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Sample records for adaptive phenotypic plasticity

  1. Phenotypic plasticity: molecular mechanisms and adaptive significance.

    PubMed

    Kelly, Scott A; Panhuis, Tami M; Stoehr, Andrew M

    2012-04-01

    Phenotypic plasticity can be broadly defined as the ability of one genotype to produce more than one phenotype when exposed to different environments, as the modification of developmental events by the environment, or as the ability of an individual organism to alter its phenotype in response to changes in environmental conditions. Not surprisingly, the study of phenotypic plasticity is innately interdisciplinary and encompasses aspects of behavior, development, ecology, evolution, genetics, genomics, and multiple physiological systems at various levels of biological organization. From an ecological and evolutionary perspective, phenotypic plasticity may be a powerful means of adaptation and dramatic examples of phenotypic plasticity include predator avoidance, insect wing polymorphisms, the timing of metamorphosis in amphibians, osmoregulation in fishes, and alternative reproductive tactics in male vertebrates. From a human health perspective, documented examples of plasticity most commonly include the results of exercise, training, and/or dieting on human morphology and physiology. Regardless of the discipline, phenotypic plasticity has increasingly become the target of a plethora of investigations with the methodological approaches utilized ranging from the molecular to whole organsimal. In this article, we provide a brief historical outlook on phenotypic plasticity; examine its potential adaptive significance; emphasize recent molecular approaches that provide novel insight into underlying mechanisms, and highlight examples in fishes and insects. Finally, we highlight examples of phenotypic plasticity from a human health perspective and underscore the use of mouse models as a powerful tool in understanding the genetic architecture of phenotypic plasticity.

  2. Reversible phenotypic plasticity with continuous adaptation.

    PubMed

    Pfab, Ferdinand; Gabriel, Wilfried; Utz, Margarete

    2016-01-01

    We introduce a novel model for continuous reversible phenotypic plasticity. The model includes a one-dimensional environmental gradient, and we describe performance of an organism as a function of the environmental state by a Gaussian tolerance curve. Organisms are assumed to adapt their tolerance curve after a change of the environmental state. We present a general framework for calculating the genotype fitness if such adaptations happen in a continuous manner and apply the model to a periodically changing environment. Significant differences of our model with previous models for plasticity are the continuity of adaptation, the presence of intermediate phenotypes, that the duration of transformations depends on their extent, fewer restrictions on the distribution of the environment, and a higher robustness with respect to assumptions about environmental fluctuations. Further, we show that continuous reversible plasticity is beneficial mainly when environmental changes occur slow enough so that fully developed phenotypes can be exhibited. Finally we discuss how the model framework can be generalized to a wide variety of biological scenarios from areas that include population dynamics, evolution of environmental tolerance and physiology.

  3. Phenotypic Plasticity and Selection: Nonexclusive Mechanisms of Adaptation

    PubMed Central

    Grenier, S.; Barre, P.; Litrico, I.

    2016-01-01

    Selection and plasticity are two mechanisms that allow the adaptation of a population to a changing environment. Interaction between these nonexclusive mechanisms must be considered if we are to understand population survival. This review discusses the ways in which plasticity and selection can interact, based on a review of the literature on selection and phenotypic plasticity in the evolution of populations. The link between selection and phenotypic plasticity is analysed at the level of the individual. Plasticity can affect an individual's response to selection and so may modify the end result of genetic diversity evolution at population level. Genetic diversity increases the ability of populations or communities to adapt to new environmental conditions. Adaptive plasticity increases individual fitness. However this effect must be viewed from the perspective of the costs of plasticity, although these are not easy to estimate. It is becoming necessary to engage in new experimental research to demonstrate the combined effects of selection and plasticity for adaptation and their consequences on the evolution of genetic diversity. PMID:27313957

  4. Phenotypic Plasticity and Selection: Nonexclusive Mechanisms of Adaptation.

    PubMed

    Grenier, S; Barre, P; Litrico, I

    2016-01-01

    Selection and plasticity are two mechanisms that allow the adaptation of a population to a changing environment. Interaction between these nonexclusive mechanisms must be considered if we are to understand population survival. This review discusses the ways in which plasticity and selection can interact, based on a review of the literature on selection and phenotypic plasticity in the evolution of populations. The link between selection and phenotypic plasticity is analysed at the level of the individual. Plasticity can affect an individual's response to selection and so may modify the end result of genetic diversity evolution at population level. Genetic diversity increases the ability of populations or communities to adapt to new environmental conditions. Adaptive plasticity increases individual fitness. However this effect must be viewed from the perspective of the costs of plasticity, although these are not easy to estimate. It is becoming necessary to engage in new experimental research to demonstrate the combined effects of selection and plasticity for adaptation and their consequences on the evolution of genetic diversity.

  5. Evolutionary adaptation of phenotypic plasticity in a synthetic microbial system

    NASA Astrophysics Data System (ADS)

    Tans, Sander

    2010-03-01

    While phenotypic plasticity -the capability to respond to the environment- is vital to organisms, tests of its adaptation have remained indecisive because constraints and selection in variable environments are unknown and entangled. We show that one can determine the phenotype-fitness landscape that specifies selection on plasticity, by uncoupling the environmental cue and stress in a genetically engineered microbial system. Evolutionary trajectories revealed genetic constraints in a regulatory protein, which imposed cross-environment trade-offs that favored specialization. However, depending on the synchronicity and amplitude of the applied cue and stress variations, adaptation could break constraints, resolve trade-offs, and evolve optimal phenotypes that exhibit qualitatively altered (inverse) responses to the cue. Our results provide a first step to explain the adaptive origins of complex behavior in heterogeneous environments.

  6. Virus infection suppresses Nicotiana benthamiana adaptive phenotypic plasticity.

    PubMed

    Bedhomme, Stéphanie; Elena, Santiago F

    2011-02-17

    Competition and parasitism are two important selective forces that shape life-histories, migration rates and population dynamics. Recently, it has been shown in various pathosystems that parasites can modify intraspecific competition, thus generating an indirect cost of parasitism. Here, we investigated if this phenomenon was present in a plant-potyvirus system using two viruses of different virulence (Tobacco etch virus and Turnip mosaic virus). Moreover, we asked if parasitism interacted with the shade avoidance syndrome, the plant-specific phenotypic plasticity in response to intraspecific competition. Our results indicate that the modification of intraspecific competition by parasitism is not present in the Nicotiana benthamiana--potyvirus system and suggests that this phenomenon is not universal but depends on the peculiarities of each pathosystem. However, whereas the healthy N. benthamiana presented a clear shade avoidance syndrome, this phenotypic plasticity totally disappeared when the plants were infected with TEV and TuMV, very likely resulting in a fitness loss and being another form of indirect cost of parasitism. This result suggests that the suppression or the alteration of adaptive phenotypic plasticity might be a component of virulence that is often overlooked.

  7. Virus Infection Suppresses Nicotiana benthamiana Adaptive Phenotypic Plasticity

    PubMed Central

    Bedhomme, Stéphanie; Elena, Santiago F.

    2011-01-01

    Competition and parasitism are two important selective forces that shape life-histories, migration rates and population dynamics. Recently, it has been shown in various pathosystems that parasites can modify intraspecific competition, thus generating an indirect cost of parasitism. Here, we investigated if this phenomenon was present in a plant-potyvirus system using two viruses of different virulence (Tobacco etch virus and Turnip mosaic virus). Moreover, we asked if parasitism interacted with the shade avoidance syndrome, the plant-specific phenotypic plasticity in response to intraspecific competition. Our results indicate that the modification of intraspecific competition by parasitism is not present in the Nicotiana benthamiana – potyvirus system and suggests that this phenomenon is not universal but depends on the peculiarities of each pathosystem. However, whereas the healthy N. benthamiana presented a clear shade avoidance syndrome, this phenotypic plasticity totally disappeared when the plants were infected with TEV and TuMV, very likely resulting in a fitness loss and being another form of indirect cost of parasitism. This result suggests that the suppression or the alteration of adaptive phenotypic plasticity might be a component of virulence that is often overlooked. PMID:21359142

  8. Invasion strategies in clonal aquatic plants: are phenotypic differences caused by phenotypic plasticity or local adaptation?

