prevent target site saturation. RmInt1 is a mobile group II intron that is widespread in natural populations of Sinorhizobium meliloti and was first described in the GR4 strain. Like other bacterial group II introns, RmInt1 tends to evolve toward an inactive form by fragmentation, with loss of the 3′ terminus. We identified genomic evidence of a fragmented intron closely related to RmInt1 buried in the genome of the extant S. meliloti/S. medicae species. By studying this intron, we obtained evidence for the occurrence of intron insertion before the divergence of ancient rhizobial species. This fragmented group II intron has thus existed for a long time and has provided sequence variation, on which selection can act, contributing to diverse genetic rearrangements, and to generate pan-genome divergence after strain differentiation. The data presented here suggest that fragmented group II introns within intergenic regions closed to functionally important neighboring genes may have been microevolutionary forces driving adaptive evolution of these rhizobial species. PMID:24736785

2b-RAD genotyping for population genomic studies of Chagas disease vectors: Rhodnius ecuadoriensis in Ecuador.

PubMed

Hernandez-Castro, Luis E; Paterno, Marta; Villacís, Anita G; Andersson, Björn; Costales, Jaime A; De Noia, Michele; Ocaña-Mayorga, Sofía; Yumiseva, Cesar A; Grijalva, Mario J; Llewellyn, Martin S

2017-07-01

Rhodnius ecuadoriensis is the main triatomine vector of Chagas disease, American trypanosomiasis, in Southern Ecuador and Northern Peru. Genomic approaches and next generation sequencing technologies have become powerful tools for investigating population diversity and structure which is a key consideration for vector control. Here we assess the effectiveness of three different 2b restriction site-associated DNA (2b-RAD) genotyping strategies in R. ecuadoriensis to provide sufficient genomic resolution to tease apart microevolutionary processes and undertake some pilot population genomic analyses. The 2b-RAD protocol was carried out in-house at a non-specialized laboratory using 20 R. ecuadoriensis adults collected from the central coast and southern Andean region of Ecuador, from June 2006 to July 2013. 2b-RAD sequencing data was performed on an Illumina MiSeq instrument and analyzed with the STACKS de novo pipeline for loci assembly and Single Nucleotide Polymorphism (SNP) discovery. Preliminary population genomic analyses (global AMOVA and Bayesian clustering) were implemented. Our results showed that the 2b-RAD genotyping protocol is effective for R. ecuadoriensis and likely for other triatomine species. However, only BcgI and CspCI restriction enzymes provided a number of markers suitable for population genomic analysis at the read depth we generated. Our preliminary genomic analyses detected a signal of genetic structuring across the study area. Our findings suggest that 2b-RAD genotyping is both a cost effective and methodologically simple approach for generating high resolution genomic data for Chagas disease vectors with the power to distinguish between different vector populations at epidemiologically relevant scales. As such, 2b-RAD represents a powerful tool in the hands of medical entomologists with limited access to specialized molecular biological equipment.

ATGC database and ATGC-COGs: an updated resource for micro- and macro-evolutionary studies of prokaryotic genomes and protein family annotation.

PubMed

Kristensen, David M; Wolf, Yuri I; Koonin, Eugene V

2017-01-04

The Alignable Tight Genomic Clusters (ATGCs) database is a collection of closely related bacterial and archaeal genomes that provides several tools to aid research into evolutionary processes in the microbial world. Each ATGC is a taxonomy-independent cluster of 2 or more completely sequenced genomes that meet the objective criteria of a high degree of local gene order (synteny) and a small number of synonymous substitutions in the protein-coding genes. As such, each ATGC is suited for analysis of microevolutionary variations within a cohesive group of organisms (e.g. species), whereas the entire collection of ATGCs is useful for macroevolutionary studies. The ATGC database includes many forms of pre-computed data, in particular ATGC-COGs (Clusters of Orthologous Genes), multiple sequence alignments, a set of 'index' orthologs representing the most well-conserved members of each ATGC-COG, the phylogenetic tree of the organisms within each ATGC, etc. Although the ATGC database contains several million proteins from thousands of genomes organized into hundreds of clusters (roughly a 4-fold increase since the last version of the ATGC database), it is now built with completely automated methods and will be regularly updated following new releases of the NCBI RefSeq database. The ATGC database is hosted jointly at the University of Iowa at dmk-brain.ecn.uiowa.edu/ATGC/ and the NCBI at ftp.ncbi.nlm.nih.gov/pub/kristensen/ATGC/atgc_home.html. Published by Oxford University Press on behalf of Nucleic Acids Research 2016. This work is written by (a) US Government employee(s) and is in the public domain in the US.

2b-RAD genotyping for population genomic studies of Chagas disease vectors: Rhodnius ecuadoriensis in Ecuador

PubMed Central

Villacís, Anita G.; Andersson, Björn; Costales, Jaime A.; De Noia, Michele; Ocaña-Mayorga, Sofía; Yumiseva, Cesar A.; Grijalva, Mario J.; Llewellyn, Martin S.

2017-01-01

Background Rhodnius ecuadoriensis is the main triatomine vector of Chagas disease, American trypanosomiasis, in Southern Ecuador and Northern Peru. Genomic approaches and next generation sequencing technologies have become powerful tools for investigating population diversity and structure which is a key consideration for vector control. Here we assess the effectiveness of three different 2b restriction site-associated DNA (2b-RAD) genotyping strategies in R. ecuadoriensis to provide sufficient genomic resolution to tease apart microevolutionary processes and undertake some pilot population genomic analyses. Methodology/Principal findings The 2b-RAD protocol was carried out in-house at a non-specialized laboratory using 20 R. ecuadoriensis adults collected from the central coast and southern Andean region of Ecuador, from June 2006 to July 2013. 2b-RAD sequencing data was performed on an Illumina MiSeq instrument and analyzed with the STACKS de novo pipeline for loci assembly and Single Nucleotide Polymorphism (SNP) discovery. Preliminary population genomic analyses (global AMOVA and Bayesian clustering) were implemented. Our results showed that the 2b-RAD genotyping protocol is effective for R. ecuadoriensis and likely for other triatomine species. However, only BcgI and CspCI restriction enzymes provided a number of markers suitable for population genomic analysis at the read depth we generated. Our preliminary genomic analyses detected a signal of genetic structuring across the study area. Conclusions/Significance Our findings suggest that 2b-RAD genotyping is both a cost effective and methodologically simple approach for generating high resolution genomic data for Chagas disease vectors with the power to distinguish between different vector populations at epidemiologically relevant scales. As such, 2b-RAD represents a powerful tool in the hands of medical entomologists with limited access to specialized molecular biological equipment. PMID:28723901

The genetic architecture of novel trophic specialists: larger effect sizes are associated with exceptional oral jaw diversification in a pupfish adaptive radiation.

PubMed

Martin, Christopher H; Erickson, Priscilla A; Miller, Craig T

2017-01-01

The genetic architecture of adaptation is fundamental to understanding the mechanisms and constraints governing diversification. However, most case studies focus on loss of complex traits or parallel speciation in similar environments. It is still unclear how the genetic architecture of these local adaptive processes compares to the architecture of evolutionary transitions contributing to morphological and ecological novelty. Here, we identify quantitative trait loci (QTL) between two trophic specialists in an excellent case study for examining the origins of ecological novelty: a sympatric radiation of pupfishes endemic to San Salvador Island, Bahamas, containing a large-jawed scale-eater and a short-jawed molluscivore with a skeletal nasal protrusion. These specialized niches and trophic traits are unique among over 2000 related species. Measurements of the fitness landscape on San Salvador demonstrate multiple fitness peaks and a larger fitness valley isolating the scale-eater from the putative ancestral intermediate phenotype of the generalist, suggesting that more large-effect QTL should contribute to its unique phenotype. We evaluated this prediction using an F2 intercross between these specialists. We present the first linkage map for pupfishes and detect significant QTL for sex and eight skeletal traits. Large-effect QTL contributed more to enlarged scale-eater jaws than the molluscivore nasal protrusion, consistent with predictions from the adaptive landscape. The microevolutionary genetic architecture of large-effect QTL for oral jaws parallels the exceptional diversification rates of oral jaws within the San Salvador radiation observed over macroevolutionary timescales and may have facilitated exceptional trophic novelty in this system. © 2016 John Wiley & Sons Ltd.

Characterization of major histocompatibility complex class I, and class II DRB loci of captive and wild Indian leopards (Panthera pardus fusca).

PubMed

Parmar, Drashti R; Mitra, Siuli; Bhadouriya, Snehalata; Rao, Tirupathi; Kunteepuram, Vaishnavi; Gaur, Ajay

2017-12-01

The major histocompatibility complex (MHC), in vertebrate animals, is a multi-genic protein complex that encodes various receptors. During a disease, MHC interacts with the antigen and triggers a cascade of adaptive immune responses to overcome a disease outbreak. The MHC is very important region from immunological point of view, but it is poorly characterized among Indian leopards. During this investigation, we examined genetic diversity for MHC class I (MHC-I) and MHC class II-DRB (MHC-II) among wild and captive Indian leopards. This study estimated a pool of 9 and 17 alleles for MHC-I and MHC-II, respectively. The wild group of individuals showed higher nucleotide diversity and amino acid polymorphism compared to the captive group. A phylogenetic comparison with other felids revealed a clustering in MHC-I and interspersed presence in MHC-II sequences. A test for selection also revealed a deviation from neutrality at MHC-II DRB loci and higher non-synonymous substitution rate (dN) among the individuals from wild group. Further, the wild individuals showed higher dN for both MHC I and II genes compared to the group that was bred under captive conditions. These findings suggest the role of micro-evolutionary forces, such as pathogen-mediated selection, to cause MHC variations among the two groups of Indian leopards, because the two groups have been bred in two different environments for a substantial period of time. Since, MHC diversity is often linked with the quality of immunological health; the results obtained from this study fill the gap of knowledge on disease predisposition among wild and captive Indian leopards.

Balancing selection and genetic drift create unusual patterns of MHCIIβ variation in Galápagos mockingbirds.

PubMed

Vlček, Jakub; Hoeck, Paquita E A; Keller, Lukas F; Wayhart, Jessica P; Dolinová, Iva; Štefka, Jan

2016-10-01

The extracellular subunit of the major histocompatibility complex MHCIIβ plays an important role in the recognition of pathogens and the initiation of the adaptive immune response of vertebrates. It is widely accepted that pathogen-mediated selection in combination with neutral micro-evolutionary forces (e.g. genetic drift) shape the diversity of MHCIIβ, but it has proved difficult to determine the relative effects of these forces. We evaluated the effect of genetic drift and balancing selection on MHCIIβ diversity in 12 small populations of Galápagos mockingbirds belonging to four different species, and one larger population of the Northern mockingbird from the continental USA. After genotyping MHCIIβ loci by high-throughput sequencing, we applied a correlational approach to explore the relationships between MHCIIβ diversity and population size by proxy of island size. As expected when drift predominates, we found a positive effect of population size on the number of MHCIIβ alleles present in a population. However, the number of MHCIIβ alleles per individual and number of supertypes were not correlated with population size. This discrepancy points to an interesting feature of MHCIIβ diversity dynamics: some levels of diversity might be shaped by genetic drift while others are independent and possibly maintained by balancing selection. © 2016 John Wiley & Sons Ltd.

The micro and macro of nutrients across biological scales.

PubMed

Warne, Robin W

2014-11-01

During the past decade, we have gained new insights into the profound effects that essential micronutrients and macronutrients have on biological processes ranging from cellular function, to whole-organism performance, to dynamics in ecological communities, as well as to the structure and function of ecosystems. For example, disparities between intake and organismal requirements for specific nutrients are known to strongly affect animal physiological performance and impose trade-offs in the allocations of resources. However, recent findings have demonstrated that life-history allocation trade-offs and even microevolutionary dynamics may often be a result of molecular-level constraints on nutrient and metabolic processing, in which limiting reactants are routed among competing biochemical pathways. In addition, recent work has shown that complex ecological interactions between organismal physiological states such as exposure to environmental stressors and infectious pathogens can alter organismal requirements for, and, processing of, nutrients, and even alter subsequent nutrient cycling in ecosystems. Furthermore, new research is showing that such interactions, coupled with evolutionary and biogeographical constraints on the biosynthesis and availability of essential nutrients and micronutrients play an important, but still under-studied role in the structuring and functioning of ecosystems. The purpose of this introduction to the symposium "The Micro and Macro of Nutrient Effects in Animal Physiology and Ecology" is to briefly review and highlight recent research that has dramatically advanced our understanding of how nutrients in their varied forms profoundly affect and shape ecological and evolutionary processes. © The Author 2014. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

Macroevolutionary Immunology: A Role for Immunity in the Diversification of Animal life

PubMed Central

Loker, Eric S.

2012-01-01

An emerging picture of the nature of immune systems across animal phyla reveals both conservatism of some features and the appearance among and within phyla of novel, lineage-specific defense solutions. The latter collectively represent a major and underappreciated form of animal diversity. Factors influencing this macroevolutionary (above the species level) pattern of novelty are considered and include adoption of different life styles, life histories, and body plans; a general advantage of being distinctive with respect to immune defenses; and the responses required to cope with parasites, many of which afflict hosts in a lineage-specific manner. This large-scale pattern of novelty implies that immunological phenomena can affect microevolutionary processes (at the population level within species) that can eventually lead to macroevolutionary events such as speciation, radiations, or extinctions. Immunologically based phenomena play a role in favoring intraspecific diversification, specialization and host specificity of parasites, and mechanisms are discussed whereby this could lead to parasite speciation. Host switching – the acquisition of new host species by parasites – is a major mechanism that drives parasite diversity and is frequently involved in disease emergence. It is also one that can be favored by reductions in immune competence of new hosts. Mechanisms involving immune phenomena favoring intraspecific diversification and speciation of host species are also discussed. A macroevolutionary perspective on immunology is invaluable in today’s world, including the need to study a broader range of species with distinctive immune systems. Many of these species are faced with extinction, another macroevolutionary process influenced by immune phenomena. PMID:22566909

Local topography shapes fine-scale spatial genetic structure in the Arkansas Valley evening primrose, Oenothera harringtonii (Onagraceae).

PubMed

Rhodes, Matthew K; Fant, Jeremie B; Skogen, Krissa A

2014-01-01

Identifying factors that shape the spatial distribution of genetic variation is crucial to understanding many population- and landscape-level processes. In this study, we explore fine-scale spatial genetic structure in Oenothera harringtonii (Onagraceae), an insect-pollinated, gravity-dispersed herb endemic to the grasslands of south-central and southeastern Colorado, USA. We genotyped 315 individuals with 11 microsatellite markers and utilized a combination of spatial autocorrelation analyses and landscape genetic models to relate life history traits and landscape features to dispersal processes. Spatial genetic structure was consistent with theoretical expectations of isolation by distance, but this pattern was weak (Sp = 0.00374). Anisotropic analyses indicated that spatial genetic structure was markedly directional, in this case consistent with increased dispersal along prominent slopes. Landscape genetic models subsequently confirmed that spatial genetic variation was significantly influenced by local topographic heterogeneity, specifically that geographic distance, elevation and aspect were important predictors of spatial genetic structure. Among these variables, geographic distance was ~68% more important than elevation in describing spatial genetic variation, and elevation was ~42% more important than aspect after removing the effect of geographic distance. From these results, we infer a mechanism of hydrochorous seed dispersal along major drainages aided by seasonal monsoon rains. Our findings suggest that landscape features may shape microevolutionary processes at much finer spatial scales than typically considered, and stress the importance of considering how particular dispersal vectors are influenced by their environmental context. © The American Genetic Association 2014. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Pan-vertebrate comparative genomics unmasks retrovirus macroevolution.

PubMed

Hayward, Alexander; Cornwallis, Charlie K; Jern, Patric

2015-01-13

Although extensive research has demonstrated host-retrovirus microevolutionary dynamics, it has been difficult to gain a deeper understanding of the macroevolutionary patterns of host-retrovirus interactions. Here we use recent technological advances to infer broad patterns in retroviral diversity, evolution, and host-virus relationships by using a large-scale phylogenomic approach using endogenous retroviruses (ERVs). Retroviruses insert a proviral DNA copy into the host cell genome to produce new viruses. ERVs are provirus insertions in germline cells that are inherited down the host lineage and consequently present a record of past host-viral associations. By mining ERVs from 65 host genomes sampled across vertebrate diversity, we uncover a great diversity of ERVs, indicating that retroviral sequences are much more prevalent and widespread across vertebrates than previously appreciated. The majority of ERV clades that we recover do not contain known retroviruses, implying either that retroviral lineages are highly transient over evolutionary time or that a considerable number of retroviruses remain to be identified. By characterizing the distribution of ERVs, we show that no major vertebrate lineage has escaped retroviral activity and that retroviruses are extreme host generalists, having an unprecedented ability for rampant host switching among distantly related vertebrates. In addition, we examine whether the distribution of ERVs can be explained by host factors predicted to influence viral transmission and find that internal fertilization has a pronounced effect on retroviral colonization of host genomes. By capturing the mode and pattern of retroviral evolution and contrasting ERV diversity with known retroviral diversity, our study provides a cohesive framework to understand host-virus coevolution better.

Pan-vertebrate comparative genomics unmasks retrovirus macroevolution

PubMed Central

Hayward, Alexander; Cornwallis, Charlie K.; Jern, Patric

2015-01-01

Although extensive research has demonstrated host-retrovirus microevolutionary dynamics, it has been difficult to gain a deeper understanding of the macroevolutionary patterns of host–retrovirus interactions. Here we use recent technological advances to infer broad patterns in retroviral diversity, evolution, and host–virus relationships by using a large-scale phylogenomic approach using endogenous retroviruses (ERVs). Retroviruses insert a proviral DNA copy into the host cell genome to produce new viruses. ERVs are provirus insertions in germline cells that are inherited down the host lineage and consequently present a record of past host–viral associations. By mining ERVs from 65 host genomes sampled across vertebrate diversity, we uncover a great diversity of ERVs, indicating that retroviral sequences are much more prevalent and widespread across vertebrates than previously appreciated. The majority of ERV clades that we recover do not contain known retroviruses, implying either that retroviral lineages are highly transient over evolutionary time or that a considerable number of retroviruses remain to be identified. By characterizing the distribution of ERVs, we show that no major vertebrate lineage has escaped retroviral activity and that retroviruses are extreme host generalists, having an unprecedented ability for rampant host switching among distantly related vertebrates. In addition, we examine whether the distribution of ERVs can be explained by host factors predicted to influence viral transmission and find that internal fertilization has a pronounced effect on retroviral colonization of host genomes. By capturing the mode and pattern of retroviral evolution and contrasting ERV diversity with known retroviral diversity, our study provides a cohesive framework to understand host–virus coevolution better. PMID:25535393

Spatially Explicit Models to Investigate Geographic Patterns in the Distribution of Forensic STRs: Application to the North-Eastern Mediterranean.

PubMed

Messina, Francesco; Finocchio, Andrea; Akar, Nejat; Loutradis, Aphrodite; Michalodimitrakis, Emmanuel I; Brdicka, Radim; Jodice, Carla; Novelletto, Andrea

2016-01-01

Human forensic STRs used for individual identification have been reported to have little power for inter-population analyses. Several methods have been developed which incorporate information on the spatial distribution of individuals to arrive at a description of the arrangement of diversity. We genotyped at 16 forensic STRs a large population sample obtained from many locations in Italy, Greece and Turkey, i.e. three countries crucial to the understanding of discontinuities at the European/Asian junction and the genetic legacy of ancient migrations, but seldom represented together in previous studies. Using spatial PCA on the full dataset, we detected patterns of population affinities in the area. Additionally, we devised objective criteria to reduce the overall complexity into reduced datasets. Independent spatially explicit methods applied to these latter datasets converged in showing that the extraction of information on long- to medium-range geographical trends and structuring from the overall diversity is possible. All analyses returned the picture of a background clinal variation, with regional discontinuities captured by each of the reduced datasets. Several aspects of our results are confirmed on external STR datasets and replicate those of genome-wide SNP typings. High levels of gene flow were inferred within the main continental areas by coalescent simulations. These results are promising from a microevolutionary perspective, in view of the fast pace at which forensic data are being accumulated for many locales. It is foreseeable that this will allow the exploitation of an invaluable genotypic resource, assembled for other (forensic) purposes, to clarify important aspects in the formation of local gene pools.

Assessment of biochemical mechanisms of tolerance to chlorpyrifos in ancient and contemporary Daphnia pulicaria genotypes.

PubMed

Simpson, Adam M; Jeyasingh, Punidan D; Belden, Jason B

2017-12-01

The evolution of tolerance to environmental contaminants in non-target taxa has been largely studied by comparing extant populations experiencing contrasting exposure. Previous research has demonstrated that "resurrected" genotypes from a population of Daphnia pulicaria express temporal variation in sensitivity to the insecticide chlorpyrifos. Ancient genotypes (1301-1646AD.) were on average more sensitive to this chemical compared to the contemporary genotypes (1967-1977AD.). To determine the physiological mechanisms of tolerance, a series of biochemical assays was performed on three ancient and three contemporary genotypes; these six genotypes exhibited the most sensitive and most tolerant phenotypes within the population, respectively. Metabolic tolerance mechanisms were evaluated using acute toxicity testing, while target-site tolerance was assessed via in vitro acetylcholinesterase (AChE) assays. Acute toxicity tests were conducted using i) the toxic metabolite chlorpyrifos-oxon (CPF-oxon) and ii) CPF-oxon co-applied with piperonyl butoxide (PBO), a known Phase-I metabolic inhibitor. Both series of toxicity tests reduced the mean variation in sensitivity between tolerant and sensitive genotypes. Exposure to CPF-O reduced the disparity from a 4.7-fold to 1.6-fold difference in sensitivity. The addition of PBO further reduced the variation to a 1.2-fold difference in sensitivity. In vitro acetylcholinesterase assays yielded no significant differences in constitutive activity or target-site sensitivity. These findings suggest that pathways involving Phase-I detoxification and/or bioactivation of chlorpyrifos play a significant role in dictating the microevolutionary trajectories of tolerance in this population. Copyright © 2017 Elsevier B.V. All rights reserved.

Distribution and predictors of wing shape and size variability in three sister species of solitary bees

PubMed Central

Prunier, Jérôme G.; Dewulf, Alexandre; Kuhlmann, Michael; Michez, Denis

2017-01-01

Morphological traits can be highly variable over time in a particular geographical area. Different selective pressures shape those traits, which is crucial in evolutionary biology. Among these traits, insect wing morphometry has already been widely used to describe phenotypic variability at the inter-specific level. On the contrary, fewer studies have focused on intra-specific wing morphometric variability. Yet, such investigations are relevant to study potential convergences of variation that could highlight micro-evolutionary processes. The recent sampling and sequencing of three solitary bees of the genus Melitta across their entire species range provides an excellent opportunity to jointly analyse genetic and morphometric variability. In the present study, we first aim to analyse the spatial distribution of the wing shape and centroid size (used as a proxy for body size) variability. Secondly, we aim to test different potential predictors of this variability at both the intra- and inter-population levels, which includes genetic variability, but also geographic locations and distances, elevation, annual mean temperature and precipitation. The comparison of spatial distribution of intra-population morphometric diversity does not reveal any convergent pattern between species, thus undermining the assumption of a potential local and selective adaptation at the population level. Regarding intra-specific wing shape differentiation, our results reveal that some tested predictors, such as geographic and genetic distances, are associated with a significant correlation for some species. However, none of these predictors are systematically identified for the three species as an important factor that could explain the intra-specific morphometric variability. As a conclusion, for the three solitary bee species and at the scale of this study, our results clearly tend to discard the assumption of the existence of a common pattern of intra-specific signal/structure within the intra-specific wing shape and body size variability. PMID:28273178

Covariance structure in the skull of Catarrhini: a case of pattern stasis and magnitude evolution.

PubMed

de Oliveira, Felipe Bandoni; Porto, Arthur; Marroig, Gabriel

2009-04-01

The study of the genetic variance/covariance matrix (G-matrix) is a recent and fruitful approach in evolutionary biology, providing a window of investigating for the evolution of complex characters. Although G-matrix studies were originally conducted for microevolutionary timescales, they could be extrapolated to macroevolution as long as the G-matrix remains relatively constant, or proportional, along the period of interest. A promising approach to investigating the constancy of G-matrices is to compare their phenotypic counterparts (P-matrices) in a large group of related species; if significant similarity is found among several taxa, it is very likely that the underlying G-matrices are also equivalent. Here we study the similarity of covariance and correlation structure in a broad sample of Old World monkeys and apes (Catarrhini). We made phylogenetically structured comparisons of correlation and covariance matrices derived from 39 skull traits, ranging from between species to the superfamily level. We also compared the overall magnitude of integration between skull traits (r2) for all Catarrhini genera. Our results show that P-matrices were not strictly constant among catarrhines, but the amount of divergence observed among taxa was generally low. There was significant and positive correlation between the amount of divergence in correlation and covariance patterns among the 30 genera and their phylogenetic distances derived from a recently proposed phylogenetic hypothesis. Our data demonstrate that the P-matrices remained relatively similar along the evolutionary history of catarrhines, and comparisons with the G-matrix available for a New World monkey genus (Saguinus) suggests that the same holds for all anthropoids. The magnitude of integration, in contrast, varied considerably among genera, indicating that evolution of the magnitude, rather than the pattern of inter-trait correlations, might have played an important role in the diversification of the catarrhine skull.

Can plant resistance to specialist herbivores be explained by plant chemistry or resource use strategy?

PubMed

Kirk, Heather; Vrieling, Klaas; Pelser, Pieter B; Schaffner, Urs

2012-04-01

At both a macro- and micro-evolutionary level, selection of and performance on host plants by specialist herbivores are thought to be governed partially by host plant chemistry. Thus far, there is little evidence to suggest that specialists can detect small structural differences in secondary metabolites of their hosts, or that such differences affect host choice or performance of specialists. We tested whether phytochemical differences between closely related plant species are correlated with specialist host choice. We conducted no-choice feeding trials using 17 plant species of three genera of tribe Senecioneae (Jacobaea, Packera, and Senecio; Asteraceae) and a more distantly related species (Cynoglossum officinale; Boraginaceae) containing pyrrolizidine alkaloids (PAs), and four PA-sequestering specialist herbivores of the genus Longitarsus (Chrysomelidae). We also assessed whether variation in feeding by specialist herbivores is attributable to different resource use strategies of the tested plant species. Plant resource use strategy was quantified by measuring leaf dry matter content, which is related to both plant nutritive value and to plant investment in quantitative defences. We found no evidence that intra-generic differences in PA profiles affect feeding by specialist herbivores. Instead, our results indicate that decisions to begin feeding are related to plant resource use strategy, while decisions to continue feeding are not based on any plant characteristics measured in this study. These findings imply that PA composition does not significantly affect host choice by these specialist herbivores. Leaf dry matter content is somewhat phylogenetically conserved, indicating that plants may have difficulty altering resource use strategy in response to selection pressure by herbivores and other environmental factors on an evolutionary time scale.

Diversification of the Salmonella Fimbriae: A Model of Macro- and Microevolution

PubMed Central

Yue, Min; Rankin, Shelley C.; Blanchet, Ryan T.; Nulton, James D.; Edwards, Robert A.; Schifferli, Dieter M.

2012-01-01

Bacteria of the genus Salmonella comprise a large and evolutionary related population of zoonotic pathogens that can infect mammals, including humans and domestic animals, birds, reptiles and amphibians. Salmonella carries a plethora of virulence genes, including fimbrial adhesins, some of them known to participate in mammalian or avian host colonization. Each type of fimbria has its structural subunit and biogenesis genes encoded by one fimbrial gene cluster (FGC). The accumulation of new genomic information offered a timely opportunity to better evaluate the number and types of FGCs in the Salmonella pangenome, to test the use of current classifications based on phylogeny, and to infer potential correlations between FGC evolution in various Salmonella serovars and host niches. This study focused on the FGCs of the currently deciphered 90 genomes and 60 plasmids of Salmonella. The analysis highlighted a fimbriome consisting of 35 different FGCs, of which 16 were new, each strain carrying between 5 and 14 FGCs. The Salmonella fimbriome was extremely diverse with FGC representatives in 8 out of 9 previously categorized fimbrial clades and subclades. Phylogenetic analysis of Salmonella suggested macroevolutionary shifts detectable by extensive FGC deletion and acquisition. In addition, microevolutionary drifts were best depicted by the high level of allelic variation in predicted or known adhesins, such as the type 1 fimbrial adhesin FimH for which 67 different natural alleles were identified in S. enterica subsp. I. Together with strain-specific collections of FGCs, allelic variation among adhesins attested to the pathoadaptive evolution of Salmonella towards specific hosts and tissues, potentially modulating host range, strain virulence, disease progression, and transmission efficiency. Further understanding of how each Salmonella strain utilizes its panel of FGCs and specific adhesin alleles for survival and infection will support the development of new approaches for the control of Salmonellosis. PMID:22701679

Spatially Explicit Models to Investigate Geographic Patterns in the Distribution of Forensic STRs: Application to the North-Eastern Mediterranean

PubMed Central

Messina, Francesco; Finocchio, Andrea; Akar, Nejat; Loutradis, Aphrodite; Michalodimitrakis, Emmanuel I.; Brdicka, Radim; Jodice, Carla

2016-01-01

Human forensic STRs used for individual identification have been reported to have little power for inter-population analyses. Several methods have been developed which incorporate information on the spatial distribution of individuals to arrive at a description of the arrangement of diversity. We genotyped at 16 forensic STRs a large population sample obtained from many locations in Italy, Greece and Turkey, i.e. three countries crucial to the understanding of discontinuities at the European/Asian junction and the genetic legacy of ancient migrations, but seldom represented together in previous studies. Using spatial PCA on the full dataset, we detected patterns of population affinities in the area. Additionally, we devised objective criteria to reduce the overall complexity into reduced datasets. Independent spatially explicit methods applied to these latter datasets converged in showing that the extraction of information on long- to medium-range geographical trends and structuring from the overall diversity is possible. All analyses returned the picture of a background clinal variation, with regional discontinuities captured by each of the reduced datasets. Several aspects of our results are confirmed on external STR datasets and replicate those of genome-wide SNP typings. High levels of gene flow were inferred within the main continental areas by coalescent simulations. These results are promising from a microevolutionary perspective, in view of the fast pace at which forensic data are being accumulated for many locales. It is foreseeable that this will allow the exploitation of an invaluable genotypic resource, assembled for other (forensic) purposes, to clarify important aspects in the formation of local gene pools. PMID:27898725

Mega-evolutionary dynamics of the adaptive radiation of birds.

PubMed

Cooney, Christopher R; Bright, Jen A; Capp, Elliot J R; Chira, Angela M; Hughes, Emma C; Moody, Christopher J A; Nouri, Lara O; Varley, Zoë K; Thomas, Gavin H

2017-02-16

The origin and expansion of biological diversity is regulated by both developmental trajectories and limits on available ecological niches. As lineages diversify, an early and often rapid phase of species and trait proliferation gives way to evolutionary slow-downs as new species pack into ever more densely occupied regions of ecological niche space. Small clades such as Darwin's finches demonstrate that natural selection is the driving force of adaptive radiations, but how microevolutionary processes scale up to shape the expansion of phenotypic diversity over much longer evolutionary timescales is unclear. Here we address this problem on a global scale by analysing a crowdsourced dataset of three-dimensional scanned bill morphology from more than 2,000 species. We find that bill diversity expanded early in extant avian evolutionary history, before transitioning to a phase dominated by packing of morphological space. However, this early phenotypic diversification is decoupled from temporal variation in evolutionary rate: rates of bill evolution vary among lineages but are comparatively stable through time. We find that rare, but major, discontinuities in phenotype emerge from rapid increases in rate along single branches, sometimes leading to depauperate clades with unusual bill morphologies. Despite these jumps between groups, the major axes of within-group bill-shape evolution are remarkably consistent across birds. We reveal that macroevolutionary processes underlying global-scale adaptive radiations support Darwinian and Simpsonian ideas of microevolution within adaptive zones and accelerated evolution between distinct adaptive peaks.

Building of an Experimental Cline With Arabidopsis thaliana to Estimate Herbicide Fitness Cost

PubMed Central

Roux, Fabrice; Giancola, Sandra; Durand, Stéphanie; Reboud, Xavier

2006-01-01

Various management strategies aim at maintaining pesticide resistance frequency under a threshold value by taking advantage of the benefit of the fitness penalty (the cost) expressed by the resistance allele outside the treated area or during the pesticide selection “off years.” One method to estimate a fitness cost is to analyze the resistance allele frequency along transects across treated and untreated areas. On the basis of the shape of the cline, this method gives the relative contributions of both gene flow and the fitness difference between genotypes in the treated and untreated areas. Taking advantage of the properties of such migration–selection balance, an artificial cline was built up to optimize the conditions where the fitness cost of two herbicide-resistant mutants (acetolactate synthase and auxin-induced target genes) in the model species Arabidopsis thaliana could be more accurately measured. The analysis of the microevolutionary dynamics in these experimental populations indicated mean fitness costs of ∼15 and 92% for the csr1-1 and axr2-1 resistances, respectively. In addition, negative frequency dependence for the fitness cost was also detected for the axr2-1 resistance. The advantages and disadvantages of the cline approach are discussed in regard to other methods of cost estimation. This comparison highlights the powerful ability of an experimental cline to measure low fitness costs and detect sensibility to frequency-dependent variations. PMID:16582450

Quasispecies evolution of the prototypical genotype 1 porcine reproductive and respiratory syndrome virus early during in vivo infection is rapid and tissue specific.

PubMed

Lu, Zen H; Wang, Xinglong; Wilson, Alison D; Dorey-Robinson, Daniel L W; Archibald, Alan L; Ait-Ali, Tahar; Frossard, Jean-Pierre

2017-08-01

Porcine reproductive and respiratory syndrome virus (PRRSV) is a major infectious threat to the pig industry worldwide. Increasing evidence suggests that microevolution within a quasispecies population can give rise to high sequence heterogeneity in PRRSV; potentially impacting the pathogenicity of the virus. Here, we report on micro-evolutionary events taking place within the viral quasispecies population in lung and lymph node 3 days post infection (dpi) following experimental in vivo infection with the prototypical Lelystad PRRSV (LV). Sequence analysis revealed 16 high frequency single nucleotide variants (SNV) or differences from the reference LV genome which are assumed to be representative of the consensus inoculum genome. Additionally, 49 other low frequency SNVs were also found in the inoculum population. At 3 dpi, a total of 9 and 10 SNVs of varying frequencies could already be detected in the LV population infecting the lung and lymph nodes, respectively. Interestingly, of these, three and four novel SNVs emerged independently in the two respective tissues when compared to the inoculum. The remaining variants, though already present at lower frequencies in the inoculum, were positively selected and their frequency increased within the quasispecies population. Hence, we were able to determine directly from tissues infected with PRRSV the repertoire of genetic variants within the viral quasispecies population. Our data also suggest that microevolution of these variants is rapid and some may be tissue-specific.

Mega-evolutionary dynamics of the adaptive radiation of birds

PubMed Central

Capp, Elliot J. R.; Chira, Angela M.; Hughes, Emma C.; Moody, Christopher J. A.; Nouri, Lara O.; Varley, Zoë K.; Thomas, Gavin H.

2017-01-01

The origin and expansion of biological diversity is regulated by both developmental trajectories1,2 and limits on available ecological niches3–7. As lineages diversify an early, often rapid, phase of species and trait proliferation gives way to evolutionary slowdowns as new species pack into ever more densely occupied regions of ecological niche space6,8. Small clades such as Darwin’s finches demonstrate that natural selection is the driving force of adaptive radiations, but how microevolutionary processes scale up to shape the expansion of phenotypic diversity over much longer evolutionary timescales is unclear9. Here we address this problem on a global scale by analysing a novel crowd-sourced dataset of 3D-scanned bill morphology from >2000 species. We find that bill diversity expanded early in extant avian evolutionary history before transitioning to a phase dominated by morphospace packing. However, this early phenotypic diversification is decoupled from temporal variation in evolutionary rate: rates of bill evolution vary among lineages but are comparatively stable through time. We find that rare but major discontinuities in phenotype emerge from rapid increases in rate along single branches, sometimes leading to depauperate clades with unusual bill morphologies. Despite these jumps between groups, the major axes of within-group bill shape evolution are remarkably consistent across birds. We reveal that macroevolutionary processes underlying global-scale adaptive radiations support Darwinian9 and Simpsonian4 ideas of microevolution within adaptive zones and accelerated evolution between distinct adaptive peaks. PMID:28146475

Replicon-dependent differentiation of symbiosis-related genes in Sinorhizobium strains nodulating Glycine max.

PubMed

Guo, Hui Juan; Wang, En Tao; Zhang, Xing Xing; Li, Qin Qin; Zhang, Yan Ming; Tian, Chang Fu; Chen, Wen Xin

2014-02-01

In order to investigate the genetic differentiation of Sinorhizobium strains nodulating Glycine max and related microevolutionary mechanisms, three housekeeping genes (SMc00019, truA, and thrA) and 16 symbiosis-related genes on the chromosome (7 genes), pSymA (6 genes), and pSymB (3 genes) were analyzed. Five distinct species were identified among the test strains by calculating the average nucleotide identity (ANI) of SMc00019-truA-thrA: Sinorhizobium fredii, Sinorhizobium sojae, Sinorhizobium sp. I, Sinorhizobium sp. II, and Sinorhizobium sp. III. These species assignments were also supported by population genetics and phylogenetic analyses of housekeeping genes and symbiosis-related genes on the chromosome and pSymB. Different levels of genetic differentiation were observed among these species or different replicons. S. sojae was the most divergent from the other test species and was characterized by its low intraspecies diversity and limited geographic distribution. Intergenic recombination dominated the evolution of 19 genes from different replicons. Intraspecies recombination happened frequently in housekeeping genes and symbiosis-related genes on the chromosome and pSymB, whereas pSymA genes showed a clear pattern of lateral-transfer events between different species. Moreover, pSymA genes were characterized by a lower level of polymorphism and recombination than those on the chromosome and pSymB. Taken together, genes from different replicons of rhizobia might be involved in the establishment of symbiosis with legumes, but these symbiosis-related genes might have evolved differently according to their corresponding replicons.

Tradeoff between robustness and elaboration in carotenoid networks produces cycles of avian color diversification.

PubMed

Badyaev, Alexander V; Morrison, Erin S; Belloni, Virginia; Sanderson, Michael J

2015-08-20

Resolution of the link between micro- and macroevolution calls for comparing both processes on the same deterministic landscape, such as genomic, metabolic or fitness networks. We apply this perspective to the evolution of carotenoid pigmentation that produces spectacular diversity in avian colors and show that basic structural properties of the underlying carotenoid metabolic network are reflected in global patterns of elaboration and diversification in color displays. Birds color themselves by consuming and metabolizing several dietary carotenoids from the environment. Such fundamental dependency on the most upstream external compounds should intrinsically constrain sustained evolutionary elongation of multi-step metabolic pathways needed for color elaboration unless the metabolic network gains robustness - the ability to synthesize the same carotenoid from an additional dietary starting point. We found that gains and losses of metabolic robustness were associated with evolutionary cycles of elaboration and stasis in expressed carotenoids in birds. Lack of metabolic robustness constrained lineage's metabolic explorations to the immediate biochemical vicinity of their ecologically distinct dietary carotenoids, whereas gains of robustness repeatedly resulted in sustained elongation of metabolic pathways on evolutionary time scales and corresponding color elaboration. The structural link between length and robustness in metabolic pathways may explain periodic convergence of phylogenetically distant and ecologically distinct species in expressed carotenoid pigmentation; account for stasis in carotenoid colors in some ecological lineages; and show how the connectivity of the underlying metabolic network provides a mechanistic link between microevolutionary elaboration and macroevolutionary diversification.

Linguistic, geographic and genetic isolation: a collaborative study of Italian populations.

PubMed

Capocasa, Marco; Anagnostou, Paolo; Bachis, Valeria; Battaggia, Cinzia; Bertoncini, Stefania; Biondi, Gianfranco; Boattini, Alessio; Boschi, Ilaria; Brisighelli, Francesca; Caló, Carla Maria; Carta, Marilisa; Coia, Valentina; Corrias, Laura; Crivellaro, Federica; De Fanti, Sara; Dominici, Valentina; Ferri, Gianmarco; Francalacci, Paolo; Franceschi, Zelda Alice; Luiselli, Donata; Morelli, Laura; Paoli, Giorgio; Rickards, Olga; Robledo, Renato; Sanna, Daria; Sanna, Emanuele; Sarno, Stefania; Sineo, Luca; Taglioli, Luca; Tagarelli, Giuseppe; Tofanelli, Sergio; Vona, Giuseppe; Pettener, Davide; Destro Bisol, Giovanni

2014-01-01

The animal and plant biodiversity of the Italian territory is known to be one of the richest in the Mediterranean basin and Europe as a whole, but does the genetic diversity of extant human populations show a comparable pattern? According to a number of studies, the genetic structure of Italian populations retains the signatures of complex peopling processes which took place from the Paleolithic to modern era. Although the observed patterns highlight a remarkable degree of genetic heterogeneity, they do not, however, take into account an important source of variation. In fact, Italy is home to numerous ethnolinguistic minorities which have yet to be studied systematically. Due to their difference in geographical origin and demographic history, such groups not only signal the cultural and social diversity of our country, but they are also potential contributors to its bio-anthropological heterogeneity. To fill this gap, research groups from four Italian Universities (Bologna, Cagliari, Pisa and Roma Sapienza) started a collaborative study in 2007, which was funded by the Italian Ministry of Education, University and Research and received partial support by the Istituto Italiano di Antropologia. In this paper, we present an account of the results obtained in the course of this initiative. Four case-studies relative to linguistic minorities from the Eastern Alps, Sardinia, Apennines and Southern Italy are first described and discussed, focusing on their micro-evolutionary and anthropological implications. Thereafter, we present the results of a systematic analysis of the relations between linguistic, geographic and genetic isolation. Integrating the data obtained in the course of the long-term study with literature and unpublished results on Italian populations, we show that a combination of linguistic and geographic factors is probably responsible for the presence of the most robust signatures of genetic isolation. Finally, we evaluate the magnitude of the diversity of Italian populations in the European context. The human genetic diversity of our country was found to be greater than observed throughout the continent at short (0-200 km) and intermediate (700-800km) distances, and accounted for most of the highest values of genetic distances observed at all geographic ranges. Interestingly, an important contribution to this pattern comes from the "linguistic islands"( e.g. German speaking groups of Sappada and Luserna from the Eastern Italian Alps), further proof of the importance of considering social and cultural factors when studying human genetic variation.

Evolutionary ecology of Chagas disease; what do we know and what do we need?

PubMed

Flores-Ferrer, Alheli; Marcou, Olivier; Waleckx, Etienne; Dumonteil, Eric; Gourbière, Sébastien

2018-04-01

The aetiological agent of Chagas disease, Trypanosoma cruzi , is a key human pathogen afflicting most populations of Latin America. This vectorborne parasite is transmitted by haematophageous triatomines, whose control by large-scale insecticide spraying has been the main strategy to limit the impact of the disease for over 25 years. While those international initiatives have been successful in highly endemic areas, this systematic approach is now challenged by the emergence of insecticide resistance and by its low efficacy in controlling species that are only partially adapted to human habitat. In this contribution, we review evidences that Chagas disease control shall now be entering a second stage that will rely on a better understanding of triatomines adaptive potential, which requires promoting microevolutionary studies and -omic approaches. Concomitantly, we show that our knowledge of the determinants of the evolution of T. cruzi high diversity and low virulence remains too limiting to design evolution-proof strategies, while such attributes may be part of the future of Chagas disease control after the 2020 WHO's target of regional elimination of intradomiciliary transmission has been reached. We should then aim at developing a theory of T. cruzi virulence evolution that we anticipate to provide an interesting enrichment of the general theory according to the specificities of transmission of this very generalist stercorarian trypanosome. We stress that many ecological data required to better understand selective pressures acting on vector and parasite populations are already available as they have been meticulously accumulated in the last century of field research. Although more specific information will surely be needed, an effective research strategy would be to integrate data into the conceptual and theoretical framework of evolutionary ecology and life-history evolution that provide the quantitative backgrounds necessary to understand and possibly anticipate adaptive responses to public health interventions.