    PubMed Central

    Riis, Tenna; Lambertini, Carla; Olesen, Birgit; Clayton, John S.; Brix, Hans; Sorrell, Brian K.

    2010-01-01

    Background and Aims The successful spread of invasive plants in new environments is often linked to multiple introductions and a diverse gene pool that facilitates local adaptation to variable environmental conditions. For clonal plants, however, phenotypic plasticity may be equally important. Here the primary adaptive strategy in three non-native, clonally reproducing macrophytes (Egeria densa, Elodea canadensis and Lagarosiphon major) in New Zealand freshwaters were examined and an attempt was made to link observed differences in plant morphology to local variation in habitat conditions. Methods Field populations with a large phenotypic variety were sampled in a range of lakes and streams with different chemical and physical properties. The phenotypic plasticity of the species before and after cultivation was studied in a common garden growth experiment, and the genetic diversity of these same populations was also quantified. Key Results For all three species, greater variation in plant characteristics was found before they were grown in standardized conditions. Moreover, field populations displayed remarkably little genetic variation and there was little interaction between habitat conditions and plant morphological characteristics. Conclusions The results indicate that at the current stage of spread into New Zealand, the primary adaptive strategy of these three invasive macrophytes is phenotypic plasticity. However, while limited, the possibility that genetic diversity between populations may facilitate ecotypic differentiation in the future cannot be excluded. These results thus indicate that invasive clonal aquatic plants adapt to new introduced areas by phenotypic plasticity. Inorganic carbon, nitrogen and phosphorous were important in controlling plant size of E. canadensis and L. major, but no other relationships between plant characteristics and habitat conditions were apparent. This implies that within-species differences in plant size can be explained

  9. Plasticity, stability, and yield: the origins of Anthony David Bradshaw's model of adaptive phenotypic plasticity.

    PubMed

    Peirson, B R Erick

    2015-04-01

    Plant ecologist Anthony David Bradshaw's account of the evolution of adaptive phenotypic plasticity remains central to contemporary research aimed at understanding how organisms persist in heterogeneous environments. Bradshaw suggested that changes in particular traits in response to specific environmental factors could be under direct genetic control, and that natural selection could therefore act directly to shape those responses: plasticity was not "noise" obscuring a genetic signal, but could be specific and refined just as any other adaptive phenotypic trait. In this paper, I document the contexts and development of Bradshaw's investigation of phenotypic plasticity in plants, including a series of unreported experiments in the late 1950s and early 1960s. Contrary to the mythology that later emerged around Bradshaw's ideas, Bradshaw was engaged in a serious and sustained empirical research program concerning plasticity in the 1950s and 1960s that went far beyond a single review paper. Moreover, that work was not isolated, but was surrounded by an already rich theoretical discourse and a substantial body of empirical research concerning the evolution of developmental plasticity and stability. Bradshaw recast the problem of how to understand (and control) plasticity and stability within an epistemic framework focused on genetic differences and natural selection.

  10. Adaptive phenotypic plasticity and local adaptation for temperature tolerance in freshwater zooplankton.

    PubMed

    Yampolsky, Lev Y; Schaer, Tobias M M; Ebert, Dieter

    2014-02-07

    Many organisms have geographical distributions extending from the tropics to near polar regions or can experience up to 30°C temperature variation within the lifespan of an individual. Two forms of evolutionary adaptation to such wide ranges in ambient temperatures are frequently discussed: local adaptation and phenotypic plasticity. The freshwater planktonic crustacean Daphnia magna, whose range extends from South Africa to near arctic sites, shows strong phenotypic and genotypic variation in response to temperature. In this study, we use D. magna clones from 22 populations (one clone per population) ranging from latitude 0° (Kenya) to 66° North (White Sea) to explore the contributions of phenotypic plasticity and local adaptation to high temperature tolerance. Temperature tolerance was studied as knockout time (time until immobilization, T(imm)) at 37°C in clones acclimatized to either 20°C or 28°C. Acclimatization to 28°C strongly increased T(imm), testifying to adaptive phenotypic plasticity. At the same time, Timm significantly correlated with average high temperature at the clones' sites of origin, suggesting local adaptation. As earlier studies have found that haemoglobin expression contributes to temperature tolerance, we also quantified haemoglobin concentration in experimental animals and found that both acclimatization temperature (AccT) and temperature at the site of origin are positively correlated with haemoglobin concentration. Furthermore, Daphnia from warmer climates upregulate haemoglobin much more strongly in response to AccT, suggesting local adaptation for plasticity in haemoglobin expression. Our results show that both local adaptation and phenotypic plasticity contribute to temperature tolerance, and elucidate a possible role of haemoglobin in mediating these effects that differs along a cold-warm gradient.

  11. Mechanisms by Which Phenotypic Plasticity Affects Adaptive Divergence and Ecological Speciation.

    PubMed

    Nonaka, Etsuko; Svanbäck, Richard; Thibert-Plante, Xavier; Englund, Göran; Brännström, Åke

    2015-11-01

    Phenotypic plasticity is the ability of one genotype to produce different phenotypes depending on environmental conditions. Several conceptual models emphasize the role of plasticity in promoting reproductive isolation and, ultimately, speciation in populations that forage on two or more resources. These models predict that plasticity plays a critical role in the early stages of speciation, prior to genetic divergence, by facilitating fast phenotypic divergence. The ability to plastically express alternative phenotypes may, however, interfere with the early phase of the formation of reproductive barriers, especially in the absence of geographic barriers. Here, we quantitatively investigate mechanisms under which plasticity can influence progress toward adaptive genetic diversification and ecological speciation. We use a stochastic, individual-based model of a predator-prey system incorporating sexual reproduction and mate choice in the predator. Our results show that evolving plasticity promotes the evolution of reproductive isolation under diversifying environments when individuals are able to correctly select a more profitable habitat with respect to their phenotypes (i.e., adaptive habitat choice) and to assortatively mate with relatively similar phenotypes. On the other hand, plasticity facilitates the evolution of plastic generalists when individuals have a limited capacity for adaptive habitat choice. We conclude that plasticity can accelerate the evolution of a reproductive barrier toward adaptive diversification and ecological speciation through enhanced phenotypic differentiation between diverging phenotypes.

  12. Phenotypic plasticity in gene expression contributes to divergence of locally adapted populations of Fundulus heteroclitus.

    PubMed

    Dayan, David I; Crawford, Douglas L; Oleksiak, Marjorie F

    2015-07-01

    We examine the interaction between phenotypic plasticity and evolutionary adaptation using muscle gene expression levels among populations of the fish Fundulus heteroclitus acclimated to three temperatures. Our analysis reveals shared patterns of phenotypic plasticity due to thermal acclimation as well as non-neutral patterns of variation among populations adapted to different thermal environments. For the majority of significant differences in gene expression levels, phenotypic plasticity and adaptation operate on different suites of genes. The subset of genes that demonstrate both adaptive differences and phenotypic plasticity, however, exhibit countergradient variation of expression. Thus, expression differences among populations counteract environmental effects, reducing the phenotypic differentiation between populations. Finally, gene-by-environment interactions among genes with non-neutral patterns of expression suggest that the penetrance of adaptive variation depends on the environmental conditions experienced by the individual.