Control Region Variability of Haplogroup C1d and the Tempo of the Peopling of the Americas

PubMed Central

Figueiro, Gonzalo; Hidalgo, Pedro C.; Sans, Mónica

2011-01-01

Background Among the founding mitochondrial haplogroups involved in the peopling of the Americas, haplogroup C1d has been viewed as problematic because of its phylogeny and because of the estimates of its antiquity, apparently being much younger than other founding haplogroups. Several recent analyses, based on data from the entire mitochondrial genome, have contributed to an advance in the resolution of these problems. The aim of our analysis is to compare the conclusions drawn from the available HVR-I and HVR-II data for haplogroup C1d with the ones based on whole mitochondrial genomes. Methodology/Principal Findings HVR-I and HVR-II sequences defined as belonging to haplogroup C1d by standard criteria were gathered from the literature as well as from population studies carried out in Uruguay. Sequence phylogeny was reconstructed using median-joining networks, geographic distribution of lineages was analyzed and the age of the most recent common ancestor estimated using the ρ-statistic and two different mutation rates. The putative ancestral forms of the haplogroup were found to be more widespread than the derived lineages, and the lineages defined by np 194 were found to be widely distributed and of equivalent age. Conclusions/Significance The analysis of control region sequences is found to still harbor great potential in tracing microevolutionary phenomena, especially those found to have occurred in more recent times. Based on the geographic distributions of the alleles of np 7697 and np 194, both discussed as possible basal mutations of the C1d phylogeny, we suggest that both alleles were part of the variability of the haplogroup at the time of its entrance. Moreover, based on the mutation rates of the different sites stated to be diagnostic, it is possible that the anomalies found when analyzing the haplogroup are due to paraphyly. PMID:21695136

Response of the seagrass Posidonia oceanica to different light environments: Insights from a combined molecular and photo-physiological study.

PubMed

Dattolo, E; Ruocco, M; Brunet, C; Lorenti, M; Lauritano, C; D'Esposito, D; De Luca, P; Sanges, R; Mazzuca, S; Procaccini, G

2014-10-01

Here we investigated mechanisms underlying the acclimation to light in the marine angiosperm Posidonia oceanica, along its bathymetric distribution (at -5 m and -25 m), combining molecular and photo-physiological approaches. Analyses were performed during two seasons, summer and autumn, in a meadow located in the Island of Ischia (Gulf of Naples, Italy), where a genetic distinction between plants growing above and below the summer thermocline was previously revealed. At molecular level, analyses carried out using cDNA-microarray and RT-qPCR, revealed the up-regulation of genes involved in photoacclimation (RuBisCO, ferredoxin, chlorophyll binding proteins), and photoprotection (antioxidant enzymes, xanthophyll-cycle related genes, tocopherol biosynthesis) in the upper stand of the meadow, indicating that shallow plants are under stressful light conditions. However, the lack of photo-damage, indicates the successful activation of defense mechanisms. This conclusion is also supported by several responses at physiological level as the lower antenna size, the higher number of reaction centers and the higher xanthophyll cycle pigment pool, which are common plant responses to high-light adaptation/acclimation. Deep plants, despite the lower available light, seem to be not light-limited, thanks to some shade-adaptation strategies (e.g. higher antenna size, lower Ek values). Furthermore, also at the molecular level there were no signs of stress response, indicating that, although the lower energy available, low-light environments are more favorable for P. oceanica growth. Globally, results of whole transcriptome analysis displayed two distinct gene expression signatures related to depth distribution, reflecting the different light-adaptation strategies adopted by P. oceanica along the depth gradient. This observation, also taking into account the genetic disjunction of clones along the bathymetry, might have important implications for micro-evolutionary processes happening at meadow scale. Further investigations in controlled conditions must be performed to respond to these questions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Recombination and evolution of duplicate control regions in the mitochondrial genome of the Asian big-headed turtle, Platysternon megacephalum.

PubMed

Zheng, Chenfei; Nie, Liuwang; Wang, Jue; Zhou, Huaxing; Hou, Huazhen; Wang, Hao; Liu, Juanjuan

2013-01-01

Complete mitochondrial (mt) genome sequences with duplicate control regions (CRs) have been detected in various animal species. In Testudines, duplicate mtCRs have been reported in the mtDNA of the Asian big-headed turtle, Platysternon megacephalum, which has three living subspecies. However, the evolutionary pattern of these CRs remains unclear. In this study, we report the completed sequences of duplicate CRs from 20 individuals belonging to three subspecies of this turtle and discuss the micro-evolutionary analysis of the evolution of duplicate CRs. Genetic distances calculated with MEGA 4.1 using the complete duplicate CR sequences revealed that within turtle subspecies, genetic distances between orthologous copies from different individuals were 0.63% for CR1 and 1.2% for CR2app:addword:respectively, and the average distance between paralogous copies of CR1 and CR2 was 4.8%. Phylogenetic relationships were reconstructed from the CR sequences, excluding the variable number of tandem repeats (VNTRs) at the 3' end using three methods: neighbor-joining, maximum likelihood algorithm, and Bayesian inference. These data show that any two CRs within individuals were more genetically distant from orthologous genes in different individuals within the same subspecies. This suggests independent evolution of the two mtCRs within each P. megacephalum subspecies. Reconstruction of separate phylogenetic trees using different CR components (TAS, CD, CSB, and VNTRs) suggested the role of recombination in the evolution of duplicate CRs. Consequently, recombination events were detected using RDP software with break points at ≈290 bp and ≈1,080 bp. Based on these results, we hypothesize that duplicate CRs in P. megacephalum originated from heterological ancestral recombination of mtDNA. Subsequent recombination could have resulted in homogenization during independent evolutionary events, thus maintaining the functions of duplicate CRs in the mtDNA of P. megacephalum.

Recombination and Evolution of Duplicate Control Regions in the Mitochondrial Genome of the Asian Big-Headed Turtle, Platysternon megacephalum

PubMed Central

Zheng, Chenfei; Nie, Liuwang; Wang, Jue; Zhou, Huaxing; Hou, Huazhen; Wang, Hao; Liu, Juanjuan

2013-01-01

Complete mitochondrial (mt) genome sequences with duplicate control regions (CRs) have been detected in various animal species. In Testudines, duplicate mtCRs have been reported in the mtDNA of the Asian big-headed turtle, Platysternon megacephalum, which has three living subspecies. However, the evolutionary pattern of these CRs remains unclear. In this study, we report the completed sequences of duplicate CRs from 20 individuals belonging to three subspecies of this turtle and discuss the micro-evolutionary analysis of the evolution of duplicate CRs. Genetic distances calculated with MEGA 4.1 using the complete duplicate CR sequences revealed that within turtle subspecies, genetic distances between orthologous copies from different individuals were 0.63% for CR1 and 1.2% for CR2app:addword:respectively, and the average distance between paralogous copies of CR1 and CR2 was 4.8%. Phylogenetic relationships were reconstructed from the CR sequences, excluding the variable number of tandem repeats (VNTRs) at the 3′ end using three methods: neighbor-joining, maximum likelihood algorithm, and Bayesian inference. These data show that any two CRs within individuals were more genetically distant from orthologous genes in different individuals within the same subspecies. This suggests independent evolution of the two mtCRs within each P. megacephalum subspecies. Reconstruction of separate phylogenetic trees using different CR components (TAS, CD, CSB, and VNTRs) suggested the role of recombination in the evolution of duplicate CRs. Consequently, recombination events were detected using RDP software with break points at ≈290 bp and ≈1,080 bp. Based on these results, we hypothesize that duplicate CRs in P. megacephalum originated from heterological ancestral recombination of mtDNA. Subsequent recombination could have resulted in homogenization during independent evolutionary events, thus maintaining the functions of duplicate CRs in the mtDNA of P. megacephalum. PMID:24367563

CRISPR Diversity and Microevolution in Clostridium difficile

PubMed Central

Andersen, Joakim M.; Shoup, Madelyn; Robinson, Cathy; Britton, Robert; Olsen, Katharina E.P.; Barrangou, Rodolphe

2016-01-01

Abstract Virulent strains of Clostridium difficile have become a global health problem associated with morbidity and mortality. Traditional typing methods do not provide ideal resolution to track outbreak strains, ascertain genetic diversity between isolates, or monitor the phylogeny of this species on a global basis. Here, we investigate the occurrence and diversity of clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated genes (cas) in C. difficile to assess the potential of CRISPR-based phylogeny and high-resolution genotyping. A single Type-IB CRISPR-Cas system was identified in 217 analyzed genomes with cas gene clusters present at conserved chromosomal locations, suggesting vertical evolution of the system, assessing a total of 1,865 CRISPR arrays. The CRISPR arrays, markedly enriched (8.5 arrays/genome) compared with other species, occur both at conserved and variable locations across strains, and thus provide a basis for typing based on locus occurrence and spacer polymorphism. Clustering of strains by array composition correlated with sequence type (ST) analysis. Spacer content and polymorphism within conserved CRISPR arrays revealed phylogenetic relationship across clades and within ST. Spacer polymorphisms of conserved arrays were instrumental for differentiating closely related strains, e.g., ST1/RT027/B1 strains and pathogenicity locus encoding ST3/RT001 strains. CRISPR spacers showed sequence similarity to phage sequences, which is consistent with the native role of CRISPR-Cas as adaptive immune systems in bacteria. Overall, CRISPR-Cas sequences constitute a valuable basis for genotyping of C. difficile isolates, provide insights into the micro-evolutionary events that occur between closely related strains, and reflect the evolutionary trajectory of these genomes. PMID:27576538

Genetic variation in horizontally transmitted fungal endophytes of pine needles reveals population structure in cryptic species.

PubMed

Oono, Ryoko; Lutzoni, François; Arnold, A Elizabeth; Kaye, Laurel; U'Ren, Jana M; May, Georgiana; Carbone, Ignazio

2014-08-01

• Fungal endophytes comprise one of the most ubiquitous groups of plant symbionts, inhabiting healthy leaves and stems of all major lineages of plants. Together, they comprise immense species richness, but little is known about the fundamental processes that generate their diversity. Exploration of their population structure is needed, especially with regard to geographic distributions and host affiliations.• We take a multilocus approach to examine genetic variation within and among populations of Lophodermium australe, an endophytic fungus commonly associated with healthy foliage of pines in the southeastern United States. Sampling focused on two pine species ranging from montane to coastal regions of North Carolina and Virginia.• Our sampling revealed two genetically distinct groups within Lophodermium australe. Our analysis detected less than one migrant per generation between them, indicating that they are distinct species. The species comprising the majority of isolates (major species) demonstrated a panmictic structure, whereas the species comprising the minority of isolates (cryptic species) demonstrated isolation by distance. Distantly related pine species hosted the same Lophodermium species, and host species did not influence genetic structure.• We present the first evidence for isolation by distance in a foliar fungal endophyte that is horizontally transmitted. Cryptic species may be common among microbial symbionts and are important to delimit when exploring their genetic structure and microevolutionary processes. The hyperdiversity of endophytic fungi may be explained in part by cryptic species without apparent ecological and morphological differences as well as genetic diversification within rare fungal species across large spatial scales. © 2014 Botanical Society of America, Inc.

Replicon-Dependent Differentiation of Symbiosis-Related Genes in Sinorhizobium Strains Nodulating Glycine max

PubMed Central

Guo, Hui Juan; Wang, En Tao; Zhang, Xing Xing; Li, Qin Qin; Zhang, Yan Ming; Chen, Wen Xin

2014-01-01

In order to investigate the genetic differentiation of Sinorhizobium strains nodulating Glycine max and related microevolutionary mechanisms, three housekeeping genes (SMc00019, truA, and thrA) and 16 symbiosis-related genes on the chromosome (7 genes), pSymA (6 genes), and pSymB (3 genes) were analyzed. Five distinct species were identified among the test strains by calculating the average nucleotide identity (ANI) of SMc00019-truA-thrA: Sinorhizobium fredii, Sinorhizobium sojae, Sinorhizobium sp. I, Sinorhizobium sp. II, and Sinorhizobium sp. III. These species assignments were also supported by population genetics and phylogenetic analyses of housekeeping genes and symbiosis-related genes on the chromosome and pSymB. Different levels of genetic differentiation were observed among these species or different replicons. S. sojae was the most divergent from the other test species and was characterized by its low intraspecies diversity and limited geographic distribution. Intergenic recombination dominated the evolution of 19 genes from different replicons. Intraspecies recombination happened frequently in housekeeping genes and symbiosis-related genes on the chromosome and pSymB, whereas pSymA genes showed a clear pattern of lateral-transfer events between different species. Moreover, pSymA genes were characterized by a lower level of polymorphism and recombination than those on the chromosome and pSymB. Taken together, genes from different replicons of rhizobia might be involved in the establishment of symbiosis with legumes, but these symbiosis-related genes might have evolved differently according to their corresponding replicons. PMID:24317084

CRISPR Diversity and Microevolution in Clostridium difficile.

PubMed

Andersen, Joakim M; Shoup, Madelyn; Robinson, Cathy; Britton, Robert; Olsen, Katharina E P; Barrangou, Rodolphe

2016-09-19

Virulent strains of Clostridium difficile have become a global health problem associated with morbidity and mortality. Traditional typing methods do not provide ideal resolution to track outbreak strains, ascertain genetic diversity between isolates, or monitor the phylogeny of this species on a global basis. Here, we investigate the occurrence and diversity of clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated genes (cas) in C. difficile to assess the potential of CRISPR-based phylogeny and high-resolution genotyping. A single Type-IB CRISPR-Cas system was identified in 217 analyzed genomes with cas gene clusters present at conserved chromosomal locations, suggesting vertical evolution of the system, assessing a total of 1,865 CRISPR arrays. The CRISPR arrays, markedly enriched (8.5 arrays/genome) compared with other species, occur both at conserved and variable locations across strains, and thus provide a basis for typing based on locus occurrence and spacer polymorphism. Clustering of strains by array composition correlated with sequence type (ST) analysis. Spacer content and polymorphism within conserved CRISPR arrays revealed phylogenetic relationship across clades and within ST. Spacer polymorphisms of conserved arrays were instrumental for differentiating closely related strains, e.g., ST1/RT027/B1 strains and pathogenicity locus encoding ST3/RT001 strains. CRISPR spacers showed sequence similarity to phage sequences, which is consistent with the native role of CRISPR-Cas as adaptive immune systems in bacteria. Overall, CRISPR-Cas sequences constitute a valuable basis for genotyping of C. difficile isolates, provide insights into the micro-evolutionary events that occur between closely related strains, and reflect the evolutionary trajectory of these genomes. © The Author(s) 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Wing geometry of Culex coronator (Diptera: Culicidae) from South and Southeast Brazil

PubMed Central

2014-01-01

Background The Coronator Group encompasses Culex coronator Dyar & Knab, Culex camposi Dyar, Culex covagarciai Forattini, Culex ousqua Dyar, Culex usquatissimus Dyar, Culex usquatus Dyar and Culex yojoae Strickman. Culex coronator has the largest geographic distribution, occurring in North, Central and South America. Moreover, it is a potential vector-borne mosquito species because females have been found naturally infected with several arboviruses, i.e., Saint Louis Encephalitis Virus, Venezuelan Equine Encephalitis Virus and West Nile Virus. Considering the epidemiological importance of Cx. coronator, we investigated the wing shape diversity of Cx. coronator from South and Southeast Brazil, a method to preliminarily estimate population diversity. Methods Field-collected immature stages of seven populations from a large geographical area in Brazil were maintained in the laboratory to obtain both females and males linked with pupal and/or larval exuviae. For each individual female, 18 landmarks of left wings were marked and digitalized. After Procrustes superimposition, discriminant analysis of shape was employed to quantify wing shape variation among populations. The isometric estimator centroid size was calculated to assess the overall wing size and allometry. Results Wing shape was polymorphic among populations of Cx. coronator. However, dissimilarities among populations were higher than those observed within each population, suggesting populational differentiation in Cx. coronator. Morphological distances between populations were not correlated to geographical distances, indicating that other factors may act on wing shape and thus, determining microevolutionary patterns in Cx. coronator. Despite the population differentiation, intrapopulational wing shape variability was equivalent among all seven populations. Conclusion The wing variability found in Cx. coronator populations brings to light a new biological problem to be investigated: the population genetics of Cx. coronator. Because of differences in the male genitalia, we also transferred Cx. yojoae to the Apicinus Subgroup. PMID:24721508

The split of the Arara population: comparison of genetic drift and founder effect.

PubMed

Ribeiro-dos-Santos, A K; Guerreiro, J F; Santos, S E; Zago, M A

2001-01-01

The total genetic diversity of the Amerindian population is as high as that observed for other continental human populations because a large contribution from variation among tribes makes up for the low variation within tribes. This is attributed mainly to genetic drift acting on small isolated populations. However, a small founder population with a low genetic diversity is another factor that may contribute to the low intratribal diversity. Small founder populations seem to be a frequent event in the formation of new tribes among the Amerindians, but this event is usually not well recorded. In this paper, we analyze the genetic diversity of the Arara of Laranjal village and the Arara of Iriri village, with respect to seven tandem repeat autosomic segments (D1S80, ApoB, D4S43, vW1, vW2, F13A1 and D12S67), two Y-chromosome-specific polymorphisms (DYS19 and DYS199), and mitochondrial DNA (mtDNA) markers (restriction fragment length polymorphisms and sequencing of a segment of the D loop region). The occurrence of a single Y chromosome and mtDNA haplotype, and only 1-4 alleles of the autosomic loci investigated, corroborates historic and demographic records that the Arara of Iriri were founded by a single couple of siblings who came from the Arara of Laranjal, the largest group. Notwithstanding this fact, the genetic distance and the molecular variance between the two Arara villages were greater than those observed between them and other Amazonian tribes, suggesting that the microevolutionary process among Brazilian Amerindians may be misinterpreted if historic demographic data are not considered. Copyright 2000 S. Karger AG, Basel.

High diversity and no significant selection signal of human ADH1B gene in Tibet

PubMed Central

2012-01-01

Background ADH1B is one of the most studied human genes with many polymorphic sites. One of the single nucleotide polymorphism (SNP), rs1229984, coding for the Arg48His substitution, have been associated with many serious diseases including alcoholism and cancers of the digestive system. The derived allele, ADH1B*48His, reaches high frequency only in East Asia and Southwest Asia, and is highly associated with agriculture. Micro-evolutionary study has defined seven haplogroups for ADH1B based on seven SNPs encompassing the gene. Three of those haplogroups, H5, H6, and H7, contain the ADH1B*48His allele. H5 occurs in Southwest Asia and the other two are found in East Asia. H7 is derived from H6 by the derived allele of rs3811801. The H7 haplotype has been shown to have undergone significant positive selection in Han Chinese, Hmong, Koreans, Japanese, Khazak, Mongols, and so on. Methods In the present study, we tested whether Tibetans also showed evidence for selection by typing 23 SNPs in the region covering the ADH1B gene in 1,175 individuals from 12 Tibetan populations representing all districts of the Tibet Autonomous Region. Multiple statistics were estimated to examine the gene diversities and positive selection signals among the Tibetans and other populations in East Asia. Results The larger Tibetan populations (Qamdo, Lhasa, Nagqu, Nyingchi, Shannan, and Shigatse) comprised mostly farmers, have around 12% of H7, and 2% of H6. The smaller populations, living on hunting or recently switched to farming, have lower H7 frequencies (Tingri 9%, Gongbo 8%, Monba and Sherpa 6%). Luoba (2%) and Deng (0%) have even lower frequencies. Long-range haplotype analyses revealed very weak signals of positive selection for H7 among Tibetans. Interestingly, the haplotype diversity of H7 is higher in Tibetans than in any other populations studied, indicating a longer diversification history for that haplogroup in Tibetans. Network analysis on the long-range haplotypes revealed that H7 in the Han Chinese did not come from the Tibetans but from a common ancestor of the two populations. Conclusions We argue that H7 of ADH1B originated in the ancestors of Sino-Tibetan populations and flowed to Tibetans very early. However, as Tibetans depend less on crops, and therefore were not significantly affected by selection. Thus, H7 has not risen to a high frequency, whereas the diversity of the haplogroup has accumulated to a very high level. PMID:23176670

Evolutionary and Morphometric Implications of Morphological Variation Among Flowers Within an Inflorescence: A Case-Study Using European Orchids

PubMed Central

BATEMAN, RICHARD M.; RUDALL, PAULA J.

2006-01-01

• Background and Aims This study explores the previously largely ignored morphological variation that occurs among flowers within a single inflorescence. • Methods Variation in four metric parameters (labellum length and width, spur length and width) that together strongly influence pollination frequency is documented within the simple racemose inflorescences of eight individuals that represent a primary hybrid and six species of European orchids. • Key Results Regression of each parameter against the location of each flower on the inflorescence, and calculation of correlation coefficients for each pair of parameters within each inflorescence, demonstrate significant decoupling of labellum and spur development, despite the fact that they are different portions of the same floral organ. Spur length and diameter are constant across inflorescences of Dactylorhiza other than the vestigial-spurred D. viridis, whereas in other genera spur length declines in parallel with labellum dimensions. These differences are likely to reflect selection pressures or developmental constraints. Strong negative deviations from the regression line for one or more parameters are evident in occasional flowers, occurring most frequently in the lowermost and uppermost one or two flowers, and so reflecting transitions in meristematic behaviour. Thus, population-level morphometric studies are best conducted on flowers taken from approximately the mid-point of the inflorescence. Moreover, in the two relatively large inflorescences where lower flowers were removed for measurement before the upper flowers had opened, labellum size increased significantly in the flowers immediately above the excisions, suggesting that excision liberated resources that were diverted into the opening buds. Repeat measurement of all flowers from one selected inflorescence demonstrated typical measurement errors of only ± 30–80 μm, irrespective of the size of the structure studied. If flowers are not mounted and measured immediately following excision, modest negative deviations of 30–50 μm result from post-mounting shrinkage; this occurs less rapidly in the spur than in the thinner labellum, which should therefore be measured first. Variation in all four parameters among all the flowers of a single inflorescence is between 42 % and 107 % of that observed between a similar number of flowers sampled from a consistent location on different (but conspecific and coexisting) inflorescences. • Conclusions This result demonstrates the strong influence of epigenesis on flower morphology and further emphasizes the importance of (a) sampling from a consistent location within the inflorescences under comparison, (b) interpreting morphometric ordinations hierarchically, building from individuals to infraspecific taxa and species via populations, and (c) considering in any microevolutionary study the potentially profound effects of the cline in flower size within each inflorescence. PMID:17018569

A role for Tn6029 in the evolution of the complex antibiotic resistance gene loci in genomic island 3 in enteroaggregative hemorrhagic Escherichia coli O104:H4.

PubMed

Roy Chowdhury, Piklu; Charles, Ian G; Djordjevic, Steven P

2015-01-01

In enteroaggregative hemorrhagic Escherichia coli (EAHEC) O104 the complex antibiotic resistance gene loci (CRL) found in the region of divergence 1 (RD1) within E. coli genomic island 3 (GI3) contains blaTEM-1, strAB, sul2, tet(A)A, and dfrA7 genes encoding resistance to ampicillin, streptomycin, sulfamethoxazole, tetracycline and trimethoprim respectively. The precise arrangement of antibiotic resistance genes and the role of mobile elements that drove the evolutionary events and created the CRL have not been investigated. We used a combination of bioinformatics and iterative BLASTn searches to determine the micro-evolutionary events that likely led to the formation of the CRL in GI3 using the closed genome sequences of EAHEC O104:H4 strains 2011C-3493 and 2009EL-2050 and high quality draft genomes of EAHEC E. coli O104:H4 isolates from sporadic cases not associated with the initial outbreak. Our analyses indicate that the CRL in GI3 evolved from a progenitor structure that contained an In2-derived class 1 integron in a Tn21/Tn1721 hybrid backbone. Within the hybrid backbone, a Tn6029-family transposon, identified here as Tn6029C abuts the sul1 gene in the 3'-Conserved Segment (-CS) of a class 1 integron generating a unique molecular signature that has only previously been observed in pASL01a, a small plasmid found in commensal E. coli in West Africa. From this common progenitor, independent IS26-mediated events created two novel transposons identified here as Tn6029D and Tn6222 in 2011C-3493 and 2009EL-2050 respectively. Analysis of RD1 within GI3 reveals IS26 has played a crucial role in the assembly of regions within the CRL.

Habitat and Host Indicate Lineage Identity in Colletotrichum gloeosporioides s.l. from Wild and Agricultural Landscapes in North America

PubMed Central

Doyle, Vinson P.; Oudemans, Peter V.; Rehner, Stephen A.; Litt, Amy

2013-01-01

Understanding the factors that drive the evolution of pathogenic fungi is central to revealing the mechanisms of virulence and host preference, as well as developing effective disease control measures. Prerequisite to these pursuits is the accurate delimitation of species boundaries. Colletotrichum gloeosporioides s.l. is a species complex of plant pathogens and endophytic fungi for which reliable species recognition has only recently become possible through a multi-locus phylogenetic approach. By adopting an intensive regional sampling strategy encompassing multiple hosts within and beyond agricultural zones associated with cranberry (Vaccinium macrocarpon Aiton), we have integrated North America strains of Colletotrichum gloeosporioides s.l. from these habitats into a broader phylogenetic framework. We delimit species on the basis of genealogical concordance phylogenetic species recognition (GCPSR) and quantitatively assess the monophyly of delimited species at each of four nuclear loci and in the combined data set with the genealogical sorting index (gsi). Our analysis resolved two principal lineages within the species complex. Strains isolated from cranberry and sympatric host plants are distributed across both of these lineages and belong to seven distinct species or terminal clades. Strains isolated from V. macrocarpon in commercial cranberry beds belong to four species, three of which are described here as new. Another species, C. rhexiae Ellis & Everh., is epitypified. Intensive regional sampling has revealed a combination of factors, including the host species from which a strain has been isolated, the host organ of origin, and the habitat of the host species, as useful indicators of species identity in the sampled regions. We have identified three broadly distributed temperate species, C. fructivorum, C. rhexiae, and C. nupharicola, that could be useful for understanding the microevolutionary forces that may lead to species divergence in this important complex of endophytes and plant pathogens. PMID:23671594

Expression Differentiation Is Constrained to Low-Expression Proteins over Ecological Timescales

PubMed Central

Margres, Mark J.; Wray, Kenneth P.; Seavy, Margaret; McGivern, James J.; Herrera, Nathanael D.; Rokyta, Darin R.

2016-01-01

Protein expression level is one of the strongest predictors of protein sequence evolutionary rate, with high-expression protein sequences evolving at slower rates than low-expression protein sequences largely because of constraints on protein folding and function. Expression evolutionary rates also have been shown to be negatively correlated with expression level across human and mouse orthologs over relatively long divergence times (i.e., ∼100 million years). Long-term evolutionary patterns, however, often cannot be extrapolated to microevolutionary processes (and vice versa), and whether this relationship holds for traits evolving under directional selection within a single species over ecological timescales (i.e., <5000 years) is unknown and not necessarily expected. Expression is a metabolically costly process, and the expression level of a particular protein is predicted to be a tradeoff between the benefit of its function and the costs of its expression. Selection should drive the expression level of all proteins close to values that maximize fitness, particularly for high-expression proteins because of the increased energetic cost of production. Therefore, stabilizing selection may reduce the amount of standing expression variation for high-expression proteins, and in combination with physiological constraints that may place an upper bound on the range of beneficial expression variation, these constraints could severely limit the availability of beneficial expression variants. To determine whether rapid-expression evolution was restricted to low-expression proteins owing to these constraints on highly expressed proteins over ecological timescales, we compared venom protein expression levels across mainland and island populations for three species of pit vipers. We detected significant differentiation in protein expression levels in two of the three species and found that rapid-expression differentiation was restricted to low-expression proteins. Our results suggest that various constraints on high-expression proteins reduce the availability of beneficial expression variants relative to low-expression proteins, enabling low-expression proteins to evolve and potentially lead to more rapid adaptation. PMID:26546003

Effects of English admixture and geographic distance on anthropometric variation and genetic structure in 19th-century Ireland.

PubMed

Relethford, J H

1988-05-01

The analysis of anthropometric data often allows investigation of patterns of genetic structure in historical populations. This paper focuses on interpopulational anthropometric variation in seven populations in Ireland using data collected in the 1890s. The seven populations were located within a 120-km range along the west coast of Ireland and include islands and mainland isolates. Two of the populations (the Aran Islands and Inishbofin) have a known history of English admixture in earlier centuries. Ten anthropometric measures (head length, breadth, and height; nose length and breadth; bizygomatic and bigonial breadth; stature; hand length; and forearm length) on 259 adult Irish males were analyzed following age adjustment. Discriminant and canonical variates analysis were used to determine the degree and pattern of among-group variation. Mahalanobis' distance measure, D2, was computed between each pair of populations and compared to distance measures based on geographic distance and English admixture (a binary measure indicating whether either of a pair of populations had historical indications of admixture). In addition, surname frequencies were used to construct distance measures based on random isonymy. Correlations were computed between distance measures, and their probabilities were derived using the Mantel matrix permutation method. English admixture has the greatest effect on anthropometric variation among these populations, followed by geographic distance. The correlation between anthropometric distance and geographic distance is not significant (r = -0.081, P = .590), but the correlation of admixture and anthropometric distance is significant (r = 0.829, P = .047). When the two admixed populations are removed from the analysis the correlation between geographic and anthropometric distance becomes significant (r = 0.718, P = .025). Isonymy distance shows a significant correlation with geographic distance (r = 0.425, P = .046) but not with admixture distance (r = -0.052, P = .524). The fact that anthropometrics show past patterns of gene flow and surnames do not reflects the greater impact of stochastic processes on surnames, along with the continued extinction of surnames. This study shows that 1) anthropometrics can be extremely useful in assessing population structure and history, 2) differential gene flow into populations can have a major impact on local genetic structure, and 3) microevolutionary processes can have different effects on biological characters and surnames.

Diversification and spatial structuring in the mutualism between Ficus septica and its pollinating wasps in insular South East Asia.

PubMed

Rodriguez, Lillian Jennifer; Bain, Anthony; Chou, Lien-Siang; Conchou, Lucie; Cruaud, Astrid; Gonzales, Regielene; Hossaert-McKey, Martine; Rasplus, Jean-Yves; Tzeng, Hsy-Yu; Kjellberg, Finn

2017-08-29

Interspecific interactions have long been assumed to play an important role in diversification. Mutualistic interactions, such as nursery pollination mutualisms, have been proposed as good candidates for diversification through co-speciation because of their intricate nature. However, little is known about how speciation and diversification proceeds in emblematic nursery pollination systems such as figs and fig wasps. Here, we analyse diversification in connection with spatial structuring in the obligate mutualistic association between Ficus septica and its pollinating wasps throughout the Philippines and Taiwan. Ceratosolen wasps pollinating F. septica are structured into a set of three vicariant black coloured species, and a fourth yellow coloured species whose distribution overlaps with those of the black species. However, two black pollinator species were found to co-occur on Lanyu island. Microsatellite data on F. septica indicates the presence of three gene pools that broadly mirrors the distribution of the three black clades. Moreover, receptive fig odours, the specific message used by pollinating wasps to locate their host tree, varied among locations. F. septica and its black pollinator clades exhibited similar geographic structuring. This could be due originally to geographic barriers leading to isolation, local adaptation, and finally co-structuring. Nevertheless, the co-occurrence of two black pollinator species on Lanyu island suggests that the parapatric distribution of the black clades is now maintained by the inability of migrating individuals of black pollinators to establish populations outside their range. On the other hand, the distribution of the yellow clade strongly suggests an initial case of character displacement followed by subsequent range extension: in our study system, phenotypic or microevolutionary plasticity has allowed the yellow clade to colonise hosts presenting distinct odours. Hence, while variation in receptive fig odours allows specificity in the interaction, this variation does not necessarily lead to coevolutionary plant-insect diversification. Globally, our results evidence evolutionary plasticity in the fig-fig wasp mutualism. This is the first documentation of the presence of two distinct processes in pollinating fig wasp diversification on a host species: the formation of vicariant species and the co-occurrence of other species over large parts of their ranges probably made possible by character displacement.

Dating the Cryptococcus gattii Dispersal to the North American Pacific Northwest

PubMed Central

Roe, Chandler C.; Bowers, Jolene; Oltean, Hanna; DeBess, Emilio; Dufresne, Philippe J.; McBurney, Scott; Overy, David P.; Wanke, Bodo; Lysen, Colleen; Chiller, Tom; Meyer, Wieland; Thompson, George R.; Lockhart, Shawn R.; Hepp, Crystal M.

2018-01-01

ABSTRACT The emergence of Cryptococcus gattii, previously regarded as a predominantly tropical pathogen, in the temperate climate of the North American Pacific Northwest (PNW) in 1999 prompted several questions. The most prevalent among these was the timing of the introduction of this pathogen to this novel environment. Here, we infer tip-dated timing estimates for the three clonal C. gattii populations observed in the PNW, VGIIa, VGIIb, and VGIIc, based on whole-genome sequencing of 134 C. gattii isolates and using Bayesian evolutionary analysis by sampling trees (BEAST). We estimated the nucleotide substitution rate for each lineage (1.59 × 10−8, 1.59 × 10−8, and 2.70 × 10−8, respectively) to be an order of magnitude higher than common neutral fungal mutation rates (2.0 × 10−9), indicating a microevolutionary rate (e.g., successive clonal generations in a laboratory) in comparison to a species’ slower, macroevolutionary rate (e.g., when using fossil records). The clonal nature of the PNW C. gattii emergence over a narrow number of years would therefore possibly explain our higher mutation rates. Our results suggest that the mean time to most recent common ancestor for all three sublineages occurred within the last 60 to 100 years. While the cause of C. gattii dispersal to the PNW is still unclear, our research estimates that the arrival is neither ancient nor very recent (i.e., <25 years ago), making a strong case for an anthropogenic introduction. IMPORTANCE The recent emergence of the pathogenic fungus Cryptococcus gattii in the Pacific Northwest (PNW) resulted in numerous investigations into the epidemiological and enzootic impacts, as well as multiple genomic explorations of the three primary molecular subtypes of the fungus that were discovered. These studies lead to the general conclusion that the subtypes identified likely emerged out of Brazil. Here, we conducted genomic dating analyses to determine the ages of the various lineages seen in the PNW and propose hypothetical causes for the dispersal events. Bayesian evolutionary analysis strongly suggests that these independent fungal populations in the PNW are all 60 to 100 years old, providing a timing that is subsequent to the opening of the Panama Canal, which allowed for more direct shipping between Brazil and the western North American coastline, a possible driving event for these fungal translocation events. PMID:29359190

Dating the Cryptococcus gattii Dispersal to the North American Pacific Northwest.

PubMed

Roe, Chandler C; Bowers, Jolene; Oltean, Hanna; DeBess, Emilio; Dufresne, Philippe J; McBurney, Scott; Overy, David P; Wanke, Bodo; Lysen, Colleen; Chiller, Tom; Meyer, Wieland; Thompson, George R; Lockhart, Shawn R; Hepp, Crystal M; Engelthaler, David M

2018-01-01

The emergence of Cryptococcus gattii , previously regarded as a predominantly tropical pathogen, in the temperate climate of the North American Pacific Northwest (PNW) in 1999 prompted several questions. The most prevalent among these was the timing of the introduction of this pathogen to this novel environment. Here, we infer tip-dated timing estimates for the three clonal C. gattii populations observed in the PNW, VGIIa, VGIIb, and VGIIc, based on whole-genome sequencing of 134 C. gattii isolates and using Bayesian evolutionary analysis by sampling trees (BEAST). We estimated the nucleotide substitution rate for each lineage (1.59 × 10 -8 , 1.59 × 10 -8 , and 2.70 × 10 -8 , respectively) to be an order of magnitude higher than common neutral fungal mutation rates (2.0 × 10 -9 ), indicating a microevolutionary rate (e.g., successive clonal generations in a laboratory) in comparison to a species' slower, macroevolutionary rate (e.g., when using fossil records). The clonal nature of the PNW C. gattii emergence over a narrow number of years would therefore possibly explain our higher mutation rates. Our results suggest that the mean time to most recent common ancestor for all three sublineages occurred within the last 60 to 100 years. While the cause of C. gattii dispersal to the PNW is still unclear, our research estimates that the arrival is neither ancient nor very recent (i.e., <25 years ago), making a strong case for an anthropogenic introduction. IMPORTANCE The recent emergence of the pathogenic fungus Cryptococcus gattii in the Pacific Northwest (PNW) resulted in numerous investigations into the epidemiological and enzootic impacts, as well as multiple genomic explorations of the three primary molecular subtypes of the fungus that were discovered. These studies lead to the general conclusion that the subtypes identified likely emerged out of Brazil. Here, we conducted genomic dating analyses to determine the ages of the various lineages seen in the PNW and propose hypothetical causes for the dispersal events. Bayesian evolutionary analysis strongly suggests that these independent fungal populations in the PNW are all 60 to 100 years old, providing a timing that is subsequent to the opening of the Panama Canal, which allowed for more direct shipping between Brazil and the western North American coastline, a possible driving event for these fungal translocation events.

Microevolutionary dynamics in Methanothermococcus populations from deep-sea hydrothermal vents in the Mid-Cayman Rise

NASA Astrophysics Data System (ADS)

Hoffert, M.; Anderson, R. E.; Stepanauskas, R.; Huber, J. A.

2017-12-01

Deep-sea hydrothermal vents sustain diverse communities of microorganisms. The effects of geochemical and biological interactions on the process of evolution in these ecosystems remains poorly understood because the majority of subsurface microorganisms remain uncultivated. By examining metagenomic samples from hydrothermal fluids and mapping the samples to closely-related genomes found in vent sites, we can better understand how the process of evolution is affected by the geochemical and environmental context in deep-sea vents. The Mid-Cayman Rise is a spreading ridge that hosts both mafic-influenced and ultramafic-influenced vent fields. Previous research on metagenomic samples from sites in the Mid-Cayman Rise has shown that these vents contain metabolically and taxonomically diverse microbial communities. Here, we investigate five single cell amplified Methanothermococcus genomes (SAGs) to investigate patterns in pangenomic variation and molecular evolution in these methanogens. Mappings of metagenomic reads from 15 sample sites to the SAGs reveal substantial variation in Methanothermococcus population abundance, nucleotide variability and selection pressure among the 15 geochemically distinct sample sites. Within each sample site, we observed distinct patterns of single nucleotide variant (SNV) accumulation and selection pressure within the SAG populations. Closely related genomes showed similar patterns of SNV accumulation. Analysis of open reading frames (ORFs) from the SAGs indicated that homologous genes accumulated variation at the same rate. For example, a genomic island for Nif genes was identified in three of the five genomes with significantly elevated SNV counts. dN/dS analyses revealed evidence for frequency-dependent selection, in which genes unique to individual SAGs displayed elevated diversifying selection relative to other genes. These results indicate that different strains of Methanothermococcus outcompete others in specific environmental settings, and that these fitness advantages may result from variation in the pangenome, as revealed by dN/dS and SNV analyses. By examining variation and the scale of nucleotide and genes, we aim to gain insight into the roles of genetic diversity and environmental selection on microbial evolution in these ecosystems.

Population genetic structure of traditional populations in the Peruvian Central Andes and implications for South American population history.

PubMed

Cabana, Graciela S; Lewis, Cecil M; Tito, Raúl Y; Covey, R Alan; Cáceres, Angela M; Cruz, Augusto F De La; Durand, Diana; Housman, Genevieve; Hulsey, Brannon I; Iannacone, Gian Carlo; López, Paul W; Martínez, Rolando; Medina, Ángel; Dávila, Olimpio Ortega; Pinto, Karla Paloma Osorio; Santillán, Susan I Polo; Domínguez, Percy Rojas; Rubel, Meagan; Smith, Heather F; Smith, Silvia E; Massa, Verónica Rubín de Celis; Lizárraga, Beatriz; Stone, Anne C

2014-01-01

Molecular-based characterizations of Andean peoples are traditionally conducted in the service of elucidating continent-level evolutionary processes in South America. Consequently, genetic variation among "western" Andean populations is often represented in relation to variation among "eastern" Amazon and Orinoco River Basin populations. This west-east contrast in patterns of population genetic variation is typically attributed to large-scale phenomena, such as dual founder colonization events or differing long-term microevolutionary histories. However, alternative explanations that consider the nature and causes of population genetic diversity within the Andean region remain underexplored. Here we examine population genetic diversity in the Peruvian Central Andes using data from the mtDNA first hypervariable region and Y-chromosome short tandem repeats among 17 newly sampled populations and 15 published samples. Using this geographically comprehensive data set, we first reassessed the currently accepted pattern of western versus eastern population genetic structure, which our results ultimately reject: mtDNA population diversities were lower, rather than higher, within Andean versus eastern populations, and only highland Y-chromosomes exhibited significantly higher within-population diversities compared with eastern groups. Multiple populations, including several highland samples, exhibited low genetic diversities for both genetic systems. Second, we explored whether the implementation of Inca state and Spanish colonial policies starting at about ad 1400 could have substantially restructured population genetic variation and consequently constitute a primary explanation for the extant pattern of population diversity in the Peruvian Central Andes. Our results suggest that Peruvian Central Andean population structure cannot be parsimoniously explained as the sole outcome of combined Inca and Spanish policies on the region's population demography: highland populations differed from coastal and lowland populations in mtDNA genetic structure only; highland groups also showed strong evidence of female-biased gene flow and/or effective sizes relative to other Peruvian ecozones. Taken together, these findings indicate that population genetic structure in the Peruvian Central Andes is considerably more complex than previously reported and that characterizations of and explanations for genetic variation may be best pursued within more localized regions and defined time periods.

Can chemical communication be cryptic? Adaptations by herbivores to natural enemies exploiting prey semiochemistry.

PubMed

Raffa, Kenneth F; Hobson, Kenneth R; Lafontaine, Sara; Aukema, Brian H

2007-10-01

Predators and parasites commonly use chemical cues associated with herbivore feeding and reproduction to locate prey. However, we currently know little about mechanisms by which herbivores may avoid such natural enemies. Pheromones are crucial to many aspects of herbivore life history, so radical alterations of these compounds could be disadvantageous despite their exploitation by predators. Instead, minor modifications in pheromone chemistry may facilitate partial escape while maintaining intraspecific functionality. We tested this hypothesis using Ips pini, an endophytic beetle that develops in the phloem tissue of pine trees. Its predominant predators in the Great Lakes region of North America are Thanasimus dubius and Platysoma cylindrica, both of which are highly attracted to I. pini's pheromones. However, there are significant disparities between prey and predator behaviors that relate to nuances of pheromone chemistry. Thanasimus dubius is most attracted to the (+) stereoisomer of ipsdienol, and P. cylindrica is most attracted to the (-) form; Ips pini prefers racemic mixtures intermediate between each predator's preferences. Further, a component that is inactive by itself, lanierone, greatly synergizes the attraction of I. pini to ipsdienol, but has a weak or no effect on its predators. A temporal component adds to this behavioral disparity: lanierone is most important in the communication of I. pini during periods when its predators are most abundant. The difficulties involved in tracking prey are further compounded by spatial and temporal variation in prey signaling on a local scale. For example, the preferences of I. pini vary significantly among sites only 50 km apart. This chemical crypsis is analogous to morphological forms of camouflage, such as color and mimicry, that are widely recognized as evasive adaptations against visually searching predators. Presumably these relationships are dynamic, with predators and prey shifting responses in microevolutionary time. However, several factors may delay predator counter adaptations. The most important appears to be the availability of alternate prey, specifically I. grandicollis, whose pheromone ipsenol is highly attractive to the above predators but not cross-attractive with I. pini. Consistent with this view, the specialist parasitoid, Tomicobia tibialis, has behavioral preferences for pheromone components that closely correspond with those of I. pini. These results are discussed in terms of population dynamics and coevolutionary theory.

Swept away: ocean currents and seascape features influence genetic structure across the 18,000 Km Indo-Pacific distribution of a marine invertebrate, the black-lip pearl oyster Pinctada margaritifera.

PubMed

Lal, Monal M; Southgate, Paul C; Jerry, Dean R; Bosserelle, Cyprien; Zenger, Kyall R

2017-01-10

Genetic structure in many widely-distributed broadcast spawning marine invertebrates remains poorly understood, posing substantial challenges for their fishery management, conservation and aquaculture. Under the Core-Periphery Hypothesis (CPH), genetic diversity is expected to be highest at the centre of a species' distribution, progressively decreasing with increased differentiation towards outer range limits, as populations become increasingly isolated, fragmented and locally adapted. The unique life history characteristics of many marine invertebrates such as high dispersal rates, stochastic survival and variable recruitment are also likely to influence how populations are organised. To examine the microevolutionary forces influencing population structure, connectivity and adaptive variation in a highly-dispersive bivalve, populations of the black-lip pearl oyster Pinctada margaritifera were examined across its ~18,000 km Indo-Pacific distribution. Analyses utilising 9,624 genome-wide SNPs and 580 oysters, discovered differing patterns of significant and substantial broad-scale genetic structure between the Indian and Pacific Ocean basins. Indian Ocean populations were markedly divergent (F st  = 0.2534-0.4177, p < 0.001), compared to Pacific Ocean oysters, where basin-wide gene flow was much higher (F st  = 0.0007-0.1090, p < 0.001). Partitioning of genetic diversity (hierarchical AMOVA) attributed 18.1% of variance between ocean basins, whereas greater proportions were resolved within samples and populations (45.8% and 35.7% respectively). Visualisation of population structure at selectively neutral loci resolved three and five discrete genetic clusters for the Indian and Pacific Oceans respectively. Evaluation of genetic structure at adaptive loci for Pacific populations (89 SNPs under directional selection; F st  = 0.1012-0.4371, FDR = 0.05), revealed five clusters identical to those detected at neutral SNPs, suggesting environmental heterogeneity within the Pacific. Patterns of structure and connectivity were supported by Mantel tests of isolation by distance (IBD) and independent hydrodynamic particle dispersal simulations. It is evident that genetic structure and connectivity across the natural range of P. margaritifera is highly complex, and produced by the interaction of ocean currents, IBD and seascape features at a broad scale, together with habitat geomorphology and local adaptation at regional levels. Overall population organisation is far more elaborate than generalised CPH predictions, however valuable insights for regional fishery management, and a greater understanding of range-wide genetic structure in a highly-dispersive marine invertebrate have been gained.

Concentrations of selected heavy metals in bryophyte tissues at Cu-mine heap Podlipa in Ľubietová (Central Slovakia)

NASA Astrophysics Data System (ADS)

Širka, Pavel; Midula, Pavol

2017-04-01

Mine heaps and wastes created by mining industry belong to one of the most extreme man-made habitat types. In addition to their specific microclimatic conditions mine heaps are also characterized by increased contents of heavy metals and toxic substances in the soil substrate. These substances are transported into plant bodies and create difficult conditions for their growth. However, there are some plants that can cope with extremely high metal contents and are capable of growing on metalliferous habitats. These plants develop unique adaptation mechanisms and basically represent modified ecotypes with specific tolerances to certain heavy metals adapted through microevolutionary processes. The toxic effects of heavy metals on vascular plants are known for quite a long time, however, bryophytes are also known to accumulate certain heavy metals without any visible signs of damage. Because of this ability they have been successfully used in biomonitoring. Chemical analysis of contaminants in samples of bryophytes can reflect the state of environmental pollution. The aim of this work was to analyze the concentrations of 6 heavy metals (Fe, Cu, Zn, Mn, Pb and Cd) in tissues of 16 bryophyte samples at an abandoned Cu deposit Podlipa in Ľubietová and to compare them with concentrations of these elemens in soil samples and 9 vascular plant species (belonging to different growth forms) in a research performed by Andráš et al. (2014) in the studied area. Bryophytes were collected at 10 sampling sites randomly chosen in the dump-field area and consist of 14 different moss species. Only above-ground parts of bryophyte thalli (separated from rhizoids, gravel, soil, needles etc.) were used for analysis. Samples were dried at room temperature and subjected to microwave mineralization (MWS - 2 Berghof). The detailed procedure is defined in the Application Report MWS - 2 / Food, Pharma, Cosmetics (Berghof). In order to determine the concentrations of studied elements, atomic absorption spectrometry with flame atomization (AVANTA Σ, GBC) was used. Concentrations of Fe in bryophyte samples were significantly higher compared to those in the soil and on average quite similar to those in vascular plants. Differences in contents of Cu were the most significant from all analyzed chemical elements. The highest concentrations of Cu in bryophyte samples were observed in both samples (9 and 10) of Pohlia drummondii (4010.3 mg.kg-1 and 1900.8 mg.kg-1 respectivelly), which in sample 9 was 18 to 470 times higher than in other bryophyte samples, slightly higher than the average value in the soil (3253 mg.kg-1) and considerably higher than in the leaves of Mentha longifolia (173.3 mg.kg-1), which had the highest concentration of Cu among vascular plants. Concentrations of Zn and Cd in bryophyte samples were on average slightly higher than in soil and vascular plant samples. On average, concentrations of Pb were considerably lower in bryophyte samples than in soil and vascular plant species. No significant differences were observed in Mn. Given their specific anatomy and morphology, there is a dispute in various studies as to whether a certain heavy metal is indeed the controlling factor for the distribution of bryophytes on metal-contaminated sites. Perhaps the tendency of these mosses to grow on mineralized substrates is a species characteristic, not a mutual one. Detailed study of bryophytes in relation to phytoextraction or phytostabilization of heavy metals may be used in succession management process aimed at restoring the environment, particularly the soil and air. Aknowledgement: This work was realised with the help of doc. RNDr. Zuzana Melichová, PhD. and Peter Harčár from the Department of Chemistry, Faculty of Natural Sciences, Matej Bel University in Banská Bystrica and financially supported by grant scheme VEGA 1/0538/15.

Meta-studies in land use science: Current coverage and prospects.

PubMed

van Vliet, Jasper; Magliocca, Nicholas R; Büchner, Bianka; Cook, Elizabeth; Rey Benayas, José M; Ellis, Erle C; Heinimann, Andreas; Keys, Eric; Lee, Tien Ming; Liu, Jianguo; Mertz, Ole; Meyfroidt, Patrick; Moritz, Mark; Poeplau, Christopher; Robinson, Brian E; Seppelt, Ralf; Seto, Karen C; Verburg, Peter H

2016-02-01

Land use science has traditionally used case-study approaches for in-depth investigation of land use change processes and impacts. Meta-studies synthesize findings across case-study evidence to identify general patterns. In this paper, we provide a review of meta-studies in land use science. Various meta-studies have been conducted, which synthesize deforestation and agricultural land use change processes, while other important changes, such as urbanization, wetland conversion, and grassland dynamics have hardly been addressed. Meta-studies of land use change impacts focus mostly on biodiversity and biogeochemical cycles, while meta-studies of socioeconomic consequences are rare. Land use change processes and land use change impacts are generally addressed in isolation, while only few studies considered trajectories of drivers through changes to their impacts and their potential feedbacks. We provide a conceptual framework for linking meta-studies of land use change processes and impacts for the analysis of coupled human-environmental systems. Moreover, we provide suggestions for combining meta-studies of different land use change processes to develop a more integrated theory of land use change, and for combining meta-studies of land use change impacts to identify tradeoffs between different impacts. Land use science can benefit from an improved conceptualization of land use change processes and their impacts, and from new methods that combine meta-study findings to advance our understanding of human-environmental systems.

"You've Changed": Low Self-Concept Clarity Predicts Lack of Support for Partner Change.

PubMed

Emery, Lydia F; Gardner, Wendi L; Finkel, Eli J; Carswell, Kathleen L

2018-03-01

People often pursue self-change, and having a romantic partner who supports these changes increases relationship satisfaction. However, most existing research focuses only on the experience of the person who is changing. What predicts whether people support their partner's change? People with low self-concept clarity resist self-change, so we hypothesized that they would be unsupportive of their partner's changes. People with low self-concept clarity did not support their partner's change (Study 1a), because they thought they would have to change, too (Study 1b). Low self-concept clarity predicted failing to support a partner's change, but not vice versa (Studies 2 and 3), and only for larger changes (Study 3). Not supporting a partner's change predicted decreases in relationship quality for both members of the couple (Studies 2 and 3). This research underscores the role of partners in self-change, suggesting that failing to support a partner's change may stem from self-concept confusion.

WATERSHED BOUNDARY CONDITIONS FOR GLOBAL CHANGE IMPACT ANALYSIS

EPA Science Inventory

The US Global Change Research Program (USGCRP) studies (among other issues) the impact of global change on water quality. This field study evaluates the impact of global changes (land-use change and climate change) on source water quality. Changes in source water quality change...

Addressing trend-related changes within cumulative effects studies in water resources planning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Canter, L.W., E-mail: envimptr@aol.com; Chawla, M.K.; Swor, C.T.

2014-01-15

Summarized herein are 28 case studies wherein trend-related causative physical, social, or institutional changes were connected to consequential changes in runoff, water quality, and riparian and aquatic ecological features. The reviewed cases were systematically evaluated relative to their identified environmental effects; usage of analytical frameworks, and appropriate models, methods, and technologies; and the attention given to mitigation and/or management of the resultant causative and consequential changes. These changes also represent important considerations in project design and operation, and in cumulative effects studies associated therewith. The cases were grouped into five categories: institutional changes associated with legislation and policies (seven cases);more » physical changes from land use changes in urbanizing watersheds (eight cases); physical changes from land use changes and development projects in watersheds (four cases); physical, institutional, and social changes from land use and related policy changes in river basins (three cases); and multiple changes within a comprehensive study of land use and policy changes in the Willamette River Basin in Oregon (six cases). A tabulation of 110 models, methods and technologies used in the studies is also presented. General observations from this review were that the features were unique for each case; the consequential changes were logically based on the causative changes; the analytical frameworks provided relevant structures for the studies, and the identified methods and technologies were pertinent for addressing both the causative and consequential changes. One key lesson was that the cases provide useful, “real-world” illustrations of the importance of addressing trend-related changes in cumulative effects studies within water resources planning. Accordingly, they could be used as an “initial tool kit” for addressing trend-related changes.« less

Physiotherapists use a small number of behaviour change techniques when promoting physical activity: A systematic review comparing experimental and observational studies.

PubMed

Kunstler, Breanne E; Cook, Jill L; Freene, Nicole; Finch, Caroline F; Kemp, Joanne L; O'Halloran, Paul D; Gaida, James E

2018-06-01

Physiotherapists promote physical activity as part of their practice. This study reviewed the behaviour change techniques physiotherapists use when promoting physical activity in experimental and observational studies. Systematic review of experimental and observational studies. Twelve databases were searched using terms related to physiotherapy and physical activity. We included experimental studies evaluating the efficacy of physiotherapist-led physical activity interventions delivered to adults in clinic-based private practice and outpatient settings to individuals with, or at risk of, non-communicable diseases. Observational studies reporting the techniques physiotherapists use when promoting physical activity were also included. The behaviour change techniques used in all studies were identified using the Behaviour Change Technique Taxonomy. The behaviour change techniques appearing in efficacious and inefficacious experimental interventions were compared using a narrative approach. Twelve studies (nine experimental and three observational) were retained from the initial search yield of 4141. Risk of bias ranged from low to high. Physiotherapists used seven behaviour change techniques in the observational studies, compared to 30 behaviour change techniques in the experimental studies. Social support (unspecified) was the most frequently identified behaviour change technique across both settings. Efficacious experimental interventions used more behaviour change techniques (n=29) and functioned in more ways (n=6) than did inefficacious experimental interventions (behaviour change techniques=10 and functions=1). Physiotherapists use a small number of behaviour change techniques. Less behaviour change techniques were identified in observational studies compared to experimental studies, suggesting physiotherapists use less BCTs clinically than experimentally. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

A Case Study of Change Strategies Implemented in a Turnaround Elementary School

ERIC Educational Resources Information Center

Colson, Jo Ann

2012-01-01

This case study examined the change strategies in a turnaround school at the elementary level to understand and describe how change occurred and was sustained at this campus. This study examined the factors which contributed to the change in academic success of students, examined beliefs about change that led to the change process, identified the…

Do MRI Findings Change Over a Period of Up to 1 Year in Patients With Low Back Pain and/or Sciatica?: A Systematic Review.

PubMed

Panagopoulos, John; Hush, Julia; Steffens, Daniel; Hancock, Mark J

2017-04-01

Systematic review OBJECTIVE.: The aim of the study was to investigate whether magnetic resonance imaging (MRI) findings change over a relatively short period of time (<1 yr) in people with low back pain (LBP) or sciatica. We also investigated whether there was an association between any change in MRI findings and change in clinical outcomes. MRI offers the potential to identify possible pathoanatomic sources of LBP and/or sciatica; however, the clinical importance of MRI findings remains unclear. Little is known about whether lumbar MRI findings change over the short term and if so whether these changes are associated with changes in clinical outcomes. Medline, EMBASE, and CINAHL databases were searched. Included were cohort studies that performed repeat MRI scans within 12 months in patients with LBP and/or sciatica. Data on study characteristics and change in MRI findings were extracted from included studies. Any data describing associations between change in MRI findings and change in clinical outcomes were also extracted. A total of 12 studies met the inclusion criteria and were included in the review. Pooling was not possible due to heterogeneity of studies and findings. Seven studies reported on changes in disc herniation and reported 15% to 93% of herniations reduced or disappeared in size. Two studies reported on changes in nerve root compression and reported 17% to 91% reduced or disappeared. Only one study reported on the association between change in MRI findings and change in clinical outcomes within 1 year, and found no association. This review found moderate evidence that the natural course of herniations and nerve root compression is favorable over a 1-year period in people with sciatica or LBP. There is a lack of evidence on whether other MRI findings change, and whether changes in MRI findings are associated with changes in clinical outcomes. 1.

A Study of the Change Process Utilized by Colorado High School Principals: The Concordance of Practice and Theory.

ERIC Educational Resources Information Center

Jacobus, Keith

A common theme in educational change literature is that principals do not truly understand the change process and therefore cannot successfully implement change. This paper presents findings of a study that examined the change processes that Colorado principals utilized when initiating and implementing change in their buildings. The study also…

78 FR 33074 - Army Science Board Summer Study Session

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-03

... ethical dimensions. Planning for Climate Change study 2013--This study considers the most likely climate change scenarios and assesses how the changes might change the way the Army fights, not just tactically...

Understanding the Relationship between Social Change and Its Impacts: The Experience of Rural Land Use Change in South-Eastern Australia

ERIC Educational Resources Information Center

Williams, Kathryn J. H.; Schirmer, Jacki

2012-01-01

This study investigated socio-economic impacts of land use change, giving explicit attention to the relationships between independently observed land use change and associated socio-economic changes, perceived land use change and socio-economic change, attributed cause of change, and experienced impacts of change. Using a case study region in…

The effects of transformational and change leadership on employees' commitment to a change: a multilevel study.

PubMed

Herold, David M; Fedor, Donald B; Caldwell, Steven; Liu, Yi

2008-03-01

The effects of transformational leadership on the outcomes of specific change initiatives are not well understood. Conversely, organizational change studies have examined leader behaviors during specific change implementations yet have failed to link these to broader leadership theories. In this study, the authors investigate the relationship between transformational and change leadership and followers' commitment to a particular change initiative as a function of the personal impact of the changes. Transformational leadership was found to be more strongly related to followers' change commitment than change-specific leadership practices, especially when the change had significant personal impact. For leaders who were not viewed as transformational, good change-management practices were found to be associated with higher levels of change commitment. Copyright 2008 APA

Modeling technical change in climate analysis: evidence from agricultural crop damages.

PubMed

Ahmed, Adeel; Devadason, Evelyn S; Al-Amin, Abul Quasem

2017-05-01

This study accounts for the Hicks neutral technical change in a calibrated model of climate analysis, to identify the optimum level of technical change for addressing climate changes. It demonstrates the reduction to crop damages, the costs to technical change, and the net gains for the adoption of technical change for a climate-sensitive Pakistan economy. The calibrated model assesses the net gains of technical change for the overall economy and at the agriculture-specific level. The study finds that the gains of technical change are overwhelmingly higher than the costs across the agriculture subsectors. The gains and costs following technical change differ substantially for different crops. More importantly, the study finds a cost-effective optimal level of technical change that potentially reduces crop damages to a minimum possible level. The study therefore contends that the climate policy for Pakistan should consider the role of technical change in addressing climate impacts on the agriculture sector.

Patterns and biases in climate change research on amphibians and reptiles: a systematic review.

PubMed

Winter, Maiken; Fiedler, Wolfgang; Hochachka, Wesley M; Koehncke, Arnulf; Meiri, Shai; De la Riva, Ignacio

2016-09-01

Climate change probably has severe impacts on animal populations, but demonstrating a causal link can be difficult because of potential influences by additional factors. Assessing global impacts of climate change effects may also be hampered by narrow taxonomic and geographical research foci. We review studies on the effects of climate change on populations of amphibians and reptiles to assess climate change effects and potential biases associated with the body of work that has been conducted within the last decade. We use data from 104 studies regarding the effect of climate on 313 species, from 464 species-study combinations. Climate change effects were reported in 65% of studies. Climate change was identified as causing population declines or range restrictions in half of the cases. The probability of identifying an effect of climate change varied among regions, taxa and research methods. Climatic effects were equally prevalent in studies exclusively investigating climate factors (more than 50% of studies) and in studies including additional factors, thus bolstering confidence in the results of studies exclusively examining effects of climate change. Our analyses reveal biases with respect to geography, taxonomy and research question, making global conclusions impossible. Additional research should focus on under-represented regions, taxa and questions. Conservation and climate policy should consider the documented harm climate change causes reptiles and amphibians.

Changes in commitment to change among leaders in home help services.

PubMed

Westerberg, Kristina; Tafvelin, Susanne

2015-07-06

The purpose of the this study was to explore the development of commitment to change among leaders in the home help services during organizational change and to study this development in relation to workload and stress. During organizational change initiatives, commitment to change among leaders is important to ensure the implementation of the change. However, little is known of development of commitment of change over time. The study used a qualitative design with semi-structured interviews with ten leaders by the time an organizational change initiative was launched and follow-up one year later. Thematic content analysis was used to analyze the interviews. Commitment to change is not static, but seems to develop over time and during organizational change. At the first interview, leaders had a varied pattern reflecting different dimensions of commitment to change. One year later, the differences between leaders' commitment to change was less obvious. Differences in commitment to change had no apparent relationship with workload or stress. The data were collected from one organization, and the number of participants were small which could affect the results on workload and stress in relation to commitment to change. It is important to support leaders during organizational change initiatives to maintain their commitment. One way to accomplish this is to use management team meetings to monitor how leaders perceive their situation. Qualitative, longitudinal and leader studies on commitment to change are all unusual, and taken together, this study shows new aspects of commitment.

Data gaps in anthropogenically driven local-scale species richness change studies across the Earth's terrestrial biomes.

PubMed

Murphy, Grace E P; Romanuk, Tamara N

2016-05-01

There have been numerous attempts to synthesize the results of local-scale biodiversity change studies, yet several geographic data gaps exist. These data gaps have hindered ecologist's ability to make strong conclusions about how local-scale species richness is changing around the globe. Research on four of the major drivers of global change is unevenly distributed across the Earth's biomes. Here, we use a dataset of 638 anthropogenically driven species richness change studies to identify where data gaps exist across the Earth's terrestrial biomes based on land area, future change in drivers, and the impact of drivers on biodiversity, and make recommendations for where future studies should focus their efforts. Across all drivers of change, the temperate broadleaf and mixed forests and the tropical moist broadleaf forests are the best studied. The biome-driver combinations we have identified as most critical in terms of where local-scale species richness change studies are lacking include the following: land-use change studies in tropical and temperate coniferous forests, species invasion and nutrient addition studies in the boreal forest, and warming studies in the boreal forest and tropics. Gaining more information on the local-scale effects of the specific human drivers of change in these biomes will allow for better predictions of how human activity impacts species richness around the globe.

Baseline Depressive Symptoms, Completion of Study Assessments, and Behavior Change in a Long-Term Dietary Intervention Among Breast Cancer Survivors.

PubMed

Wang, Julie B; Pierce, John P; Ayala, Guadalupe X; Cadmus-Bertram, Lisa A; Flatt, Shirley W; Madanat, Hala; Newman, Vicky A; Nichols, Jeanne F; Natarajan, Loki

2015-12-01

Depressive symptoms can lower adherence and change in dietary studies. Behavioral activation may reduce these effects. This study aims to assess relationships among depressive symptoms on adherence and dietary change in the Women's Healthy Eating and Living (WHEL) Study Secondary analyses from the WHEL Study, which achieved major dietary change in breast cancer survivors (N = 2817), were conducted. Logistic regressions were undertaken of baseline depressive symptoms (six-item Center for Epidemiologic Studies Depression Scale (CES-D)) with (1) completion of 1- and 4-year study assessments and (2) validated change in dietary behavior in the intervention group. In the comparison group (vs. intervention), depressive symptoms lowered completion of dietary recalls and clinic visits [4 years: odds ratio (OR) = 2.0; 95 % confidence interval (CI) = 1.4-3.0]. The behaviorally oriented intervention achieved major change in those furthest from study targets, although changes were lower in those with depressive symptoms: fruit/vegetable (+37.2 %), fiber (+49.0 %), and fat (-22.4 %). Behavioral activation in dietary change interventions can overcome the impact of depressive symptoms.

A Case Study of Teachers' Perceptions of Change and Change Implementation at a Rural Public School

ERIC Educational Resources Information Center

Irvin, Jennifer Beckum

2010-01-01

With demands for producing results in education, the problem for many teachers is accepting and implementing mandated changes. This study sought to determine the relationship between high school teachers' perceptions of change and change implementation at a rural high school in a southeastern US state. This study was based on planned behavior…

Patterns and biases in climate change research on amphibians and reptiles: a systematic review

PubMed Central

2016-01-01

Climate change probably has severe impacts on animal populations, but demonstrating a causal link can be difficult because of potential influences by additional factors. Assessing global impacts of climate change effects may also be hampered by narrow taxonomic and geographical research foci. We review studies on the effects of climate change on populations of amphibians and reptiles to assess climate change effects and potential biases associated with the body of work that has been conducted within the last decade. We use data from 104 studies regarding the effect of climate on 313 species, from 464 species–study combinations. Climate change effects were reported in 65% of studies. Climate change was identified as causing population declines or range restrictions in half of the cases. The probability of identifying an effect of climate change varied among regions, taxa and research methods. Climatic effects were equally prevalent in studies exclusively investigating climate factors (more than 50% of studies) and in studies including additional factors, thus bolstering confidence in the results of studies exclusively examining effects of climate change. Our analyses reveal biases with respect to geography, taxonomy and research question, making global conclusions impossible. Additional research should focus on under-represented regions, taxa and questions. Conservation and climate policy should consider the documented harm climate change causes reptiles and amphibians. PMID:27703684

Evolutionary and plastic responses to climate change in terrestrial plant populations

PubMed Central

Franks, Steven J; Weber, Jennifer J; Aitken, Sally N

2014-01-01

As climate change progresses, we are observing widespread changes in phenotypes in many plant populations. Whether these phenotypic changes are directly caused by climate change, and whether they result from phenotypic plasticity or evolution, are active areas of investigation. Here, we review terrestrial plant studies addressing these questions. Plastic and evolutionary responses to climate change are clearly occurring. Of the 38 studies that met our criteria for inclusion, all found plastic or evolutionary responses, with 26 studies showing both. These responses, however, may be insufficient to keep pace with climate change, as indicated by eight of 12 studies that examined this directly. There is also mixed evidence for whether evolutionary responses are adaptive, and whether they are directly caused by contemporary climatic changes. We discuss factors that will likely influence the extent of plastic and evolutionary responses, including patterns of environmental changes, species’ life history characteristics including generation time and breeding system, and degree and direction of gene flow. Future studies with standardized methodologies, especially those that use direct approaches assessing responses to climate change over time, and sharing of data through public databases, will facilitate better predictions of the capacity for plant populations to respond to rapid climate change. PMID:24454552

Prevalence of primary outcome changes in clinical trials registered on ClinicalTrials.gov: a cross-sectional study.

PubMed

Ramagopalan, Sreeram; Skingsley, Andrew P; Handunnetthi, Lahiru; Klingel, Michelle; Magnus, Daniel; Pakpoor, Julia; Goldacre, Ben

2014-01-01

An important principle in the good conduct of clinical trials is that a summary of the trial protocol, with a pre-defined primary outcome, should be freely available before the study commences. The clinical trials registry ClinicalTrials.gov provides one method of doing this, and once the trial is registered, any changes made to the primary outcome are documented. The objectives of this study were: to assess the proportion of registered trials on ClinicalTrials.gov that had the primary outcome changed; to assess when the primary outcome was changed in relation to the listed study start and end dates and to assess whether the primary outcome change had any relation to the study sponsor. A cross-sectional analysis of all interventional clinical trials registered on ClinicalTrials.gov as of 25 October 2012 was performed. The main outcome was any change made to the initially listed primary outcome and the time of the change in relation to the trial start and end date. Our analysis showed that 28229 of 89204 (31.7%) registered studies had their primary outcome changed.  Industry funding was associated with all primary outcome changes, odds ratio (OR)= 1.36, 95% confidence interval (CI)=1.31-1.41, p<0.001; with primary outcome changes after study start date OR=1.37, 95% CI=1.32-1.42, p<0.001; with primary outcome changes after primary completion date OR=1.84, 95% CI=1.75-1.94, p<0.001 and with primary outcome changes after study completion date OR=1.82, 95% CI=1.73-1.91, p<0.001.  Conclusions A significant proportion of interventional trials registered on ClinicalTrials.gov have their primary outcomes altered after the listed study start and completion dates. These changes are associated with funding source.

Optical Coherence Tomography Measurements and Analysis Methods in Optical Coherence Tomography Studies of Diabetic Macular Edema

PubMed Central

Browning, David J.; Glassman, Adam R.; Aiello, Lloyd P.; Bressler, Neil M.; Bressler, Susan; Danis, Ronald P.; Davis, Matthew D.; Ferris, Frederick L.; Huang, Suber S.; Kaiser, Peter K.; Kollman, Craig; Sadda, Srinavas; Scott, Ingrid U.; Qin, Haijing

2009-01-01

Objective To evaluate optical coherence tomography (OCT) measurements and methods of analysis of OCT data in studies of diabetic macular edema (DME). Design Associations of pairs of OCT variables and results of three analysis methods using data from two studies of DME. Participants Two hundred sixty-three subjects from a study of modified Early Treatment of Diabetic Retinopathy Study (mETDRS) versus modified macular grid (MMG) photocoagulation for DME and 96 subjects from a study of diurnal variation of DME. Methods Correlations were calculated for pairs of OCT variables at baseline and for changes in the variables over time. Distribution of OCT measurement changes, predictive factors for OCT measurement changes, and treatment group outcomes were compared when three measures of change in macular thickness were analyzed: absolute change in retinal thickness, relative change in retinal thickness, and relative change in retinal thickening. Main Outcome Measures Concordance of results using different OCT variables and analysis methods. Results Center point thickness correlated highly with central subfield mean thickness (CSMT) at baseline (0.98–0.99). The distributions of changes in CSMT were approximately normally distributed for absolute change in retinal thickness and relative change in retinal thickness, but not for relative change in retinal thickening. The macular thinning in the mETDRS group was significantly greater than in the MMG group when absolute change in retinal thickness was used, but not when relative change in thickness and relative change in thickening were used. Relative change in macular thickening provides unstable data in eyes with mild degrees of baseline thickening, unlike the situation with absolute or relative change in retinal thickness. Conclusions Central subfield mean thickness is the preferred OCT measurement for the central macula because of its higher reproducibility and correlation with other measurements of the central macula. Total macular volume may be preferred when the central macula is less important. Absolute change in retinal thickness is the preferred analysis method in studies involving eyes with mild macular thickening. Relative change in thickening may be preferable when retinal thickening is more severe. PMID:18675696

Optical coherence tomography measurements and analysis methods in optical coherence tomography studies of diabetic macular edema.

PubMed

Browning, David J; Glassman, Adam R; Aiello, Lloyd P; Bressler, Neil M; Bressler, Susan B; Danis, Ronald P; Davis, Matthew D; Ferris, Frederick L; Huang, Suber S; Kaiser, Peter K; Kollman, Craig; Sadda, Srinavas; Scott, Ingrid U; Qin, Haijing

2008-08-01

To evaluate optical coherence tomography (OCT) measurements and methods of analysis of OCT data in studies of diabetic macular edema (DME). Associations of pairs of OCT variables and results of 3 analysis methods using data from 2 studies of DME. Two hundred sixty-three subjects from a study of modified Early Treatment of Diabetic Retinopathy Study (mETDRS) versus modified macular grid (MMG) photocoagulation for DME and 96 subjects from a study of diurnal variation of DME. Correlations were calculated for pairs of OCT variables at baseline and for changes in the variables over time. Distribution of OCT measurement changes, predictive factors for OCT measurement changes, and treatment group outcomes were compared when 3 measures of change in macular thickness were analyzed: absolute change in retinal thickness, relative change in retinal thickness, and relative change in retinal thickening. Concordance of results using different OCT variables and analysis methods. Center point thickness correlated highly with central subfield mean thickness (CSMT) at baseline (0.98-0.99). The distributions of changes in CSMT were approximately normally distributed for absolute change in retinal thickness and relative change in retinal thickness, but not for relative change in retinal thickening. Macular thinning in the mETDRS group was significantly greater than in the MMG group when absolute change in retinal thickness was used, but not when relative change in thickness and relative change in thickening were used. Relative change in macular thickening provides unstable data in eyes with mild degrees of baseline thickening, unlike the situation with absolute or relative change in retinal thickness. Central subfield mean thickness is the preferred OCT measurement for the central macula because of its higher reproducibility and correlation with other measurements of the central macula. Total macular volume may be preferred when the central macula is less important. Absolute change in retinal thickness is the preferred analysis method in studies involving eyes with mild macular thickening. Relative change in thickening may be preferable when retinal thickening is more severe.

A Longitudinal Study of the Determinants and Outcomes of Career Change

ERIC Educational Resources Information Center

Carless, Sally A.; Arnup, Jessica L.

2011-01-01

The present longitudinal field study investigated the antecedents and consequences of an actual career change. The framework for this study was Rhodes and Doering's (1983) model of career change. We examined the effect of individual and organisational characteristics on career change behaviour. The individual characteristics were: traits (Openness…

[The influence of meaning making following stressful life experiences on change of self-concept].

PubMed

Horita, Ryo; Sugie, Masashi

2013-10-01

As interest in meaning making following stressful life experiences continues to grow, it is important to clarify the features and functions of the meaning- making process. We examined the influence of meaning making following stressful life experiences on change of self-concept. In two studies, university students selected their most stressful life experience and completed the Assimilation and Accommodation of Meaning Making Scale. In Study 1, 235 university students also completed questionnaires regarding post-traumatic growth and positive change of the sense of identity following their stressful life experience. The results of covariance structure analysis indicated that accommodation promoted a positive change of self-concept. In Study 2, 199 university students completed questionnaires regarding change of self-concept and emotion as a positive or negative change following stressful life experiences. The results of covariance structure analysis indicated that accommodation promoted a positive change, similar to the results of Study 1. In addition, accommodation also promoted negative change. However, assimilation did not promote positive change but did restrain negative change.

Is There a Temperate Bias in Our Understanding of How Climate Change Will Alter Plant-Herbivore Interactions? A Meta-analysis of Experimental Studies.

PubMed

Mundim, Fabiane M; Bruna, Emilio M

2016-09-01

Climate change can drive major shifts in community composition and interactions between resident species. However, the magnitude of these changes depends on the type of interactions and the biome in which they take place. We review the existing conceptual framework for how climate change will influence tropical plant-herbivore interactions and formalize a similar framework for the temperate zone. We then conduct the first biome-specific tests of how plant-herbivore interactions change in response to climate-driven changes in temperature, precipitation, ambient CO2, and ozone. We used quantitative meta-analysis to compare predicted and observed changes in experimental studies. Empirical studies were heavily biased toward temperate systems, so testing predicted changes in tropical plant-herbivore interactions was virtually impossible. Furthermore, most studies investigated the effects of CO2 with limited plant and herbivore species. Irrespective of location, most studies manipulated only one climate change factor despite the fact that different factors can act in synergy to alter responses of plants and herbivores. Finally, studies of belowground plant-herbivore interactions were also rare; those conducted suggest that climate change could have major effects on belowground subsystems. Our results suggest that there is a disconnection between the growing literature proposing how climate change will influence plant-herbivore interactions and the studies testing these predictions. General conclusions will also be hampered without better integration of above- and belowground systems, assessing the effects of multiple climate change factors simultaneously, and using greater diversity of species in experiments.

Behaviour change interventions to promote physical activity in rheumatoid arthritis: a systematic review.

PubMed

Larkin, Louise; Gallagher, Stephen; Cramp, Fiona; Brand, Charles; Fraser, Alexander; Kennedy, Norelee

2015-10-01

Research has shown that people who have rheumatoid arthritis (RA) do not usually participate in enough physical activity to obtain the benefits of optimal physical activity levels, including quality of life, aerobic fitness and disease-related characteristics. Behaviour change theory underpins the promotion of physical activity. The aim of this systematic review was to explore behaviour change interventions which targeted physical activity behaviour in people who have RA, focusing on the theory underpinning the interventions and the behaviour change techniques utilised using specific behaviour change taxonomy. An electronic database search was conducted via EBSCOhost, PubMed, Cochrane Central Register of Controlled Trials and Web of Science databases in August 2014, using Medical Subject Headings and keywords. A manual search of reference lists was also conducted. Randomised control trials which used behaviour change techniques and targeted physical activity behaviour in adults who have RA were included. Two reviewers independently screened studies for inclusion. Methodological quality was assessed using the Cochrane risk of bias tool. Five studies with 784 participants were included in the review. Methodological quality of the studies was mixed. The studies consisted of behaviour change interventions or combined practical physical activity and behaviour change interventions and utilised a large variety of behaviour change techniques. Four studies reported increased physical activity behaviour. All studies used subjective methods of assessing physical activity with only one study utilising an objective measure. There has been varied success of behaviour change interventions in promoting physical activity behaviour in people who have RA. Further studies are required to develop and implement the optimal behaviour change intervention in this population.

Analyzing the impacts of final demand changes on total output using input-output approach: The case of Japanese ICT sectors

NASA Astrophysics Data System (ADS)

Zuhdi, Ubaidillah

2014-03-01

The purpose of this study is to analyze the impacts of final demand changes on total output of Japanese Information and Communication Technologies (ICT) sectors in future time. This study employs one of analysis tool in Input-Output (IO) analysis, demand-pull IO quantity model, in achieving the purpose. There are three final demand changes used in this study, namely (1) export, (2) import, and (3) outside households consumption changes. This study focuses on "pure change" condition, the condition that final demand changes only appear in analyzed sectors. The results show that export and outside households consumption modifications give positive impact while opposite impact could be seen in import change.

Visual search for changes in scenes creates long-term, incidental memory traces.

PubMed

Utochkin, Igor S; Wolfe, Jeremy M

2018-05-01

Humans are very good at remembering large numbers of scenes over substantial periods of time. But how good are they at remembering changes to scenes? In this study, we tested scene memory and change detection two weeks after initial scene learning. In Experiments 1-3, scenes were learned incidentally during visual search for change. In Experiment 4, observers explicitly memorized scenes. At test, after two weeks observers were asked to discriminate old from new scenes, to recall a change that they had detected in the study phase, or to detect a newly introduced change in the memorization experiment. Next, they performed a change detection task, usually looking for the same change as in the study period. Scene recognition memory was found to be similar in all experiments, regardless of the study task. In Experiment 1, more difficult change detection produced better scene memory. Experiments 2 and 3 supported a "depth-of-processing" account for the effects of initial search and change detection on incidental memory for scenes. Of most interest, change detection was faster during the test phase than during the study phase, even when the observer had no explicit memory of having found that change previously. This result was replicated in two of our three change detection experiments. We conclude that scenes can be encoded incidentally as well as explicitly and that changes in those scenes can leave measurable traces even if they are not explicitly recalled.

Spatiotemporal analysis of land use and land cover change in the Brazilian Amazon

PubMed Central

Li, Guiying; Moran, Emilio; Hetrick, Scott

2013-01-01

This paper provides a comparative analysis of land use and land cover (LULC) changes among three study areas with different biophysical environments in the Brazilian Amazon at multiple scales, from per-pixel, polygon, census sector, to study area. Landsat images acquired in the years of 1990/1991, 1999/2000, and 2008/2010 were used to examine LULC change trajectories with the post-classification comparison approach. A classification system composed of six classes – forest, savanna, other-vegetation (secondary succession and plantations), agro-pasture, impervious surface, and water, was designed for this study. A hierarchical-based classification method was used to classify Landsat images into thematic maps. This research shows different spatiotemporal change patterns, composition and rates among the three study areas and indicates the importance of analyzing LULC change at multiple scales. The LULC change analysis over time for entire study areas provides an overall picture of change trends, but detailed change trajectories and their spatial distributions can be better examined at a per-pixel scale. The LULC change at the polygon scale provides the information of the changes in patch sizes over time, while the LULC change at census sector scale gives new insights on how human-induced activities (e.g., urban expansion, roads, and land use history) affect LULC change patterns and rates. This research indicates the necessity to implement change detection at multiple scales for better understanding the mechanisms of LULC change patterns and rates. PMID:24127130

Determination of channel change for selected streams, Maricopa County, Arizona

USGS Publications Warehouse

Capesius, Joseph P.; Lehman, Ted W.

2002-01-01

In Maricopa County, Arizona, 10 sites on seven streams were studied to determine the lateral and vertical change of the channel. Channel change was studied over time scales ranging from individual floods to decades using cross-section surveys, discharge measurements, changes in the point of zero flow, and repeat photography. All of the channels showed some change in cross-section area or hydraulic radius over the time scales studied, but the direction and mag-nitude of change varied considerably from one flow, or series of flows, to another. The documentation of cross-section geometry for streams in Maricopa County for long-term monitoring was begun in this study.

Behaviour change techniques in physical activity interventions for men with prostate cancer: A systematic review.

PubMed

Hallward, Laura; Patel, Nisha; Duncan, Lindsay R

2018-02-01

Physical activity interventions can improve prostate cancer survivors' health. Determining the behaviour change techniques used in physical activity interventions can help elucidate the mechanisms by which an intervention successfully changes behaviour. The purpose of this systematic review was to identify and evaluate behaviour change techniques in physical activity interventions for prostate cancer survivors. A total of 7 databases were searched and 15 studies were retained. The studies included a mean 6.87 behaviour change techniques (range = 3-10), and similar behaviour change techniques were implemented in all studies. Consideration of how behaviour change techniques are implemented may help identify how behaviour change techniques enhance physical activity interventions for prostate cancer survivors.

Multiscale Spatial Assessment of Determinant Factors of Land Use Change: Study at Urban Area of Yogyakarta

NASA Astrophysics Data System (ADS)

Susilo, Bowo

2017-12-01

Studies of land use change have been undertaken by different researchers using various methods. Among those methods, modelling is widely utilized. Modelling land use change required several components remarked as model variables. Those represent any conditions or factors which considered relevant or have some degree of correlation to the changes of land use. Variables which have significant correlation to land use change are referred as determinant factors or driving forces. Those factors as well as changes of land use are distributed across space and therefore referred as spatial determinant factors. The main objective of the research was to examine land use change and its determinant factors. Area and location of land use change were analysed based on three different years of land use maps, which are 1993, 2000 and 2007. Spatial and temporal analysis were performed which emphasize to the influence of scale to both of analysis’s. Urban area of Yogyakarta was selected as study area. Study area covered three different districts (kabupaten), involving 20 sub districts and totally consists of 74 villages. Result of this study shows that during 14 years periods (1993 to 2007), there were about 1,460 hectares of land use change had been taken place. Dominant type of land use change is agricultural to residential. The uses of different spatial and temporal scale in analysis were able to reveal different factors related to land use change. In general, factors influencing the quantities of land use change in the study area were population growth and the availability of land. The use of data with different spatial resolution can reveal the presence of various factors associated with the location of the change. Locations of land use change were influenced or determined by accessibility factors.

A plant’s perspective of extremes: Terrestrial plant responses to changing climatic variability

PubMed Central

Reyer, C.; Leuzinger, S.; Rammig, A.; Wolf, A.; Bartholomeus, R. P.; Bonfante, A.; de Lorenzi, F.; Dury, M.; Gloning, P.; Abou Jaoudé, R.; Klein, T.; Kuster, T. M.; Martins, M.; Niedrist, G.; Riccardi, M.; Wohlfahrt, G.; de Angelis, P.; de Dato, G.; François, L.; Menzel, A.; Pereira, M.

2013-01-01

We review observational, experimental and model results on how plants respond to extreme climatic conditions induced by changing climatic variability. Distinguishing between impacts of changing mean climatic conditions and changing climatic variability on terrestrial ecosystems is generally underrated in current studies. The goals of our review are thus (1) to identify plant processes that are vulnerable to changes in the variability of climatic variables rather than to changes in their mean, and (2) to depict/evaluate available study designs to quantify responses of plants to changing climatic variability. We find that phenology is largely affected by changing mean climate but also that impacts of climatic variability are much less studied but potentially damaging. We note that plant water relations seem to be very vulnerable to extremes driven by changes in temperature and precipitation and that heatwaves and flooding have stronger impacts on physiological processes than changing mean climate. Moreover, interacting phenological and physiological processes are likely to further complicate plant responses to changing climatic variability. Phenological and physiological processes and their interactions culminate in even more sophisticated responses to changing mean climate and climatic variability at the species and community level. Generally, observational studies are well suited to study plant responses to changing mean climate, but less suitable to gain a mechanistic understanding of plant responses to climatic variability. Experiments seem best suited to simulate extreme events. In models, temporal resolution and model structure are crucial to capture plant responses to changing climatic variability. We highlight that a combination of experimental, observational and /or modeling studies have the potential to overcome important caveats of the respective individual approaches. PMID:23504722

Studying plant–pollinator interactions in a changing climate: A review of approaches1

PubMed Central

Byers, Diane L.