  13. Adaptive phenotypic plasticity in the Midas cichlid fish pharyngeal jaw and its relevance in adaptive radiation

    PubMed Central

    2011-01-01

    Background Phenotypic evolution and its role in the diversification of organisms is a central topic in evolutionary biology. A neglected factor during the modern evolutionary synthesis, adaptive phenotypic plasticity, more recently attracted the attention of many evolutionary biologists and is now recognized as an important ingredient in both population persistence and diversification. The traits and directions in which an ancestral source population displays phenotypic plasticity might partly determine the trajectories in morphospace, which are accessible for an adaptive radiation, starting from the colonization of a novel environment. In the case of repeated colonizations of similar environments from the same source population this "flexible stem" hypothesis predicts similar phenotypes to arise in repeated subsequent radiations. The Midas Cichlid (Amphilophus spp.) in Nicaragua has radiated in parallel in several crater-lakes seeded by populations originating from the Nicaraguan Great Lakes. Here, we tested phenotypic plasticity in the pharyngeal jaw of Midas Cichlids. The pharyngeal jaw apparatus of cichlids, a second set of jaws functionally decoupled from the oral ones, is known to mediate ecological specialization and often differs strongly between sister-species. Results We performed a common garden experiment raising three groups of Midas cichlids on food differing in hardness and calcium content. Analyzing the lower pharyngeal jaw-bones we find significant differences between diet groups qualitatively resembling the differences found between specialized species. Observed differences in pharyngeal jaw expression between groups were attributable to the diet's mechanical resistance, whereas surplus calcium in the diet was not found to be of importance. Conclusions The pharyngeal jaw apparatus of Midas Cichlids can be expressed plastically if stimulated mechanically during feeding. Since this trait is commonly differentiated - among other traits - between

  14. Modifying effects of phenotypic plasticity on interactions among natural selection, adaptation and gene flow.

    PubMed

    Crispo, E

    2008-11-01

    Divergent natural selection, adaptive divergence and gene flow may interact in a number of ways. Recent studies have focused on the balance between selection and gene flow in natural populations, and empirical work has shown that gene flow can constrain adaptive divergence, and that divergent selection can constrain gene flow. A caveat is that phenotypic diversification may be under the direct influence of environmental factors (i.e. it may be due to phenotypic plasticity), in addition to partial genetic influence. In this case, phenotypic divergence may occur between populations despite high gene flow that imposes a constraint on genetic divergence. Plasticity may dampen the effects of natural selection by allowing individuals to rapidly adapt phenotypically to new conditions, thus slowing adaptive genetic divergence. On the other hand, plasticity may promote future adaptive divergence by allowing populations to persist in novel environments. Plasticity may promote gene flow between selective regimes by allowing dispersers to adapt to alternate conditions, or high gene flow may result in the selection for increased plasticity. Here I expand frameworks for understanding relationships among selection, adaptation and gene flow to include the effects of phenotypic plasticity in natural populations, and highlight its importance in evolutionary diversification.

  15. Regulatory gene networks that shape the development of adaptive phenotypic plasticity in a cichlid fish.

    PubMed

    Schneider, Ralf F; Li, Yuanhao; Meyer, Axel; Gunter, Helen M

    2014-09-01

    Phenotypic plasticity is the ability of organisms with a given genotype to develop different phenotypes according to environmental stimuli, resulting in individuals that are better adapted to local conditions. In spite of their ecological importance, the developmental regulatory networks underlying plastic phenotypes often remain uncharacterized. We examined the regulatory basis of diet-induced plasticity in the lower pharyngeal jaw (LPJ) of the cichlid fish Astatoreochromis alluaudi, a model species in the study of adaptive plasticity. Through raising juvenile A. alluaudi on either a hard or soft diet (hard-shelled or pulverized snails) for between 1 and 8 months, we gained insight into the temporal regulation of 19 previously identified candidate genes during the early stages of plasticity development. Plasticity in LPJ morphology was first detected between 3 and 5 months of diet treatment. The candidate genes, belonging to various functional categories, displayed dynamic expression patterns that consistently preceded the onset of morphological divergence and putatively contribute to the initiation of the plastic phenotypes. Within functional categories, we observed striking co-expression, and transcription factor binding site analysis was used to examine the prospective basis of their coregulation. We propose a regulatory network of LPJ plasticity in cichlids, presenting evidence for regulatory crosstalk between bone and muscle tissues, which putatively facilitates the development of this highly integrated trait. Through incorporating a developmental time-course into a phenotypic plasticity study, we have identified an interconnected, environmentally responsive regulatory network that shapes the development of plasticity in a key innovation of East African cichlids.

  16. Evidence of concurrent local adaptation and high phenotypic plasticity in a polar microeukaryote.

    PubMed

    Rengefors, Karin; Logares, Ramiro; Laybourn-Parry, Johanna; Gast, Rebecca J

    2015-05-01

    Here we investigated whether there is evidence of local adaptation in strains of an ancestrally marine dinoflagellate to the lacustrine environment they now inhabit (optimal genotypes) and/or if they have evolved phenotypic plasticity (a range of phenotypes). Eleven strains of Polarella glacialis were isolated and cultured from three different environments: the polar seas, a hyposaline and a hypersaline Antarctic lake. Local adaptation was tested by comparing growth rates of lacustrine and marine strains at their own and reciprocal site conditions. To determine phenotypic plasticity, we measured the reaction norm for salinity. We found evidence of both, limited local adaptation and higher phenotypic plasticity in lacustrine strains when compared with marine ancestors. At extreme high salinities, local lake strains outperformed other strains, and at extreme low salinities, strains from the hyposaline lake outperformed all other strains. The data suggest that lake populations may have evolved higher phenotypic plasticity in the lake habitats compared with the sea, presumably due to the high temporal variability in salinity in the lacustrine systems. Moreover, the interval of salinity tolerance differed between strains from the hyposaline and hypersaline lakes, indicating local adaptation promoted by different salinity.

  17. Predator-induced phenotypic plasticity in metabolism and rate of growth: rapid adaptation to a novel environment.

    PubMed

    Handelsman, Corey A; Broder, E Dale; Dalton, Christopher M; Ruell, Emily W; Myrick, Christopher A; Reznick, David N; Ghalambor, Cameron K

    2013-12-01

    Novel environments often impose directional selection for a new phenotypic optimum. Novel environments, however, can also change the distribution of phenotypes exposed to selection by inducing phenotypic plasticity. Plasticity can produce phenotypes that either align with or oppose the direction of selection. When plasticity and selection are parallel, plasticity is considered adaptive because it provides a better pairing between the phenotype and the environment. If the plastic response is incomplete and falls short of producing the optimum phenotype, synergistic selection can lead to genetic divergence and bring the phenotype closer to the optimum. In contrast, non-adaptive plasticity should increase the strength of selection, because phenotypes will be further from the local optimum, requiring antagonistic selection to overcome the phenotype-environment mismatch and facilitate adaptive divergence. We test these ideas by documenting predator-induced plasticity for resting metabolic rate and growth rate in populations of the Trinidadian guppy (Poecilia reticulata) adapted to high and low predation. We find reduced metabolic rates and growth rates when cues from a predator are present during development, a pattern suggestive of adaptive and non-adaptive plasticity, respectively. When we compared populations recently transplanted from a high-predation environment into four streams lacking predators, we found evidence for rapid adaptive evolution both in metabolism and growth rate. We discuss the implications for predicting how traits will respond to selection, depending on the type of plasticity they exhibit.

  18. Role of phenotypic plasticity and population differentiation in adaptation to novel environmental conditions.

    PubMed

    Volis, Sergei; Ormanbekova, Danara; Yermekbayev, Kanat

    2015-09-01

    Species can adapt to new environmental conditions either through individual phenotypic plasticity, intraspecific genetic differentiation in adaptive traits, or both. Wild emmer wheat, Triticum dicoccoides, an annual grass with major distribution in Eastern Mediterranean region, is predicted to experience in the near future, as a result of global climate change, conditions more arid than in any part of the current species distribution. To understand the role of the above two means of adaptation, and the effect of population range position, we analyzed reaction norms, extent of plasticity, and phenotypic selection across two experimental environments of high and low water availability in two core and two peripheral populations of this species. We studied 12 quantitative traits, but focused primarily on the onset of reproduction and maternal investment, which are traits that are closely related to fitness and presumably involved in local adaptation in the studied species. We hypothesized that the population showing superior performance under novel environmental conditions will either be genetically differentiated in quantitative traits or exhibit higher phenotypic plasticity than the less successful populations. We found the core population K to be the most plastic in all three trait categories (phenology, reproductive traits, and fitness) and most successful among populations studied, in both experimental environments; at the same time, the core K population was clearly genetically differentiated from the two edge populations. Our results suggest that (1) two means of successful adaptation to new environmental conditions, phenotypic plasticity and adaptive genetic differentiation, are not mutually exclusive ways of achieving high adaptive ability; and (2) colonists from some core populations can be more successful in establishing beyond the current species range than colonists from the range extreme periphery with conditions seemingly closest to those in the new

  19. Phenotypic plasticity and genetic adaptation to high-altitude hypoxia in vertebrates

    PubMed Central

    Storz, Jay F.; Scott, Graham R.; Cheviron, Zachary A.

    2010-01-01

    High-altitude environments provide ideal testing grounds for investigations of mechanism and process in physiological adaptation. In vertebrates, much of our understanding of the acclimatization response to high-altitude hypoxia derives from studies of animal species that are native to lowland environments. Such studies can indicate whether phenotypic plasticity will generally facilitate or impede adaptation to high altitude. Here, we review general mechanisms of physiological acclimatization and genetic adaptation to high-altitude hypoxia in birds and mammals. We evaluate whether the acclimatization response to environmental hypoxia can be regarded generally as a mechanism of adaptive phenotypic plasticity, or whether it might sometimes represent a misdirected response that acts as a hindrance to genetic adaptation. In cases in which the acclimatization response to hypoxia is maladaptive, selection will favor an attenuation of the induced phenotypic change. This can result in a form of cryptic adaptive evolution in which phenotypic similarity between high- and low-altitude populations is attributable to directional selection on genetically based trait variation that offsets environmentally induced changes. The blunted erythropoietic and pulmonary vasoconstriction responses to hypoxia in Tibetan humans and numerous high-altitude birds and mammals provide possible examples of this phenomenon. When lowland animals colonize high-altitude environments, adaptive phenotypic plasticity can mitigate the costs of selection, thereby enhancing prospects for population establishment and persistence. By contrast, maladaptive plasticity has the opposite effect. Thus, insights into the acclimatization response of lowland animals to high-altitude hypoxia can provide a basis for predicting how altitudinal range limits might shift in response to climate change. PMID:21112992

  20. A Test for Pre-Adapted Phenotypic Plasticity in the Invasive Tree Acer negundo L.

    PubMed Central

    Lamarque, Laurent J.; Porté, Annabel J.; Eymeric, Camille; Lasnier, Jean-Baptiste; Lortie, Christopher J.; Delzon, Sylvain

    2013-01-01

    Phenotypic plasticity is a key mechanism associated with the spread of exotic plants and previous studies have found that invasive species are generally more plastic than co-occurring species. Comparatively, the evolution of phenotypic plasticity in plant invasion has received less attention, and in particular, the genetic basis of plasticity is largely unexamined. Native from North America, Acer negundo L. is aggressively impacting the riparian forests of southern and eastern Europe thanks to higher plasticity relative to co-occurring native species. We therefore tested here whether invasive populations have evolved increased plasticity since introduction. The performance of 1152 seedlings from 8 native and 8 invasive populations was compared in response to nutrient availability. Irrespective of nutrients, invasive populations had higher growth and greater allocation to above-ground biomass relative to their native conspecifics. More importantly, invasive genotypes did not show increased plasticity in any of the 20 traits examined. This result suggests that the high magnitude of plasticity to nutrient variation of invasive seedlings might be pre-adapted in the native range. Invasiveness of A. negundo could be explained by higher mean values of traits due to genetic differentiation rather than by evolution of increased plasticity. PMID:24040212

  1. Phenotypic plasticity as an adaptation to a functional trade-off.

    PubMed

    Yi, Xiao; Dean, Antony M

    2016-10-03

    We report the evolution of a phenotypically plastic behavior that circumvents the hardwired trade-off that exists when resources are partitioned between growth and motility in Escherichia coli. We propagated cultures in a cyclical environment, alternating between growth up to carrying capacity and selection for chemotaxis. Initial adaptations boosted overall swimming speed at the expense of growth. The effect of the trade-off was subsequently eased through a change in behavior; while individual cells reduced motility during exponential growth, the faction of the population that was motile increased as the carrying capacity was approached. This plastic behavior was produced by a single amino acid replacement in FliA, a regulatory protein central to the chemotaxis network. Our results illustrate how phenotypic plasticity potentiates evolvability by opening up new regions of the adaptive landscape.

  2. Adaptive patterns of phenotypic plasticity in laboratory and field environments in Drosophila melanogaster.

    PubMed

    Mathur, Vinayak; Schmidt, Paul S

    2017-02-01

    Identifying mechanisms of adaptation to variable environments is essential in developing a comprehensive understanding of evolutionary dynamics in natural populations. Phenotypic plasticity allows for phenotypic change in response to changes in the environment, and as such may play a major role in adaptation to environmental heterogeneity. Here, the plasticity of stress response in Drosophila melanogaster originating from two distinct geographic regions and ecological habitats was examined. Adults were given a short-term, 5-day exposure to combinations of temperature and photoperiod to elicit a plastic response for three fundamental aspects of stress tolerance that vary adaptively with geography. This was replicated both in the laboratory and in outdoor enclosures in the field. In the laboratory, geographic origin was the primary determinant of the stress response. Temperature and the interaction between temperature and photoperiod also significantly affected stress resistance. In the outdoor enclosures, plasticity was distinct among traits and between geographic regions. These results demonstrate that short-term exposure of adults to ecologically relevant environmental cues results in predictable effects on multiple aspects of fitness. These patterns of plasticity vary among traits and are highly distinct between the two examined geographic regions, consistent with patterns of local adaptation to climate and associated environmental parameters.

  3. Environmental Adaptation, Phenotypic Plasticity, and Associative Learning in Insects: The Desert Locust as a Case Study.

    PubMed

    Simões, Patrício M V; Ott, Swidbert R; Niven, Jeremy E

    2016-11-01

    The ability to learn and store information should be adapted to the environment in which animals operate to confer a selective advantage. Yet the relationship between learning, memory, and the environment is poorly understood, and further complicated by phenotypic plasticity caused by the very environment in which learning and memory need to operate. Many insect species show polyphenism, an extreme form of phenotypic plasticity, allowing them to occupy distinct environments by producing two or more alternative phenotypes. Yet how the learning and memories capabilities of these alternative phenotypes are adapted to their specific environments remains unknown for most polyphenic insect species. The desert locust can exist as one of two extreme phenotypes or phases, solitarious and gregarious. Recent studies of associative food-odor learning in this locust have shown that aversive but not appetitive learning differs between phases. Furthermore, switching from the solitarious to the gregarious phase (gregarization) prevents locusts acquiring new learned aversions, enabling them to convert an aversive memory formed in the solitarious phase to an appetitive one in the gregarious phase. This conversion provides a neuroecological mechanism that matches key changes in the behavioral environments of the two phases. These findings emphasize the importance of understanding the neural mechanisms that generate ecologically relevant behaviors and the interactions between different forms of behavioral plasticity.