2017-01-01

Plant–pollinator interactions are potentially at risk due to climate change. Because of the spatial and temporal variation associated with the effects of climate change and the responses of both actors, research to assess this interaction requires creative approaches. This review focuses on assessments of plants’ and pollinators’ altered phenology in response to environmental changes, as phenology is one of the key responses. I reviewed research methods with the goal of presenting the wide diversity of available techniques for addressing changes in these interactions. Approaches ranged from use of historical specimens to multisite experimental community studies; while differing in depth of historical information and community interactions, all contribute to assessment of phenology changes. Particularly insightful were those studies that directly assessed the environmental changes across spatial and temporal scales and the responses of plants and pollinators at these scales. Longer-term studies across environmental gradients, potentially with reciprocal transplants, enable an assessment of climate impacts at both scales. While changes in phenology are well studied, the impacts of phenology changes are not. Future research should include approaches to address this gap. PMID:28690933

Believe, and you will achieve: changes over time in self-efficacy, engagement, and performance.

PubMed

Ouweneel, Else; Schaufeli, Wilmar B; Le Blanc, Pascale M

2013-07-01

In order to answer the question whether changes in students' self-efficacy levels co-vary with similar changes in engagement and performance, a field study and an experimental study were conducted among university students. In order to do this, we adopted a subgroup approach. We created "natural" (Study 1) and manipulated (Study 2) subgroups based upon their change in self-efficacy over time and examined whether these subgroups showed similar changes over time in engagement and performance. The results of both studies are partly in line with Social Cognitive Theory, in that they confirm that changes in self-efficacy may have a significant impact on students' changes in cognition and motivation (i.e. engagement), as well as behavior (i.e. performance). More specifically, our results show that students' increases/decreases in self-efficacy were related to corresponding increases/decreases in their study engagement and task performance over time. Examining the consequences of changes in students' self-efficacy levels seems promising, both for research and practice. © 2013 The Authors. Applied Psychology: Health and Well-Being © 2013 The International Association of Applied Psychology.

Managing Dualities in Planned Change Initiatives

ERIC Educational Resources Information Center

Barge, J. Kevin; Lee, Michael; Maddux, Kristy; Nabring, Richard; Townsend, Bryan

2008-01-01

Dualities play an important role in creating the conditions for change and managing planned change initiatives. Building on Seo, Putnam, and Bartunek's (2003) work, this study focuses on the dualities associated with managing change processes. A case study of a planned change process called the Circle of Prosperity Initiative, a multi-stakeholder…

The Self-Aware Organization: A Metacognitive Approach to Change Management in a Small Rural School District

ERIC Educational Resources Information Center

Harrison, Charles E., Jr.

2010-01-01

Educational leaders have often been ineffective in managing change in their environment. Change vectors were used in the current study to identify areas of needed change, along with a metacognitive approach to organizational change. A qualitative case study was employed to explore the use of such a metacognitive approach to change by a small rural…

The Link between the Process of Change and Coaching in an Organization--A Case Study

ERIC Educational Resources Information Center

Jim, Josephine

2016-01-01

The aim of this case study was to highlight coaching in the process of change using a real life information technology and operational change project in an institution. It demonstrates the critical importance of coaching in change management, for successful change to occur. Any sustaining change requires ongoing coaching as an integral part of the…

Relating protein conformational changes to packing efficiency and disorder

PubMed Central

Bhardwaj, Nitin; Gerstein, Mark

2009-01-01

Changes in protein conformation play key roles in facilitating various biochemical processes, ranging from signaling and phosphorylation to transport and catalysis. While various factors that drive these motions such as environmental changes and binding of small molecules are well understood, specific causative effects on the structural features of the protein due to these conformational changes have not been studied on a large scale. Here, we study protein conformational changes in relation to two key structural metrics: packing efficiency and disorder. Packing has been shown to be crucial for protein stability and function by many protein design and engineering studies. We study changes in packing efficiency during conformational changes, thus extending the analysis from a static context to a dynamic perspective and report some interesting observations. First, we study various proteins that adopt alternate conformations and find that tendencies to show motion and change in packing efficiency are correlated: residues that change their packing efficiency show larger motions. Second, our results suggest that residues that show higher changes in packing during motion are located on the changing interfaces which are formed during these conformational changes. These changing interfaces are slightly different from shear or static interfaces that have been analyzed in previous studies. Third, analysis of packing efficiency changes in the context of secondary structure shows that, as expected, residues buried in helices show the least change in packing efficiency, whereas those embedded in bends are most likely to change packing. Finally, by relating protein disorder to motions, we show that marginally disordered residues which are ordered enough to be crystallized but have sequence patterns indicative of disorder show higher dislocation and a higher change in packing than ordered ones and are located mostly on the changing interfaces. Overall, our results demonstrate that between the two conformations, the cores of the proteins remain mostly intact, whereas the interfaces display the most elasticity, both in terms of disorder and change in packing efficiency. By doing a variety of tests, we also show that our observations are robust to the solvation state of the proteins. PMID:19472340

Final Report for Dynamic Models for Causal Analysis of Panel Data. Models for Change in Quantitative Variables, Part III: Estimation from Panel Data. Part II, Chapter 5.

ERIC Educational Resources Information Center

Hannan, Michael T.

This document is part of a series of chapters described in SO 011 759. Addressing the problems of studying change and the change process, the report argues that sociologists should study coupled changes in qualitative and quantitative outcomes (e.g., marital status and earnings). The author presents a model for sociological studies of change in…

Understanding the impacts of climate change and human activities on streamflow: a case study of the Soan River basin, Pakistan

NASA Astrophysics Data System (ADS)

Shahid, Muhammad; Cong, Zhentao; Zhang, Danwu

2017-09-01

Climate change and land use change are the two main factors that can alter the catchment hydrological process. The objective of this study is to evaluate the relative contribution of climate change and land use change to runoff change of the Soan River basin. The Mann-Kendal and the Pettit tests are used to find out the trends and change point in hydroclimatic variables during the period 1983-2012. Two different approaches including the abcd hydrological model and the Budyko framework are then used to quantify the impact of climate change and land use change on streamflow. The results from both methods are consistent and show that annual runoff has significantly decreased with a change point around 1997. The decrease in precipitation and increases in potential evapotranspiration contribute 68% of the detected change while the rest of the detected change is due to land use change. The land use change acquired from Landsat shows that during post-change period, the agriculture has increased in the Soan basin, which is in line with the positive contribution of land use change to runoff decrease. This study concludes that aforementioned methods performed well in quantifying the relative contribution of land use change and climate change to runoff change.

Longitudinal Association of Anthropometry with Mammographic Breast Density in the Study of Women's Health Across the Nation (Swan)

PubMed Central

Reeves, Katherine W.; Stone, Roslyn A.; Modugno, Francesmary; Ness, Roberta B.; Vogel, Victor G.; Weissfeld, Joel L.; Habel, Laurel A.; Sternfeld, Barbara; Cauley, Jane A.

2009-01-01

High percent mammographic breast density is strongly associated with increased breast cancer risk. Though body mass index (BMI) is positively associated with risk of postmenopausal breast cancer, BMI is negatively associated with percent breast density in cross-sectional studies. Few longitudinal studies have evaluated associations between BMI and weight and mammographic breast density. We studied the longitudinal relationships between anthropometry and breast density in a prospective cohort of 834 pre- and perimenopausal women enrolled in an ancillary study to the Study of Women's Health Across the Nation (SWAN). Routine screening mammograms were collected and read for breast density. Random intercept regression models were used to evaluate whether annual BMI change was associated with changes over time in dense breast area and percent density. The study population was 7.4% African American, 48.8% Caucasian, 21.8% Chinese, and 21.9% Japanese. Mean follow-up was 4.8 years. Mean annual weight change was +0.32 kg/year, mean change in dense area was -0.77 cm2/year, and mean change in percent density was -1.14%/year. In fully adjusted models, annual change in BMI was not significantly associated with changes in dense breast area (-0.17 cm2, 95% CI -0.64, 0.29). Borderline significant negative associations were observed between annual BMI change and annual percent density change, with percent density decreasing 0.36% (95% CI -0.74, 0.02) for a one unit increase in BMI over a year. This longitudinal study provides modest evidence that changes in BMI are not associated with changes in dense area, yet may be negatively associated with percent density. PMID:19065651

Women and Cardiovascular Disease: Learning Communities and Experiences that Influence Lifestyle Change

ERIC Educational Resources Information Center

Shockley, Carrie Lenora

2010-01-01

This qualitative study examined women's learning in making healthy lifestyle changes after a cardiac event. The study examined how and what learning women identified as important to learning behavioral change and the meaning making experiences that influenced changes in self-perception and outlook. The study also focused on the role of the cardiac…

Conceptions of Change: A Phenomenographical Study of the Reinvention Initiative at the City Colleges of Chicago

ERIC Educational Resources Information Center

Horace, Jennifer M.

2016-01-01

The purpose of this study was to add to the literature on community colleges and organizational change. This study explored how interested parties, internal and external, understood the organizational change called the Reinvention Initiative occurring at the City Colleges of Chicago and how this organizational change influenced constituencies'…

Synthesis in land change science: methodological patterns, challenges, and guidelines.

PubMed

Magliocca, Nicholas R; Rudel, Thomas K; Verburg, Peter H; McConnell, William J; Mertz, Ole; Gerstner, Katharina; Heinimann, Andreas; Ellis, Erle C

Global and regional economic and environmental changes are increasingly influencing local land-use, livelihoods, and ecosystems. At the same time, cumulative local land changes are driving global and regional changes in biodiversity and the environment. To understand the causes and consequences of these changes, land change science (LCS) draws on a wide array synthetic and meta-study techniques to generate global and regional knowledge from local case studies of land change. Here, we review the characteristics and applications of synthesis methods in LCS and assess the current state of synthetic research based on a meta-analysis of synthesis studies from 1995 to 2012. Publication of synthesis research is accelerating, with a clear trend toward increasingly sophisticated and quantitative methods, including meta-analysis. Detailed trends in synthesis objectives, methods, and land change phenomena and world regions most commonly studied are presented. Significant challenges to successful synthesis research in LCS are also identified, including issues of interpretability and comparability across case-studies and the limits of and biases in the geographic coverage of case studies. Nevertheless, synthesis methods based on local case studies will remain essential for generating systematic global and regional understanding of local land change for the foreseeable future, and multiple opportunities exist to accelerate and enhance the reliability of synthetic LCS research in the future. Demand for global and regional knowledge generation will continue to grow to support adaptation and mitigation policies consistent with both the local realities and regional and global environmental and economic contexts of land change.

Interpreting change from patient reported outcome (PRO) endpoints: patient global ratings of concept versus patient global ratings of change, a case study among osteoporosis patients.

PubMed

Nixon, Annabel; Doll, Helen; Kerr, Cicely; Burge, Russel; Naegeli, April N

2016-02-19

Regulatory guidance recommends anchor-based methods for interpretation of treatment effects measured by PRO endpoints. Methodological pros and cons of patient global ratings of change vs. patient global ratings of concept have been discussed but empirical evidence in support of either approach is lacking. This study evaluated the performance of patient global ratings of change and patient global ratings of concept for interpreting patient stability and patient improvement. Patient global ratings of change and patient global ratings of concept were included in a psychometric validation study of an osteoporosis-targeted PRO instrument (the OPAQ-PF) to assess its ability to detect change and to derive responder definitions. 144 female osteoporosis patients with (n = 37) or without (n = 107) a recent (within 6 weeks) fragility fracture completed the OPAQ-PF and global items at baseline, 2 weeks (no recent fracture), and 12 weeks (recent fracture) post-baseline. Results differed between the two methods. Recent fracture patients reported more improvement while patients without recent fracture reported more stability on ratings of change than ratings of concept. However, correlations with OPAQ-PF score change were stronger for ratings of concept than ratings of change (both groups). Effect sizes for OPAQ-PF score change increased consistently with level of change in ratings of concept but inconsistently with ratings of change, with the mean AUC for prediction of a one-point change being 0.72 vs. 0.56. This study provides initial empirical support for methodological and regulatory recommendations to use patient global ratings of concept rather than ratings of change when interpreting change captured by PRO instruments in studies evaluating treatment effects. These findings warrant being confirmed in a purpose-designed larger scale analysis.

Driver Behavior During Overtaking Maneuvers from the 100-Car Naturalistic Driving Study.

PubMed

Chen, Rong; Kusano, Kristofer D; Gabler, Hampton C

2015-01-01

Lane changes with the intention to overtake the vehicle in front are especially challenging scenarios for forward collision warning (FCW) designs. These overtaking maneuvers can occur at high relative vehicle speeds and often involve no brake and/or turn signal application. Therefore, overtaking presents the potential of erroneously triggering the FCW. A better understanding of driver behavior during lane change events can improve designs of this human-machine interface and increase driver acceptance of FCW. The objective of this study was to aid FCW design by characterizing driver behavior during lane change events using naturalistic driving study data. The analysis was based on data from the 100-Car Naturalistic Driving Study, collected by the Virginia Tech Transportation Institute. The 100-Car study contains approximately 1.2 million vehicle miles of driving and 43,000 h of data collected from 108 primary drivers. In order to identify overtaking maneuvers from a large sample of driving data, an algorithm to automatically identify overtaking events was developed. The lead vehicle and minimum time to collision (TTC) at the start of lane change events was identified using radar processing techniques developed in a previous study. The lane change identification algorithm was validated against video analysis, which manually identified 1,425 lane change events from approximately 126 full trips. Forty-five drivers with valid time series data were selected from the 100-Car study. From the sample of drivers, our algorithm identified 326,238 lane change events. A total of 90,639 lane change events were found to involve a closing lead vehicle. Lane change events were evenly distributed between left side and right side lane changes. The characterization of lane change frequency and minimum TTC was divided into 10 mph speed bins for vehicle travel speeds between 10 and 90 mph. For all lane change events with a closing lead vehicle, the results showed that drivers change lanes most frequently in the 40-50 mph speed range. Minimum TTC was found to increase with travel speed. The variability in minimum TTC between drivers also increased with travel speed. This study developed and validated an algorithm to detect lane change events in the 100-Car Naturalistic Driving Study and characterized lane change events in the database. The characterization of driver behavior in lane change events showed that driver lane change frequency and minimum TTC vary with travel speed. The characterization of overtaking maneuvers from this study will aid in improving the overall effectiveness of FCW systems by providing active safety system designers with further understanding of driver action in overtaking maneuvers, thereby increasing system warning accuracy, reducing erroneous warnings, and improving driver acceptance.

Ambivalence toward imposed change: the conflict between dispositional resistance to change and the orientation toward the change agent.

PubMed

Oreg, Shaul; Sverdlik, Noga

2011-03-01

Following an analysis of the concept of "imposed change," we propose 2 factors that jointly contribute to an individual's experience of ambivalence to imposed change. In a secondary analysis of data (N = 172) and 2 field studies (N = 104, N = 89), we showed that individuals' personal orientation toward change interacts with their orientation toward the change agent and yields ambivalence. Specifically, among employees with a positive orientation toward the change agent (i.e., high trust in management, identification with the organization), the relationship between employees' dispositional resistance to change and ambivalence was positive. The opposite pattern emerged among employees with a negative orientation toward the change agent (Studies 2 and 3). Our findings suggest that researchers may have been misinterpreting employees' reactions to change, neglecting the possibility that some may simultaneously hold strong, yet conflicting, views about the change. By accounting for, and predicting, ambivalence, these studies provide a more accurate explanation of employees' responses to change. PsycINFO Database Record (c) 2011 APA, all rights reserved.

Perceptions of a Changing World Induce Hope and Promote Peace in Intractable Conflicts

PubMed Central

Cohen-Chen, Smadar; Crisp, Richard J.; Halperin, Eran

2015-01-01

The importance of hope in promoting conciliatory attitudes has been asserted in the field of conflict resolution. However, little is known about conditions inducing hope, especially in intractable conflicts, where reference to the outgroup may backfire. In the current research, five studies yielded convergent support for the hypothesis that hope for peace stems from a general perception of the world as changing. In Study 1, coders observed associations between belief in a changing world, hope regarding peace, and support for concessions. Study 2 revealed the hypothesized relations using self-reported measures. Studies 3 and 4 established causality by instilling a perception of the world as changing (vs. unchanging) using narrative and drawing manipulations. Study 5 compared the changing world message with a control condition during conflict escalation. Across studies, although the specific context was not referred to, the belief in a changing world increased support for concessions through hope for peace. PMID:25713171

Association between posttraumatic stress and acceptance of social changes: Findings from a general population study and proposal of a new concept.

PubMed

Kazlauskas, Evaldas; Zelviene, Paulina

2017-03-01

There is a growing understanding of the importance of the social factors of posttraumatic stress disorder. This study expands research on association between posttraumatic stress and social factors by introducing the measure of the acceptance of social changes and evaluating possible links between posttraumatic stress disorder symptoms and acceptance of social changes. A general population sample ( n = 778) aged from 18 to 89 years ( M = 40.2) from Lithuania participated in our study, of whom 68% reported exposure to traumatic events. Posttraumatic stress reactions were measured with the Impact of Event Scale - Revised (IES-R), and acceptance of social changes was measured with the Acceptance of Social Changes Instrument (SOCHI) developed by the authors of this study. About 8% of the participants had a potential posttraumatic stress disorder (PTSD) diagnosis. Acceptance of social changes was negatively associated with posttraumatic stress. PTSD was related to lower acceptance of social changes ( d = .61). Structural equation model (SEM) revealed the mediating role of PTSD for acceptance of social changes following trauma exposure. Findings of our study indicate that the acceptance of social changes might be an important psychosocial factor of PTSD.

'Power base' tactics for workplace change - an interview study with industrial engineers and ergonomists.

PubMed

Berlin, Cecilia; Neumann, W Patrick; Theberge, Nancy; Örtengren, Roland

2017-05-01

The work activities of industrial engineers (IEs) and ergonomists drive workplace changes. The purpose of this study is to compare the work practices of the two professions and examine (1) how IEs and ergonomists gain influence over workplace changes and (2) whether there are prevailing types of intentional interaction behaviours called Power bases (PB) present in the interaction tactics they employ. The study identified key behavioural strategies used by the interviewees to successfully influence workplace changes; these were then mapped to their corresponding PB. Results showed that IEs and ergonomists were successfully influencing workplace changes using several tactics across the spectrum of PB, with the exception of Reward and Coercion. The study concludes with a list of recommended workplace change agent tactics, and proposes that a PB 'analytical lens' can serve to increase the budding ergonomists' critical and analytical skills when considering possible workplace change tactics. Practitioner Summary: This interview study examines how workplace ergonomics change agents, represented by the two professions: industrial engineers and ergonomists, perceive and exercise their capacity to influence workplace change. Key behavioural tactics that interviewees have found successful are reported, alongside effects on short- and long-term relations with other workplace-influencing stakeholders.

The Role of Moral Beliefs, Memories, and Preferences in Representations of Identity.

PubMed

Heiphetz, Larisa; Strohminger, Nina; Young, Liane L

2017-04-01

People perceive that if their memories and moral beliefs changed, they would change. We investigated why individuals respond this way. In Study 1, participants judged that identity would change more after changes to memories and widely shared moral beliefs (e.g., about murder) versus preferences and controversial moral beliefs (e.g., about abortion). The extent to which participants judged that changes would affect their relationships predicted identity change (Study 2) and mediated the relationship between type of moral belief and perceived identity change (Study 3). We discuss the role that social relationships play in judgments of identity and highlight implications for psychology and philosophy. Copyright © 2016 Cognitive Science Society, Inc.

A Study of Changes in Parents Employed as Paraprofessionals in a Home Intervention Follow Through Program.

ERIC Educational Resources Information Center

Greenwood, Gordon E.; And Others

This study attempted to determine whether parent educators in the Florida Follow Through Model were affected by their work in the program. The following changes in parent educators were studied: (1) Significant increase in feelings of self-esteem, (2) significant changes in teaching behavior, and (3) changes in life style. Self-esteem was assessed…

Organizational Change and How It Affects Healthcare Employees: A Study on Employee Resistance to Change in Electronic Medical Record Implementation

ERIC Educational Resources Information Center

Adeyemi, Oluwakemi A.

2017-01-01

The purpose of the exploratory qualitative study was to explore the strategies for reducing employee resistance to Electronic Medical Record (EMR) technology changes in a healthcare organization during implementation. The study focused on EPIC as the EMR application. Ten healthcare participants who had experienced a change to EMR were selected in…

How does climate change cause extinction?

PubMed Central

Cahill, Abigail E.; Aiello-Lammens, Matthew E.; Fisher-Reid, M. Caitlin; Hua, Xia; Karanewsky, Caitlin J.; Yeong Ryu, Hae; Sbeglia, Gena C.; Spagnolo, Fabrizio; Waldron, John B.; Warsi, Omar; Wiens, John J.

2013-01-01

Anthropogenic climate change is predicted to be a major cause of species extinctions in the next 100 years. But what will actually cause these extinctions? For example, will it be limited physiological tolerance to high temperatures, changing biotic interactions or other factors? Here, we systematically review the proximate causes of climate-change related extinctions and their empirical support. We find 136 case studies of climatic impacts that are potentially relevant to this topic. However, only seven identified proximate causes of demonstrated local extinctions due to anthropogenic climate change. Among these seven studies, the proximate causes vary widely. Surprisingly, none show a straightforward relationship between local extinction and limited tolerances to high temperature. Instead, many studies implicate species interactions as an important proximate cause, especially decreases in food availability. We find very similar patterns in studies showing decreases in abundance associated with climate change, and in those studies showing impacts of climatic oscillations. Collectively, these results highlight our disturbingly limited knowledge of this crucial issue but also support the idea that changing species interactions are an important cause of documented population declines and extinctions related to climate change. Finally, we briefly outline general research strategies for identifying these proximate causes in future studies. PMID:23075836

Factors influencing smallholder farmers' behavioural intention towards adaptation to climate change in transitional climatic zones: A case study of Hwedza District in Zimbabwe.

PubMed

Zamasiya, Byron; Nyikahadzoi, Kefasi; Mukamuri, Billy Billiard

2017-08-01

This paper examines factors influencing behavioural change among smallholder farmers towards adaptation to climate change in transitional climatic zones of Africa, specifically, Hwedza District in Zimbabwe. Data for this study were collected from 400 randomly-selected smallholder farmers, using a structured questionnaire, focus group discussions and key informant interviews. The study used an ordered logit model to examine the factors that influence smallholder farmers' behavioural intention towards adaptation to climate change. Results from the study show that the gender of the household head, access to extension services on crop and livestock production, access to climate information, membership to social groups and experiencing a drought have a positive influence on farmers' attitude towards adaptation to climate change and variability. The study concluded that although the majority of smallholder farmers perceive that the climate is changing, they continue to habour negative attitudes towards prescribed climate change adaptation techniques. This study recommends more education on climate change, as well as adaptation strategies for both agricultural extension workers and farmers. This can be complemented by disseminating timely climate information through extension officers and farmers' groups. Copyright © 2017 Elsevier Ltd. All rights reserved.

How does climate change cause extinction?

PubMed

Cahill, Abigail E; Aiello-Lammens, Matthew E; Fisher-Reid, M Caitlin; Hua, Xia; Karanewsky, Caitlin J; Ryu, Hae Yeong; Sbeglia, Gena C; Spagnolo, Fabrizio; Waldron, John B; Warsi, Omar; Wiens, John J

2013-01-07

Anthropogenic climate change is predicted to be a major cause of species extinctions in the next 100 years. But what will actually cause these extinctions? For example, will it be limited physiological tolerance to high temperatures, changing biotic interactions or other factors? Here, we systematically review the proximate causes of climate-change related extinctions and their empirical support. We find 136 case studies of climatic impacts that are potentially relevant to this topic. However, only seven identified proximate causes of demonstrated local extinctions due to anthropogenic climate change. Among these seven studies, the proximate causes vary widely. Surprisingly, none show a straightforward relationship between local extinction and limited tolerances to high temperature. Instead, many studies implicate species interactions as an important proximate cause, especially decreases in food availability. We find very similar patterns in studies showing decreases in abundance associated with climate change, and in those studies showing impacts of climatic oscillations. Collectively, these results highlight our disturbingly limited knowledge of this crucial issue but also support the idea that changing species interactions are an important cause of documented population declines and extinctions related to climate change. Finally, we briefly outline general research strategies for identifying these proximate causes in future studies.

The Impact of Technological Change; The American Experience. Studies in Employment and Unemployment.

ERIC Educational Resources Information Center

Haber, William; And Others

Technological change is a complex term involving many more factors than "changes in machinery or automation." Six changes which affect jobs and influence skills in our industrial systems that could logically be called technological change have been identified: (1) scientific management, or time and motion studies, (2) mergers and consolidations,…

Diluting Education? An Ethnographic Study of Change in an Australian Ministry of Education

ERIC Educational Resources Information Center

Robinson, Sarah

2011-01-01

This ethnographic study captures the processes that led to change in an Australian public education system. The changes were driven by strong neo-liberal discourses which resulted in a shift from a shared understanding about leading educational change in schools by knowledge transfer to managing educational change as a process, in other words,…

Evaluation of how a real time pre-registration health care curricula was managed through the application of a newly designed Change Management Model: A qualitative case study.

PubMed

Chowthi-Williams, Annette

2018-02-01

Curricula change in nurse education is of international importance. The pace of such change has been continuous and has triggered criticisms of inadequate preparation of practitioners. There are no change formulae for managing curricula change and despite a raft of change methods, globally change success remains low. A lack of a unified voice, undue focus on cognition, and arguably no existing models for academia and a literature gap contribute to change challenge. A new Change Management Model designed from research with emotion as its underpinning philosophy is evaluated. Evaluation of a newly designed Change Management Model through a real time pre-registration health care curricula change. A qualitative case study was adopted. The single case study was the new pre-registration health care curricula. This study took place in a Faculty of Health and Social care in one HEI in the UK. Four senior academics and fifteen academics across professions and specialisms involved in the curricula change took part in the study. The findings suggested that leadership operated differently throughout the organisation. Distributive and collective leadership created a critical mass of people to help deliver the new curricula but academics felt excluded at the strategic level. Emotion at the strategic level inhibited innovation but boosted engagement, emotional relationships and creativity at the operational level. Face to face communication was favoured for its emotional connection. A top down approach created an emotional disconnect and impacted inclusiveness, engagement, empowerment, vision and readiness for change. Testing the new model widely not only in organisations, practice and team changes but personal change in improving health and wellbeing could be beneficial. The continuing gap in knowledge on the link between emotion and curricula change, practice and organisational change and therapeutic value of the model also warrants further research. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

Assessing sensitivity to change: choosing the appropriate change coefficient.

PubMed

Stratford, Paul W; Riddle, Daniel L

2005-04-05

The past 20-years have seen the development and evaluation of many health status measures. Unlike the high standards demanded of those who conduct and report clinical intervention trials, the methodological rigor for studies examining the sensitivity to change of health status measures are less demanding. It is likely that the absence of a criterion standard for change in health status contributes to this shortcoming. To increase confidence in the results of these types of studies investigators have often calculated multiple change coefficients for the same patient sample. The purpose of this report is to identify the conflict that arises when multiple change coefficients are applied to the same patient sample. Three families of change coefficients based on different assumptions concerning the sample composition are identified: (1) the sample is homogeneous with respect to change; (2) subgroups of patients who truly change by different amounts exist; (3) individual patients, many of whom truly change by different amounts exist. We present several analyses which illustrate a major conceptual conflict: the signal (a measure's true ability to detect change) for some of these coefficients appears in the noise term (measurement error) of the others. We speculate that this dilemma occurs as a result of insufficient preparatory work such as pilot studies to establish the likely change characteristic of the patient population of interest. Uncertainty in the choice of change coefficient could be overcome by conducting pilot studies to ascertain the likely change characteristic of the population of interest. Once the population's change characteristic is identified, the choice of change coefficient should be clear.

Communicating for Climate Change Adaptation: Lessons from a Case Study with Nature-Based Tour Operators

NASA Astrophysics Data System (ADS)

Timm, K.; Sparrow, E. B.; Pettit, E. C.; Trainor, S. F.; Taylor, K.

2014-12-01

Increasing temperatures are projected to have a positive effect on the length of Alaska's tourism season, but the natural attractions that tourism relies on, such as glaciers, wildlife, fish, or other natural resources, may change. In order to continue to derive benefits from these resources, nature-based tour operators may have to adapt to these changes, and communication is an essential, but poorly understood, component of the climate change adaptation process. The goal of this study was to determine how to provide useful climate change information to nature-based tour operators by answering the following questions: 1. What environmental changes do nature-based tour operators perceive? 2. How are nature-based tour operators responding to climate and environmental change? 3. What climate change information do nature-based tour operators need? To answer these questions, twenty-four nature-based tour operators representing 20 different small and medium sized businesses in Juneau, Alaska were interviewed. The results show that many of Juneau's nature-based tour operators are observing, responding to, and in some cases, actively planning for further changes in the environment. The types of responses tended to vary depending on the participants' certainty in climate change and the perceived risks to their organization. Using these two factors, this study proposes a framework to classify climate change responses for the purpose of generating meaningful information and communication processes that promote adaptation and build adaptive capacity. During the course of the study, several other valuable lessons were learned about communicating about adaptation. The results of this study demonstrate that science communication research has an important place in the practice of promoting and fostering climate change adaptation. While the focus of this study was tour operators, the lessons learned may be valuable to other organizations striving to engage unique groups in climate change adaptation planning efforts and to social scientists trying to understanding of the role of communication in climate change adaptation.

Potential individual versus simultaneous climate change effects on soybean (C 3) and maize (C 4) crops: An agrotechnology model based study

NASA Astrophysics Data System (ADS)

Mera, Roberto J.; Niyogi, Dev; Buol, Gregory S.; Wilkerson, Gail G.; Semazzi, Fredrick H. M.

2006-11-01

Landuse/landcover change induced effects on regional weather and climate patterns and the associated plant response or agricultural productivity are coupled processes. Some of the basic responses to climate change can be detected via changes in radiation ( R), precipitation ( P), and temperature ( T). Past studies indicate that each of these three variables can affect LCLUC response and the agricultural productivity. This study seeks to address the following question: What is the effect of individual versus simultaneous changes in R, P, and T on plant response such as crop yields in a C 3 and a C 4 plant? This question is addressed by conducting model experiments for soybean (C 3) and maize (C 4) crops using the DSSAT: Decision Support System for Agrotechnology Transfer, CROPGRO (soybean), and CERES-Maize (maize) models. These models were configured over an agricultural experiment station in Clayton, NC [35.65°N, 78.5°W]. Observed weather and field conditions corresponding to 1998 were used as the control. In the first set of experiments, the CROPGRO (soybean) and CERES-Maize (maize) responses to individual changes in R and P (25%, 50%, 75%, 150%) and T (± 1, ± 2 °C) with respect to control were studied. In the second set, R, P, and T were simultaneously changed by 50%, 150%, and ± 2 °C, and the interactions and direct effects of individual versus simultaneous variable changes were analyzed. For the model setting and the prescribed environmental changes, results from the first set of experiments indicate: (i) precipitation changes were most sensitive and directly affected yield and water loss due to evapotranspiration; (ii) radiation changes had a non-linear effect and were not as prominent as precipitation changes; (iii) temperature had a limited impact and the response was non-linear; (iv) soybeans and maize responded differently for R, P, and T, with maize being more sensitive. The results from the second set of experiments indicate that simultaneous change analyses do not necessarily agree with those from individual changes, particularly for temperature changes. Our analysis indicates that for the changing climate, precipitation (hydrological), temperature, and radiative feedbacks show a non-linear effect on yield. Study results also indicate that for studying the feedback between the land surface and the atmospheric changes, (i) there is a need for performing simultaneous parameter changes in the response assessment of cropping patterns and crop yield based on ensembles of projected climate change, and (ii) C 3 crops are generally considered more sensitive than C 4; however, the temperature-radiation related changes shown in this study also effected significant changes in C 4 crops. Future studies assessing LCLUC impacts, including those from agricultural cropping patterns and other LCULC-climate couplings, should advance beyond the sensitivity mode and consider multivariable, ensemble approaches to identify the vulnerability and feedbacks in estimating climate-related impacts.

Long-term changes after brief dynamic psychotherapy: symptomatic versus dynamic assessments.

PubMed

Høglend, P; Sørlie, T; Sørbye, O; Heyerdahl, O; Amlo, S

1992-08-01

Dynamic change in psychotherapy, as measured by theory-related or mode-specific instruments, have been criticized for being too intercorrelated with symptomatic change measures. In this study, long-term changes after brief dynamic psychotherapy were studied in 45 moderately disturbed neurotic patients by a reliable outcome battery. The factor structure of all the change variables suggested that they tapped 2 distinct and stable sources of variance: dynamic and symptomatic change. The categories of overall dynamic change were different from categories of change on the Global Assessment Scale. A small systematic difference was found between the categories of overall dynamic change and the categories of target complaints change also, due to false solutions of dynamic conflicts.

Biomedical journal title changes: reasons, trends, and impact.

PubMed Central

Afes, V B; Wrynn, P E

1993-01-01

A study was conducted to document the impact of biomedical journal title changes on medical libraries and to increase awareness of the reasons titles are changed. The study consisted of two parts: a survey of academic health sciences libraries in the United States and Canada and an analysis of title changes from two different years. The survey response rate was 83%. The majority of respondents commented on difficulties in identifying and processing title changes, often resulting in the delay or loss of information. The analysis revealed that a third of title changes were not justified by the journal. The study results substantiate the need to standardize title change reporting by publishers. A standard developed by the National Information Standards Organization requires publishers to conform to standardized practices for notification. This standard precisely reflects the concerns reflected in both the survey and the study of title changes, and librarians are urged to ensure that the standard is implemented by publishers. PMID:8428189

Changing Forms of Teacher Education in South Africa: A Case Study of Policy Change

ERIC Educational Resources Information Center

Sayed, Yusuf

2002-01-01

This paper examines some aspects of teacher education policy change in South Africa. It contextualises the changes by firstly examining the apartheid teacher education system and then mapping the changes that have occurred in teacher education in South Africa since 1994. Using a case study of the Further Diploma in Educational Management at the…

Climate change helplessness and the (de)moralization of individual energy behavior.

PubMed

Salomon, Erika; Preston, Jesse L; Tannenbaum, Melanie B

2017-03-01

Although most people understand the threat of climate change, they do little to modify their own energy conservation behavior. One reason for this gap between belief and behavior may be that individual actions seem unimpactful and therefore are not morally relevant. This research investigates how climate change helplessness-belief that one's actions cannot affect climate change-can undermine the moralization of climate change and personal energy conservation. In Study 1, climate change efficacy predicted both moralization of energy use and energy conservation intentions beyond individual belief in climate change. In Studies 2 and 3, participants read information about climate change that varied in efficacy message, that is, whether individual actions (e.g., using less water, turning down heat) make a difference in the environment. Participants who read that their behavior made no meaningful impact reported weaker moralization and intentions (Study 2), and reported more energy consumption 1 week later (Study 3). Moreover, effects on intentions and actions were mediated by changes in moralization. We discuss ways to improve climate change messages to foster environmental efficacy and moralization of personal energy use. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Assessing the Impact of Psychotropic Medication Changes on Challenging Behavior of Individuals with Intellectual Disabilities

PubMed Central

Valdovinos, Maria G.; Henninger-McMahon, Meara; Schieber, Elizabeth; Beard, Lisa; Conley, Brenna; Haas, Annette

2016-01-01

Objective The use of psychotropic medication to address challenging behavior in individuals diagnosed with intellectual disabilities is common practice; however, very few studies have examined how multiple medication use (or combination treatment) impacts the behaviors these medications are prescribed to treat. Method The current study followed eight individuals over a two-year period as they experienced changes in their psychotropic medication regimens. During that time, data from functional analyses and indirect assessments of challenging behavior were collected. Results The results suggest that changes in psychotropic medication regimens can produce changes in functional assessment outcomes, suggesting a need for continued behavioral assessment to better inform medication practices and behavioral treatment. Of the eight participants in the study, five participants’ behaviors varied in rate of responding in FAs across all medication changes. Additionally, three participants’ FAs produced changes in outcomes; however, those changes were not consistent across all medication changes, that is, not every medication change yielded different outcomes from previous assessments. Conclusion This study demonstrates how the outcome of an FA can be used to monitor the effects of psychotropic medication changes, specifically when medications are combined, on challenging behavior in individuals with intellectual and developmental disabilities. PMID:27429750

Natural history collections as windows on evolutionary processes.

PubMed

Holmes, Michael W; Hammond, Talisin T; Wogan, Guinevere O U; Walsh, Rachel E; LaBarbera, Katie; Wommack, Elizabeth A; Martins, Felipe M; Crawford, Jeremy C; Mack, Katya L; Bloch, Luke M; Nachman, Michael W

2016-02-01

Natural history collections provide an immense record of biodiversity on Earth. These repositories have traditionally been used to address fundamental questions in biogeography, systematics and conservation. However, they also hold the potential for studying evolution directly. While some of the best direct observations of evolution have come from long-term field studies or from experimental studies in the laboratory, natural history collections are providing new insights into evolutionary change in natural populations. By comparing phenotypic and genotypic changes in populations through time, natural history collections provide a window into evolutionary processes. Recent studies utilizing this approach have revealed some dramatic instances of phenotypic change over short timescales in response to presumably strong selective pressures. In some instances, evolutionary change can be paired with environmental change, providing a context for potential selective forces. Moreover, in a few cases, the genetic basis of phenotypic change is well understood, allowing for insight into adaptive change at multiple levels. These kinds of studies open the door to a wide range of previously intractable questions by enabling the study of evolution through time, analogous to experimental studies in the laboratory, but amenable to a diversity of species over longer timescales in natural populations. © 2016 John Wiley & Sons Ltd.

Natural history collections as windows on evolutionary processes

PubMed Central

Holmes, Michael W.; Hammond, Talisin T.; Wogan, Guinevere O.U.; Walsh, Rachel E.; LaBarbera, Katie; Wommack, Elizabeth A.; Martins, Felipe M.; Crawford, Jeremy C.; Mack, Katya L.; Bloch, Luke M.; Nachman, Michael W.

2016-01-01

Natural history collections provide an immense record of biodiversity on Earth. These repositories have traditionally been used to address fundamental questions in biogeography, systematics, and conservation. However, they also hold the potential for studying evolution directly. While some of the best direct observations of evolution have come from long-term field studies or from experimental studies in the lab, natural history collections are providing new insights into evolutionary change in natural populations. By comparing phenotypic and genotypic changes in populations through time, natural history collections provide a window into evolutionary processes. Recent studies utilizing this approach have revealed some dramatic instances of phenotypic change over short time scales in response to presumably strong selective pressures. In some instances evolutionary change can be paired with environmental change, providing a context for potential selective forces. Moreover, in a few cases, the genetic basis of phenotypic change is well understood, allowing for insight into adaptive change at multiple levels. These kinds of studies open the door to a wide range of previously intractable questions by enabling the study of evolution through time, analogous to experimental studies in the laboratory, but amenable to a diversity of species over longer timescales in natural populations. PMID:26757135

Impact of Pretreatment Change on Mechanism of Behavior Change Research: An Applied Example Using Alcohol Abstinence Self-Efficacy.

PubMed

Noyes, Emily T; Levine, Jacob A; Schlauch, Robert C; Crane, Cory A; Connors, Gerard J; Maisto, Stephen A; Dearing, Ronda L

2018-03-01

With the growing recognition that, for some, significant changes in drinking occur before the first treatment session (i.e., pretreatment change), researchers have called for the careful assessment of when change occurs and its potential impact on mechanism of behavior change (MOBC) research. Using a commonly hypothesized MOBC variable, alcohol abstinence self-efficacy, the primary aim of this study was to examine the effect of pretreatment change on the study of MOBCs. Sixty-three individuals diagnosed with alcohol dependence were recruited to participate in a 12-week cognitive-behavioral treatment. Participants completed weekly assessments of self-efficacy and drinking behaviors. Multilevel time-lagged regression models indicated that pretreatment change significantly moderated the effect of self-efficacy on the number of drinking days, such that among those higher on pretreatment change, higher self-efficacy ratings predicted lower rates of drinking days in the week until the next treatment session. In contrast, pretreatment change did not moderate the effect of self-efficacy on the rate of heavy drinking days. Results from the current study add to a small but growing body of research highlighting the importance of pretreatment change when studying MOBCs. Further, these results provide important insights into the conditions in which self-efficacy may play an important role in treatment outcomes.

The Impact of Traumatic Brain Injury on Self-Identity: A Systematic Review of the Evidence for Self-Concept Changes.

PubMed

Beadle, Elizabeth Jane; Ownsworth, Tamara; Fleming, Jennifer; Shum, David

2016-01-01

This review systematically appraised the evidence for changes to self-identity after traumatic brain injury (TBI) in adults and investigated associations between self-concept changes and neurocognitive and psychosocial functioning. Systematic searches of 4 databases (PsycINFO, PubMed, CINAHL, and Cochrane Systematic Review Database) were undertaken from January 1983 to July 2014. Empirical studies were included if they used a quantitative measure of pre-/postinjury changes in self-concept after TBI or compared levels of self-concept between TBI and control participants. Fifteen studies met the review criteria and, despite methodological differences, provided mostly evidence of negative changes to self-concept. However, stability in self-concept and positive changes to sense of self were also reported in some studies. Furthermore, levels of self-esteem and personality characteristics did not significantly differ between participants with TBI and orthopedic/trauma controls. Negative self-concept changes were associated with emotional distress in 3 studies. People with TBI most commonly experience negative changes in self-identity; however, such changes are also reported after other traumatic events or injuries. Greater consistency in measurement of self-identity change and use of longitudinal designs is recommended to improve understanding of factors contributing to self-concept changes after TBI and to guide clinical interventions.

Lifestyle Changes and Pressure Ulcer Prevention in Adults With Spinal Cord Injury in the Pressure Ulcer Prevention Study Lifestyle Intervention

PubMed Central

Ghaisas, Samruddhi; Pyatak, Elizabeth A.; Blanche, Erna; Clark, Florence

2015-01-01

Pressure ulcers (PrUs) are a major burden to patients with spinal cord injury (SCI), affecting their psychological, physical, and social well-being. Lifestyle choices are thought to contribute to the risk of developing PrUs. This article focuses on the interaction between lifestyle choices and the development of PrUs in community settings among participants in the University of Southern California–Rancho Los Amigos National Rehabilitation Center Pressure Ulcer Prevention Study (PUPS II), a randomized controlled trial of a lifestyle intervention for adults with SCI. We conducted a secondary cross-case analysis of treatment notes of 47 PUPS II participants and identified four patterns relating PrU development to lifestyle changes: positive PrU changes (e.g., healing PrUs) with positive lifestyle changes, negative or no PrU changes with positive lifestyle changes, positive PrU changes with minor lifestyle changes, and negative or no PrU changes with no lifestyle changes. We present case studies exemplifying each pattern. PMID:25553751

Changes in the Precision of a Study from Planning Phase to Implementation Phase: Evidence from the First Wave of Group Randomized Trials Launched by the Institute of Education Sciences

ERIC Educational Resources Information Center

Spybrook, Jessaca; Lininger, Monica; Cullen, Anne

2011-01-01

The purpose of this study is to extend the work of Spybrook and Raudenbush (2009) and examine how the research designs and sample sizes changed from the planning phase to the implementation phase in the first wave of studies funded by IES. The authors examine the impact of the changes in terms of the changes in the precision of the study from the…

CLIMATE CHANGE: Information on Limitations and Assumptions of DOE’s Five-Lab Study

DTIC Science & Technology

1998-09-01

the potential consequences of climate change , the United States and other countries have entered into international negotiations and agreements. In...energy savings estimated to roughly equal or exceed costs. In view of the study’s potential influence on U.S. climate change policy, as requested, we...the study’s results, (3) the study’s role in the formulation of the Oct. 󈨥 climate change proposal and the Kyoto Conference’s emission-reduction goals for the U.S.

Self-perceptions of stability and change in personality at midlife: the UNC Alumni Heart Study.

PubMed

Herbst, J H; McCrae, R R; Costa, P T; Feaganes, J R; Siegler, I C

2000-12-01

The finding of personality stability in adulthood may be counterintuitive to people who perceive a great deal of change in their own personality. The purpose of this study is to determine whether self-reported perceived changes in personality are associated with actual changes based on a 6- to 9-year follow-up of 2,242 middle-aged male and female participants of the UNC Alumni Heart Study (UNCAHS). Respondents completed the Revised NEO Personality Inventory on two occasions and were asked to reflect back over a 6-year period and assess changes in their personality. The majority of respondents (n = 1,177; 52.5%) reported they had "stayed the same," while 863 (38.5%) reported they had "changed a little" and 202 (9%) reported they had "changed a good deal." Coefficients of personality profile agreement computed to evaluate global personality change for the three perceived change groups were essentially equivalent. Further, directional analyses of domain-specific changes in personality showed that perceived changes were weak predictors of residual gain scores. In an absolute sense, perceptions of stability or change were discordant in 8 of 15 (53%) comparisons. Self-perceptions of change are not an adequate substitute for objective assessments.

Shenandoah National Park Phenology Project-Weather data collection, description, and processing

USGS Publications Warehouse

Jones, John W.; Aiello, Danielle P.; Osborne, Jesse D.

2010-01-01

The weather data described in this document are being collected as part of a U.S. Geological Survey (USGS) study of changes in Shenandoah National Park (SNP) landscape phenology (Jones and Osbourne, 2008). Phenology is the study of the timing of biological events, such as annual plant flowering and seasonal bird migration. These events are partially driven by changes in temperature and precipitation; therefore, phenology studies how these events may reflect changes in climate. Landscape phenology is the study of changes in biological events over broad areas and assemblages of vegetation. To study climate-change relations over broad areas (at landscape scale), the timing and amount of annual tree leaf emergence, maximum foliage, and leaf fall for forested areas are of interest. To better link vegetation changes with climate, weather data are necessary. This report documents weather-station data collection and processing procedures used in the Shenandoah National Park Phenology Project.

New systems of work organization and workers' health.

PubMed

Kompier, Michiel A J

2006-12-01

This paper aims at identifying major changes in and around work organizations, their effects upon job characteristics and the health and well-being of today's employees, and related research challenges. Increased internationalization and competition, increased utilization of information and communication technology, the changing workforce configuration, and flexibility and new organizational practices are considered. As work has changed from physical to mental in nature, job characteristics have changed significantly. Meanwhile work and family life have blended. New systems of work organization have become more prevalent, but they do not represent a radical change across the whole economy. New practices may have an adverse impact upon job characteristics, but their effects depend on their design, implementation, and management. Research recommendations include improved monitoring of changes in work organization and studies into their health and safety consequences, intervention studies, studies into the motivating potential of modern work practices, studies of marginalized workers and workers in less developed countries, and "mechanism studies".

Climate change impacts in Iran: assessing our current knowledge

NASA Astrophysics Data System (ADS)

Rahimi, Jaber; Malekian, Arash; Khalili, Ali

2018-02-01

During recent years, various studies have focused on investigating the direct and indirect impacts of climate changes in Iran while the noteworthy fact is the achievement gained by these researches. Furthermore, what should be taken into consideration is whether these studies have been able to provide appropriate opportunities for improving further studies in this particular field or not. To address these questions, this study systematically reviewed and summarized the current available literature (n = 150) regarding the impacts of climate change on temperature and precipitation in Iran to assess our current state of knowledge. The results revealed that while all studies discuss the probable changes in temperature and precipitation over the next decades, serious contradictions could be seen in their results; also, the general pattern of changes was different in most of the cases. This matter may have a significant effect on public beliefs in climate change, which can be a serious warning for the activists in this realm.

A Study of Impact of Technological Change in Library Service Facilities: Changes in Use of the Public Catalog at the New York State Library Associated with the Introduction of Online Subject Searching Capability in the Public Catalog. Summary Report.

ERIC Educational Resources Information Center

Lipetz, Ben-Ami; Paulson, Peter J.

To study the users and use of the subject searching capability offered by the new online public catalog at the New York State Library (NYSL) a study was begun before the catalog change in mid-1983 and continued for a considerable time after the change. Data were collected during three 1-week periods; one preceded the catalog change and two…

The impacts of final demand changes on total output of Indonesian ICT sectors: An analysis using input-output approach

NASA Astrophysics Data System (ADS)

Zuhdi, Ubaidillah

2014-06-01

The purpose of this study is to analyze the impacts of final demand changes on total output of Indonesian Information and Communication Technology (ICT) sectors. This study employs Input-Output (IO) analysis as a tool of analysis. More specifically, demand-pull IO quantity model is applied in order to achieve the objective. "Whole sector change" and "pure change" conditions are considered in this study. The results of calculation show that, in both conditions, the biggest positive impact to the total output of the sectors is given by the change of households consumption while the change of import has a negative impact. One of the recommendations suggested from this study is to construct import restriction policy for ICT products.

Analysis of change in timber volume on non-Federal timberlands in Washington.

Treesearch

Daniel D. Oswald

1986-01-01

This report presents the findings of a study conducted to determine change in per acre timber volume on non-Federal timberlands in Washington from the mid-1960’s to 1978-80. The basis for the-study was the measurement of 1,576 permanent plots at two occasions. The study findings include estimates of change in volume and of the components of change-growth, mortality,...

Landuse/Landcover and Climate Change Interaction in the Derived Savannah Region of Nigeria

NASA Astrophysics Data System (ADS)

Akintuyi, A. O.; Fasona, M.; Soneye, A. S. O.

2016-12-01

The interaction of landuse/Landcover (LULC) and climate change, to a large extent, involves anthropogenic activities. This study was carried out in the derived savannah of Nigeria, a delicate ecological zone where the interaction of LULC and climate change could be well appreciated. The study evaluated coupled interaction between LULC and climate change and assessed the changes in the landuse/landcover patterns for the periods 1972, 1986, 2002 and 2010, evaluated the present (1941 - 2010) and future (2011 - 2050) variability in rainfall patterns and an attempt was made to predict the interaction between LULC and climate change during future climate. The study adopted remote sensing and GIS techniques, land change modeller and multivariate statistics The results suggest that the built up area, farmland, waterbody and woodland experienced a rapid increase of about 1,134.69%, 1,202.85%, 631.51% and 188.09%, respectively, while the forest cover, degraded surfaces and grassland lost about 19.32%, 72.76% and 0.05% respectively between 1972 and 2010. Furthermore, the study predicted 40.28% and 37.84% reduction in the forested area between 1986 and 2050 and 2010 and 2050 respectively. The study concludes that rainfall will be the major driver of LULC change within the study area under a future climate.

A prospective longitudinal study testing relationships between meaningful activities, basic psychological needs fulfillment, and meaning in life.

PubMed

Eakman, Aaron M

2014-01-01

The current study used a prospective longitudinal design to determine whether change in meaningful activity over an 11-month period could help explain change in meaning in life in a sample of 174 undergraduate and graduate students. The Engagement in Meaningful Activities Survey, Basic Psychological Needs Scales (i.e., autonomy, competence, relatedness), and the Meaning in Life Questionnaire were used as indicators of the constructs of meaningful activity, basic psychological needs fulfillment, and meaning and purpose in life. The findings were in support of the study hypotheses and indicated that change in meaningful activity explained both change in basic psychological needs fulfillment (i.e., autonomy, competence, relatedness) and change in meaning in life. Further, this study reports findings consistent with results from cross-sectional studies in support of the hypothesis that change in meaningful activity may influence change in meaning in life through two pathways: a direct path of influence from meaningful activity to meaning in life and an indirect path through change in basic psychological needs fulfillment. The current study contributes to a growing literature implicating subjective evaluations of day-to-day action (or meaningful activity) as a fruitful means for exploring relationships between occupation and well-being. Copyright 2014, SLACK Incorporated.

Motivation to change in eating disorder patients: a conceptual clarification on the basis of self-determination theory.

PubMed

Vansteenkiste, Maarten; Soenens, Bart; Vandereycken, Walter

2005-04-01

The current study critically reviews the different motivational frameworks that are applied in the study of eating disorders and provides a more comprehensive conceptualization of motivation to change on the basis of self-determination theory. The most important conceptualizations of motivation to change among eating disorder patients are identified. Eating disorder patients' motivation to change has been defined very differently, adding confusion to the field and preventing research from being cumulative. On the basis of self-determination theory we argue (a) that the quality of motivation to change is primarily reflected in the degree of internalization of change rather than by the intrinsic motivation to change; (b) that the internalization of change suggests more than only the change being initiated from within the person (internal motivation) for it requires an acceptance of the personal importance of change; and (c) that, in addition to its quality, the quantity of motivation to change should be considered too. These three conceptual issues are applied to the study of motivational dynamics in eating-disordered patients. 2005 by Wiley Periodicals, Inc.

Perceptions of a changing world induce hope and promote peace in intractable conflicts.

PubMed

Cohen-Chen, Smadar; Crisp, Richard J; Halperin, Eran

2015-04-01

The importance of hope in promoting conciliatory attitudes has been asserted in the field of conflict resolution. However, little is known about conditions inducing hope, especially in intractable conflicts, where reference to the outgroup may backfire. In the current research, five studies yielded convergent support for the hypothesis that hope for peace stems from a general perception of the world as changing. In Study 1, coders observed associations between belief in a changing world, hope regarding peace, and support for concessions. Study 2 revealed the hypothesized relations using self-reported measures. Studies 3 and 4 established causality by instilling a perception of the world as changing (vs. unchanging) using narrative and drawing manipulations. Study 5 compared the changing world message with a control condition during conflict escalation. Across studies, although the specific context was not referred to, the belief in a changing world increased support for concessions through hope for peace. © 2015 by the Society for Personality and Social Psychology, Inc.

Sociology, Music Education, and Social Change: The Prospect of Addressing Their Relations by Attending to Some Central, Expanded Concepts

ERIC Educational Resources Information Center

Johansen, Geir

2014-01-01

Studies on sociology and music education are important because they can enlighten how music education relates to social change. By studying how music education changes and is changed by society we enable ourselves to describe how it can contribute to the understanding of social change generally. This may lay the ground for us in contributing to…

Competitiveness of Educational Quality of the State College of Islamic Studies (STAIN) Pontianak after Status Change to the State Institute of Islamic Studies (IAIN) Pontianak

ERIC Educational Resources Information Center

Misdah

2016-01-01

The purpose of this study was to determine: 1) Reality competition education quality of The State college of Islamic studies (STAIN) Pontianak after status change to the state institute of Islamic studies (IAIN) Pontianak, 2) Education quality management strategy of The State college of Islamic studies (STAIN) Pontianak after status change to the…

Conceptual Change in Understanding the Nature of Science Learning: An Interpretive Phenomenological Analysis

NASA Astrophysics Data System (ADS)

DiBenedetto, Christina M.

This study is the first of its kind to explore the thoughts, beliefs, attitudes and values of secondary educators as they experience conceptual change in their understanding of the nature of science learning vis a vis the Framework for K-12 Science Education published by the National Research Council. The study takes aim at the existing gap between the vision for science learning as an active process of inquiry and current pedagogical practices in K-12 science classrooms. For students to understand and explain everyday science ideas and succeed in science studies and careers, the means by which they learn science must change. Focusing on this change, the study explores the significance of educator attitudes, beliefs and values to science learning through interpretive phenomenological analysis around the central question, "In what ways do educators understand and articulate attitudes and beliefs toward the nature of science learning?" The study further explores the questions, "How do educators experience changes in their understanding of the nature of science learning?" and "How do educators believe these changes influence their pedagogical practice?" Study findings converge on four conceptions that science learning: is the action of inquiry; is a visible process initiated by both teacher and learner; values student voice and changing conceptions is science learning. These findings have implications for the primacy of educator beliefs, attitudes and values in reform efforts, science teacher leadership and the explicit instruction of both Nature of Science and conceptual change in educator preparation programs. This study supports the understanding that the nature of science learning is cognitive and affective conceptual change. Keywords: conceptual change, educator attitudes and beliefs, framework for K-12 science education, interpretive phenomenological analysis, nature of science learning, next generation science standards, science professional development, secondary science education.

Functions of behavior change interventions when implementing multi-professional teamwork at an emergency department: a comparative case study

PubMed Central

2014-01-01

Background While there is strong support for the benefits of working in multi-professional teams in health care, the implementation of multi-professional teamwork is reported to be complex and challenging. Implementation strategies combining multiple behavior change interventions are recommended, but the understanding of how and why the behavior change interventions influence staff behavior is limited. There is a lack of studies focusing on the functions of different behavior change interventions and the mechanisms driving behavior change. In this study, applied behavior analysis is used to analyze the function and impact of different behavior change interventions when implementing multi-professional teamwork. Methods A comparative case study design was applied. Two sections of an emergency department implemented multi-professional teamwork involving changes in work processes, aimed at increasing inter-professional collaboration. Behavior change interventions and staff behavior change were studied using observations, interviews and document analysis. Using a hybrid thematic analysis, the behavior change interventions were categorized according to the DCOM® model. The functions of the behavior change interventions were then analyzed using applied behavior analysis. Results The two sections used different behavior change interventions, resulting in a large difference in the degree of staff behavior change. The successful section enabled staff performance of teamwork behaviors with a strategy based on ongoing problem-solving and frequent clarification of directions. Managerial feedback initially played an important role in motivating teamwork behaviors. Gradually, as staff started to experience positive outcomes of the intervention, motivation for teamwork behaviors was replaced by positive task-generated feedback. Conclusions The functional perspective of applied behavior analysis offers insight into the behavioral mechanisms that describe how and why behavior change interventions influence staff behavior. The analysis demonstrates how enabling behavior change interventions, managerial feedback and task-related feedback interact in their influence on behavior and have complementary functions during different stages of implementation. PMID:24885212

Nursing students' well-being using the job-demand-control model: A longitudinal study.

PubMed

Tuomi, Jouni; Aimala, Anna-Mari; Žvanut, Boštjan

2016-10-01

Students' well-being is very important both for students and institutions. However, this field lacks longitudinal research, which focuses on the change of nursing students' well-being during their study. In order to asses such changes the four study types according to Job-Demand-Control-Support-model were used: passive, high-strain, low-strain, and active. A longitudinal design was employed: participants were recruited in 2010/2011 (phase I) and at the end of their study in 2012 (phase II). The study was performed in one school of health care in a university of applied sciences in Finland. The final sample consisted of 135 nursing students (BSc) who started their study either in September 2008 or January 2009, and finished in December 2011 or May 2012. The participants responded to the same close-ended questionnaire in both phases. The majority of the participants experienced the study type as low-strain (phase I: 61.5%; phase II: 48.2%). The distribution according to their study type did not change substantially between both phases, although 42.2% of the participants changed their study type. The major changes of study types were from low-strain to others (21.4%), and from other study types to the active one (12.6%). The results indicate that the majority of students do not change their study type and consequentially their well-being during their study, which is in contrast with previous research. Special attention should be put to the identification of students who change their study type to high-strain or remain in it. Copyright © 2016 Elsevier Ltd. All rights reserved.

Exploratory Study of Changing Ethnic Stereotypes of the Ukrainian Teacher Candidates towards Peaceful Attitudes

ERIC Educational Resources Information Center

Koshmanova, Tetyana; Hapon, Nadia

2007-01-01

The study focuses on exploring the method of changing pre-service teachers' stereotypes about different ethnicities. The purpose of the study is to test, or try out, an approach for changing beliefs and attitudes of teacher candidates towards peace-building, democracy, humanism, and accepting others. The procedure for this study involved…

The Effects of Policy Changes on the Educational Opportunity Centers: A Case Study

ERIC Educational Resources Information Center

Fountain-Ellis, Debra L.

2011-01-01

The purpose of this study is to explore the programmatic changes that occurred in the Educational Opportunity Centers (EOC) and how those changes influenced educational opportunities for adults. A case study design was used for this investigation. The directors of three EOCs were selected and interviewed for the study. These directors combined…

University Positioning and Changing Patterns of Doctoral Study: The Case of the University of Bath

ERIC Educational Resources Information Center

Jamieson, Ian; Naidoo, Rajani

2007-01-01

The study examines the changing nature of doctoral study in higher education in the context of significant global changes in higher education. From its origins with Humboldt, the trajectory of doctoral study is traced through the traditional Ph.D, the extended "American model", to the professional doctorate. A university case study…

Perceptions of changes in practice following peer review in the National Chronic Obstructive Pulmonary Disease Resources and Outcomes Project.

PubMed

Rivas, Carol; Taylor, Stephanie; Abbott, Stephen; Clarke, Aileen; Griffiths, Chris; Roberts, C Michael; Stone, Robert

2012-01-01

The purpose of this paper is to examine perceptions of local service change and concepts of change amongst participants in a UK nationwide randomised controlled trial of informal, structured, reciprocated, multidisciplinary peer review with feedback to promote quality improvement: the National Chronic Obstructive Pulmonary Disease Resources and Outcomes Project (NCROP). The paper takes the form of a qualitative study, involving semi-structured interviews with 43 hospital respiratory consultants, nurses and general managers at 24 intervention and 11 control NCROP sites. Thematic analysis resulted in adoption of Joss and Kogan's quality indicators as an analytic framework. The paper finds that peer review was associated with positive changes, which may lead to sustained service improvement. Differences existed in perceptions of change among clinicians and between clinicians and managers. "Generic changes" (e.g. changes in interpersonal relations or cultural changes), were often not perceived as change. The study highlights the significance of generic change in evaluations of change processes. Most participants were clinicians limiting inter-professional comparisons. Some clinical staff failed to recognise changes they accomplished or their significance, perceiving change differently to others within their professional group. These findings have implications for policy and research. They should be considered when developing frameworks for assessing quality improvements and staff engagement with change. This is the first qualitative study exploring participants' experience of peer review for quality improvement in healthcare. The study adds to previous research into UK health service improvement, which has had a more restricted focus on inter-professional differences.

Modic changes of the cervical spine in patients with whiplash injury: a prospective 11-year follow-up study.

PubMed

Matsumoto, Morio; Ichihara, Daisuke; Okada, Eijiro; Toyama, Yoshiaki; Fujiwara, Hirokazu; Momoshima, Suketaka; Nishiwaki, Yuji; Takahata, Takeshi

2013-06-01

There are few studies on Modic changes of the cervical spine in patients suffering from whiplash. This study compared Modic changes seen in whiplash patients 10 years after the injury with those observed in asymptomatic volunteers. This is a follow-up study of 133 patients who suffered whiplash injuries in 1994-1996 and underwent MRI with a superconductive imager (63 men, 70 women, mean age 49.6±15.3 years, mean follow-up 11.4 years). In addition, 223 healthy volunteers who underwent MRI during the same period were included as controls (123 men, 100 women, mean age 50.5±15.0 years, mean follow-up 11.6 years). All participants underwent follow-up MRI. We examined all participants for Modic changes, and investigated relationships between Modic changes and clinical symptoms or potentially related factors. Modic changes were observed in 4 patients (3%) and at 7 intervertebral levels in the initial study, and in 17 patients (12.8%) and at 30 intervertebral levels at the follow-up. Modic Type 2 changes were the most prevalent in the whiplash patients in both the initial and follow-up studies. There was no significant difference in the percentage of whiplash patients versus control subjects with positive Modic changes, either at the initial study or at follow-up. Modic changes were not related to clinical symptoms present at follow-up, but were associated with preexisting disc degeneration. There was no association between Modic changes and the details of the car accident that caused the injury. While Modic changes became more common in whiplash patients in the 10-year period after the accident, they occurred with a similar frequency in control subjects. We did not find any association between Modic changes and the nature of the car accident in which the whiplash occurred. Modic changes found in whiplash patients may be a result of the physiological ageing process rather than pathological findings relating to the whiplash injury. Copyright © 2012 Elsevier Ltd. All rights reserved.

Malaria and global change: Insights, uncertainties and possible surprises

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin, P.H.; Steel, A.

Malaria may change with global change. Indeed, global change may affect malaria risk and malaria epidemiology. Malaria risk may change in response to a greenhouse warming; malaria epidemiology, in response to the social, economic, and political developments which a greenhouse warming may trigger. To date, malaria receptivity and epidemiology futures have been explored within the context of equilibrium studies. Equilibrium studies of climate change postulate an equilibrium present climate (the starting point) and a doubled-carbon dioxide climate (the end point), simulate conditions in both instances, and compare the two. What happens while climate changes, i.e., between the starting point andmore » the end point, is ignored. The present paper focuses on malaria receptivity and addresses what equilibrium studies miss, namely transient malaria dynamics.« less

Maintaining perceptual constancy while remaining vigilant: left hemisphere change blindness and right hemisphere vigilance.

PubMed

Vos, Leia; Whitman, Douglas

2014-01-01

A considerable literature suggests that the right hemisphere is dominant in vigilance for novel and survival-related stimuli, such as predators, across a wide range of species. In contrast to vigilance for change, change blindness is a failure to detect obvious changes in a visual scene when they are obscured by a disruption in scene presentation. We studied lateralised change detection using a series of scenes with salient changes in either the left or right visual fields. In Study 1 left visual field changes were detected more rapidly than right visual field changes, confirming a right hemisphere advantage for change detection. Increasing stimulus difficulty resulted in greater right visual field detections and left hemisphere detection was more likely when change occurred in the right visual field on a prior trial. In Study 2 an intervening distractor task disrupted the influence of prior trials. Again, faster detection speeds were observed for the left visual field changes with a shift to a right visual field advantage with increasing time-to-detection. This suggests that a right hemisphere role for vigilance, or catching attention, and a left hemisphere role for target evaluation, or maintaining attention, is present at the earliest stage of change detection.

The usefulness of electrodiagnostic studies in the diagnosis and management of neuromuscular disorders.

PubMed

Lindstrom, Heather; Ashworth, Nigel L

2018-03-13

This study seeks to evaluate the usefulness of electrodiagnostic (EDX) studies in terms of the patient's diagnosis and subsequent management and to identify patient groups in which EDX is particularly useful. The records of new patients referred to a single tertiary hospital EDX laboratory during 1 calendar year were reviewed to determine whether results of EDX studies led to a changed diagnosis and/or management plan. Logistic regression was used to determine whether any factors were associated with changed diagnosis or management. Results of EDX studies led to a change in diagnosis and a confirmation in diagnosis in 51.5% and 46.5% of the cases, respectively. Results of EDX studies led to a change in the management plan in 63.4% of all cases. The diagnosis and management plan were more likely to be changed in older patients and patients referred in hospital. EDX studies seem useful for confirming or changing the diagnosis and in guiding management in patients with suspected neuromuscular disorders. Muscle Nerve, 2018. © 2018 Wiley Periodicals, Inc.

Public health impacts of climate change in Nepal.

PubMed

Joshi, H D; Dhimal, B; Dhimal, M; Bhusal, C L

2011-04-01

Climate change is a global issue in this century which has challenged the survival of living creatures affecting the life supporting systems of the earth: atmosphere, hydrosphere and lithosphere. Scientists have reached in a consensus that climate change is happening. The anthropogenic emission of greenhouse gases is responsible for global warming and therefore climate change. Climate change may directly or indirectly affect human health through a range of pathways related to temperature and precipitation. The aim of this article is to share knowledge on how climate change can affect public health in Nepal based on scientific evidence from global studies and experience gained locally. In this review attempt has been made to critically analyze the scientific studies as well as policy documents of Nepalese Government and shed light on public health impact of climate change in the context of Nepal. Detailed scientific study is recommended to discern impact of climate change on public health problems in Nepal.

Shifts Toward Morningness During Behavioral Sleep Interventions Are Associated With Improvements in Depression, Positive Affect, and Sleep Quality.

PubMed

Hasler, Brant P; Buysse, Daniel J; Germain, Anne

2016-01-01

Morningness-eveningness (M-E) is typically considered to be a trait-like construct. However, M-E could plausibly shift in concert with changes in circadian or homeostatic processes. We examined M-E changes across three studies employing behavioral or pharmacological sleep treatments. Baseline and posttreatment M-E scores were strongly correlated across all three samples. M-E showed small but systematic changes toward morningness in sleep-disturbed military veterans receiving behavioral interventions. No systematic M-E changes were observed in the two pharmacological studies (sleep-disturbed military veterans and adults with primary insomnia, respectively). In the behavioral study, M-E changes correlated with changes in depression, positive affect, and sleep quality. M-E changes also correlated with changes in positive affect in the adult insomnia group. M-E appears to exhibit state-like aspects in addition to trait-like aspects.

A Six-Year Follow-Up Study of Social Network Changes among African-American, Caribbean, and U.S.-Born Caucasian Urban Older Adults

ERIC Educational Resources Information Center

Conway, Francine; Magai, Carol; Jones, Samuel; Fiori, Katherine; Gillespie, Michael

2013-01-01

This study explores dynamic changes in network size and composition by examining patterns of older adults' social network change over time, that is: types of movements; the reason for the loss of network members; and the relation of movement and composition in concert. This study is a 6-year follow up of changes in the social networks of U.S.-Born…

Climate change and the water cycle in newly irrigated areas.

PubMed

Abrahão, Raphael; García-Garizábal, Iker; Merchán, Daniel; Causapé, Jesús

2015-02-01

Climate change is affecting agriculture doubly: evapotranspiration is increasing due to increments in temperature while the availability of water resources is decreasing. Furthermore, irrigated areas are expanding worldwide. In this study, the dynamics of climate change impacts on the water cycle of a newly irrigated watershed are studied through the calculation of soil water balances. The study area was a 752-ha watershed located on the left side of the Ebro river valley, in Northeast Spain. The soil water balance procedures were carried out throughout 1827 consecutive days (5 years) of hydrological and agronomical monitoring in the study area. Daily data from two agroclimatic stations were used as well. Evaluation of the impact of climate change on the water cycle considered the creation of two future climate scenarios for comparison: 2070 decade with climate change and 2070 decade without climate change. The main indicators studied were precipitation, irrigation, reference evapotranspiration, actual evapotranspiration, drainage from the watershed, and irrigation losses. The aridity index was also applied. The results represent a baseline scenario in which adaptation measures may be included and tested to reduce the impacts of climate change in the studied area and other similar areas.

Association between disk position and degenerative bone changes of the temporomandibular joints: an imaging study in subjects with TMD.

PubMed

Cortés, Daniel; Sylvester, Daniel Cortés; Exss, Eduardo; Marholz, Carlos; Millas, Rodrigo; Moncada, Gustavo

2011-04-01

The aim of this study was to determine the frequency and relationship between disk position and degenerative bone changes in the temporomandibular joints (TMJ), in subjects with internal derangement (ID). MRI and CT scans of 180 subjects with temporomandibular disorders (TMD) were studied. Different image parameters or characteristics were observed, such as disk position, joint effusion, condyle movement, degenerative bone changes (flattened, cortical erosions and irregularities), osteophytes, subchondral cysts and idiopathic condyle resorption. The present study concluded that there is a significant association between disk displacement without reduction and degenerative bone changes in patients with TMD. The study also found a high probability of degenerative bone changes when disk displacement without reduction is present. No association was found between TMD and condyle range of motion, joint effusion and/or degenerative bone changes. The following were the most frequent morphological changes observed: flattening of the anterior surface of the condyle; followed by erosions and irregularities of the joint surfaces; flattening of the articular surface of the temporal eminence, subchondral cysts, osteophytes; and idiopathic condyle resorption, in decreasing order.

Monitoring change in mountainous dry-heath vegetation at a regional scale using multitemporal Landsat TM data.

PubMed

Nordberg, Maj-Liz; Evertson, Joakim

2003-12-01

Vegetation cover-change analysis requires selection of an appropriate set of variables for measuring and characterizing change. Satellite sensors like Landsat TM offer the advantages of wide spatial coverage while providing land-cover information. This facilitates the monitoring of surface processes. This study discusses change detection in mountainous dry-heath communities in Jämtland County, Sweden, using satellite data. Landsat-5 TM and Landsat-7 ETM+ data from 1984, 1994 and 2000, respectively, were used. Different change detection methods were compared after the images had been radiometrically normalized, georeferenced and corrected for topographic effects. For detection of the classes change--no change the NDVI image differencing method was the most accurate with an overall accuracy of 94% (K = 0.87). Additional change information was extracted from an alternative method called NDVI regression analysis and vegetation change in 3 categories within mountainous dry-heath communities were detected. By applying a fuzzy set thresholding technique the overall accuracy was improved from of 65% (K = 0.45) to 74% (K = 0.59). The methods used generate a change product showing the location of changed areas in sensitive mountainous heath communities, and it also indicates the extent of the change (high, moderate and unchanged vegetation cover decrease). A total of 17% of the dry and extremely dry-heath vegetation within the study area has changed between 1984 and 2000. On average 4% of the studied heath communities have been classified as high change, i.e. have experienced "high vegetation cover decrease" during the period. The results show that the low alpine zone of the southern part of the study area shows the highest amount of "high vegetation cover decrease". The results also show that the main change occurred between 1994 and 2000.

Relationship of night and shift work with weight change and lifestyle behaviors.

PubMed

Bekkers, Marga B M; Koppes, Lando L J; Rodenburg, Wendy; van Steeg, Harry; Proper, Karin I

2015-04-01

To prospectively study the association of night and shift work with weight change and lifestyle behaviors. Workers participating in the Netherlands Working Conditions Cohort Study (2008 and 2009) (N = 5951) reported night and shift work, weight and height. Groups included stable night or shift work, from day work to night or shift work, from night or shift work to day work, and no night or shift work in 2008 and 2009. Regression analyses were used to study association changes in night and shift work with weight change and changes in lifestyle behaviors. A larger weight change was seen in normal-weight workers changing from day to shift work (β = 0.93%; 95% confidence interval, 0.01 to 1.85) compared with stable no shift workers. No further associations of night and shift work with weight change were observed, neither in normal-weight, overweight, and obese workers. Despite the fact that starting night or shift work is associated with some unhealthy lifestyle habits, this study did not confirm a positive association of night and shift work with weight change over 1 year, except for normal-weight workers moving from day to shift work.

Changes in diffusion path length with old age in diffuse optical tomography

NASA Astrophysics Data System (ADS)

Bonnéry, Clément; Leclerc, Paul-Olivier; Desjardins, Michèle; Hoge, Rick; Bherer, Louis; Pouliot, Philippe; Lesage, Frédéric

2012-05-01

Diffuse, optical near infrared imaging is increasingly being used in various neurocognitive contexts where changes in optical signals are interpreted through activation maps. Statistical population comparison of different age or clinical groups rely on the relative homogeneous distribution of measurements across subjects in order to infer changes in brain function. In the context of an increasing use of diffuse optical imaging with older adult populations, changes in tissue properties and anatomy with age adds additional confounds. Few studies investigated these changes with age. Duncan et al. measured the so-called diffusion path length factor (DPF) in a large population but did not explore beyond the age of 51 after which physiological and anatomical changes are expected to occur [Pediatr. Res. 39(5), 889-894 (1996)]. With increasing interest in studying the geriatric population with optical imaging, we studied changes in tissue properties in young and old subjects using both magnetic resonance imaging (MRI)-guided Monte-Carlo simulations and time-domain diffuse optical imaging. Our results, measured in the frontal cortex, show changes in DPF that are smaller than previously measured by Duncan et al. in a younger population. The origin of these changes are studied using simulations and experimental measures.

Relationship between staff-reported culture change and occupancy rate and organizational commitment among nursing homes in South Korea.

PubMed

Lee, Minhong; Choi, Jae-Sung; Lim, Jinseop; Kim, Young Sun

2013-04-01

This study aims to examine culture change in nursing homes in South Korea and to identify the outcomes of culture change implementation. Data were taken from survey responses from 223 top- or mid-level staff among nursing homes in South Korea that were selected through a proportionate random-stratified sampling method from four regions nationwide. Culture change in nursing homes was operationalized by five person-directed care (PDC) constructs and three organizational environment constructs, and outcome quality was indicated by changes to occupancy rate and organizational commitment. After controlling for facility characteristics, the effect of staff-reported culture change on occupancy rate and organizational commitment was analyzed through the multiple-regression method. Consistent with previous research, this study revealed positive effects of culture change for nursing homes in South Korea. The study found that staff-reported culture change correlated with occupancy rate and organizational commitment. Given that culture change variables were significantly related to occupancy rate and organizational commitment, the findings of the study provide a persuasive argument that policies and/or programs to support culture change in nursing homes should be enhanced. Management-level workers in these facilities should have the skills and knowledge to foster more PDC and a more person-directed environment.

Temporal change in fragmentation of continental US forests

Treesearch

James D. Wickham; Kurt H. Riitters; Timothy G. Wade; Collin Homer

2008-01-01

Changes in forest ecosystem function and condition arise from changes in forest fragmentation. Previous studies estimated forest fragmentation for the continental United States (US). In this study, new temporal land-cover data from the National Land Cover Database (NLCD) were used to estimate changes in forest fragmentation at multiple scales for the continental US....

Heroes, Teams, and Teachers: A Study of Leadership for Change.

ERIC Educational Resources Information Center

Heller, Marjorie F.; Firestone, William A.

Research on leadership for change should focus more on what leaders do and less on who the key leaders are. This study identifies a set of change leadership functions, including providing and selling a vision of change, obtaining resources, providing encouragement and recognition, adapting standard operating procedures, monitoring the improvement…

Changes in the Nature and Structure of Work: Implications for Skill Requirements and Skill Formation.

ERIC Educational Resources Information Center

Bailey, Thomas

Changes in the economy and the workplace are changing job skill requirements and the process of skill acquisition. A study analyzed occupational trends and projections, performed case studies of four industry sectors (apparel and textile, accounting, management consulting, and software development), and reviewed research on changing skill demands…

The Adolescent Female Changing Voice: A Phenomenological Investigation

ERIC Educational Resources Information Center

Sweet, Bridget

2015-01-01

The purpose of this phenomenological study was to investigate the experience of female voice change from the perspective of female middle and high school choral students. The study was guided by two questions: How do adolescent female choir students experience voice change? What is the essence of the experience of voice change for middle school…

Cigarette Advertising: My, How You've Changed!

ERIC Educational Resources Information Center

England, Bill; And Others

A study examined the changes that have occurred in the content of cigarette advertising in magazines from 1945 to 1985 in the context of changes in the product itself, in advertising science, and in government regulation. Specifically, the study examined how advertisements had changed in terms of format, brand segmentation, major sales point or…

Changing the Education of Teachers.

ERIC Educational Resources Information Center

Hawley, Willis D.; And Others

This study examines the changes that have occurred in the ways colleges and universities in the Southern Regional Education Board (SREB) seek to prepare teachers. Particular focus is on the effects of state policies and on the role of college and university leaders in bringing about change. The study describes and explains changes in the way…

Environmental Sustainability Change Management in SMEs: Learning from Sustainability Champions

ERIC Educational Resources Information Center

Chadee, Doren; Wiesner, Retha; Roxas, Banjo

2011-01-01

This study identifies the change management processes involved in undertaking environmental sustainability (ES) initiatives within Small and Medium Size Enterprises (SMEs) and relate these to the main attributes of learning organisations. Using case study techniques, the study draws from the change management experiences of a sample of 12 ES…

Eating a Home: Food, Imaginary Selves and Study Abroad Testimonials

ERIC Educational Resources Information Center

Hanna, Barbara E.

2016-01-01

Discourses around Study Abroad (SA) consistently portray a transformational experience for participants who return home forever changed. This article investigates how such change is inscribed in texts addressed to Australian tertiary students considering SA. Acknowledging the significant role of the non-study component of SA in triggering change,…

Conceptualizing the Role of Culture in Political Change.

ERIC Educational Resources Information Center

Aronoff, Myron J.

Using as a point of departure anthropologist Clifford Geertz's study of culture with special emphasis on political change, the paper develops a theoretical framework for studying the relationship between culture and political change. A major objective of this anthropological approach to the study of political culture is to help political…

A Multivariate Model of Conceptual Change

ERIC Educational Resources Information Center

Taasoobshirazi, Gita; Heddy, Benjamin; Bailey, MarLynn; Farley, John

2016-01-01

The present study used the Cognitive Reconstruction of Knowledge Model (CRKM) model of conceptual change as a framework for developing and testing how key cognitive, motivational, and emotional variables are linked to conceptual change in physics. This study extends an earlier study developed by Taasoobshirazi and Sinatra ("J Res Sci…

Acclimatization and Adaptive Capacity of Marine Species in a Changing Ocean.

PubMed

Foo, S A; Byrne, M

To persist in an ocean changing in temperature, pH and other stressors related to climate change, many marine species will likely need to acclimatize or adapt to avoid extinction. If marine populations possess adequate genetic variation in tolerance to climate change stressors, species might be able to adapt to environmental change. Marine climate change research is moving away from single life stage studies where individuals are directly placed into projected scenarios ('future shock' approach), to focus on the adaptive potential of populations in an ocean that will gradually change over coming decades. This review summarizes studies that consider the adaptive potential of marine invertebrates to climate change stressors and the methods that have been applied to this research, including quantitative genetics, laboratory selection studies and trans- and multigenerational experiments. Phenotypic plasticity is likely to contribute to population persistence providing time for genetic adaptation to occur. Transgenerational and epigenetic effects indicate that the environmental and physiological history of the parents can affect offspring performance. There is a need for long-term, multigenerational experiments to determine the influence of phenotypic plasticity, genetic variation and transgenerational effects on species' capacity to persist in a changing ocean. However, multigenerational studies are only practicable for short generation species. Consideration of multiple morphological and physiological traits, including changes in molecular processes (eg, DNA methylation) and long-term studies that facilitate acclimatization will be essential in making informed predictions of how the seascape and marine communities will be altered by climate change. © 2016 Elsevier Ltd. All rights reserved.

Meta-analysis of changes in temperature and precipitation in Florida in the context of food-energy-water nexus

NASA Astrophysics Data System (ADS)

Anandhi, A.; Sharma, A.

2017-12-01

Florida is a hotspot of endemism for plants, vertebrates, and insects outside of the tropics. The state has extensive coastline, with the maximum distance from the coast less than 150 km which has diverse ecosystems and landscapes, as well as habitat for many endangered species. Additionally, agriculture is one of the most important economic resources in Florida and is ranked second in the U.S. for value of vegetable production. Florida's biodiversity is threatened by stressors such as increasing urbanization and population, land-use change and socio-economic growth. Given that, climate change and variability will interact with these stresses, potentially accentuating their negative impacts, there are several studies, concerning climate change impacts on Florida's ecosystem to date. The specific objectives of this study were to demonstrate the decision support tool developed from meta-analysis. The Tool was developed using the temperature and precipitation changes in Florida identified from peer reviewed studies. These change values were then synthesized using simple statistical techniques (e.g., histogram, line plots and density plots). Our results indicate a wide variability in the temperature and precipitation changes observed in the studies for Florida. The studies showed a temperature change ranged between +5 °C and -3 °C, while the precipitation change ranged between +30% and -40% in the state. These changes have series implications on the food-water-energy nexus. Some of the potential implications of these changes in the context of the nexus are discussed using causal chains developed from meta-analysis.

Building social cognitive models of language change.

PubMed

Hruschka, Daniel J; Christiansen, Morten H; Blythe, Richard A; Croft, William; Heggarty, Paul; Mufwene, Salikoko S; Pierrehumbert, Janet B; Poplack, Shana

2009-11-01

Studies of language change have begun to contribute to answering several pressing questions in cognitive sciences, including the origins of human language capacity, the social construction of cognition and the mechanisms underlying culture change in general. Here, we describe recent advances within a new emerging framework for the study of language change, one that models such change as an evolutionary process among competing linguistic variants. We argue that a crucial and unifying element of this framework is the use of probabilistic, data-driven models both to infer change and to compare competing claims about social and cognitive influences on language change.

Impacts of Low-Flow and Stream-Temperature Changes on Endangered Atlantic Salmon - Current Research

USGS Publications Warehouse

Dudley, Robert W.; Hodgkins, Glenn A.; Letcher, Benjamin H.

2008-01-01

Recent climate studies in New England and the northeastern United States have shown evidence of physical changes over time, including trends toward earlier snowmelt runoff, decreasing river ice, and increasing spring water temperatures. A U.S. Geological Survey (USGS) study funded by the National Global Warming and Wildlife Science Center will be investigating changes in summer low streamflows and stream temperatures and the potential effects of those changes on endangered Atlantic salmon populations. The study also will evaluate management options that would be most likely to mitigate the effects of any changes in streamflow and temperature.

Theories Applied to m-Health Interventions for Behavior Change in Low- and Middle-Income Countries: A Systematic Review.

PubMed

Cho, Yoon-Min; Lee, Seohyun; Islam, Sheikh Mohammed Shariful; Kim, Sun-Young

2018-02-13

Recently there has been dramatic increase in the use of mobile technologies for health (m-Health) in both high and low- and middle-income countries (LMICs). However, little is known whether m-Health interventions in LMICs are based on relevant theories critical for effective implementation of such interventions. This review aimed to systematically identify m-Health studies on health behavioral changes in LMICs and to examine how each study applied behavior change theories. A systematic review was conducted using the standard method from the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. By searching electronic databases (MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials [CENTRAL]), we identified eligible studies published in English from inception to June 30, 2017. For the identified m-Health studies in LMICs, we examined their theoretical bases, use of behavior change techniques (BCTs), and modes of delivery. A total of 14 m-Health studies on behavioral changes were identified and, among them, only 5 studies adopted behavior change theory. The most frequently cited theory was the health belief model, which was adopted in three studies. Likewise, studies have applied only a limited number of BCTs. Among the seven BCTs identified, the most frequently used one was the social support (practical) technique for medication reminder and medical appointment. m-Health studies in LMICs most commonly used short messaging services and phone calls as modes of delivery for behavior change interventions. m-Health studies in LMICs are suboptimally based on behavior change theory yet. To maximize effectiveness of m-Health, rigorous delivery methods as well as theory-based intervention designs will be needed.

Sample size and classification error for Bayesian change-point models with unlabelled sub-groups and incomplete follow-up.

PubMed

White, Simon R; Muniz-Terrera, Graciela; Matthews, Fiona E

2018-05-01

Many medical (and ecological) processes involve the change of shape, whereby one trajectory changes into another trajectory at a specific time point. There has been little investigation into the study design needed to investigate these models. We consider the class of fixed effect change-point models with an underlying shape comprised two joined linear segments, also known as broken-stick models. We extend this model to include two sub-groups with different trajectories at the change-point, a change and no change class, and also include a missingness model to account for individuals with incomplete follow-up. Through a simulation study, we consider the relationship of sample size to the estimates of the underlying shape, the existence of a change-point, and the classification-error of sub-group labels. We use a Bayesian framework to account for the missing labels, and the analysis of each simulation is performed using standard Markov chain Monte Carlo techniques. Our simulation study is inspired by cognitive decline as measured by the Mini-Mental State Examination, where our extended model is appropriate due to the commonly observed mixture of individuals within studies who do or do not exhibit accelerated decline. We find that even for studies of modest size ( n = 500, with 50 individuals observed past the change-point) in the fixed effect setting, a change-point can be detected and reliably estimated across a range of observation-errors.

Exploring change in a group-based psychological intervention for multiple sclerosis patients.