  4. Testing the role of phenotypic plasticity for local adaptation: growth and development in time-constrained Rana temporaria populations.

    PubMed

    Lind, M I; Johansson, F

    2011-12-01

    Phenotypic plasticity can be important for local adaptation, because it enables individuals to survive in a novel environment until genetic changes have been accumulated by genetic accommodation. By analysing the relationship between development rate and growth rate, it can be determined whether plasticity in life-history traits is caused by changed physiology or behaviour. We extended this to examine whether plasticity had been aiding local adaptation, by investigating whether the plastic response had been fixed in locally adapted populations. Tadpoles from island populations of Rana temporaria, locally adapted to different pool-drying regimes, were monitored in a common garden. Individual differences in development rate were caused by different foraging efficiency. However, developmental plasticity was physiologically mediated by trading off growth against development rate. Surprisingly, plasticity has not aided local adaptation to time-stressed environments, because local adaptation was not caused by genetic assimilation but on selection on the standing genetic variation in development time.

  5. The Phenotypic Plasticity of Duplicated Genes in Saccharomyces cerevisiae and the Origin of Adaptations

    PubMed Central

    Mattenberger, Florian; Sabater-Muñoz, Beatriz; Toft, Christina; Fares, Mario A.

    2016-01-01

    Gene and genome duplication are the major sources of biological innovations in plants and animals. Functional and transcriptional divergence between the copies after gene duplication has been considered the main driver of innovations . However, here we show that increased phenotypic plasticity after duplication plays a more major role than thought before in the origin of adaptations. We perform an exhaustive analysis of the transcriptional alterations of duplicated genes in the unicellular eukaryote Saccharomyces cerevisiae when challenged with five different environmental stresses. Analysis of the transcriptomes of yeast shows that gene duplication increases the transcriptional response to environmental changes, with duplicated genes exhibiting signatures of adaptive transcriptional patterns in response to stress. The mechanism of duplication matters, with whole-genome duplicates being more transcriptionally altered than small-scale duplicates. The predominant transcriptional pattern follows the classic theory of evolution by gene duplication; with one gene copy remaining unaltered under stress, while its sister copy presents large transcriptional plasticity and a prominent role in adaptation. Moreover, we find additional transcriptional profiles that are suggestive of neo- and subfunctionalization of duplicate gene copies. These patterns are strongly correlated with the functional dependencies and sequence divergence profiles of gene copies. We show that, unlike singletons, duplicates respond more specifically to stress, supporting the role of natural selection in the transcriptional plasticity of duplicates. Our results reveal the underlying transcriptional complexity of duplicated genes and its role in the origin of adaptations. PMID:27799339

  6. The Phenotypic Plasticity of Duplicated Genes in Saccharomyces cerevisiae and the Origin of Adaptations.

    PubMed

    Mattenberger, Florian; Sabater-Muñoz, Beatriz; Toft, Christina; Fares, Mario A

    2017-01-05

    Gene and genome duplication are the major sources of biological innovations in plants and animals. Functional and transcriptional divergence between the copies after gene duplication has been considered the main driver of innovations . However, here we show that increased phenotypic plasticity after duplication plays a more major role than thought before in the origin of adaptations. We perform an exhaustive analysis of the transcriptional alterations of duplicated genes in the unicellular eukaryote Saccharomyces cerevisiae when challenged with five different environmental stresses. Analysis of the transcriptomes of yeast shows that gene duplication increases the transcriptional response to environmental changes, with duplicated genes exhibiting signatures of adaptive transcriptional patterns in response to stress. The mechanism of duplication matters, with whole-genome duplicates being more transcriptionally altered than small-scale duplicates. The predominant transcriptional pattern follows the classic theory of evolution by gene duplication; with one gene copy remaining unaltered under stress, while its sister copy presents large transcriptional plasticity and a prominent role in adaptation. Moreover, we find additional transcriptional profiles that are suggestive of neo- and subfunctionalization of duplicate gene copies. These patterns are strongly correlated with the functional dependencies and sequence divergence profiles of gene copies. We show that, unlike singletons, duplicates respond more specifically to stress, supporting the role of natural selection in the transcriptional plasticity of duplicates. Our results reveal the underlying transcriptional complexity of duplicated genes and its role in the origin of adaptations.

  7. Climate change, adaptation, and phenotypic plasticity: the problem and the evidence

    PubMed Central

    Merilä, Juha; Hendry, Andrew P

    2014-01-01

    Many studies have recorded phenotypic changes in natural populations and attributed them to climate change. However, controversy and uncertainty has arisen around three levels of inference in such studies. First, it has proven difficult to conclusively distinguish whether phenotypic changes are genetically based or the result of phenotypic plasticity. Second, whether or not the change is adaptive is usually assumed rather than tested. Third, inferences that climate change is the specific causal agent have rarely involved the testing – and exclusion – of other potential drivers. We here review the various ways in which the above inferences have been attempted, and evaluate the strength of support that each approach can provide. This methodological assessment sets the stage for 11 accompanying review articles that attempt comprehensive syntheses of what is currently known – and not known – about responses to climate change in a variety of taxa and in theory. Summarizing and relying on the results of these reviews, we arrive at the conclusion that evidence for genetic adaptation to climate change has been found in some systems, but is still relatively scarce. Most importantly, it is clear that more studies are needed – and these must employ better inferential methods – before general conclusions can be drawn. Overall, we hope that the present paper and special issue provide inspiration for future research and guidelines on best practices for its execution. PMID:24454544

  8. Quantitative assessment of the importance of phenotypic plasticity in adaptation to climate change in wild bird populations.

    PubMed

    Vedder, Oscar; Bouwhuis, Sandra; Sheldon, Ben C

    2013-07-01

    Predictions about the fate of species or populations under climate change scenarios typically neglect adaptive evolution and phenotypic plasticity, the two major mechanisms by which organisms can adapt to changing local conditions. As a consequence, we have little understanding of the scope for organisms to track changing environments by in situ adaptation. Here, we use a detailed individual-specific long-term population study of great tits (Parus major) breeding in Wytham Woods, Oxford, UK to parameterise a mechanistic model and thus directly estimate the rate of environmental change to which in situ adaptation is possible. Using the effect of changes in early spring temperature on temporal synchrony between birds and a critical food resource, we focus in particular on the contribution of phenotypic plasticity to population persistence. Despite using conservative estimates for evolutionary and reproductive potential, our results suggest little risk of population extinction under projected local temperature change; however, this conclusion relies heavily on the extent to which phenotypic plasticity tracks the changing environment. Extrapolating the model to a broad range of life histories in birds suggests that the importance of phenotypic plasticity for adjustment to projected rates of temperature change increases with slower life histories, owing to lower evolutionary potential. Understanding the determinants and constraints on phenotypic plasticity in natural populations is thus crucial for characterising the risks that rapidly changing environments pose for the persistence of such populations.

  9. Quantitative Assessment of the Importance of Phenotypic Plasticity in Adaptation to Climate Change in Wild Bird Populations

    PubMed Central

    Vedder, Oscar; Bouwhuis, Sandra; Sheldon, Ben C.