PubMed

Borghi, Martina; Bonino, Silvia; Graziano, Federica; Calandri, Emanuela

2018-07-01

The study is focused on a group-based cognitive behavioral intervention aimed at promoting the quality of life and psychological well-being of multiple sclerosis patients. The study investigates how the group intervention promoted change among participants and fostered their adjustment to the illness. The intervention involved six groups of patients (a total of 41 patients) and included four consecutive sessions and a 6-month follow-up. To explore change, verbatim transcripts of the intervention sessions were analyzed using a mixed-methods content analysis with qualitative data combined with descriptive statistics. The categories of resistance and openness to change were used to describe the process of change. Resistance and openness to change coexisted during the intervention. Only in the first session did resistance prevail over openness to change; thereafter, openness to change gradually increased and stabilized over time, and openness to change was then always stronger than resistance. The study builds on previous research on the effectiveness of group-based psychological interventions for multiple sclerosis patients and gives methodological and clinical suggestions to health care professionals working with multiple sclerosis patients. Implications for rehabilitation The study suggests that a group-based cognitive behavioral intervention for multiple sclerosis patients focused on the promotion of identity redefinition, a sense of coherence and self-efficacy in dealing with multiple sclerosis fosters the process of change and may be effective in promoting patients' adjustment to their illness. Health care professionals leading group-based psychological interventions for multiple sclerosis patients should be aware that resistance and openness to change coexist in the process of change. The study suggests that the duration of the intervention is a crucial factor: a minimum of three sessions appears to be necessary for group participants to develop greater openness to change and follow-up sessions should be implemented to maintain positive changes among participants. The use of qualitative instruments to evaluate group interventions captures the complexity of processes and gives useful indications to health professionals to improve rehabilitation programs.

Shifts in frog size and phenology: Testing predictions of climate change on a widespread anuran using data from prior to rapid climate warming.

PubMed

Sheridan, Jennifer A; Caruso, Nicholas M; Apodaca, Joseph J; Rissler, Leslie J

2018-01-01

Changes in body size and breeding phenology have been identified as two major ecological consequences of climate change, yet it remains unclear whether climate acts directly or indirectly on these variables. To better understand the relationship between climate and ecological changes, it is necessary to determine environmental predictors of both size and phenology using data from prior to the onset of rapid climate warming, and then to examine spatially explicit changes in climate, size, and phenology, not just general spatial and temporal trends. We used 100 years of natural history collection data for the wood frog, Lithobates sylvaticus with a range >9 million km 2 , and spatially explicit environmental data to determine the best predictors of size and phenology prior to rapid climate warming (1901-1960). We then tested how closely size and phenology changes predicted by those environmental variables reflected actual changes from 1961 to 2000. Size, phenology, and climate all changed as expected (smaller, earlier, and warmer, respectively) at broad spatial scales across the entire study range. However, while spatially explicit changes in climate variables accurately predicted changes in phenology, they did not accurately predict size changes during recent climate change (1961-2000), contrary to expectations from numerous recent studies. Our results suggest that changes in climate are directly linked to observed phenological shifts. However, the mechanisms driving observed body size changes are yet to be determined, given the less straightforward relationship between size and climate factors examined in this study. We recommend that caution be used in "space-for-time" studies where measures of a species' traits at lower latitudes or elevations are considered representative of those under future projected climate conditions. Future studies should aim to determine mechanisms driving trends in phenology and body size, as well as the impact of climate on population density, which may influence body size.

Change over time in alcohol consumption in control groups in brief intervention studies: systematic review and meta-regression study.

PubMed

Jenkins, Richard J; McAlaney, John; McCambridge, Jim

2009-02-01

Reactivity to assessment has attracted recent attention in the brief alcohol intervention literature. This systematic review sought to examine the nature of change in alcohol consumption over time in control groups in brief intervention studies. Primary studies were identified from existing reviews published in English language, peer-reviewed journals between 1995 and 2005. Change in alcohol consumption and selected study-level characteristics for each primary study were extracted. Consumption change data were pooled in random effects models and meta-regression was used to explore predictors of change. Eleven review papers reported the results of 44 individual studies. Twenty-six of these studies provided data suitable for quantitative study. Extreme heterogeneity was identified and the extent of observed reduction in consumption over time was greater in studies undertaken in Anglophone countries, with single gender study participants, and without special targeting by age. Heterogeneity was reduced but was still substantial in a sub-set of 15 general population studies undertaken in English language countries. The actual content of the control group procedure itself was not predictive of reduction in drinking, nor were a range of other candidate variables including setting, the exclusion of dependent drinkers, the collection of a biological sample at follow-up, and duration of study. Further investigations may yield novel insights into the nature of behaviour change with potential to inform brief interventions design.

Changes in composition, ecology and structure of high-mountain vegetation: a re-visitation study over 42 years.

PubMed

Evangelista, Alberto; Frate, Ludovico; Carranza, Maria Laura; Attorre, Fabio; Pelino, Giovanni; Stanisci, Angela

2016-01-27

High-mountain ecosystems are increasingly threatened by climate change, causing biodiversity loss, habitat degradation and landscape modifications. However, very few detailed studies have focussed on plant biodiversity in the high mountains of the Mediterranean. In this study, we investigated the long-term changes that have occurred in the composition, structure and ecology of high-mountain vegetation in the central Apennines (Majella) over the last 42 years. We performed a re-visitation study, using historical and newly collected vegetation data to explore which ecological and structural features have been the most successful in coping with climatic changes. Vegetation changes were analysed by comparing geo-referenced phytosociological relevés collected in high-mountain habitats (dolines, gentle slopes and ridges) on the Majella massif in 1972 and in 2014. Composition analysis was performed by detrended correspondence analysis, followed by an analysis of similarities for statistical significance assessment and by similarity percentage procedure (SIMPER) for identifying which species indicate temporal changes. Changes in ecological and structural indicators were analysed by a permutational multivariate analysis of variance, followed by a post hoc comparison. Over the last 42 years, clear floristic changes and significant ecological and structural variations occurred. We observed a significant increase in the thermophilic and mesonitrophilic plant species and an increment in the frequencies of hemicryptophytes. This re-visitation study in the Apennines agrees with observations in other alpine ecosystems, providing new insights for a better understanding of the effects of global change on Mediterranean high-mountain biodiversity. The observed changes in floristic composition, the thermophilization process and the shift towards a more nutrient-demanding vegetation are likely attributable to the combined effect of higher temperatures and the increase in soil nutrients triggered by global change. The re-visitation approach adopted herein represents a powerful tool for studying climate-related changes in sensitive high-mountain habitats. Published by Oxford University Press on behalf of the Annals of Botany Company.

Revised Study Design for Final Phase of the Change Agent Study. Study of Change Agent Programs: A Working Note.

ERIC Educational Resources Information Center

Bass, G.; And Others

The Rand change agent study was designed to determine the factors for successful implementation and continuation of selected federal programs--the Elementary and Secondary Education Act, Title III, Innovation Projects; ESEA Title VII, Bilingual Projects; Vocational Education Part D, Exemplary Programs; and the Right-to-Read program. This report…

Plastic and evolutionary responses to climate change in fish

PubMed Central

Crozier, Lisa G; Hutchings, Jeffrey A

2014-01-01

The physical and ecological ‘fingerprints’ of anthropogenic climate change over the past century are now well documented in many environments and taxa. We reviewed the evidence for phenotypic responses to recent climate change in fish. Changes in the timing of migration and reproduction, age at maturity, age at juvenile migration, growth, survival and fecundity were associated primarily with changes in temperature. Although these traits can evolve rapidly, only two studies attributed phenotypic changes formally to evolutionary mechanisms. The correlation-based methods most frequently employed point largely to ‘fine-grained’ population responses to environmental variability (i.e. rapid phenotypic changes relative to generation time), consistent with plastic mechanisms. Ultimately, many species will likely adapt to long-term warming trends overlaid on natural climate oscillations. Considering the strong plasticity in all traits studied, we recommend development and expanded use of methods capable of detecting evolutionary change, such as the long term study of selection coefficients and temporal shifts in reaction norms, and increased attention to forecasting adaptive change in response to the synergistic interactions of the multiple selection pressures likely to be associated with climate change. PMID:24454549

Plastic and evolutionary responses to climate change in fish.

PubMed

Crozier, Lisa G; Hutchings, Jeffrey A

2014-01-01

The physical and ecological 'fingerprints' of anthropogenic climate change over the past century are now well documented in many environments and taxa. We reviewed the evidence for phenotypic responses to recent climate change in fish. Changes in the timing of migration and reproduction, age at maturity, age at juvenile migration, growth, survival and fecundity were associated primarily with changes in temperature. Although these traits can evolve rapidly, only two studies attributed phenotypic changes formally to evolutionary mechanisms. The correlation-based methods most frequently employed point largely to 'fine-grained' population responses to environmental variability (i.e. rapid phenotypic changes relative to generation time), consistent with plastic mechanisms. Ultimately, many species will likely adapt to long-term warming trends overlaid on natural climate oscillations. Considering the strong plasticity in all traits studied, we recommend development and expanded use of methods capable of detecting evolutionary change, such as the long term study of selection coefficients and temporal shifts in reaction norms, and increased attention to forecasting adaptive change in response to the synergistic interactions of the multiple selection pressures likely to be associated with climate change.

Beyond dichotomies: Gender and intersecting inequalities in climate change studies.

PubMed

Djoudi, Houria; Locatelli, Bruno; Vaast, Chloe; Asher, Kiran; Brockhaus, Maria; Basnett Sijapati, Bimbika

2016-12-01

Climate change and related adaptation strategies have gender-differentiated impacts. This paper reviews how gender is framed in 41 papers on climate change adaptation through an intersectionality lens. The main findings show that while intersectional analysis has demonstrated many advantages for a comprehensive study of gender, it has not yet entered the field of climate change and gender. In climate change studies, gender is mostly handled in a men-versus-women dichotomy and little or no attention has been paid to power and social and political relations. These gaps which are echoed in other domains of development and gender research depict a 'feminization of vulnerability' and reinforce a 'victimization' discourse within climate change studies. We argue that a critical intersectional assessment would contribute to unveil agency and emancipatory pathways in the adaptation process by providing a better understanding of how the differential impacts of climate change shape, and are shaped by, the complex power dynamics of existing social and political relations.

A Qualitative Study on Change Management in Primary Schools Award Winning and Non-Award Winning Schools Case in Study of TQM

ERIC Educational Resources Information Center

Altunay, Esen; Arli, Didem; Yalcinkaya, Munevver

2012-01-01

The aim of this study was to determine the need of change in primary schools and to reveal out the principals' experiences during the change process by taking the total quality management practices into consideration and finally give suggestions according to the results of the study. In this study by employing qualitative research method, semi…

Farmers' perceptions of and adaptation strategies to climate change and their determinants; the case of Punjab province, Pakistan

NASA Astrophysics Data System (ADS)

Abid, M.; Scheffran, J.; Schneider, U. A.; Ashfaq, M.

2014-10-01

Climate change is a global environmental threat to all economic sectors, particularly the agricultural sector. Pakistan is one of the negatively affected countries from climate change due to its high exposure to extreme events and low adaptive capacity. In Pakistan, farmers are the primary stakeholders in agriculture and are more at risk due to climate vulnerability. Based on farm household data of 450 households collected from three districts in three agro-ecological zones in Punjab province of Pakistan, this study examined how farmers perceive climate change and how they adapt their farming in response to perceived changes in climate. The results demonstrate that awareness to climate change persists in the area, and farm households make adjustments to adapt their agriculture in response to climatic change. Overall 58% of the farm households adapted their farming to climate change. Changing crop varieties, changing planting dates, plantation of trees and changing fertilizer were the main adaptation methods implemented by farm households in the study area. Results from the binary logistic model revealed that education, farm experience, household size, land area, tenancy status, ownership of tube-well, access to market information, information on weather forecasting and extension all influence the farmers' choice of adaptation measures. Results also indicate that adaptation to climate change is constrained by several factors such as lack of information; lack of money; resource constraint and shortage of irrigation water in the study area. Findings of the study suggest the need of greater investment in farmer education and improved institutional setup for climate change adaptation to improve farmers' wellbeing.

Study of Pattern of Change in Handwriting Class Characters with Different Grades of Myopia.

PubMed

Hedge, Shruti Prabhat; Dayanidhi, Vijay Kautilya; Sriram

2015-12-01

Handwriting is a visuo-motor skill highly dependent on visual skills. Any defect in the visual inputs could affect a change in the handwriting. Understanding the variation in handwriting characters caused by visual acuity change can help in identifying learning disabilities in children and also assess the disability in elderly. In our study we try to analyse and catalogue these changes in the handwriting of a person. The study was conducted among 100 subjects having normal visual acuity. They were asked to perform a set of writing tasks, after which the same tasks were repeated after inducing different grades of myopia. Changes in the handwriting class characters were analysed and compared in all grades of myopia. In the study it was found that the letter size, pastiosity, word omissions, inability to stay on line all increase with changes in visual acuity. However these finding are not proportional to the grade of myopia. From the findings of the study it can be concluded that myopia significantly influences the handwriting and any change in visual acuity would induce corresponding changes in handwriting. There is increase in letter size, pastiosity where as the ability to stay on line and space between the lines decrease in different grades of myopia. The changes are not linear and cannot be used to predict the grade of myopia but can be used as parameters suggestive of refractive error.

Undergraduate Students' Conceptions of Natural and Anthropogenic Climate Change

NASA Astrophysics Data System (ADS)

Trenbath, K. L.

2011-12-01

Scientists and educators strive to improve climate literacy throughout society, whether through communication of research findings or though classroom teaching. Despite these efforts, climate change misconceptions exist in students and the general public. When educators present evidence that contradicts misconceptions, students may begin to struggle with their inaccurate ideas and perhaps transition towards a scientifically-accepted understanding. These transitions, called conceptual change, can occur in college climate change courses. The purpose of this presentation is to describe college students' ideas of natural and anthropogenic climate change and the way these ideas change throughout a climate change course. This presentation is based on five case studies of undergraduate students in a large lecture-hall course dedicated to climate change. Each case study student represents a different level of climate change understanding at the beginning of the semester. These case studies and subsequent cross-case analyses result from a qualitative research study using interviews, field notes, artifact analysis, coding and categorization, and research memos. The cases show shifts in all five students' ideas of natural and anthropogenic climate change. During the first month of class, the three lower achieving students expressed uncertainty about the increase in average global temperatures due to anthropogenic climate change. At the end of the semester, these students explained that warming from climate change is natural, yet the rate of this warming is increasing due to human activities. Two of the lower achieving students constructed definitions of climate change different than the definition used by the professor in the classroom. These students solidified the idea that the term "climate change" describes the change that results from natural forcings only, while the term "global warming" describes change in the climate that results from human-caused forcings. Their constructed definition removes human-causes from association with the word "climate change", which may influence their climate change understanding. Of the two higher achieving students, one emphasized anthropogenic climate change at the beginning of the semester, but later focused on natural climate change during his interviews. The other high achieving student included tangential environmental topics in her descriptions of climate change throughout the entire semester, thus conflating climate change's definition. These alternative definitions of climate change indicate that the learners constructed hybrid conceptions in order to incorporate class content with their prior ideas. These hybrid conceptions indicate that the students' understandings lie somewhere between misconceptions and conceptual change. Since the students demonstrated these hybrid conceptions at the end of class, perhaps more time is needed for the students to process the information. These case studies identify the gaps the professor should address for conceptual change to fully occur.

A review of patient-centred post-fracture interventions in the context of theories of health behaviour change.

PubMed

Sujic, R; Gignac, M A; Cockerill, R; Beaton, D E

2011-08-01

The purpose of this literature review is to determine whether and to what extent current post-fracture osteoporosis interventions utilize theories of health behaviour change and whether those that are theory-based are more successful in producing desired behaviour changes. Studies were identified by applying additional criteria to the final selection stage of a systematic review of non-surgical osteoporosis interventions in the orthopaedic environment. We identified 42 primary studies targeted at patients and improving post-fracture osteoporosis care. As well as describing the studies (in terms of design, population, interventions, outcomes), we focused on theoretical framework and elements of behaviour change models. The 42 studies included in this review utilized a variety of post-fracture interventions; however, none of them reported using an underlying theoretical base. Only three studies drew on what we felt to be elements of a theoretical framework. The lack of theoretically based studies points to a currently under-utilized area of behaviour change research that could be applied to post-fracture interventions in order to make them more effective. Despite an abundance of literature supporting theories of behaviour change, post-fracture osteoporosis interventions do not report utilizing these theories. Theories of behaviour change could be applied to post-fracture osteoporosis interventions to explain why patients initiate osteoporosis management. Future research should explore the application of theories of health behaviour change to post-fracture interventions.

Impact of differential attrition on the association of education with cognitive change over 20 years of follow-up: the ARIC neurocognitive study.

PubMed

Gottesman, Rebecca F; Rawlings, Andreea M; Sharrett, A Richey; Albert, Marilyn; Alonso, Alvaro; Bandeen-Roche, Karen; Coker, Laura H; Coresh, Josef; Couper, David J; Griswold, Michael E; Heiss, Gerardo; Knopman, David S; Patel, Mehul D; Penman, Alan D; Power, Melinda C; Selnes, Ola A; Schneider, Andrea L C; Wagenknecht, Lynne E; Windham, B Gwen; Wruck, Lisa M; Mosley, Thomas H

2014-04-15

Studies of long-term cognitive change should account for the potential effects of education on the outcome, since some studies have demonstrated an association of education with dementia risk. Evaluating cognitive change is more ideal than evaluating cognitive performance at a single time point, because it should be less susceptible to confounding. In this analysis of 14,020 persons from a US cohort study, the Atherosclerosis Risk in Communities (ARIC) Study, we measured change in performance on 3 cognitive tests over a 20-year period, from ages 48-67 years (1990-1992) through ages 70-89 years (2011-2013). Generalized estimating equations were used to evaluate the association between education and cognitive change in unweighted adjusted models, in models incorporating inverse probability of attrition weighting, and in models using cognitive scores imputed from the Telephone Interview for Cognitive Status for participants not examined in person. Education did not have a strong relationship with change in cognitive test performance, although the rate of decline was somewhat slower among persons with lower levels of education. Methods used to account for selective dropout only marginally changed these observed associations. Future studies of risk factors for cognitive impairment should focus on cognitive change, when possible, to allow for reduction of confounding by social or cultural factors.

[Changes in academic motivation among elementary and junior high school students].

PubMed

Nishimura, Takuma; Sakurai, Shigeo

2013-02-01

This study examined changes in academic motivation among elementary and junior high school students. Based on self-determination theory (Ryan & Deci, 2000a), we focused on changes in autonomous and controlled motivation. In Study 1, we examined inter-individual changes in academic motivation among 5th to 9th grade students (N = 1 572) through a cross-sectional study. In Study 2, we examined intra-individual changes in academic motivation among students (N = 128) who were in transition from elementary to junior high school through a longitudinal study. All participants completed the Academic Motivation Scale (Nishimura, Kawamura, & Sakurai, 2011) that measured autonomous and controlled motivation. The results revealed that autonomous motivation decreased in the students from elementary to junior high school, while controlled motivation increased during the same period. This is a unique finding because a prior study conducted in a Western culture suggested that both motivations decrease gradually in school.

[The Munich Attachment and Effectiveness Study: Study Design and a Case Example].

PubMed

Hörz-Sagstetter, Susanne; Minow, Anna-Rahel; Erhardt, Ingrid; Barten-Hohn, Julia; Denscherz, Claudia; Buchheim, Anna; Taubner, Svenja; Mertens, Wolfgang

2016-03-01

The "Munich Attachment and Effectiveness Study" is a prospective psychotherapy study examining process and outcome of psychoanalytic psychotherapies. The study design and results are exemplified in a single case. At 6 points in time audio-taped and transcribed therapy sessions are evaluated using process instruments (e. g. Psychotherapy Process Q-Set PQS) and interviews (e. g. Operationalized Psychodynamic Diagnostics OPD, Heidelberg Structural Change Scale HSCS, Adult Attachment Interview AAI). In the single case, findings from the psychotherapeutic process (e. g. "therapist is empathic" according to PQS) complement the achieved changes. 5 HSCS problem foci reached level of "restructuring", on the Reflective Functioning Scale a marked change of RF took place and the attachment classification changed over time. The instruments employed in this study corresponded well in assessing change processes in spite of differing theoretical background. © Georg Thieme Verlag KG Stuttgart · New York.

A longitudinal, mixed methods study of sexual position identity, behavior, and fantasies among young sexual minority men.

PubMed

Pachankis, John E; Buttenwieser, Indiana G; Bernstein, Laura B; Bayles, Damon O

2013-10-01

Recent evidence suggests that young sexual minority men's sexual position identities (e.g., "top," "bottom," "versatile") may be governed by dynamic influences. Yet, no study has prospectively examined whether, how, and why this aspect of sexual minority men's sexuality changes over time. Consequently, the present study investigated the extent to which young sexual minority men use sexual position identities consistently over time, typical patterns of position identity change, explanations given for this change, and the correspondence of changing sexual position identities with changing sexual behavior and fantasies. A total of 93 young sexual minority men indicated their sexual position identity, behavior, and fantasies at two assessment points separated by 2 years. Following the second assessment, a subset (n = 28) of participants who represented the various sexual position identity change patterns provided explanations for their change. More than half (n = 48) of participants changed their sexual position identity. Participants showed a significant move away from not using sexual position identities toward using them and a significant move toward using "mostly top." Changes in position identity were reflected, although imperfectly, in changes in sexual behavior and largely not reflected in fantasy changes. Participants offered 11 classes of explanations for their identity changes referencing personal development, practical reasons, changing relationships, and sociocultural influences. Previous investigations of sexual minority men's sexual position identities have not adequately attended to the possibility of the changing use of the sexual position categories "top," "bottom," and "versatile" across young adulthood. Results of the present study suggest the possibility of a more fluid, context-dependent use of these terms than previously documented.

A Systematic Review of Genetic Testing and Lifestyle Behaviour Change: Are We Using High-Quality Genetic Interventions and Considering Behaviour Change Theory?

PubMed

Horne, Justine; Madill, Janet; O'Connor, Colleen; Shelley, Jacob; Gilliland, Jason

2018-04-10

Studying the impact of genetic testing interventions on lifestyle behaviour change has been a priority area of research in recent years. Substantial heterogeneity exists in the results and conclusions of this literature, which has yet to be explained using validated behaviour change theory and an assessment of the quality of genetic interventions. The theory of planned behaviour (TPB) helps to explain key contributors to behaviour change. It has been hypothesized that personalization could be added to this theory to help predict changes in health behaviours. This systematic review provides a detailed, comprehensive identification, assessment, and summary of primary research articles pertaining to lifestyle behaviour change (nutrition, physical activity, sleep, and smoking) resulting from genetic testing interventions. The present review further aims to provide in-depth analyses of studies conducted to date within the context of the TPB and the quality of genetic interventions provided to participants while aiming to determine whether or not genetic testing facilitates changes in lifestyle habits. This review is timely in light of a recently published "call-to-action" paper, highlighting the need to incorporate the TPB into personalized healthcare behaviour change research. Three bibliographic databases, one key website, and article reference lists were searched for relevant primary research articles. The PRISMA Flow Diagram and PRISMA Checklist were used to guide the search strategy and manuscript preparation. Out of 32,783 titles retrieved, 26 studies met the inclusion criteria. Three quality assessments were conducted and included: (1) risk of bias, (2) quality of genetic interventions, and (3) consideration of theoretical underpinnings - primarily the TPB. Risk of bias in studies was overall rated to be "fair." Consideration of the TPB was "poor," with no study making reference to this validated theory. While some studies (n = 11; 42%) made reference to other behaviour change theories, these theories were generally mentioned briefly, and were not thoroughly incorporated into the study design or analyses. The genetic interventions provided to participants were overall of "poor" quality. However, a separate analysis of studies using controlled intervention research methods demonstrated the use of higher-quality genetic interventions (overall rated to be "fair"). The provision of actionable recommendations informed by genetic testing was more likely to facilitate behaviour change than the provision of genetic information without actionable lifestyle recommendations. Several studies of good quality demonstrated changes in lifestyle habits arising from the provision of genetic interventions. The most promising lifestyle changes were changes in nutrition. It is possible to facilitate behaviour change using genetic testing as the catalyst. Future research should ensure that high-quality genetic interventions are provided to participants, and should consider validated theories such as the TPB in their study design and analyses. Further recommendations for future research are provided. © 2018 S. Karger AG, Basel.

Mining the management literature for insights into implementing evidence-based change in healthcare.

PubMed

Harlos, Karen; Tetroe, Jacqueline; Graham, Ian D; Bird, Madeleine; Robinson, Nicole

2012-08-01

We synthesized the management and health literatures for insights into implementing evidence-based change in healthcare drawn from industry-specific data. Because change principles based on evidence often fail to be translated into organizational practice or policy, we sought studies at the nexus of organizational change and knowledge translation. We reviewed five top management journals to identify an initial pool of 3,091 studies, which yielded a final sample of 100 studies. Data were abstracted, verified by the original authors and revised before entry into a database. We employed a systematic narrative synthesis approach using words and text to distill data and explain relationships. We categorized studies by varying levels of relevance for knowledge translation as (1) primary, direct; (2) intermediate; and (3) secondary, indirect. We also identified recurring categories of change-related organizational factors. The current analysis examines these factors in studies of primary relevance to knowledge translation, which we also coded for intervention readiness to reflect how readily change can be implemented. Preliminary Results centred on five change-related categories: Tailoring the Intervention Message; Institutional Links/Social Networks; Training; Quality of Work Relationships; and Fit to Organization. In particular, networks across institutional and individual levels appeared as prominent pathways for changing healthcare organizations. Power dynamics, positive social relations and team structures also played key roles in implementing change and translating it into practice. We analyzed journals in which first authors of these studies typically publish, and found evidence that management and health sciences remain divided. Bridging these disciplines through research syntheses promises a wealth of evidence and insights, well worth mining in the search for change that works in healthcare transformation. Copyright © 2012 Longwoods Publishing.

Understanding general practice: a conceptual framework developed from case studies in the UK NHS.

PubMed

Checkland, Kath

2007-01-01

General practice in the UK is undergoing a period of rapid and profound change. Traditionally, research into the effects of change on general practice has tended to regard GPs as individuals or as members of a professional group. To understand the impact of change, general practices should also be considered as organisations. To use the organisational studies literature to build a conceptual framework of general practice organisations, and to test and develop this empirically using case studies of change in practice. This study used the implementation of National Service Frameworks (NSFs) and the new General Medical Services (GMS) contract as incidents of change. In-depth, qualitative case studies. The design was iterative: each case study was followed by a review of the theoretical ideas. The final conceptual framework was the result of the dynamic interplay between theory and empirical evidence. Five general practices in England, selected using purposeful sampling. Semi-structured interviews with all clinical and managerial personnel in each practice, participant and nonparticipant observation, and examination of documents. A conceptual framework was developed that can be used to understand how and why practices respond to change. This framework enabled understanding of observed reactions to the introduction of NSFs and the new GMS contract. Important factors for generating responses to change included the story that the practice members told about their practice, beliefs about what counted as legitimate work, the role played by the manager, and previous experiences of change. Viewing general practices as small organisations has generated insights into factors that influence responses to change. Change tends to occur from the bottom up and is determined by beliefs about organisational reality. The conceptual framework suggests some questions that can be asked of practices to explain this internal reality.

Mining the Management Literature for Insights into Implementing Evidence-Based Change in Healthcare

PubMed Central

Harlos, Karen; Tetroe, Jacqueline; Graham, Ian D.; Bird, Madeleine; Robinson, Nicole

2012-01-01

Objective: We synthesized the management and health literatures for insights into implementing evidence-based change in healthcare drawn from industry-specific data. Because change principles based on evidence often fail to be translated into organizational practice or policy, we sought studies at the nexus of organizational change and knowledge translation. Methods: We reviewed five top management journals to identify an initial pool of 3,091 studies, which yielded a final sample of 100 studies. Data were abstracted, verified by the original authors and revised before entry into a database. We employed a systematic narrative synthesis approach using words and text to distill data and explain relationships. We categorized studies by varying levels of relevance for knowledge translation as (1) primary, direct; (2) intermediate; and (3) secondary, indirect. We also identified recurring categories of change-related organizational factors. The current analysis examines these factors in studies of primary relevance to knowledge translation, which we also coded for intervention readiness to reflect how readily change can be implemented. Preliminary Results and Conclusions: Results centred on five change-related categories: Tailoring the Intervention Message; Institutional Links/Social Networks; Training; Quality of Work Relationships; and Fit to Organization. In particular, networks across institutional and individual levels appeared as prominent pathways for changing healthcare organizations. Power dynamics, positive social relations and team structures also played key roles in implementing change and translating it into practice. We analyzed journals in which first authors of these studies typically publish, and found evidence that management and health sciences remain divided. Bridging these disciplines through research syntheses promises a wealth of evidence and insights, well worth mining in the search for change that works in healthcare transformation. PMID:23968602

Views of Primary School Administrators on Change in Schools and Change Management Practices

ERIC Educational Resources Information Center

Hosgörür, Vural

2016-01-01

The aim of this study is to determine the opinions of primary school administrators about change, and to reveal which strategies they use to manage change in schools. This is a qualitative study conducted in 2014 academic year in Mugla province. Research data were collected from primary school administrators through semi-structured interviews.…

Changing Family Habits: A Case Study into Climate Change Mitigation Behavior in Families

ERIC Educational Resources Information Center

Leger, Michel T.; Pruneau, Diane

2012-01-01

A case-study methodology was used to explore the process of change as experienced by 3 suburban families in an attempt to incorporate climate change mitigation behavior into their day to day life. Cross-case analysis of the findings revealed the emergence of three major conceptual themes associated with behavior adoption: collectively applied…

To Change or Not to Change: Investigating the Value of MCQ Answer Changing for Gulf Arab Students

ERIC Educational Resources Information Center

Al-Hamly, Mashael; Coombe, Christine

2005-01-01

This study investigates whether the practice of answer changing on multiple-choice questions (MCQs) is beneficial to Gulf Arab students' overall test performance. The proficiency exam used in this study is the Michigan English Language Institute College English Test - Grammar, Cloze, Vocabulary, Reading (MELICET-GCVR), which was developed using…

Change Management Model for Implementing an Effective First-Year Experience Program in the Community College Setting

ERIC Educational Resources Information Center

Tucker, Joy C.

2015-01-01

This study provides evidence that systematic management of change can facilitate the implementation of first-year experience programming that leads to improved results in retention and student success for community college students. The study includes four major themes: (a) first-year experience, (b) change management, (c) change leadership, and…

Sustaining the Momentum for the Change Process: An Historical Case Study of a Midwestern High School

ERIC Educational Resources Information Center

Onsager, Tim A.

2010-01-01

Although many high schools have failed to bring meaningful change, an increasing number of schools have experienced the successful implementation of a school-wide continuous improvement process. This study explored the change process as experienced by members of a high school community intent on establishing and sustaining change to better meet…

Conceptual Change Texts in Chemistry Teaching: A Study on the Particle Model of Matter

ERIC Educational Resources Information Center

Beerenwinkel, Anne; Parchmann, Ilka; Grasel, Cornelia

2011-01-01

This study explores the effect of a conceptual change text on students' awareness of common misconceptions on the particle model of matter. The conceptual change text was designed based on principles of text comprehensibility, of conceptual change instruction and of instructional approaches how to introduce the particle model. It was evaluated in…

Professional Development Design Considerations in Climate Change Education: Teacher Enactment and Student Learning

ERIC Educational Resources Information Center

Drewes, Andrea; Henderson, Joseph; Mouza, Chrystalla

2018-01-01

Climate change is one of the most pressing challenges facing society, and climate change educational models are emerging in response. This study investigates the implementation and enactment of a climate change professional development (PD) model for science educators and its impact on student learning. Using an intrinsic case study methodology,…

An Empirical Study on the Role of Context Factors in Employees' Commitment to Change

ERIC Educational Resources Information Center

Soumyaja, Devi; Kamlanabhan, T. J.; Bhattacharyya, Sanghamitra

2011-01-01

The study attempts to address the gap of exploring the possible antecedents of employees' commitment to change and its three dimensions. The role of context factors--participation in decision making, quality of communication, trust in management and history of change--are tested on overall commitment to change and also on its three…

Adapting to Change: The Value of Change Information and Meaning-Making

ERIC Educational Resources Information Center

van den Heuvel, Machteld; Demerouti, Evangelia; Bakker, Arnold B.; Schaufeli, Wilmar B.

2013-01-01

The purpose of this 3-wave study is to examine the micro process of how employees adapt to change over time. We combined Conservation of Resources theory with insights from the organizational change literature to study employees in a Dutch police district undergoing reorganization. A model was tested where employee adaptability, operationalized by…

Examination of a Process Model of Adolescent Smoking Self-Change Efforts in Relation to Gender

ERIC Educational Resources Information Center

MacPherson, Laura; Myers, Mark G.

2010-01-01

Little information describes how adolescents change their smoking behavior. This study investigated the role of gender in the relationship of motivation and cognitive variables with adolescent smoking self-change efforts. Self-report and semi-structured interview data from a prospective study of smoking self-change efforts were examined among 98…

The Role of Teaching Experience in Language Teachers' Perceptions of a Top-Down Curriculum Change

ERIC Educational Resources Information Center

Rahimi, Mehrak; Alavi, Jalil

2017-01-01

The current study aimed to investigate the role of teaching experience in language teachers' perceptions of a top-down curriculum change. One hundred twenty-seven language teachers who have been experiencing the change for three years participated in the study. Their perceptions of change were quantitatively assessed by perceptions of change…

Educational Leadership and Market Values: A Study of School Principals in Iceland

ERIC Educational Resources Information Center

Lárusdóttir, Steinunn Helga

2014-01-01

This article reports on the findings of a larger case study about the impact of values on educational leaders in Iceland. The environment of Icelandic schools has changed considerably in recent years. These changes have affected schools and changed the nature and scope of principals' work. Scholars have argued that these changes are primarily…

The Principal as Change Agent. The Best of ERIC on Educational Management, Number 55.

ERIC Educational Resources Information Center

ERIC Clearinghouse on Educational Management, Eugene, OR.

Twelve essays and books reviewed in this annotated bibliography contribute information about how principals can identify the need for change and how they can implement successful change strategies. The literature contains several case studies as well as empirical research data. One study concludes that change is more likely to occur when…

The Relationship between Intimacy Change and Passion: A Dyadic Diary Study.

PubMed

Aykutoğlu, Bülent; Uysal, Ahmet

2017-01-01

In the current study we investigated the association between intimacy and passion by testing whether increases in intimacy generates passion (Baumeister and Bratslavsky, 1999). Furthermore, we examined whether there are partner effects in intimacy change and passion link. Couples ( N = 75) participated in a 14-day long diary study. Dyadic multilevel analyses with residualized intimacy change scores showed that both actors' and partners' intimacy change positively predicted actor's passion. However, analyses also showed that residualized passion change scores positively predicted intimacy. Although these findings provide some empirical evidence for the intimacy change model, in line with the previous research (Rubin and Campbell, 2012), they also suggest that it is not possible to discern whether intimacy increment generates passion or passion increment generates intimacy.

Multiple health behavior change in adults with or at risk for cancer: a systematic review.

PubMed

Green, Amanda C; Hayman, Laura L; Cooley, Mary E

2015-05-01

To identify components of efficacious interventions for multiple health behavior change (MHBC) in adult cancer survivors or adults at high risk for cancer. A systematic review of MHBC interventions was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses framework. Ten studies met inclusion criteria. Most studies changed at least 2 health behaviors. Diet, exercise, and smoking cessation were consistently changed with in-person interventions. Longer duration interventions using phone or mail contact had a positive association with changing diet and exercise. MHBC interventions positively influenced behavior change in adults with cancer and those at high risk for cancer. Future studies should focus on increasing dissemination and implementation of efficacious interventions.

Physical Education Teacher Change: Initial Validation of the Teacher Change Questionnaire-Physical Education

ERIC Educational Resources Information Center

Kern, Ben D.; Graber, Kim C.

2017-01-01

Program satisfaction, self-efficacy to change, and willingness to change, are dispositions that influence physical education teacher change. The study purpose was to validate an instrument measuring program satisfaction, self-efficacy to change, and willingness to change relative to teachers' likelihood to change. A 15-item Teacher Change…

Passing over: Identity Transition in Widows

ERIC Educational Resources Information Center

Cheek, Cheryl

2010-01-01

This qualitative study of nine women examined the changes in their everyday lives as they cared for their terminally-ill husbands and after their husbands died. It also studied how the women coped with these changes, and how their coping contributed to their identity change from wife to widow. Symbolic interaction was utilized to study the changes…

Case Studies in Educational Change: An International Perspective.

ERIC Educational Resources Information Center

Carter, David S. G., Ed.; O'Neill, Marnie H., Ed.

This book is the second in a two-volume series of studies of educational change organized around three themes--systemic change, the transformation of policy into practice, and curriculum contexts. The book presents case studies from Australia, Great Britain, Israel, the United States, and New Zealand to illustrate the cross-cultural complexity of…

The Changing Role of the Reading Specialist: A Case Study

ERIC Educational Resources Information Center

Ginsburg, Victoria Elaine

2012-01-01

This descriptive qualitative case study explored the changing role of the reading specialist through various perceptions of professionals in the Neon Shadow School District. The purpose of the study was to explore what, how, and why the duties and responsibilities of the reading specialist have changed since first employed as an…

Conceptual Change and Physics Instruction: A Longitudinal Study.

ERIC Educational Resources Information Center

Searle, Peter; Gunstone, Richard F.

This paper reports an action study of conceptual change in mechanics using an instructional strategy based on a constructivist view of learning. The aims of the study were to determine: (1) what effect the instructional strategy had on achieving conceptual change; (2) what devices or strategies students used in their attempts to understand…

Outcomes of Global Education: External and Internal Change Associated with Study Abroad

ERIC Educational Resources Information Center

Miller-Perrin, Cindy; Thompson, Don

2014-01-01

This chapter provides an overview of external and internal changes associated with collegiate study abroad experiences. A brief review of the research literature is included along with recent research that sheds light on potential mechanisms associated with study abroad-related change. Recommendations for enhancing outcomes associated with study…

Effects of Information Feedback and Self-Administered Consequences on Self-Monitoring Study Behavior

ERIC Educational Resources Information Center

Richards, C. Steven; And Others

1976-01-01

The hypotheses tested among college students (N=87) concerned about study habits were: (a) self-monitoring changes study behavior; (b) information feedback accounts for some of this change; and (c) this change can be enhanced by manipulating the quantity and quality of information feedback and self-administered consequences associated with…

Curriculum Change and Self-Governing Agreements: A Yukon First Nation Case Study

ERIC Educational Resources Information Center

Lewthwaite, Brian Ellis; Owen, Thomas; Doiron, Ashley

2015-01-01

Recent developments in Canada's Yukon Territory draw attention to how political changes have potential for accelerating practices in education that are responsive to Indigenous Peoples' cultural knowledge systems and practices. In this study, through the use of case study methodology, an account of the changes that have occurred in one First…

Network destabilization and transition in depression: New methods for studying the dynamics of therapeutic change

PubMed Central

Hayes, Adele M.; Yasinski, Carly; Barnes, J. Ben; Bockting, Claudi L. H.

2015-01-01

The science of dynamic systems is the study of pattern formation and system change. Dynamic systems theory can provide a useful framework for understanding the chronicity of depression and its treatment. We propose a working model of therapeutic change with potential to organize findings from psychopathology and treatment research, suggest new ways to study change, facilitate comparisons across studies, and stimulate treatment innovation. We describe a treatment for depression that we developed to apply principles from dynamic systems theory and then present a program of research to examine the utility of this application. Recent methodological and technological developments are also discussed to further advance the search for mechanisms of therapeutic change. PMID:26197726

Impact of organisational change on mental health: a systematic review.

PubMed

Bamberger, Simon Grandjean; Vinding, Anker Lund; Larsen, Anelia; Nielsen, Peter; Fonager, Kirsten; Nielsen, René Nesgaard; Ryom, Pia; Omland, Øyvind

2012-08-01

Although limited evidence is available, organisational change is often cited as the cause of mental health problems. This paper provides an overview of the current literature regarding the impact of organisational change on mental health. A systematic search in PUBMED, PsychInfo and Web of Knowledge combining MeSH search terms for exposure and outcome. The criterion for inclusion was original data on exposure to organisational change with mental health problems as outcome. Both cross-sectional and longitudinal studies were included. We found in 11 out of 17 studies, an association between organisational change and elevated risk of mental health problems was observed, with a less provident association in the longitudinal studies. Based on the current research, this review cannot provide sufficient evidence of an association between organisational change and elevated risk of mental health problems. More studies of long-term effects are required including relevant analyses of confounders.

Linking Essential Tremor to the Cerebellum: Neuropathological Evidence.

PubMed

Louis, Elan D

2016-06-01

A fundamental question about essential tremor (ET) is whether its associated pathological changes and disease mechanisms are linkable to a specific brain region. To that end, recent tissue-based studies have made significant strides in elucidating changes in the ET brain. Emerging from these studies is increasing neuropathological evidence linking ET to the cerebellum. These studies have systematically identified a broad range of structural, degenerative changes in the ET cerebellum, spanning across all Purkinje cell compartments. These include the dendritic compartment (where there is an increase in number of Purkinje cell dendritic swellings, a pruning of the dendritic arbor, and a reduction in spine density), the cell body (where, aside from reductions in Purkinje cell linear density in some studies, there is an increase in the number of heterotopic Purkinje cell soma), and the axonal compartment (where a plethora of changes in axonal morphology have been observed, including an increase in the number of thickened axonal profiles, torpedoes, axonal recurrent collaterals, axonal branching, and terminal axonal sprouting). Additional changes, possibly due to secondary remodeling, have been observed in neighboring neuronal populations. These include a hypertrophy of basket cell axonal processes and changes in the distribution of climbing fiber-Purkinje cell synapses. These changes all distinguish ET from normal control brains. Initial studies further indicate that the profile (i.e., constellation) of these changes may separate ET from other diseases of the cerebellum, thereby serving as a disease signature. With the discovery of these changes, a new model of ET has arisen, which posits that it may be a neurodegenerative disorder centered in the cerebellar cortex. These newly emerging neuropathological studies pave the way for anatomically focused, hypothesis-driven, molecular mechanistic studies of disease pathogenesis.

Assessment of Reliable Change Using 95% Credible Intervals for the Differences in Proportions: A Statistical Analysis for Case-Study Methodology

ERIC Educational Resources Information Center

Unicomb, Rachael; Colyvas, Kim; Harrison, Elisabeth; Hewat, Sally

2015-01-01

Purpose: Case-study methodology studying change is often used in the field of speech-language pathology, but it can be criticized for not being statistically robust. Yet with the heterogeneous nature of many communication disorders, case studies allow clinicians and researchers to closely observe and report on change. Such information is valuable…

Impacts of changes in climate and land use/land cover under IPCC RCP scenarios on streamflow in the Hoeya River Basin, Korea.

PubMed

Kim, Jinsoo; Choi, Jisun; Choi, Chuluong; Park, Soyoung

2013-05-01

This study examined the separate and combined impacts of future changes in climate and land use/land cover (LULC) on streamflow in the Hoeya River Basin, South Korea, using the representative concentration pathway (RCP) 4.5 and 8.5 scenarios of the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC). First, a LULC change model was developed using RCP 4.5 and RCP 8.5 storylines and logistic regression. Three scenarios (climate change only, LULC change only, and climate and LULC change combined) were established, and the streamflow in future periods under these scenarios was simulated by the Soil and Water Assessment Tool (SWAT) model. Each scenario showed distinct seasonal variations in streamflow. Under climate change only, streamflow increased in spring and winter but decreased in summer and autumn, whereas LULC change increased high flow during wet periods but decreased low flow in dry periods. Although the LULC change had less effect than climate change on the changes in streamflow, the effect of LULC change on streamflow was significant. The result for the combined scenario was similar to that of the climate change only scenario, but with larger seasonal changes in streamflow. Although the effects of LULC change were smaller than those caused by climate change, LULC changes may heighten the problems of increased seasonal variability in streamflow caused by climate change. The results obtained in this study provide further insight into the availability of future streamflow and can aid in water resource management planning in the study area. Copyright © 2013 Elsevier B.V. All rights reserved.