    2013-01-01

    Predictions about the fate of species or populations under climate change scenarios typically neglect adaptive evolution and phenotypic plasticity, the two major mechanisms by which organisms can adapt to changing local conditions. As a consequence, we have little understanding of the scope for organisms to track changing environments by in situ adaptation. Here, we use a detailed individual-specific long-term population study of great tits (Parus major) breeding in Wytham Woods, Oxford, UK to parameterise a mechanistic model and thus directly estimate the rate of environmental change to which in situ adaptation is possible. Using the effect of changes in early spring temperature on temporal synchrony between birds and a critical food resource, we focus in particular on the contribution of phenotypic plasticity to population persistence. Despite using conservative estimates for evolutionary and reproductive potential, our results suggest little risk of population extinction under projected local temperature change; however, this conclusion relies heavily on the extent to which phenotypic plasticity tracks the changing environment. Extrapolating the model to a broad range of life histories in birds suggests that the importance of phenotypic plasticity for adjustment to projected rates of temperature change increases with slower life histories, owing to lower evolutionary potential. Understanding the determinants and constraints on phenotypic plasticity in natural populations is thus crucial for characterising the risks that rapidly changing environments pose for the persistence of such populations. PMID:23874152

  10. Phenotypic plasticity and adaptive evolution contribute to advancing flowering phenology in response to climate change

    PubMed Central

    Anderson, Jill T.; Inouye, David W.; McKinney, Amy M.; Colautti, Robert I.; Mitchell-Olds, Tom

    2012-01-01

    Anthropogenic climate change has already altered the timing of major life-history transitions, such as the initiation of reproduction. Both phenotypic plasticity and adaptive evolution can underlie rapid phenological shifts in response to climate change, but their relative contributions are poorly understood. Here, we combine a continuous 38 year field survey with quantitative genetic field experiments to assess adaptation in the context of climate change. We focused on Boechera stricta (Brassicaeae), a mustard native to the US Rocky Mountains. Flowering phenology advanced significantly from 1973 to 2011, and was strongly associated with warmer temperatures and earlier snowmelt dates. Strong directional selection favoured earlier flowering in contemporary environments (2010–2011). Climate change could drive this directional selection, and promote even earlier flowering as temperatures continue to increase. Our quantitative genetic analyses predict a response to selection of 0.2 to 0.5 days acceleration in flowering per generation, which could account for more than 20 per cent of the phenological change observed in the long-term dataset. However, the strength of directional selection and the predicted evolutionary response are likely much greater now than even 30 years ago because of rapidly changing climatic conditions. We predict that adaptation will likely be necessary for long-term in situ persistence in the context of climate change. PMID:22787021

  11. Phenotypic plasticity and adaptive evolution contribute to advancing flowering phenology in response to climate change.

    PubMed

    Anderson, Jill T; Inouye, David W; McKinney, Amy M; Colautti, Robert I; Mitchell-Olds, Tom

    2012-09-22

    Anthropogenic climate change has already altered the timing of major life-history transitions, such as the initiation of reproduction. Both phenotypic plasticity and adaptive evolution can underlie rapid phenological shifts in response to climate change, but their relative contributions are poorly understood. Here, we combine a continuous 38 year field survey with quantitative genetic field experiments to assess adaptation in the context of climate change. We focused on Boechera stricta (Brassicaeae), a mustard native to the US Rocky Mountains. Flowering phenology advanced significantly from 1973 to 2011, and was strongly associated with warmer temperatures and earlier snowmelt dates. Strong directional selection favoured earlier flowering in contemporary environments (2010-2011). Climate change could drive this directional selection, and promote even earlier flowering as temperatures continue to increase. Our quantitative genetic analyses predict a response to selection of 0.2 to 0.5 days acceleration in flowering per generation, which could account for more than 20 per cent of the phenological change observed in the long-term dataset. However, the strength of directional selection and the predicted evolutionary response are likely much greater now than even 30 years ago because of rapidly changing climatic conditions. We predict that adaptation will likely be necessary for long-term in situ persistence in the context of climate change.

  12. Species-specific differences in adaptive phenotypic plasticity in an ecologically relevant trophic trait: hypertrophic lips in Midas cichlid fishes.

    PubMed

    Machado-Schiaffino, Gonzalo; Henning, Frederico; Meyer, Axel

    2014-07-01

    The spectacular species richness of cichlids and their diversity in morphology, coloration, and behavior have made them an ideal model for the study of speciation and adaptive evolution. Hypertrophic lips evolved repeatedly and independently in African and Neotropical cichlid radiations. Cichlids with hypertrophic lips forage predominantly in rocky crevices and it has been hypothesized that mechanical stress caused by friction could result in larger lips through phenotypic plasticity. To test the influence of the environment on the size and development of lips, we conducted a series of breeding and feeding experiments on Midas cichlids. Full-sibs of Amphilophus labiatus (thick-lipped) and Amphilophus citrinellus (thin-lipped) each were split into a control group which was fed food from the water column and a treatment group whose food was fixed to substrates. We found strong evidence for phenotypic plasticity on lip area in the thick-lipped species, but not in the thin-lipped species. Intermediate phenotypic values were observed in hybrids from thick- and thin-lipped species reared under "control" conditions. Thus, both a genetic, but also a phenotypic plastic component is involved in the development of hypertrophic lips in Neotropical cichlids. Moreover, species-specific adaptive phenotypic plasticity was found, suggesting that plasticity is selected for in recent thick-lipped species.

  13. Testing local host adaptation and phenotypic plasticity in a herbivore when alternative related host plants occur sympatrically.

    PubMed

    Ruiz-Montoya, Lorena; Núñez-Farfán, Juan

    2013-01-01

    Host race formation in phytophagous insects can be an early stage of adaptive speciation. However, the evolution of phenotypic plasticity in host use is another possible outcome. Using a reciprocal transplant experiment we tested the hypothesis of local adaptation in the aphid Brevicoryne brassicae. Aphid genotypes derived from two sympatric host plants, Brassica oleracea and B. campestris, were assessed in order to measure the extent of phenotypic plasticity in morphological and life history traits in relation to the host plants. We obtained an index of phenotypic plasticity for each genotype. Morphological variation of aphids was summarized by principal components analysis. Significant effects of recipient host on morphological variation and life history traits (establishment, age at first reproduction, number of nymphs, and intrinsic growth rate) were detected. We did not detected genotype × host plant interaction; in general the genotypes developed better on B. campestris, independent of the host plant species from which they were collected. Therefore, there was no evidence to suggest local adaptation. Regarding plasticity, significant differences among genotypes in the index of plasticity were detected. Furthermore, significant selection on PC1 (general aphid body size) on B. campestris, and on PC1 and PC2 (body length relative to body size) on B. oleracea was detected. The elevation of the reaction norm of PC1 and the slope of the reaction norm for PC2 (i.e., plasticity) were under directional selection. Thus, host plant species constitute distinct selective environments for B. brassicae. Aphid genotypes expressed different phenotypes in response to the host plant with low or nil fitness costs. Phenotypic plasticity and gene flow limits natural selection for host specialization promoting the maintenance of genetic variation in host exploitation.

  14. Testing Local Host Adaptation and Phenotypic Plasticity in a Herbivore When Alternative Related Host Plants Occur Sympatrically

    PubMed Central

    Ruiz-Montoya, Lorena; Núñez-Farfán, Juan

    2013-01-01

    Host race formation in phytophagous insects can be an early stage of adaptive speciation. However, the evolution of phenotypic plasticity in host use is another possible outcome. Using a reciprocal transplant experiment we tested the hypothesis of local adaptation in the aphid Brevicoryne brassicae. Aphid genotypes derived from two sympatric host plants, Brassica oleracea and B. campestris, were assessed in order to measure the extent of phenotypic plasticity in morphological and life history traits in relation to the host plants. We obtained an index of phenotypic plasticity for each genotype. Morphological variation of aphids was summarized by principal components analysis. Significant effects of recipient host on morphological variation and life history traits (establishment, age at first reproduction, number of nymphs, and intrinsic growth rate) were detected. We did not detected genotype × host plant interaction; in general the genotypes developed better on B. campestris, independent of the host plant species from which they were collected. Therefore, there was no evidence to suggest local adaptation. Regarding plasticity, significant differences among genotypes in the index of plasticity were detected. Furthermore, significant selection on PC1 (general aphid body size) on B. campestris, and on PC1 and PC2 (body length relative to body size) on B. oleracea was detected. The elevation of the reaction norm of PC1 and the slope of the reaction norm for PC2 (i.e., plasticity) were under directional selection. Thus, host plant species constitute distinct selective environments for B. brassicae. Aphid genotypes expressed different phenotypes in response to the host plant with low or nil fitness costs. Phenotypic plasticity and gene flow limits natural selection for host specialization promoting the maintenance of genetic variation in host exploitation. PMID:24265743

  15. Do invasive species show higher phenotypic plasticity than native species and, if so, is it adaptive? A meta-analysis.

    PubMed

    Davidson, Amy Michelle; Jennions, Michael; Nicotra, Adrienne B

    2011-04-01

    Do invasive plant species have greater phenotypic plasticity than non-invasive species? And, if so, how does this affect their fitness relative to native, non-invasive species? What role might this play in plant invasions? To answer these long-standing questions, we conducted a meta-analysis using data from 75 invasive/non-invasive species pairs. Our analysis shows that invasive species demonstrate significantly higher phenotypic plasticity than non-invasive species. To examine the adaptive benefit of this plasticity, we plotted fitness proxies against measures of plasticity in several growth, morphological and physiological traits to test whether greater plasticity is associated with an improvement in estimated fitness. Invasive species were nearly always more plastic in their response to greater resource availability than non-invasives but this plasticity was only sometimes associated with a fitness benefit. Intriguingly, non-invasive species maintained greater fitness homoeostasis when comparing growth between low and average resource availability. Our finding that invasive species are more plastic in a variety of traits but that non-invasive species respond just as well, if not better, when resources are limiting, has interesting implications for predicting responses to global change.

  16. Adaptive phenotypic plasticity of Siberian elm in response to drought stress: increased stomatal pore depth.

    PubMed

    Park, Go Eun; Kim, Ki Woo; Lee, Don Koo; Hyun, Jung Oh

    2013-08-01

    Leaf stomatal characteristics of Siberian elm (Ulmus pumila) were investigated by electron microscopy and white light scanning interferometry. On the basis of average annual precipitations, two types of tree specimens were collected from Korea, China, and Mongolia: (1) trees under normal environmental conditions and (2) trees under arid conditions. Field emission scanning electron microscopy revealed oval-shaped stomata on the lower surface, and they were ca. 20 μm in width. In-lens secondary electron imaging showed differences in electron density and stomatal pore depth between the two types. According to the line profile analysis by white light scanning interferometry, stomata under arid conditions appeared to have higher levels of the stomatal pore depth than ones under normal conditions. Focused ion beam-field emission electron microscopy supported the increased stomatal pore depth with the increasing drought stress gradient. These results suggest that complementary microscopy can be employed to unravel the adaptive phenotypic plasticity of Siberian elm in response to drought stress.

  17. Regulatory mechanisms link phenotypic plasticity to evolvability.

    PubMed

    van Gestel, Jordi; Weissing, Franz J

    2016-04-18

    Organisms have a remarkable capacity to respond to environmental change. They can either respond directly, by means of phenotypic plasticity, or they can slowly adapt through evolution. Yet, how phenotypic plasticity links to evolutionary adaptability is largely unknown. Current studies of plasticity tend to adopt a phenomenological reaction norm (RN) approach, which neglects the mechanisms underlying plasticity. Focusing on a concrete question - the optimal timing of bacterial sporulation - we here also consider a mechanistic approach, the evolution of a gene regulatory network (GRN) underlying plasticity. Using individual-based simulations, we compare the RN and GRN approach and find a number of striking differences. Most importantly, the GRN model results in a much higher diversity of responsive strategies than the RN model. We show that each of the evolved strategies is pre-adapted to a unique set of unseen environmental conditions. The regulatory mechanisms that control plasticity therefore critically link phenotypic plasticity to the adaptive potential of biological populations.

  18. The effects of phenotypic plasticity and local adaptation on forecasts of species range shifts under climate change.

    PubMed

    Valladares, Fernando; Matesanz, Silvia; Guilhaumon, François; Araújo, Miguel B; Balaguer, Luis; Benito-Garzón, Marta; Cornwell, Will; Gianoli, Ernesto; van Kleunen, Mark; Naya, Daniel E; Nicotra, Adrienne B; Poorter, Hendrik; Zavala, Miguel A

    2014-11-01

    Species are the unit of analysis in many global change and conservation biology studies; however, species are not uniform entities but are composed of different, sometimes locally adapted, populations differing in plasticity. We examined how intraspecific variation in thermal niches and phenotypic plasticity will affect species distributions in a warming climate. We first developed a conceptual model linking plasticity and niche breadth, providing five alternative intraspecific scenarios that are consistent with existing literature. Secondly, we used ecological niche-modeling techniques to quantify the impact of each intraspecific scenario on the distribution of a virtual species across a geographically realistic setting. Finally, we performed an analogous modeling exercise using real data on the climatic niches of different tree provenances. We show that when population differentiation is accounted for and dispersal is restricted, forecasts of species range shifts under climate change are even more pessimistic than those using the conventional assumption of homogeneously high plasticity across a species' range. Suitable population-level data are not available for most species so identifying general patterns of population differentiation could fill this gap. However, the literature review revealed contrasting patterns among species, urging greater levels of integration among empirical, modeling and theoretical research on intraspecific phenotypic variation.

  19. Habitat Choice and Temporal Variation Alter the Balance between Adaptation by Genetic Differentiation, a Jack-of-All-Trades Strategy, and Phenotypic Plasticity.

    PubMed

    Scheiner, Samuel M

    2016-05-01

    Confronted with variable environments, species adapt in several ways, including genetic differentiation, a jack-of-all-trades strategy, or phenotypic plasticity. Adaptive habitat choice favors genetic differentiation and local adaptation over a generalist, jack-of-all-trades strategy. Models predict that, absent plasticity costs, variable environments generally favor phenotypic plasticity over genetic differentiation and being a jack-of-all-trades generalist. It is unknown how habitat choice might affect the evolution of plasticity. Using an individual-based simulation model, I explored the interaction of choice and plasticity. With only spatial variation, habitat choice promotes genetic differentiation over a jack-of-all-trades strategy or phenotypic plasticity. In the absence of plasticity, temporal variation favors a jack-of-all-trades strategy over choice-mediated genetic differentiation; when plasticity is an option, it is favored. This occurs because habitat choice creates a feedback between genetic differentiation and dispersal rates. As demes become better adapted to their local environments, the effective dispersal rate decreases, because more individuals have very high fitness and so choose not to disperse, reinforcing local stabilizing selection and negating selection for plasticity. Temporal variation breaks that feedback. These results point to a potential data paradox: systems with habitat choice may have the lowest actual movement rates. The potential for adaptive habitat choice may be very common, but its existence may reduce observed dispersal rates enough that we do not recognize systems where it may be present, warranting further exploration of likely systems.