Decadal changes in north-American tundra plant communities

NASA Astrophysics Data System (ADS)

Villarreal, S.; Johnson, D. R.; Webber, P.; Ebert-May, D.; Hollister, R. D.; Tweedie, C. E.

2013-12-01

Improving our understanding of how tundra vegetation responds to environmental change over decadal time scales is important. Tundra plants and ecosystems are well-recognized for their susceptibility to be impacted by climate warming; changes in land-atmosphere carbon, water, and energy balance in tundra landscapes have the potential to impact regional to global-scale climate, and relatively few studies examining change in tundra landscapes have spanned decadal time scales. The majority of our understanding of tundra vegetation responses to environmental change has been derived from studies along environmental gradients, experimental manipulations, and modeling. This study synthesizes the rescue and resampling of historic vegetation study sites established during the 1960's and 1970's at three arctic tundra locations (Baffin Island, Canada, Barrow, Alaska, and Atqasuk, Alaska), and one alpine tundra location (Niwot Ridge, Colorado). We conducted a meta-analysis to examine decadal changes in plant community composition, species richness, species evenness, and species diversity at all locations and for three broad soil moisture classes (dry, moist, wet). For all sites, except Baffin Island, change over the last decade was compared with long term change to determine if rates of change have altered over time. Change in plant community composition was most dramatic at Barrow and Baffin Island (P < 0.05), while less change was detected at Niwot Ridge (P < 0.10), and Atqasuk. Plant communities also changed for all soil moisture classes. The rate of change at Barrow and in moist soil classes appears to have quickened over the last decade. Rates of early plant successional change at Baffin Island appear to have quickened relative to rates documented in the mid 1960's. There were no changes in species richness at any of the locations, but there appears to be acceleration in the loss of species richness for dry and moist tundra. Species evenness increased at Atqasuk and in dry and wet tundra but decreased at Niwot Ridge in moist tundra. A loss in species diversity was detected in moist tundra in the decadal study, while diversity increased for dry and wet tundra. Baffin Island was the only location to show evidence of an increase in species diversity. This study appears to be among the first to document an acceleration of vegetation change in tundra landscapes using decadal time scale observational data, and highlights the importance of both sustained monitoring, and the rescue and resampling of historic sites, which have proven to be effective in advancing our knowledge of vegetation change dynamics. This project was a contribution to the International Polar Year Back to the Future project (IPY#512).

Change detection and change blindness in pigeons (Columba livia).

PubMed

Herbranson, Walter T; Trinh, Yvan T; Xi, Patricia M; Arand, Mark P; Barker, Michael S K; Pratt, Theodore H

2014-05-01

Change blindness is a phenomenon in which even obvious details in a visual scene change without being noticed. Although change blindness has been studied extensively in humans, we do not yet know if it is a phenomenon that also occurs in other animals. Thus, investigation of change blindness in a nonhuman species may prove to be valuable by beginning to provide some insight into its ultimate causes. Pigeons learned a change detection task in which pecks to the location of a change in a sequence of stimulus displays were reinforced. They were worse at detecting changes if the stimulus displays were separated by a brief interstimulus interval, during which the display was blank, and this primary result matches the general pattern seen in previous studies of change blindness in humans. A second experiment attempted to identify specific stimulus characteristics that most reliably produced a failure to detect changes. Change detection was more difficult when interstimulus intervals were longer and when the change was iterated fewer times. ©2014 APA, all rights reserved.

Dynamic Computation of Change Operations in Version Management of Business Process Models

NASA Astrophysics Data System (ADS)

Küster, Jochen Malte; Gerth, Christian; Engels, Gregor

Version management of business process models requires that changes can be resolved by applying change operations. In order to give a user maximal freedom concerning the application order of change operations, position parameters of change operations must be computed dynamically during change resolution. In such an approach, change operations with computed position parameters must be applicable on the model and dependencies and conflicts of change operations must be taken into account because otherwise invalid models can be constructed. In this paper, we study the concept of partially specified change operations where parameters are computed dynamically. We provide a formalization for partially specified change operations using graph transformation and provide a concept for their applicability. Based on this, we study potential dependencies and conflicts of change operations and show how these can be taken into account within change resolution. Using our approach, a user can resolve changes of business process models without being unnecessarily restricted to a certain order.

The effect of urodynamic testing on clinical diagnosis, treatment plan and outcomes in women undergoing stress urinary incontinence surgery.

PubMed

Sirls, Larry T; Richter, Holly E; Litman, Heather J; Kenton, Kimberly; Lemack, Gary E; Lukacz, Emily S; Kraus, Stephen R; Goldman, Howard B; Weidner, Alison; Rickey, Leslie; Norton, Peggy; Zyczynski, Halina M; Kusek, John W

2013-01-01

We evaluated the influence of preoperative urodynamic studies on diagnoses, global treatment plans and outcomes in women treated with surgery for uncomplicated stress predominant urinary incontinence. We performed a secondary analysis from a multicenter, randomized trial of the value of preoperative urodynamic studies. Physicians provided diagnoses before and after urodynamic studies and global treatment plans, defined as proceeding with surgery, surgery type, surgical modification and nonoperative therapy. Treatment plan changes and surgical outcomes between office evaluation and office evaluation plus urodynamic studies were compared by the McNemar test. Of 315 subjects randomized to urodynamic studies after office evaluation 294 had evaluable data. Urodynamic studies changed the office evaluation diagnoses in 167 women (56.8%), decreasing the diagnoses of overactive bladder-wet (41.6% to 25.2%, p <0.001), overactive bladder-dry (31.4% to 20.8%, p = 0.002) and intrinsic sphincter deficiency (19.4% to 12.6%, p = 0.003) but increasing the diagnosis of voiding dysfunction (2.2% to 11.9%, p <0.001). After urodynamic studies physicians canceled surgery in 4 of 294 women (1.4%), changed the incontinence procedure in 13 (4.4%) and planned to modify mid urethral sling tension (more or less obstructive) in 20 women (6.8%). Nonoperative treatment plans changed in 40 of 294 women (14%). Urodynamic study driven treatment plan changes were not associated with treatment success (OR 0.96, 95% CI 0.41, 2.25, p = 0.92) but they were associated with increased postoperative treatment for urge urinary incontinence (OR 3.23, 95% CI 1.46, 7.14, p = 0.004). Urodynamic studies significantly changed clinical diagnoses but infrequently changed the global treatment plan or influenced surgeon decision to cancel, change or modify surgical plans. Global treatment plan changes were associated with increased treatment for postoperative urgency urinary incontinence. Copyright © 2013 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Measuring Historical Coastal Change using GIS and the Change Polygon Approach

USGS Publications Warehouse

Smith, M.J.; Cromley, R.G.

2012-01-01

This study compares two automated approaches, the transect-from-baseline technique and a new change polygon method, for quantifying historical coastal change over time. The study shows that the transect-from-baseline technique is complicated by choice of a proper baseline as well as generating transects that intersect with each other rather than with the nearest shoreline. The change polygon method captures the full spatial difference between the positions of the two shorelines and average coastal change is the defined as the ratio of the net area divided by the shoreline length. Although then change polygon method is sensitive to the definition and measurement of shoreline length, the results are more invariant to parameter changes than the transect-from-baseline method, suggesting that the change polygon technique may be a more robust coastal change method. ?? 2012 Blackwell Publishing Ltd.

Simulation of regional temperature change effect of land cover change in agroforestry ecotone of Nenjiang River Basin in China

NASA Astrophysics Data System (ADS)

Liu, Tingxiang; Zhang, Shuwen; Yu, Lingxue; Bu, Kun; Yang, Jiuchun; Chang, Liping

2017-05-01

The Northeast China is one of typical regions experiencing intensive human activities within short time worldwide. Particularly, as the significant changes of agriculture land and forest, typical characteristics of pattern and process of agroforestry ecotone change formed in recent decades. The intensive land use change of agroforestry ecotone has made significant change for regional land cover, which had significant impact on the regional climate system elements and the interactions among them. This paper took agroforestry ecotone of Nenjiang River Basin in China as study region and simulated temperature change based on land cover change from 1950s to 1978 and from 1978 to 2010. The analysis of temperature difference sensitivity to land cover change based on Weather Research and Forecasting (WRF) model showed that the land cover change from 1950s to 1978 induced warming effect over all the study area, including the change of grassland to agriculture land, grassland to deciduous broad-leaved forest, and deciduous broad-leaved forest to shrub land. The land cover change from 1978 to 2010 induced cooling effect over all the study area, including the change of deciduous broad-leaved forest to agriculture land, grassland to agriculture land, shrub land to agriculture land, and deciduous broad-leaved forest to grassland. In addition, the warming and cooling effect of land cover change was more significant in the region scale than specific land cover change area.

Accounting for health in climate change policies: a case study of Fiji.

PubMed

Morrow, Georgina; Bowen, Kathryn

2014-01-01

Climate change is expected to affect the health of most populations in the coming decades, having the greatest impact on the poorest and most disadvantaged people in the world. The Pacific islands, including Fiji, are particularly vulnerable to the effects of climate change. The three major health impacts of climate change in Fiji explored in this study were dengue fever, diarrhoeal disease, and malnutrition, as they each pose a significant threat to human health. The aim of this study was to investigate to what extent the Fiji National Climate Change Policy, and a selection of relevant sectoral policies, account for these human health effects of climate change. The study employed a three-pronged policy analysis to evaluate: 1) the content of the Fijian National Climate Change Policy and to what extent health was incorporated within this; 2) the context within which the policy was developed; 3) the relevant processes; and 4) the actors involved. A selection of relevant sectoral policies were also analysed to assess the extent to which these included climate change and health considerations. The policy analysis showed that these three health impacts of climate change were only considered to a minor extent, and often indirectly, in both the Fiji National Climate Change Policy and the corresponding National Climate Change Adaptation Strategy, as well as the Public Health Act. Furthermore, supporting documents in relevant sectors including water and agriculture made no mention of climate change and health impacts. The projected health impacts of climate change should be considered as part of reviewing the Fiji National Climate Change Policy and National Climate Change Adaptation Strategy, and the Public Health Act. In the interest of public health, this should include strategies for combating dengue fever, malnutrition, and water-borne disease. Related sectoral policies in water and agriculture should also be revised to consider climate change and its impact on human health. Approaches to include health aspects of climate change within sectoral and climate change specific policies should be encouraged, via a number of mechanisms, such as the Health in All Policies approach. Future research could support the Fiji health sector in developing climate change and health programmes.

A wearable wound moisture sensor as an indicator for wound dressing change: an observational study of wound moisture and status.

PubMed

Milne, Stephen D; Seoudi, Ihab; Al Hamad, Hanadi; Talal, Talal K; Anoop, Anzila A; Allahverdi, Niloofar; Zakaria, Zain; Menzies, Robert; Connolly, Patricia

2016-12-01

Wound moisture is known to be a key parameter to ensure optimum healing conditions in wound care. This study tests the moisture content of wounds in normal practice in order to observe the moisture condition of the wound at the point of dressing change. This study is also the first large-scale observational study that investigates wound moisture status at dressing change. The WoundSense sensor is a commercially available moisture sensor which sits directly on the wound in order to find the moisture status of the wound without disturbing or removing the dressing. The results show that of the 588 dressing changes recorded, 44·9% were made when the moisture reading was in the optimum moisture zone. Of the 30 patients recruited for this study, 11 patients had an optimum moisture reading for at least 50% of the measurements before dressing change. These results suggest that a large number of unnecessary dressing changes are being made. This is a significant finding of the study as it suggests that the protocols currently followed can be modified to allow fewer dressing changes and less disturbance of the healing wound bed. © 2015 The Authors. International Wound Journal published by Medicalhelplines.com Inc and John Wiley & Sons Ltd.

Hydrological effects of cropland and climatic changes in arid and semi-arid river basins: A case study from the Yellow River basin, China

NASA Astrophysics Data System (ADS)

Li, Huazhen; Zhang, Qiang; Singh, Vijay P.; Shi, Peijun; Sun, Peng

2017-06-01

The Yellow River basin is a typical semi-arid river basin in northern China. Serious water shortages have negative impacts on regional socioeconomic development. Recent years have witnessed changes in streamflow processes due to increasing human activities, such as agricultural activities and construction of dams and water reservoirs, and climatic changes, e.g. precipitation and temperature. This study attempts to investigate factors potentially driving changes in different streamflow components defined by different quantiles. The data used were daily streamflow data for the 1959-2005 period from 5 hydrological stations, daily precipitation and temperature data from 77 meteorological stations and data pertaining to cropland and large reservoirs. Results indicate a general decrease in streamflow across the Yellow River basin. Moreover significant decreasing streamflow has been observed in the middle and lower Yellow River basin with change points during the mid-1980s till the mid-1990s. The changes of cropland affect the streamflow components and also the cumulative effects on streamflow variations. Recent years have witnessed moderate cropland variations which result in moderate streamflow changes. Further, precipitation also plays a critical role in changes of streamflow components and human activities, i.e. cropland changes, temperature changes and building of water reservoirs, tend to have increasing impacts on hydrological processes across the Yellow River basin. This study provides a theoretical framework for the study of the hydrological effects of human activities and climatic changes on basins over the globe.

Predicting hydrological response to forest changes by simple statistical models: the selection of the best indicator of forest changes with a hydrological perspective

NASA Astrophysics Data System (ADS)

Ning, D.; Zhang, M.; Ren, S.; Hou, Y.; Yu, L.; Meng, Z.

2017-01-01

Forest plays an important role in hydrological cycle, and forest changes will inevitably affect runoff across multiple spatial scales. The selection of a suitable indicator for forest changes is essential for predicting forest-related hydrological response. This study used the Meijiang River, one of the headwaters of the Poyang Lake as an example to identify the best indicator of forest changes for predicting forest change-induced hydrological responses. Correlation analysis was conducted first to detect the relationships between monthly runoff and its predictive variables including antecedent monthly precipitation and indicators for forest changes (forest coverage, vegetation indices including EVI, NDVI, and NDWI), and by use of the identified predictive variables that were most correlated with monthly runoff, multiple linear regression models were then developed. The model with best performance identified in this study included two independent variables -antecedent monthly precipitation and NDWI. It indicates that NDWI is the best indicator of forest change in hydrological prediction while forest coverage, the most commonly used indicator of forest change is insignificantly related to monthly runoff. This highlights the use of vegetation index such as NDWI to indicate forest changes in hydrological studies. This study will provide us with an efficient way to quantify the hydrological impact of large-scale forest changes in the Meijiang River watershed, which is crucial for downstream water resource management and ecological protection in the Poyang Lake basin.

Change in Psychotherapy: A Dialogical Analysis Single-Case Study of a Patient with Bulimia Nervosa

PubMed Central

Salvini, Alessandro; Faccio, Elena; Mininni, Giuseppe; Romaioli, Diego; Cipolletta, Sabrina; Castelnuovo, Gianluca

2012-01-01

Starting from the critical review of various motivational frameworks of change that have been applied to the study of eating disorders, the present paper provides an alternative conceptualization of the change in psychotherapy presenting a single-case study. We analyzed six psychotherapeutic conversations with a bulimic patient and found out narratives “for” and “against” change. We read them in terms of tension between dominance and exchange in I-positions, as described by Hermans. These results indicate that the dialogical analysis of clinical discourse may be a useful method to investigate change from the beginning to the end of therapy. PMID:23233845

Reconstructing Student Conceptions of Climate Change; An Inquiry Approach

NASA Astrophysics Data System (ADS)

McClelland, J. Collin

No other environmental issue today has as much potential to alter life on Earth as does global climate change. Scientific evidence continues to grow; indicating that climate change is occurring now, and that change is a result of human activities (National Research Council [NRC], 2010). The need for climate literacy in society has become increasingly urgent. Unfortunately, understanding the concepts necessary for climate literacy remains a challenge for most individuals. A growing research base has identified a number of common misconceptions people have about climate literacy concepts (Leiserowitz, Smith, & Marlon 2011; Shepardson, Niyogi, Choi, & Charusombat, 2009). However, few have explored this understanding in high school students. This sequential mixed methods study explored the changing conceptions of global climate change in 90 sophomore biology students through the course of their participation in an eight-week inquiry-based global climate change unit. The study also explored changes in students' attitudes over the course of the study unit, contemplating possible relationships between students' conceptual understanding of and attitudes toward global climate change. Phase I of the mixed methods study included quantitative analysis of pre-post content knowledge and attitude assessment data. Content knowledge gains were statistically significant and over 25% of students in the study shifted from an expressed belief of denial or uncertainty about global warming to one of belief in it. Phase II used an inductive approach to explore student attitudes and conceptions. Conceptually, very few students grew to a scientifically accurate understanding of the greenhouse effect or the relationship between global warming and climate change. However, they generally made progress in their conceptual understanding by adding more specific detail to explain their understanding. Phase III employed a case study approach with eight purposefully selected student cases, identifying five common conceptual and five common attitudebased themes. Findings suggest similar misconceptions revealed in prior research also occurred in this study group. Some examples include; connecting global warming to the hole in the ozone layer, and falsely linking unrelated environmental issues like littering to climate change. Data about students' conceptual understanding of energy may also have implications for education research curriculum development. Similar to Driver & While no statistical relationship between students' attitudes about global climate change and overall conceptual understanding emerged, some data suggested that climate change skeptics may perceive the concept of evidence differently than non-skeptics. One-way ANOVA data comparing skeptics with other students on evidence-based assessment items was significant. This study offers insights to teachers of potential barriers students face when trying to conceptualize global climate change concepts. More importantly it reinforces the idea that students generally find value in learning about global climate change in the classroom.

The Applicability of Standard Error of Measurement and Minimal Detectable Change to Motor Learning Research-A Behavioral Study.

PubMed

Furlan, Leonardo; Sterr, Annette

2018-01-01

Motor learning studies face the challenge of differentiating between real changes in performance and random measurement error. While the traditional p -value-based analyses of difference (e.g., t -tests, ANOVAs) provide information on the statistical significance of a reported change in performance scores, they do not inform as to the likely cause or origin of that change, that is, the contribution of both real modifications in performance and random measurement error to the reported change. One way of differentiating between real change and random measurement error is through the utilization of the statistics of standard error of measurement (SEM) and minimal detectable change (MDC). SEM is estimated from the standard deviation of a sample of scores at baseline and a test-retest reliability index of the measurement instrument or test employed. MDC, in turn, is estimated from SEM and a degree of confidence, usually 95%. The MDC value might be regarded as the minimum amount of change that needs to be observed for it to be considered a real change, or a change to which the contribution of real modifications in performance is likely to be greater than that of random measurement error. A computer-based motor task was designed to illustrate the applicability of SEM and MDC to motor learning research. Two studies were conducted with healthy participants. Study 1 assessed the test-retest reliability of the task and Study 2 consisted in a typical motor learning study, where participants practiced the task for five consecutive days. In Study 2, the data were analyzed with a traditional p -value-based analysis of difference (ANOVA) and also with SEM and MDC. The findings showed good test-retest reliability for the task and that the p -value-based analysis alone identified statistically significant improvements in performance over time even when the observed changes could in fact have been smaller than the MDC and thereby caused mostly by random measurement error, as opposed to by learning. We suggest therefore that motor learning studies could complement their p -value-based analyses of difference with statistics such as SEM and MDC in order to inform as to the likely cause or origin of any reported changes in performance.

Behavior problems and placement change in a national child welfare sample: a prospective study.

PubMed

Aarons, Gregory A; James, Sigrid; Monn, Amy R; Raghavan, Ramesh; Wells, Rebecca S; Leslie, Laurel K

2010-01-01

There is ongoing debate regarding the impact of youth behavior problems on placement change in child welfare compared to the impact of placement change on behavior problems. Existing studies provide support for both perspectives. The purpose of this study was to prospectively examine the relations of behavior problems and placement change in a nationally representative sample of youths in the National Survey of Child and Adolescent Well-Being. The sample consisted of 500 youths in the child welfare system with out-of-home placements over the course of the National Survey of Child and Adolescent Well-Being study. We used a prospective cross-lag design and path analysis to examine reciprocal effects of behavior problems and placement change, testing an overall model and models examining effects of age and gender. In the overall model, out of a total of eight path coefficients, behavior problems significantly predicted placement changes for three paths and placement change predicted behavior problems for one path. Internalizing and externalizing behavior problems at baseline predicted placement change between baseline and 18 months. Behavior problems at an older age and externalizing behavior at 18 months appear to confer an increased risk of placement change. Of note, among female subjects, placement changes later in the study predicted subsequent internalizing and externalizing behavior problems. In keeping with recommendations from a number of professional bodies, we suggest that initial and ongoing screening for internalizing and externalizing behavior problems be instituted as part of standard practice for youths entering or transitioning in the child welfare system.

Cognitive behavioral therapy changes functional connectivity between medial prefrontal and anterior cingulate cortices.

PubMed

Yoshimura, Shinpei; Okamoto, Yasumasa; Matsunaga, Miki; Onoda, Keiichi; Okada, Go; Kunisato, Yoshihiko; Yoshino, Atsuo; Ueda, Kazutaka; Suzuki, Shin-Ichi; Yamawaki, Shigeto

2017-01-15

Depression is characterized by negative self-cognition. Our previous study (Yoshimura et al. 2014) revealed changes in brain activity after cognitive behavioral therapy (CBT) for depression, but changes in functional connectivity were not assessed. This study included 29 depressive patients and 15 healthy control participants. Functional Magnetic Resonance Imaging was used to investigate possible CBT-related functional connectivity changes associated with negative emotional self-referential processing. Depressed and healthy participants (overlapping with our previous study, Yoshimura et al. 2014) were included. We defined a seed region (medial prefrontal cortex) and coupled region (ACC) based on our previous study, and we examined changes in MPFC-ACC functional connectivity from pretreatment to posttreatment. CBT was associated with reduced functional connectivity between the MPFC and ACC. Symptom change with CBT was positively correlated with change in MPFC-ACC functional connectivity. Patients received pharmacotherapy including antidepressant. The present sample size was quite small and more study is needed. Statistical threshold in fMRI analysis was relatively liberal. CBT for depression may disrupt MPFC-ACC connectivity, with associated improvements in depressive symptoms and dysfunctional cognition. Copyright © 2016 Elsevier B.V. All rights reserved.

Assessment of Reliable Change Using 95% Credible Intervals for the Differences in Proportions: A Statistical Analysis for Case-Study Methodology.

PubMed

Unicomb, Rachael; Colyvas, Kim; Harrison, Elisabeth; Hewat, Sally

2015-06-01

Case-study methodology studying change is often used in the field of speech-language pathology, but it can be criticized for not being statistically robust. Yet with the heterogeneous nature of many communication disorders, case studies allow clinicians and researchers to closely observe and report on change. Such information is valuable and can further inform large-scale experimental designs. In this research note, a statistical analysis for case-study data is outlined that employs a modification to the Reliable Change Index (Jacobson & Truax, 1991). The relationship between reliable change and clinical significance is discussed. Example data are used to guide the reader through the use and application of this analysis. A method of analysis is detailed that is suitable for assessing change in measures with binary categorical outcomes. The analysis is illustrated using data from one individual, measured before and after treatment for stuttering. The application of this approach to assess change in categorical, binary data has potential application in speech-language pathology. It enables clinicians and researchers to analyze results from case studies for their statistical and clinical significance. This new method addresses a gap in the research design literature, that is, the lack of analysis methods for noncontinuous data (such as counts, rates, proportions of events) that may be used in case-study designs.

Neural Correlates of Psychotherapy in Anxiety and Depression: A Meta-Analysis

PubMed Central

Messina, Irene; Sambin, Marco; Palmieri, Arianna; Viviani, Roberto

2013-01-01

Several studies have used neuroimaging methods to identify neural change in brain networks associated to emotion regulation after psychotherapy of depression and anxiety. In the present work we adopted a meta-analytic technique specific to neuroimaging data to evaluate the consistence of empirical findings and assess models of therapy that have been proposed in the literature. Meta-analyses were conducted with the Activation Likelihood Estimation technique, which evaluates the overlap between foci of activation across studies. The analysis included 16 studies found in Pubmed (200 foci of activation and 193 patients). Separate meta-analyses were conducted on studies of 1) depression, post-traumatic stress disorder and panic disorder investigated with rest state metabolism (6 studies, 70 patients); 2) depression, post-traumatic stress disorder and panic disorder investigated with task-related activation studies (5 studies, 65 patients); 3) the previous studies considered jointly; and 4) phobias investigated with studies on exposure-related activation (5 studies, 57 patients). Studies on anxiety and depression gave partially consistent results for changes in the dorsomedial prefrontal cortex and in the posterior cingulated gyrus/precuneus. Several areas of change in the temporal lobes were also observed. Studies on the therapy of phobia were consistent with a reduction of activity in medial temporal areas. The cluster of change in the prefrontal cortex may refer to increased recruitment of control processes, as hypothesized by influential models of emotion regulation changes due to psychotherapy. However, not all areas associated with controlled emotion regulation were detected in the meta-analysis, while involvement of midline structures suggested changes in self-related information processing. Changes in phobia were consistent with reduced reactivity to phobic stimuli. PMID:24040309

Physiological changes associated with routine nursing procedures in critically ill are common: an observational pilot study.

PubMed

Engström, J; Bruno, E; Reinius, H; Fröjd, C; Jonsson, H; Sannervik, J; Larsson, A

2017-01-01

Nursing procedures that are routinely performed in the intensive care unit (ICU) are assumed to have minimal side effects. However, these procedures may sometimes cause physiological changes that negatively affect the patient. We hypothesized that physiological changes associated with routine nursing procedures in the ICU are common. A clinical observational study of 16 critically ill patients in a nine-bed mixed university hospital ICU. All nursing procedures were observed, and physiological data were collected and subsequently analyzed. Minor physiological changes were defined as minimal changes in respiratory or circulatory variables, and major physiological changes were marked as hyper/hypotension, bradycardia/tachycardia, bradypnea/tachypnea, ventilatory distress, and peripheral blood oxygen desaturation. In the 16 patients, 668 procedures generated 158 major and 692 minor physiological changes during 187 observational hours. The most common procedure was patient position change, which also generated the majority of the physiological changes. The most common major physiological changes were blood oxygen desaturation, ventilatory distress, and hypotension, and the most common minor changes were arterial pressure alteration, coughing, and increase in respiratory rate. In this pilot study, we examined physiological changes in connection with all regular routine nursing procedures in the ICU. We found that physiological changes were common and sometimes severe. © 2016 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

'I don't get this climate stuff!' Making sense of climate change among the corporate middle class in Lagos.

PubMed

Asiyanbi, Adeniyi P

2015-11-01

Public engagement continues to be central to wider efforts to address climate change. This study contributes to public engagement debates by investigating engagement with climate change among an often overlooked group, the corporate middle class in Africa's second largest megacity, Lagos. Combining survey and interviews, I focus analysis on three aspects: awareness, knowledge and concern; role of scientific and social frames in shaping general attitude; and spatial attribution of causes and consequences. The study reveals a universal awareness and high concern about climate change among the respondents, although understanding and perceptions of climate change are significantly socially framed. Social situatedness, more than scientific facts, is the most important definer of overall engagement with climate change. This study thus underscores a nuanced constructionist stance, showing how corporate professionals' 'ways of knowing' climate change is underpinned by a certain co-production between scientific and socio-experiential frames. I highlight implications for research and public engagement with climate change. © The Author(s) 2015.

Detection and attribution of flood change across the United States

NASA Astrophysics Data System (ADS)

Archfield, Stacey

2017-04-01

In the United States, there have a been an increasing number of studies quantifying trends in the annual maximum flood; yet, few studies examine trends in floods that may occur more than once in a given year and even fewer assess trends in floods on rivers that have undergone substantial changes due to urbanization, land-cover change, and agricultural drainage practices. Previous research has shown that, for streamgages having minimal direct human intervention, trends in the peak magnitude, frequency, duration and volume of frequent floods (floods occurring at an average of two events per year relative to a base period) across the United States show large changes; however, few trends are found to be statistically significant. This study extends previous research to provide a comprehensive assessment of flood change across the United States that includes streamgages having experienced confounding alterations to streamflow (urbanization, storage, and land-cover changes) that provides a comprehensive assessment of flood change. Attribution of these changes is also explored.

Social and economic behavior shift in the suburban society

NASA Astrophysics Data System (ADS)

Harianto, S.; Imron, A.; Setiawan, K. G.; Sadewo, F. X. S.

2018-01-01

One of the changes in the suburban area is marked by changes in land conversion, from agriculture pattern to non-farming pattern, which also affects changes in people’s livelihoods and occupation such as a craftsman and shoe trader. Using a qualitative approach, this study focuses to examine how changes in social and economic behavior of suburban communities as a result of urban development. This study founded that there was a change of livelihood in village people occupation from farmers to craftsmen and slippers traders. These changes have an impact on changing patterns of social relationships such as social interaction, social awareness, and social solidarity. In addition, the increase in income of village residents also impact on lifestyle changes such as diet and entertainment. Thus it can be concluded that urban development has an impact on suburban societies in social relations and income generation. The results of this study can be used as a reference for the city government and district governments in arranging the layout and build prosperity of the community suburban.

Understanding general practice: a conceptual framework developed from case studies in the UK NHS

PubMed Central

Checkland, Kath

2007-01-01

Background General practice in the UK is undergoing a period of rapid and profound change. Traditionally, research into the effects of change on general practice has tended to regard GPs as individuals or as members of a professional group. To understand the impact of change, general practices should also be considered as organisations. Aim To use the organisational studies literature to build a conceptual framework of general practice organisations, and to test and develop this empirically using case studies of change in practice. This study used the implementation of National Service Frameworks (NSFs) and the new General Medical Services (GMS) contract as incidents of change. Design of study In-depth, qualitative case studies. The design was iterative: each case study was followed by a review of the theoretical ideas. The final conceptual framework was the result of the dynamic interplay between theory and empirical evidence. Setting Five general practices in England, selected using purposeful sampling. Method Semi-structured interviews with all clinical and managerial personnel in each practice, participant and non-participant observation, and examination of documents. Results A conceptual framework was developed that can be used to understand how and why practices respond to change. This framework enabled understanding of observed reactions to the introduction of NSFs and the new GMS contract. Important factors for generating responses to change included the story that the practice members told about their practice, beliefs about what counted as legitimate work, the role played by the manager, and previous experiences of change. Conclusion Viewing general practices as small organisations has generated insights into factors that influence responses to change. Change tends to occur from the bottom up and is determined by beliefs about organisational reality. The conceptual framework suggests some questions that can be asked of practices to explain this internal reality. PMID:17244426

Total, LDL, and HDL cholesterol decrease with age in older men and women. The Rancho Bernardo Study 1984-1994.

PubMed

Ferrara, A; Barrett-Connor, E; Shan, J

1997-07-01

The purpose of the present study was to study the effects of age, weight change, and covariates on lipid and lipoprotein levels cross-sectionally and prospectively in an elderly population. A community-based sample of 1041 men and 1303 women aged 50 to 93 years was studied cross-sectionally in 1984 to 1987, with follow-up of 372 men and 545 women 8 years later. In the cross-sectional study, levels of total cholesterol (TC) and LDL cholesterol (LDL-C) decreased and levels of HDL cholesterol (HDLC) increased with age in men (all P < .001) but not in women. In the prospective study, TC, LDL-C, and HDL-C levels all decreased in both men and women, in all age groups (50 to 64 years, 65 to 74 years, and > or = 75 years) and in all weight change groups (> 2.5-kg loss, change within 2.5 kg, and > 2.5-kg gain) and in all waist girth change groups, for an overall decrement of approximately 1% per year. In multiple linear regression models, change in weight was the most important independent and consistent predictor of changes in TC, LDL-C, and HDL-C. Similar results were obtained in analyses excluding subjects taking lipid-lowering drugs or estrogen and in analyses adjusted for changes in cigarette smoking, alcohol intake, physical activity, medication use, and incident myocardial infarction, cancer, or diabetes. Cross-sectional decrements in TC and LDL-C with age in men are not explained by survivor bias because they are also observed prospectively. Although weight change was the most important explanatory variable, TC, LDL-C, and HDL-C levels also decreased in those who lost or gained weight. Age was not an independent predictor of change. Other prospective studies are recommended to better define the causes and consequences of cholesterol and lipoprotein changes in old age.

The Role of Prediction In Perception: Evidence From Interrupted Visual Search

PubMed Central

Mereu, Stefania; Zacks, Jeffrey M.; Kurby, Christopher A.; Lleras, Alejandro

2014-01-01

Recent studies of rapid resumption—an observer’s ability to quickly resume a visual search after an interruption—suggest that predictions underlie visual perception. Previous studies showed that when the search display changes unpredictably after the interruption, rapid resumption disappears. This conclusion is at odds with our everyday experience, where the visual system seems to be quite efficient despite continuous changes of the visual scene; however, in the real world, changes can typically be anticipated based on previous knowledge. The present study aimed to evaluate whether changes to the visual display can be incorporated into the perceptual hypotheses, if observers are allowed to anticipate such changes. Results strongly suggest that an interrupted visual search can be rapidly resumed even when information in the display has changed after the interruption, so long as participants not only can anticipate them, but also are aware that such changes might occur. PMID:24820440

Shame and the motivation to change the self.

PubMed

Lickel, Brian; Kushlev, Kostadin; Savalei, Victoria; Matta, Shashi; Schmader, Toni

2014-12-01

A central question of human psychology is whether and when people change for the better. Although it has long been assumed that emotion plays a central role in self-regulation, the role of specific emotions in motivating a desire for self-change has been largely ignored. We report 2 studies examining people's lived experiences of self-conscious emotions, particularly shame, in motivating a desire for self-change. Study 1 revealed that when participants recalled experiences of shame, guilt, or embarrassment, shame-and, to some degree, guilt-predicted a motivation for self-change. Study 2 compared shame, guilt, and regret for events and found that although shame experiences often involved high levels of both regret and guilt, it was feelings of shame that uniquely predicted a desire for self-change, whereas regret predicted an interest in mentally undoing the past and repairing harm done. Implications for motivating behavior change are discussed.

Genetics of climate change adaptation.

PubMed

Franks, Steven J; Hoffmann, Ary A

2012-01-01

The rapid rate of current global climate change is having strong effects on many species and, at least in some cases, is driving evolution, particularly when changes in conditions alter patterns of selection. Climate change thus provides an opportunity for the study of the genetic basis of adaptation. Such studies include a variety of observational and experimental approaches, such as sampling across clines, artificial evolution experiments, and resurrection studies. These approaches can be combined with a number of techniques in genetics and genomics, including association and mapping analyses, genome scans, and transcription profiling. Recent research has revealed a number of candidate genes potentially involved in climate change adaptation and has also illustrated that genetic regulatory networks and epigenetic effects may be particularly relevant for evolution driven by climate change. Although genetic and genomic data are rapidly accumulating, we still have much to learn about the genetic architecture of climate change adaptation.

Trends and driving mechanism of land-use change in metropolitan areas of Pearl River Delta

NASA Astrophysics Data System (ADS)

Chen, Feng-gui; Zhang, Hong-ou; Wang, Juan; Wu, Qi-tao

2008-10-01

Taking Pearl River Delta for an example this study focuses on the trends and the driving mechanism of land-use changes in metropolises, in order to achieve the fundamental objectives of LUCC study increasing the awareness on dynamics of global land-use and land-cover changes, and improving the ability of forecasting LUCC. By analyzing the land-use change in Pearl River Delta from 1996 to 2006, it is found that the differences among internal space are notable. By establishing time-sequence-curve with SPSS software, it is shown that trends of land-use change are very clear. With factor analysis on land-use change, the study summarizes four factors of driving mechanism, including factors of economic development level, regional industrial structure, demographic and agricultural structure adjustment, which impact land change in Pearl River Delta to a different extent.

Farmers' perceptions of and adaptation strategies to climate change and their determinants: the case of Punjab province, Pakistan

NASA Astrophysics Data System (ADS)

Abid, M.; Scheffran, J.; Schneider, U. A.; Ashfaq, M.

2015-05-01

Climate change is a global environmental threat to all economic sectors, particularly the agricultural sector. Pakistan is one of the countries negatively affected by climate change due to its high exposure to extreme events and low adaptive capacity. In Pakistan, farmers are the primary stakeholders in agriculture and are more at risk due to climate vulnerability. Based on farm household data from 450 households collected from three districts in three agroecological zones in the Punjab province of Pakistan, this study examines how farmers perceive climate change and how they adapt their farming in response to perceived changes in climate. The results demonstrate that awareness of climate change is widespread throughout the area, and farm households make adjustments to adapt their agriculture in response to climatic change. Overall 58% of the farm households adapted their farming to climate change. Changing crop varieties, changing planting dates, planting of shade trees and changing fertilizers were the main adaptation methods implemented by farm households in the study area. The results from the binary logistic model reveal that education, farm experience, household size, land area, tenancy status, ownership of a tube well, access to market information, information on weather forecasting and agricultural extension services all influence farmers' choices of adaptation measures. The results also indicate that adaptation to climate change is constrained by several factors such as lack of information, lack of money, resource constraints and shortage of irrigation water in the study area. Findings of the study suggest the need for greater investment in farmer education and improved institutional setup for climate change adaptation to improve farmers' wellbeing.

Improvements in stage of change correlate to changes in dietary intake and clinical outcomes in a 5-year lifestyle intervention in young high-risk Sri Lankans.

PubMed

Guess, N; Vasantharajah, L; Gulliford, M; Viberti, G; Gnudi, L; Karalliedde, J; Wijesuriya, M

2016-09-01

The objectives of a stage-matched approach to lifestyle change are that individuals progress forward through the stages of change. It also posits that progression through the stages of change is associated with positive changes in lifestyle behaviours. Measuring the relationship between stage of change and food intake is challenging due to the plurality of dietary behaviours. Furthermore, it is not clear whether changes in behaviour are sustained long-term. In this study we assess the movement through stages of change in the intensive (visits every 3months) and control groups (visits annually) of a large-scale primary prevention study in cardiovascular disease, carried out in 2637 children and young adults in Sri Lanka between 2007 and 2012. We also examine their relationship to dietary behaviours and clinical outcomes. We demonstrate that individuals in both groups continue to progress through stages of change over the course of the study and that measures of dietary behaviours improved from baseline to final follow-up. We also demonstrate that stage of change positively correlates to dietary behaviours including the ratio of recommended:not-recommended items, unpolished:polished starches and low-fat:high-fat food items throughout each year of the study. Finally, participants in the later stages of change at Y2, Y3 and Y4, had a significantly attenuated increase in weight and waist circumference at the final visit in both groups. We therefore demonstrate the usefulness of stage-matched approach in modifying complex dietary behaviours, and that stage of change is a valid measure of dietary behaviours across a large population over time. Copyright © 2016 Elsevier Inc. All rights reserved.

The A-Framework: The Role of Access, Attributes, and Affordance in the Adoption of Distance Education Technology for Lifestyle Change

ERIC Educational Resources Information Center

Tierney, Patrick J.; Moisey, Susan

2014-01-01

This exploratory mixed methods case study examined the use of distance education technology for lifestyle change within the context of obesity treatment and weight management. In the quantitative phase of the study, 19 adults involved in an obesity-related lifestyle change program or change process completed a questionnaire that determined their…

Prediction of climate change impacts on agricultural watersheds and the performance of winter cover crops: Case study of the upper region of the Choptank River Watershed

USDA-ARS?s Scientific Manuscript database

Elevated CO2 concentration, temperature, and precipitation intensity driven by climate change are expected to cause significant environmental changes in the Chesapeake Bay Watershed (CBW). Although the potential effects of climate change are widely reported, few studies have been conducted to unders...

Do Labels Matter When Implementing Change? Implications of Labelling an Academic as a Champion--Results from a Case Study

ERIC Educational Resources Information Center

Cordiner, Moira; Thomas, Sharon; Green, Wendy

2018-01-01

Organisational change literature is littered with labels for those who instigate, support, resist, or implement change. Absent is research into the perspectives of those who are given these labels. This paper reports findings from a literature search, journal scan and a case study of an Australian university where change agents were labelled…

How will climate change affect wildland fire severity in the western US?

Treesearch

Sean A. Parks; Carol Miller; John T. Abatzoglou; Lisa M. Holsinger; Marc-Andre Parisien; Solomon Z. Dobrowski

2016-01-01

Fire regime characteristics in North America are expected to change over the next several decades as a result of anthropogenic climate change. Although some fire regime characteristics (e.g., area burned and fire season length) are relatively well-studied in the context of a changing climate, fire severity has received less attention. In this study, we used...

Lies, Damn Lies, and Statistics Revisited: A Comparison of Three Methods of Representing Change. AIR 1991 Annual Forum Paper.

ERIC Educational Resources Information Center

Pike, Gary R.

Because change is fundamental to education and the measurement of change assesses the quality and effectiveness of postsecondary education, this study examined three methods of measuring change: (1) gain scores; (2) residual scores; and (3) repeated measures. Data for the study was obtained from transcripts of 722 graduating seniors at the…

Multidirectional abundance shifts among North American birds and the relative influence of multifaceted climate factors.

PubMed

Huang, Qiongyu; Sauer, John R; Dubayah, Ralph O

2017-09-01

Shifts in species distributions are major fingerprint of climate change. Examining changes in species abundance structures at a continental scale enables robust evaluation of climate change influences, but few studies have conducted these evaluations due to limited data and methodological constraints. In this study, we estimate temporal changes in abundance from North American Breeding Bird Survey data at the scale of physiographic strata to examine the relative influence of different components of climatic factors and evaluate the hypothesis that shifting species distributions are multidirectional in resident bird species in North America. We quantify the direction and velocity of the abundance shifts of 57 permanent resident birds over 44 years using a centroid analysis. For species with significant abundance shifts in the centroid analysis, we conduct a more intensive correlative analysis to identify climate components most strongly associated with composite change of abundance within strata. Our analysis focus on two contrasts: the relative importance of climate extremes vs. averages, and of temperature vs. precipitation in strength of association with abundance change. Our study shows that 36 species had significant abundance shifts over the study period. The average velocity of the centroid is 5.89 km·yr -1 . The shifted distance on average covers 259 km, 9% of range extent. Our results strongly suggest that the climate change fingerprint in studied avian distributions is multidirectional. Among 6 directions with significant abundance shifts, the northwestward shift was observed in the largest number of species (n = 13). The temperature/average climate model consistently has greater predictive ability than the precipitation/extreme climate model in explaining strata-level abundance change. Our study shows heterogeneous avian responses to recent environmental changes. It highlights needs for more species-specific approaches to examine contributing factors to recent distributional changes and for comprehensive conservation planning for climate change adaptation. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

Policy Discourses and Changing Practice: Diversity and the University-College

ERIC Educational Resources Information Center

Chan, Adrienne S.

2005-01-01

This study reports the results of research with respect to policy and diversity, as part of a larger case study of a Canadian university-college. The study details an examination of policy discourses as a vehicle for institutional change and provides insights into the everyday experiences of educators, their perspectives on policy and change, and…

Modeling changes in rill erodibility and critical shear stress on native surface roads

Treesearch

Randy B. Foltz; Hakjun Rhee; William J. Elliot

2008-01-01

This study investigated the effect of cumulative overland flow on rill erodibility and critical shear stress on native surface roads in central Idaho. Rill erodibility decreased exponentially with increasing cumulative overland flow depth; however, critical shear stress did not change. The study demonstrated that road erodibility on the studied road changes over the...

Social Change and New Profiles of Educational Personnel. National Studies--India, Nepal, Philippines, Republic of Korea.

ERIC Educational Resources Information Center

United Nations Educational, Scientific, and Cultural Organization, Bangkok (Thailand). Regional Office for Education in Asia and the Pacific.

Papers from India, Nepal, the Philippines, and the Republic of Korea, from a seminar (Bangkok, 1980) on new personnel profiles in relation to changes in society and educational systems, present studies dealing with national mechanisms for preparing and updating profiles of educational personnel. The Indian study indicates that: changes in…

Variability in Fundamental Frequency during Speech in Prodromal and Incipient Parkinson's Disease: A Longitudinal Case Study

ERIC Educational Resources Information Center

Harel, Brian; Cannizzaro, Michael; Snyder, Peter J.

2004-01-01

Nearly two centuries ago, Parkinson (1817) first observed that a particular pattern of speech changes occur in patients with idiopathic Parkinson's disease (PD). Numerous studies have documented these changes using a wide variety of acoustic measures, and yet few studies have attempted to quantify any such changes longitudinally, through the early…

Effect of Technology Enhanced Conceptual Change Texts on Students' Understanding of Buoyant Force

ERIC Educational Resources Information Center

Ozkan, Gulbin; Selcuk, Gamze Sezgin

2015-01-01

In this study, the effect of technology enhanced conceptual change texts on elementary school students' understanding of buoyant force was investigated. The conceptual change texts (written forms) used in this study are proven for effectiveness and are enriched by using technology support in this study. These texts were tried out on two groups. A…

A Video Recall Study of In-session Changes in Sentiment Override.

PubMed

Johnson, Lee N; Tambling, Rachel B; Anderson, Shayne R

2015-09-01

This study examines in-session changes in sentiment override over the first three sessions of couple therapy. Couples viewed a video recording of therapy sessions immediately after each of the first three sessions and continuously rated their level of sentiment override. Ninety-eight changes were randomly chosen for analysis. Three talk turns prior to each change was coded using the Family Relational Communication Control Coding System. Results show that changes in sentiment override occur frequently. Repeated incidents of communication control were related to negative change in sentiment override for females. Repeated incidents of being left out of the conversation were related to negative changes in sentiment override for females and positive changes for males. © 2014 Family Process Institute.

Changing Me, Changing Us: Relationship Quality and Collective Efficacy as Major Outcomes in Systemic Couple Therapy.

PubMed

Aguilar-Raab, Corina; Grevenstein, Dennis; Gotthardt, Linda; Jarczok, Marc N; Hunger, Christina; Ditzen, Beate; Schweitzer, Jochen

2018-06-01

We examine the sensitivity to change in the Evaluation of Social Systems (EVOS) scale, which assesses relationship quality and collective efficacy. In Study 1 we conducted a waitlist-control, short-term couple therapy RCT study (N = 43 couples) with five systemic therapy sessions treating communication and partnership problems; our intent was to provide high external validity. Construct validity of EVOS was assessed by comparison with additionally applied scales (Family Scales; Outcome Questionnaire, OQ-45.2). In Study 2, N = 332 individuals completed an experiment with high internal validity in order to verify sensitivity to change in three different social contexts. Results from Study 1 revealed a significant increase in relationship quality in the treatment group directly after treatment, as compared to the control group. Sensitivity to change was slightly better for EVOS than for other measures. While this positive change could not be fully sustained between posttreatment and a 4-week follow-up, EVOS score did not fall below baseline and pretreatment levels, supporting moderate-to-large sensitivity to change. Study 2 supported high sensitivity to change in EVOS for couple relations, family relations, and work-team relationships. Therefore, EVOS can be used as an outcome measure to monitor the process of systemic interventions focusing on relationship quality and collective efficacy. Due to its sensitivity to change, EVOS can provide evidence for treatment success with regard to relationship aspects. © 2017 Family Process Institute.

Study of Pattern of Change in Handwriting Class Characters with Different Grades of Myopia

PubMed Central

Hedge, Shruti Prabhat; Sriram

2015-01-01

Introduction Handwriting is a visuo-motor skill highly dependent on visual skills. Any defect in the visual inputs could affect a change in the handwriting. Understanding the variation in handwriting characters caused by visual acuity change can help in identifying learning disabilities in children and also assess the disability in elderly. In our study we try to analyse and catalogue these changes in the handwriting of a person. Materials and Methods The study was conducted among 100 subjects having normal visual acuity. They were asked to perform a set of writing tasks, after which the same tasks were repeated after inducing different grades of myopia. Changes in the handwriting class characters were analysed and compared in all grades of myopia. Results In the study it was found that the letter size, pastiosity, word omissions, inability to stay on line all increase with changes in visual acuity. However these finding are not proportional to the grade of myopia. Conclusion From the findings of the study it can be concluded that myopia significantly influences the handwriting and any change in visual acuity would induce corresponding changes in handwriting. There is increase in letter size, pastiosity where as the ability to stay on line and space between the lines decrease in different grades of myopia. The changes are not linear and cannot be used to predict the grade of myopia but can be used as parameters suggestive of refractive error. PMID:26816917

Linking pulses of atmospheric deposition to DOC release in an upland peat-covered catchment

NASA Astrophysics Data System (ADS)

Worrall, F.; Burt, T. P.; Adamson, J. K.

2008-12-01

Changes in atmospheric deposition have been proposed as one possible explanation of the widespread increase in DOC concentration observed in many Northern Hemisphere catchments. This study uses detailed, long-term, monthly monitoring records of pH, conductivity SO4, and DOC in precipitation, soil water, and runoff chemistry from an upland peat-covered catchment in northern England. By deriving impulse transfer functions this study explores whether changes in deposition lead to significant changes in the occurrence of each component in the soil and runoff water; especially significant changes in DOC. The study shows that (1) impulses in the deposition of acidity have no significant effect upon pH or DOC in soil water or runoff. (2) DOC in soil water and runoff is responsive to impulses in SO4 and conductivity, but only when those impulses are changes in soil water chemistry and not when they are in atmospheric deposition. (3) The effects of changes in SO4 and/or conductivity can easily be overemphasized if memory effects are not accounted for, and their effect is limited to only 1 or 2 months after a severe drought. This study can support the view that changes in ionic strength can result in changes in DOC concentration in soil water or runoff, but the system studied is unresponsive to changes in atmospheric deposition. Impulses in soil water SO4 do not lead to increases in DOC concentrations, and so this mechanism does not provide an explanation for DOC increases.

Herbarium specimens, photographs, and field observations show Philadelphia area plants are responding to climate change.

PubMed

Panchen, Zoe A; Primack, Richard B; Anisko, Tomasz; Lyons, Robert E

2012-04-01

The global climate is changing rapidly and is expected to continue changing in coming decades. Studying changes in plant flowering times during a historical period of warming temperatures gives us a way to examine the impacts of climate change and allows us to predict further changes in coming decades. The Greater Philadelphia region has a long and rich history of botanical study and documentation, with abundant herbarium specimens, field observations, and botanical photographs from the mid-1800s onward. These extensive records also provide an opportunity to validate methodologies employed by other climate change researchers at a different biogeographical area and with a different group of species. Data for 2539 flowering records from 1840 to 2010 were assessed to examine changes in flowering response over time and in relation to monthly minimum temperatures of 28 Piedmont species native to the Greater Philadelphia region. Regression analysis of the date of flowering with year or with temperature showed that, on average, the Greater Philadelphia species studied are flowering 16 d earlier over the 170-yr period and 2.7 d earlier per 1°C rise in monthly minimum temperature. Of the species studied, woody plants with short flowering duration are the best indicators of a warming climate. For monthly minimum temperatures, temperatures 1 or 2 mo prior to flowering are most significantly correlated with flowering time. Studies combining herbarium specimens, photographs, and field observations are an effective method for detecting the effects of climate change on flowering times.

The effectiveness of mobile-health behaviour change interventions for cardiovascular disease self-management: A systematic review.

PubMed

Pfaeffli Dale, Leila; Dobson, Rosie; Whittaker, Robyn; Maddison, Ralph

2016-05-01

Mobile wireless devices (mHealth) have been used to deliver cardiovascular disease self-management interventions to educate and support patients in making healthy lifestyle changes. This systematic review aimed to determine the effectiveness of mHealth interventions on behavioural lifestyle changes and medication adherence for cardiovascular disease self-management. A comprehensive literature search was conducted from inception through to 3 March 2015 using MEDLINE, PubMed, PsycINFO, EMBASE and The Cochrane Library. Eligible studies used an experimental trial design to determine the effectiveness of an mHealth intervention to change lifestyle behaviours in any cardiovascular disease population. Data extracted included intervention and comparison group characteristics with a specific focus on the use of behaviour change techniques. Seven studies met our inclusion criteria and were included in the qualitative synthesis. All interventions were delivered in part by mobile phone text messaging. Three studies were effective at improving adherence to medication and two studies increased physical activity behaviour. No effects were observed on dietary behaviour or smoking cessation, measured in one study each. Simple text messaging interventions appeared to be most effective; however, no clear relationships were found between study findings and intervention dose, duration or behaviour change techniques targeted. Our review found mHealth has the potential to change lifestyle behaviour. Results are still limited to a small number of trials, inconsistent outcome measures and ineffective reporting of intervention characteristics. Large scale, longitudinal studies are now warranted to gain a clear understanding of the effects of mHealth on behaviour change in the cardiovascular disease population. © The European Society of Cardiology 2015.

Technology-Rich Learning Environments in Elementary and Secondary Schools: An Interactive Study of Physical Settings and Educational Change.

ERIC Educational Resources Information Center

Stuebing, Susan; And Others

This paper reviews an ongoing study on the physical settings of education with technology at the elementary and high school levels. The study, which is multi-disciplinary in nature, is based in sites in the process of change in teaching strategies, using learning technology as a catalyst for this change to take place. The focus of the study is on…

What Did the New Social Studies Program Change in Upper Primary Level Social Studies Education in Turkish Schools? An Assessment from Teachers' Perspectives

ERIC Educational Resources Information Center

Incekara, Suleyman

2010-01-01

The Turkish education system has undergone radical changes since 2004 in all educational curricula, including social studies at the primary and secondary levels. Today, almost six years after its inception, an assessment is needed as to whether the reforms of 2004 affected beneficial changes in the social studies program. If not, it is important…

Personality Types in Adolescence: Change and Stability and Links with Adjustment and Relationships--A Five-Wave Longitudinal Study

ERIC Educational Resources Information Center

Meeus, Wim; Van de Schoot, Rens; Klimstra, Theo; Branje, Susan

2011-01-01

We examined change and stability of the 3 personality types identified by Block and Block (1980) and studied their links with adjustment and relationships. We used data from a 5-wave study of 923 early-to-middle and 390 middle-to-late adolescents, thereby covering the ages of 12-20 years. In Study 1, systematic evidence for personality change was…

The Relationship between Intimacy Change and Passion: A Dyadic Diary Study

PubMed Central

Aykutoğlu, Bülent; Uysal, Ahmet

2017-01-01

In the current study we investigated the association between intimacy and passion by testing whether increases in intimacy generates passion (Baumeister and Bratslavsky, 1999). Furthermore, we examined whether there are partner effects in intimacy change and passion link. Couples (N = 75) participated in a 14-day long diary study. Dyadic multilevel analyses with residualized intimacy change scores showed that both actors’ and partners’ intimacy change positively predicted actor’s passion. However, analyses also showed that residualized passion change scores positively predicted intimacy. Although these findings provide some empirical evidence for the intimacy change model, in line with the previous research (Rubin and Campbell, 2012), they also suggest that it is not possible to discern whether intimacy increment generates passion or passion increment generates intimacy. PMID:29312093

Identifying stakeholder-relevant climate change impacts: a case study in the Yakima River Basin, Washington, USA

USGS Publications Warehouse

Jenni, K.; Graves, D.; Hardiman, Jill M.; Hatten, James R.; Mastin, Mark C.; Mesa, Matthew G.; Montag, J.; Nieman, Timothy; Voss, Frank D.; Maule, Alec G.

2014-01-01

Designing climate-related research so that study results will be useful to natural resource managers is a unique challenge. While decision makers increasingly recognize the need to consider climate change in their resource management plans, and climate scientists recognize the importance of providing locally-relevant climate data and projections, there often remains a gap between management needs and the information that is available or is being collected. We used decision analysis concepts to bring decision-maker and stakeholder perspectives into the applied research planning process. In 2009 we initiated a series of studies on the impacts of climate change in the Yakima River Basin (YRB) with a four-day stakeholder workshop, bringing together managers, stakeholders, and scientists to develop an integrated conceptual model of climate change and climate change impacts in the YRB. The conceptual model development highlighted areas of uncertainty that limit the understanding of the potential impacts of climate change and decision alternatives by those who will be most directly affected by those changes, and pointed to areas where additional study and engagement of stakeholders would be beneficial. The workshop and resulting conceptual model highlighted the importance of numerous different outcomes to stakeholders in the basin, including social and economic outcomes that go beyond the physical and biological outcomes typically reported in climate impacts studies. Subsequent studies addressed several of those areas of uncertainty, including changes in water temperatures, habitat quality, and bioenergetics of salmonid populations.

Climate change, tropospheric ozone and particulate matter, and health impacts.

PubMed

Ebi, Kristie L; McGregor, Glenn

2008-11-01

Because the state of the atmosphere determines the development, transport, dispersion, and deposition of air pollutants, there is concern that climate change could affect morbidity and mortality associated with elevated concentrations of these gases and fine particles. We review how climate change could affect future concentrations of tropospheric ozone and particulate matter (PM), and what changing concentrations could mean for population health. We review studies projecting the impacts of climate change on air quality and studies projecting the impacts of these changes on morbidity and mortality. Climate change could affect local to regional air quality through changes in chemical reaction rates, boundary layer heights that affect vertical mixing of pollutants, and changes in synoptic airflow patterns that govern pollutant transport. Sources of uncertainty include the degree of future climate change, future emissions of air pollutants and their precursors, and how population vulnerability may change in the future. Given these uncertainties, projections suggest that climate change will increase concentrations of tropospheric ozone, at least in high-income countries when precursor emissions are held constant, which would increase morbidity and mortality. Few projections are available for low- and middle-income countries. The evidence is less robust for PM, primarily because few studies have been conducted. Additional research is needed to better understand the possible impacts of climate change on air pollution-related health impacts. If improved models continue to project higher ozone concentrations with climate change, then reducing greenhouse gas emissions would enhance the health of current and future generations.

Implementing Strategic Change: A Practical Guide for Business.

ERIC Educational Resources Information Center

Grundy, Tony

This book is designed to serve as a practical guide to planning and managing change within a business, and as a text for graduate business students studying change strategies. It focuses on the rationale for change, managing the change process, tools for change, creating a strategic vision for change, and checklists for implementing strategic…

Higher Education Change and Its Managers: Alternative Constructions

ERIC Educational Resources Information Center

Hotho, Sabine

2013-01-01

This article is based on a case study conducted in the context of UK higher education change. The article argues that "change" is a construct created in discourses of change policy and change management, and resulting in reductivist change management discourses which may impede rather than facilitate effective change management in the…

Analysis of air pollution mortality in terms of life expectancy changes: relation between time series, intervention, and cohort studies.

PubMed

Rabl, Ari

2006-02-01

Information on life expectancy change is of great concern for policy makers, as evidenced by the discussions of the so-called "harvesting" issue (i.e. the question being, how large a loss each death corresponds to in the mortality results of time series studies). Whereas most epidemiological studies of air pollution mortality have been formulated in terms of mortality risk, this paper shows that a formulation in terms of life expectancy change is mathematically equivalent, but offers several advantages: it automatically takes into account the constraint that everybody dies exactly once, regardless of pollution; it provides a unified framework for time series, intervention studies and cohort studies; and in time series and intervention studies, it yields the life expectancy change directly as a time integral of the observed mortality rate. Results are presented for life expectancy change in time series studies. Determination of the corresponding total number of attributable deaths (as opposed to the number of observed deaths) is shown to be problematic. The time variation of mortality after a change in exposure is shown to depend on the processes by which the body can repair air pollution damage, in particular on their time constants. Hypothetical results are presented for repair models that are plausible in view of the available intervention studies of air pollution and of smoking cessation. If these repair models can also be assumed for acute effects, the results of cohort studies are compatible with those of time series. The proposed life expectancy framework provides information on the life expectancy change in time series studies, and it clarifies the relation between the results of time series, intervention, and cohort studies.

Management of change for nurses: lessons from the discipline of organizational studies.

PubMed

Shanley, Chris

2007-07-01

This paper explores the literature on change management from the discipline of organizational studies to provide insights that nurse managers can use in their professional practice. The paper will benefit nurse managers by extending the nursing discourse on change management to include wider theoretical and academic perspectives. Important aspects of change management explored are the roles of power and political behaviour, how much change can be planned and controlled, how to combine top-down and bottom-up approaches to change, the role of emotions in the change management process, a comparison of prescriptive and analytical approaches to understanding change, and the connection between theory and practice in managing change. While nurses can draw much useful information from within the nursing discipline, they can also benefit by exploring other disciplinary areas. In the case of change management, there are many useful lessons nurses can carry over into their professional practice.

Climate change and mammals: evolutionary versus plastic responses.

PubMed

Boutin, Stan; Lane, Jeffrey E

2014-01-01

Phenotypic plasticity and microevolution are the two primary means by which organisms respond adaptively to local conditions. While these mechanisms are not mutually exclusive, their relative magnitudes will influence both the rate of, and ability to sustain, phenotypic responses to climate change. We review accounts of recent phenotypic changes in wild mammal populations with the purpose of critically evaluating the following: (i) whether climate change has been identified as the causal mechanism producing the observed change; (ii) whether the change is adaptive; and (iii) the relative influences of evolution and/or phenotypic plasticity underlying the change. The available data for mammals are scant. We found twelve studies that report changes in phenology, body weight or litter size. In all cases, the observed response was primarily due to plasticity. Only one study (of advancing parturition dates in American red squirrels) provided convincing evidence of contemporary evolution. Subsequently, however, climate change has been shown to not be the causal mechanism underlying this shift. We also summarize studies that have shown evolutionary potential (i.e. the trait is heritable and/or under selection) in traits with putative associations with climate change and discuss future directions that need to be undertaken before a conclusive demonstration of plastic or evolutionary responses to climate change in wild mammals can be made.

Stakeholder Participation in System Change: A New Conceptual Model.

PubMed

O'Rourke, Tammy; Higuchi, Kathryn S; Hogg, William

2016-08-01

A recent change in Canada's primary care system led to the introduction of Nurse Practitioner-Led clinics. The literature suggests that stakeholders can influence system change initiatives. However, very little is known about healthcare stakeholder motivations, particularly stakeholders who are seen as resistors to change. To examine stakeholder participation in the system change process that led to the introduction of the first Nurse Practitioner-Led clinic in Ontario. This single case study included two site visits, semistructured individual tape-recorded interviews, and the examination of relevant public documents. Qualitative content analysis was used to analyze the data. Sixteen individuals from different healthcare sectors and professions participated in the interviews and 20 documents were reviewed. Six key themes emerged from the data. Linking Evidence to Action The findings from the study present a new perspective on stakeholder participation that includes both those who supported the proposed change and those who advocated for a different change. The findings identify stakeholder activities used to shape, share, and protect their visions for system change. The conceptual model presented in this study adds to the understanding of challenges and complexities involved in healthcare system change. Understanding why and how stakeholders participate in change can help healthcare leaders in planning activities to enhance stakeholder involvement in healthcare system change. © 2016 Sigma Theta Tau International.

Climate change and mammals: evolutionary versus plastic responses

PubMed Central

Boutin, Stan; Lane, Jeffrey E

2014-01-01

Phenotypic plasticity and microevolution are the two primary means by which organisms respond adaptively to local conditions. While these mechanisms are not mutually exclusive, their relative magnitudes will influence both the rate of, and ability to sustain, phenotypic responses to climate change. We review accounts of recent phenotypic changes in wild mammal populations with the purpose of critically evaluating the following: (i) whether climate change has been identified as the causal mechanism producing the observed change; (ii) whether the change is adaptive; and (iii) the relative influences of evolution and/or phenotypic plasticity underlying the change. The available data for mammals are scant. We found twelve studies that report changes in phenology, body weight or litter size. In all cases, the observed response was primarily due to plasticity. Only one study (of advancing parturition dates in American red squirrels) provided convincing evidence of contemporary evolution. Subsequently, however, climate change has been shown to not be the causal mechanism underlying this shift. We also summarize studies that have shown evolutionary potential (i.e. the trait is heritable and/or under selection) in traits with putative associations with climate change and discuss future directions that need to be undertaken before a conclusive demonstration of plastic or evolutionary responses to climate change in wild mammals can be made. PMID:24454546

How well does climate change and human health research match the demands of policymakers? A scoping review.

PubMed

Hosking, Jamie; Campbell-Lendrum, Diarmid

2012-08-01

In 2008, the World Health Organization (WHO) Member States passed a World Health Assembly resolution that identified the following five priority areas for research and pilot projects on climate change and human health: health vulnerability, health protection, health impacts of mitigation and adaptation policies, decision-support and other tools, and costs of health protection from climate change. To assess the extent to which recently published research corresponds to these priorities, we undertook a scoping review of original research on climate change and human health. Scoping reviews address topics that are too broad for a systematic review and commonly aim to identify research gaps in existing literature. We also assessed recent publication trends for climate change and health research. We searched for original quantitative research published from 2008 onward. We included disease burden studies that were specific to climate change and health and included intervention studies that focused on climate change and measured health outcomes. We used MEDLINE, Embase, and Web of Science databases and extracted data on research priority areas, geographic regions, health fields, and equity (systematic differences between advantaged and disadvantaged social groups). We identified 40 eligible studies. Compared with other health topics, the number of climate change publications has grown rapidly, with a larger proportion of reviews or editorials. Recent original research addressed four of the five priority areas identified by the WHO Member States, but we found no eligible studies of health adaptation interventions, and most of the studies focused on high-income countries. Climate change and health is a rapidly growing area of research, but quantitative studies remain rare. Among recently published studies, we found gaps in adaptation research and a deficit of studies in most developing regions. Funders and researchers should monitor and respond to research gaps to help ensure that the needs of policymakers are met.

Identification of formulation and manufacturing variables that influence in vitro dissolution and in vivo bioavailability of propranolol hydrochloride tablets.

PubMed

Eddington, N D; Ashraf, M; Augsburger, L L; Leslie, J L; Fossler, M J; Lesko, L J; Shah, V P; Rekhi, G S

1998-11-01

The purpose of this study was to evaluate the effect of formulation and processing changes on the dissolution and bioavailability of propranolol hydrochloride tablets. Directly compressed blends of 6 kg (20,000 units) were prepared by mixing in a 16-qt V blender and tablets were compressed on an instrumented Manesty D3B tablet press. A half-factorial (2(5-1), Resolution V) design was used to study the following variables: filler ratio (lactose/dicalcium phosphate), sodium starch glycolate level, magnesium stearate level, lubricant blend time, and compression force. The levels and ranges of the excipients and processing changes studied represented level 2 or greater changes as indicated by the Scale-up and Post Approval Changes (SUPAC-IR) Guidance. Changes in filler ratio, disintegrant level, and compression force were significant in affecting percent drug released (Q) in 5 min (Q5) and Q10. However, changes in magnesium stearate level and lubricant blend time did not influence Q5 and Q10. Hardness was found to be affected by changes in all of the variables studied. Some interaction effects between the variables studied were also found to be significant. To examine the impact of formulation and processing variables on in vivo absorption, three batches were selected for a bioavailability study based on their dissolution profiles. Thirteen subjects received four propranolol treatments (slow-, medium-, and fast-dissolving formulations and Inderal 80 mg) separated by 1 week washout according to a randomized crossover design. The formulations were found to be bioequivalent with respect to the log Cmax and log AUC0-infinity. The results of this study suggest that (i) bioavailability/bioequivalency studies may not be necessary for propranolol and perhaps other class 1 drugs after level 2 type changes, and (ii) in vitro dissolution tests may be used to show bioequivalence of propranolol formulations with processing or formulation changes within the specified level 2 ranges examined.

MRI Markers of Neurodegenerative and Neurovascular Changes in Relation to Postoperative Delirium and Postoperative Cognitive Decline.

PubMed

Kant, Ilse M J; de Bresser, Jeroen; van Montfort, Simone J T; Slooter, Arjen J C; Hendrikse, Jeroen

2017-10-01

Postoperative delirium (POD) and postoperative cognitive decline (POCD) are common in elderly patients. The aim of the present review was to explore the association of neurodegenerative and neurovascular changes with the occurrence of POD and POCD. Fifteen MRI studies were identified by combining multiple search terms for POD, POCD, and brain imaging. These studies described a total of 1,422 patients and were all observational in design. Neurodegenerative changes (global and regional brain volumes) did not show a consistent association with the occurrence of POD (four studies) or POCD (two studies). In contrast, neurovascular changes (white matter hyperintensities and cerebral infarcts) were more consistently associated with the occurrence of POD (seven studies) and POCD (five studies). In conclusion, neurovascular changes appear to be consistently associated with the occurrence of POD and POCD, and may identify patients at increased risk of these conditions. Larger prospective studies are needed to study the consistency of these findings and to unravel the underlying pathophysiological mechanisms. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

An exploratory study of Mindfulness Based Stress Reduction for emotional eating.

PubMed

Levoy, Emily; Lazaridou, Asimina; Brewer, Judson; Fulwiler, Carl

2017-02-01

Emotional eating is an important predictor of weight loss and weight regain after weight loss. This two part study's primary aim was to explore changes in emotional eating in a general population of individuals taking the Mindfulness Based Stress Reduction (MBSR) program, with a secondary aim to explore whether changes in mindfulness predicted changes in emotional eating. Self-reported survey data exploring these questions were collected before and after the intervention for two sequential studies (Study 1 and Study 2). While there were no control groups for either study, in both studies emotional eating scores following the MBSR were significantly lower than scores prior to taking the MBSR (p < 0.001; p < 0.001) In Study 2, changes in mindfulness were correlated with changes in emotional eating (r = 0.317, p = 0.004). These results suggest that MBSR may be an effective intervention for emotional eating, and that further research is warranted to examine effects on weight loss and maintenance. Copyright © 2016 Elsevier Ltd. All rights reserved.

Transformational change in healthcare: an examination of four case studies.

PubMed

Charlesworth, Kate; Jamieson, Maggie; Davey, Rachel; Butler, Colin D

2016-04-01

Objectives Healthcare leaders around the world are calling for radical, transformational change of our health and care systems. This will be a difficult and complex task. In this article, we examine case studies in which transformational change has been achieved, and seek to learn from these experiences. Methods We used the case study method to investigate examples of transformational change in healthcare. The case studies were identified from preliminary doctoral research into the transition towards future sustainable health and social care systems. Evidence was collected from multiple sources, key features of each case study were displayed in a matrix and thematic analysis was conducted. The results are presented in narrative form. Results Four case studies were selected: two from the US, one from Australia and one from the UK. The notable features are discussed for each case study. There were many common factors: a well communicated vision, innovative redesign, extensive consultation and engagement with staff and patients, performance management, automated information management and high-quality leadership. Conclusions Although there were some notable differences between the case studies, overall the characteristics of success were similar and collectively provide a blueprint for transformational change in healthcare. What is known about the topic? Healthcare leaders around the world are calling for radical redesign of our systems in order to meet the challenges of modern society. What does this paper add? There are some remarkable examples of transformational change in healthcare. The key factors in success are similar across the case studies. What are the implications for practitioners? Collectively, these key factors can guide future attempts at transformational change in healthcare.

Differences in change blindness to real-life scenes in adults with autism spectrum conditions.

PubMed

Ashwin, Chris; Wheelwright, Sally; Baron-Cohen, Simon

2017-01-01

People often fail to detect large changes to visual scenes following a brief interruption, an effect known as 'change blindness'. People with autism spectrum conditions (ASC) have superior attention to detail and better discrimination of targets, and often notice small details that are missed by others. Together these predict people with autism should show enhanced perception of changes in simple change detection paradigms, including reduced change blindness. However, change blindness studies to date have reported mixed results in ASC, which have sometimes included no differences to controls or even enhanced change blindness. Attenuated change blindness has only been reported to date in ASC in children and adolescents, with no study reporting reduced change blindness in adults with ASC. The present study used a change blindness flicker task to investigate the detection of changes in images of everyday life in adults with ASC (n = 22) and controls (n = 22) using a simple change detection task design and full range of original scenes as stimuli. Results showed the adults with ASC had reduced change blindness compared to adult controls for changes to items of marginal interest in scenes, with no group difference for changes to items of central interest. There were no group differences in overall response latencies to correctly detect changes nor in the overall number of missed detections in the experiment. However, the ASC group showed greater missed changes for marginal interest changes of location, showing some evidence of greater change blindness as well. These findings show both reduced change blindness to marginal interest changes in ASC, based on response latencies, as well as greater change blindness to changes of location of marginal interest items, based on detection rates. The findings of reduced change blindness are consistent with clinical reports that people with ASC often notice small changes to less salient items within their environment, and are in-line with theories of enhanced local processing and greater attention to detail in ASC. The findings of lower detection rates for one of the marginal interest conditions may be related to problems in shifting attention or an overly focused attention spotlight.

Development of the LaComm 1.0, A French medical communication analysis software: A study assessing its sensitivity to change.

PubMed

Gibon, Anne-Sophie; Durieux, Jean-François; Merckaert, Isabelle; Delvaux, Nicole; Farvacques, Christine; Libert, Yves; Marchal, Serge; Moucheux, Angélique; Slachmuylder, Jean-Louis; Razavi, Darius

2017-02-01

To test and compare the sensitivity to change of a communication analysis software, the LaComm 1.0, to the CRCWEM's using data from a randomized study assessing the efficacy of a communication skills training program designed for nurses. The program assessment included the recording of two-person simulated interviews at baseline and after training or 3 months later. Interview transcripts were analyzed using the CRCWEM and the LaComm 1.0 tools. One hundred and nine oncology nurses (mainly graduated or certified) were included in the study. The CRCWEM detected 5 changes out of 13 expected changes (38%) (e.g., more open directive questions after training) and the LaComm 1.0, 4 changes out of 7 expected changes (57%) (e.g., more empathic statements after training). For open directive question, the effect sizes of the group-by-time changes were slightly different between tools (CRCWEM: Cohen's d=0.97; LaComm 1.0: Cohen's d=0.67). This study shows that the LaComm 1.0 is sensitive to change. The LaComm 1.0 is a valid method to assess training effectiveness in French. The use of the Lacomm 1.0 in future French communication skills training programs will allow comparisons of studies. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Impact of Differential Attrition on the Association of Education With Cognitive Change Over 20 Years of Follow-up

PubMed Central

Gottesman, Rebecca F.; Rawlings, Andreea M.; Sharrett, A. Richey; Albert, Marilyn; Alonso, Alvaro; Bandeen-Roche, Karen; Coker, Laura H.; Coresh, Josef; Couper, David J.; Griswold, Michael E.; Heiss, Gerardo; Knopman, David S.; Patel, Mehul D.; Penman, Alan D.; Power, Melinda C.; Selnes, Ola A.; Schneider, Andrea L. C.; Wagenknecht, Lynne E.; Windham, B. Gwen; Wruck, Lisa M.; Mosley, Thomas H.

2014-01-01

Studies of long-term cognitive change should account for the potential effects of education on the outcome, since some studies have demonstrated an association of education with dementia risk. Evaluating cognitive change is more ideal than evaluating cognitive performance at a single time point, because it should be less susceptible to confounding. In this analysis of 14,020 persons from a US cohort study, the Atherosclerosis Risk in Communities (ARIC) Study, we measured change in performance on 3 cognitive tests over a 20-year period, from ages 48–67 years (1990–1992) through ages 70–89 years (2011–2013). Generalized estimating equations were used to evaluate the association between education and cognitive change in unweighted adjusted models, in models incorporating inverse probability of attrition weighting, and in models using cognitive scores imputed from the Telephone Interview for Cognitive Status for participants not examined in person. Education did not have a strong relationship with change in cognitive test performance, although the rate of decline was somewhat slower among persons with lower levels of education. Methods used to account for selective dropout only marginally changed these observed associations. Future studies of risk factors for cognitive impairment should focus on cognitive change, when possible, to allow for reduction of confounding by social or cultural factors. PMID:24627572

Organizational change to transfer knowledge and improve quality and outcomes of care for patients with severe mental illness: a systematic overview of reviews.

PubMed

Franx, Gerdien; Kroon, Hans; Grimshaw, Jeremy; Drake, Robert; Grol, Richard; Wensing, Michel

2008-05-01

To provide a comprehensive overview of the research on organizational changes aimed at improving health care for patients with severe mental illness and to learn lessons for mental health practice from the results. We searched for systematic literature reviews published in English during 2000 to 2007 in PubMed, PsycINFO, CINAHL, EMBASE, and the Cochrane Central Register of Systematic Reviews. Three reviewers independently selected and assessed the studies' quality. Studies involving changes of who delivers health care, how care is organized, or where care is delivered were included. We categorized the studies using an existing taxonomy of 6 broad categories of strategies for organizational change. A total of 21 reviews were included. Among these, 17 had reasonably good methodological quality, Almost all reviews included or intended to include randomized controlled trials (RCTs), 6 reviews did not identify studies that met eligibility criteria. Multidisciplinary teams and integrated care models had been reviewed most frequently (a total of 15 reviews). In most studies, these types of changes showed better outcomes in terms of symptom severity, functioning, employment, and housing, compared with conventional services. Different results were found on cost savings. Other types of organizational changes, such as changing professional roles or introducing quality management or knowledge management, were much less frequently reviewed. Very few reviews looked at effects of organizational changes on professional performance. There is a fairly large body of evidence of the positive impact of multidisciplinary teams and integrated care changes on symptom severity, functioning, employment, and housing of people with severe mental illness, compared with conventional services. Other strategies, such as changes in professional roles, quality or knowledge management, have either not been the subject of systematic reviews or have not been evaluated in RCTs. There is still a lack of insight in the so-called black box of change processes and the impact of change on professional performance.

Considering Students' Out-of-School Lives and Values in Designing Learning Environments for Climate Change

NASA Astrophysics Data System (ADS)

Walsh, E.; Tsurusaki, B.

2012-12-01

What are the implications of social controversy for the teaching and learning of climate change science? How do the political dimensions of this controversy affect learners' attitudes towards and reasoning about climate change and climate science? Case studies from a pilot enactment of an ecological impacts of climate change curriculum explore these questions by describing how five high school students' understandings of climate change science developed at the intersection of political and scientific values, attitudes, and ways of knowing. Case studies combine qualitative, ethnographic methods including interviews and classroom video observations with quantitative pre/post-assessments of student conceptual understandings and weekly surveys of student engagement. Data indicate that students had initial perceptions of climate change informed by the media and their families—both supporting and rejecting the scientific consensus—that influenced how they engaged with the scientific evidence. While students who were initially antagonistic to anthropogenic climate change did develop conceptual understandings of the scientific evidence for human-influences on climate change, this work was challenging and at times frustrating for them. These case studies demonstrate the wide range of initial attitudes and understandings that students bring to the study of climate change. They also demonstrate that it is possible to make significant shifts in students' understandings of climate change science, even in students who were initially resistant to the idea of anthropogenic climate change. Finally, multiple case studies discuss ways that the learning that occurred in the classroom crossed out of the classroom into the students' homes and family talk. This work highlights how learners' pathways are shaped not only by their developing understanding of the scientific evidence but also by the political and social influences that learners navigate across the contexts of their lives. It underscores the need to understand and support students as they interact with climate change across the contexts of their lives.

Changes in BSc Business Administration and Psychology Students' Learning Styles over One, Two and Three Years of Study

ERIC Educational Resources Information Center

Nielsen, Tine

2013-01-01

Knowledge on general or discipline-specific changes in the learning styles of university students can be utilised in the design and execution of courses, but little is known of such changes. The study examined the changes in the learning styles of three year groups of BSc Business Administration and Psychology students from admittance to one, two…

The Influence of Causal Knowledge on the Willingness to Change Attitude towards Climate Change: Results from an Empirical Study

ERIC Educational Resources Information Center

Tasquier, Giulia; Pongiglione, Francesca

2017-01-01

Climate change is one of the significant global challenges currently facing humanity. Even though its seriousness seems to be common knowledge among the public, the reaction of individuals to it has been slow and uncertain. Many studies assert that simply knowing about climate change is not enough to generate people's behavioural response. They…

Stem form changes in upland oaks after thinning

Treesearch

Donald E. Hilt; Martin E. Dale

1979-01-01

Results of two independent studies were analyzed to determine whether residual stocking after thinning had any effect on change in stem form of upland oak. One study is based on 15 years' change in Girard Form Class after thinning of an 80-year-old white oak stand in eastern Kentucky. The other, 12-year changes in Girard Form Class and breast-height form factor...

The Role of Cognitive, Metacognitive, and Motivational Variables in Conceptual Change: Preservice Early Childhood Teachers' Conceptual Understanding of the Cause of Lunar Phases

ERIC Educational Resources Information Center

Sackes, Mesut

2010-01-01

This study seeks to explore and describe the role of cognitive, metacognitive, and motivational variables in conceptual change. More specifically, the purposes of the study were (1) to investigate the predictive ability of a learning model that was developed based on the intentional conceptual change perspective in predicting change in conceptual…

K-8th Grade Korean Students' Conceptions of 'Changes of State' and 'Conditions for Changes of State'. Research Report

ERIC Educational Resources Information Center

Paik, Seoung-Hey; Kim, Hyo-Nam; Cho, Boo-Kyoung; Park, Jae-Won

2004-01-01

This study investigates the various conceptions held by K-8th Korean grade students regarding the 'changes of state' and the 'conditions for changes of state'. The study used a sample of five kindergarteners, five secondgrade students, five fourth-grade students, five sixth-grade students, and five eighth-grade students. The 25 students attend…

Changes in the Structure of Relations Between Groups and the Emergence of Political Movements: The Student Movement at Harvard and Wisconsin, 1930-1969. A Thesis.

ERIC Educational Resources Information Center

Swirski, Shlomo

This study presents a theoretical approach to the study of the emergence of movements for political change. It was postulated that changes outside the university role set --industrial systems development, political, military, scientific competition between the United States and Soviet Union-- brought about the following structural changes within…

How Teachers' Beliefs About Climate Change Influence Their Instruction and Resulting Student Outcomes

NASA Astrophysics Data System (ADS)

Nation, M.; Feldman, A.; Smith, G.

2017-12-01

The purpose of the study was to understand the relationship between teachers' beliefs and understandings of climate change and their instructional practices to determine if and how they impact student outcomes. Limited research has been done in the area of teacher beliefs on climate change, their instruction, and resulting student outcomes. This study contributes to the greater understanding of teachers' beliefs and impact on climate change curriculum implementation. The study utilized a mixed methods approach to data collection and analysis. Data were collected in the form of classroom observations, surveys, and interviews from teachers and students participating in the study over a four-month period. Qualitative and quantitative findings were analyzed through thematic coding and descriptive analysis and compared in an effort to triangulate findings. The results of the study suggest teachers and students believe climate change is occurring and humans are largely to blame. Personal beliefs are important when teaching controversial topics, such as climate change, but participants maintained neutrality within their instruction of the topic, as not to appear biased or influence students' decisions about climate change, and avoid political controversy in the classroom. Overall, the study found teachers' level of understandings and beliefs about climate change had little impact on their instruction and resulting student outcomes. Based on the findings, simply adding climate change to the existing science curriculum is not sufficient for teachers or students. Teachers need to be better prepared about effective pedagogical practices of the content in order to effectively teach a climate-centered curriculum. The barriers that exist for the inclusion of teachers' personal beliefs need to be removed in order for teachers to assert their own personal beliefs about climate change within their classroom instruction. Administrators and stakeholders need to support science teachers' beliefs about climate change, and uphold the efforts of the scientific community, regardless of political hierarchy. Students are loosing an opportunity for insight into educated, knowledgeable mentors, and are by-in-large left to the opinions of climate change that overwhelm news media, which may not be as trustworthy.

The scene and the unseen: manipulating photographs for experiments on change blindness and scene memory: image manipulation for change blindness.

PubMed

Ball, Felix; Elzemann, Anne; Busch, Niko A

2014-09-01

The change blindness paradigm, in which participants often fail to notice substantial changes in a scene, is a popular tool for studying scene perception, visual memory, and the link between awareness and attention. Some of the most striking and popular examples of change blindness have been demonstrated with digital photographs of natural scenes; in most studies, however, much simpler displays, such as abstract stimuli or "free-floating" objects, are typically used. Although simple displays have undeniable advantages, natural scenes remain a very useful and attractive stimulus for change blindness research. To assist researchers interested in using natural-scene stimuli in change blindness experiments, we provide here a step-by-step tutorial on how to produce changes in natural-scene images with a freely available image-processing tool (GIMP). We explain how changes in a scene can be made by deleting objects or relocating them within the scene or by changing the color of an object, in just a few simple steps. We also explain how the physical properties of such changes can be analyzed using GIMP and MATLAB (a high-level scientific programming tool). Finally, we present an experiment confirming that scenes manipulated according to our guidelines are effective in inducing change blindness and demonstrating the relationship between change blindness and the physical properties of the change and inter-individual differences in performance measures. We expect that this tutorial will be useful for researchers interested in studying the mechanisms of change blindness, attention, or visual memory using natural scenes.

Exploring mechanisms of change in schema therapy for chronic depression.

PubMed

Renner, Fritz; DeRubeis, Robert; Arntz, Arnoud; Peeters, Frenk; Lobbestael, Jill; Huibers, Marcus J H

2018-03-01

The underlying mechanisms of symptom change in schema therapy (ST) for chronic major depressive disorder (cMDD) have not been studied. The aim of this study was to explore the impact of two potentially important mechanisms of symptom change, maladaptive schemas (proxied by negative idiosyncratic core-beliefs) and the therapeutic alliance. We drew data from a single-case series of ST for cMDD. Patients with cMDD (N = 20) received on average 78 repeated weekly assessments over a course of up to 65 individual sessions of ST. Focusing on repeated assessments within-individuals, we used mixed regression to test whether change in core-beliefs and therapeutic alliance preceded, followed, or occurred concurrently with change in depressive symptoms. Changes in core-beliefs did not precede but were concurrently related to changes in symptoms. Repeated goal and task agreement ratings (specific aspects of alliance) of the same session, completed on separate days, were at least in part associated with concurrent changes in symptoms. By design this study had a small sample-size and no control group. Contrary to what would be expected based on theory, our findings suggest that change in core-beliefs does not precede change in symptoms. Instead, change in these variables occurs concurrently. Moreover, alliance ratings seem to be at least in part colored by changes in current mood state. Copyright © 2017 Elsevier Ltd. All rights reserved.

Mapping human dimensions of climate change research in the Canadian Arctic.

PubMed

Ford, James D; Bolton, Kenyon; Shirley, Jamal; Pearce, Tristan; Tremblay, Martin; Westlake, Michael

2012-12-01

This study maps current understanding and research trends on the human dimensions of climate change (HDCC) in the eastern and central Canadian Arctic. Developing a systematic literature review methodology, 117 peer reviewed articles are identified and examined using quantitative and qualitative methods. The research highlights the rapid expansion of HDCC studies over the last decade. Early scholarship was dominated by work documenting Inuit observations of climate change, with research employing vulnerability concepts and terminology now common. Adaptation studies which seek to identify and evaluate opportunities to reduce vulnerability to climate change and take advantage of new opportunities remain in their infancy. Over the last 5 years there has been an increase social science-led research, with many studies employing key principles of community-based research. We currently have baseline understanding of climate change impacts, adaptation, and vulnerability in the region, but key gaps are evident. Future research needs to target significant geographic disparities in understanding, consider risks and opportunities posed by climate change outside of the subsistence hunting sector, complement case study research with regional analyses, and focus on identifying and characterizing sustainable and feasible adaptation interventions.