  20. Population differences in host use by a seed-beetle: local adaptation, phenotypic plasticity and maternal effects.

    PubMed

    Amarillo-Suárez, Angela R; Fox, Charles W

    2006-11-01

    For insects that develop inside discrete hosts, both host size and host quality constrain offspring growth, influencing the evolution of body size and life history traits. Using a two-generation common garden experiment, we quantified the contribution of maternal and rearing hosts to differences in growth and life history traits between populations of the seed-feeding beetle Stator limbatus that use a large-seeded host, Acacia greggii, and a small-seeded host, Pseudosamanea guachapele. Populations differed genetically for all traits when beetles were raised in a common garden. Contrary to expectations from the local adaptation hypothesis, beetles from all populations were larger, developed faster and had higher survivorship when reared on seeds of A. greggii (the larger host), irrespective of their native host. We observed two host plant-mediated maternal effects: offspring matured sooner, regardless of their rearing host, when their mothers were reared on P. guachapele (this was not caused by an effect of rearing host on egg size), and females laid larger eggs on P. guachapele. This is the first study to document plasticity by S. limbatus in response to P. guachapele, suggesting that plasticity is an ancestral trait in S. limbatus that likely plays an important role in diet expansion. Although differences between populations in growth and life history traits are likely adaptations to their host plants, host-associated maternal effects, partly mediated by maternal egg size plasticity, influence growth and life history traits and likely play an important role in the evolution of the breadth of S. limbatus' diet. More generally, phenotypic plasticity mediates the fitness consequences of using novel hosts, likely facilitating colonization of new hosts, but also buffering herbivores from selection post-colonization. Plasticity in response to novel versus normal hosts varied among our study populations such that disentangling the historical role of plasticity in

  1. Ecotope effect in Triatoma brasiliensis (Hemiptera: Reduviidae) suggests phenotypic plasticity rather than adaptation.

    PubMed

    Batista, V S P; Fernandes, F A; Cordeiro-Estrela, P; Sarquis, O; Lima, M M

    2013-09-01

    Triatoma brasiliensis (Hemiptera: Reduviidae) is an important vector of Chagas' disease in both sylvatic and peridomestic ecotopes. Discriminating between these populations of Triatominae has been proposed as a means of investigating re-infestation rates of human dwellings. Geometric morphometrics have been widely applied in the study of Triatominae polymorphisms at species and population levels. This study characterizes morphometric differences between sylvatic and peridomestic populations, as well as between sexes in T. brasiliensis specimens from Jaguaruana, Ceará, in northeastern Brazil. No differences in either the shape or size of the cephalic capsule were apparent between sexes or ecotopes. However, the wings showed differentiation in shape and size. Sexual dimorphism was detected, with females presenting significantly higher values and conformations. Size differentiation was also evident, with sylvatic specimens being generally larger than peridomestic examples. These results indicate that differences in the wings of T. brasiliensis may be related to the existence of phenotypic plasticity, and variations in size and shape may be associated with different ecotopes, possibly as a result of conditions in each micro-habitat, such as temperature, relative humidity, food supply and density.

  2. Phenotypic plasticity and local adaptation in leaf ecophysiological traits of 13 contrasting cork oak populations under different water availabilities.

    PubMed

    Ramírez-Valiente, Jose Alberto; Sánchez-Gómez, David; Aranda, Ismael; Valladares, Fernando

    2010-05-01

    Plants distributed across a wide range of environmental conditions are submitted to differential selective pressures. Long-term selection can lead to the development of adaptations to the local environment, generating ecotypic differentiation. Additionally, plant species can cope with this environmental variability by phenotypic plasticity. In this study, we examine the importance of both processes in coping with environmental heterogeneity in the Mediterranean sclerophyllous cork oak Quercus suber. For this purpose, we measured growth and key functional traits at the leaf level in 9-year-old plants across 2 years of contrasting precipitation (2005 and 2006) in a common garden. Plants were grown from acorns originated from 13 populations spanning a wide range of climates along the distribution range of the species. The traits measured were: leaf size (LS), specific leaf area (SLA), carbon isotope discrimination (Delta(13)C) and leaf nitrogen content per unit mass (N(mass)). Inter-population differences in LS, SLA and Delta(13)C were found. These differences were associated with rainfall and temperature at the sites of origin, suggesting local adaptation in response to diverging climates. Additionally, SLA and LS exhibited positive responses to the increase in annual rainfall. Year effect explained 28% of the total phenotypic variance in LS and 2.7% in SLA. There was a significant genotype x environment interaction for shoot growth and a phenotypic correlation between the difference in shoot growth among years and the annual mean temperature at origin. This suggests that populations originating from warm sites can benefit more from wet conditions than populations from cool sites. Finally, we investigated the relationships between functional traits and aboveground growth by several regression models. Our results showed that plants with lower SLA presented larger aboveground growth in a dry year and plants with larger leaf sizes displayed larger growth rates in both

  3. Phenotypic plasticity and experimental evolution.

    PubMed

    Garland, Theodore; Kelly, Scott A

    2006-06-01

    Natural or artificial selection that favors higher values of a particular trait within a given population should engender an evolutionary response that increases the mean value of the trait. For this prediction to hold, the phenotypic variance of the trait must be caused in part by additive effects of alleles segregating in the population, and also the trait must not be too strongly genetically correlated with other traits that are under selection. Another prediction, rarely discussed in the literature, is that directional selection should favor alleles that increase phenotypic plasticity in the direction of selection, where phenotypic plasticity is defined as the ability of one genotype to produce more than one phenotype when exposed to different environments. This prediction has received relatively little empirical attention. Nonetheless, many laboratory experiments impose selection regimes that could allow for the evolution of enhanced plasticity (e.g. desiccation trials with Drosophila that last for several hours or days). We review one example that involved culturing of Drosophila on lemon for multiple generations and then tested for enhanced plasticity of detoxifying enzymes. We also review an example with vertebrates that involves selective breeding for high voluntary activity levels in house mice, targeting wheel-running behavior on days 5+6 of a 6-day wheel exposure. This selection regime allows for the possibility of wheel running itself or subordinate traits that support such running to increase in plasticity over days 1-4 of wheel access. Indeed, some traits, such as the concentration of the glucose transporter GLUT4 in gastrocnemius muscle, do show enhanced plasticity in the selected lines over a 5-6 day period. In several experiments we have housed mice from both the Selected (S) and Control (C) lines with or without wheel access for several weeks to test for differences in plasticity (training effects). A variety of patterns were observed, including

  4. Phenotypic plasticity in bacterial plasmids.

    PubMed Central

    Turner, Paul E

    2004-01-01

    Plasmid pB15 was previously shown to evolve increased horizontal (infectious) transfer at the expense of reduced vertical (intergenerational) transfer and vice versa, a key trade-off assumed in theories of parasite virulence. Whereas the models predict that susceptible host abundance should determine which mode of transfer is selectively favored, host density failed to mediate the trade-off in pB15. One possibility is that the plasmid's transfer deviates from the assumption that horizontal spread (conjugation) occurs in direct proportion to cell density. I tested this hypothesis using Escherichia coli/pB15 associations in laboratory serial culture. Contrary to most models of plasmid transfer kinetics, my data show that pB15 invades static (nonshaking) bacterial cultures only at intermediate densities. The results can be explained by phenotypic plasticity in traits governing plasmid transfer. As cells become more numerous, the plasmid's conjugative transfer unexpectedly declines, while the trade-off between transmission routes causes vertical transfer to increase. Thus, at intermediate densities the plasmid's horizontal transfer can offset selection against plasmid-bearing cells, but at high densities pB15 conjugates so poorly that it cannot invade. I discuss adaptive vs. nonadaptive causes for the phenotypic plasticity, as well as potential mechanisms that may lead to complex transfer dynamics of plasmids in liquid environments. PMID:15166133

  5. Covariance of phenotypically plastic traits induces an adaptive shift in host selection behaviour

    PubMed Central

    Henry, Lee M; Roitberg, Bernard D; Gillespie, David R

    2006-01-01

    Flexibility in adult body size allows generalist parasitoids to use many host species at a cost of producing a range of adult sizes. Consequently, host selection behaviour must also maintain a level of flexibility as adult size is related to capture efficiency. In the present study, we investigated covariance of two plastic traits—size at pupation and host size selection behaviour—using Aphidius ervi reared on either Acyrthosiphon pisum or Aulacorthum solani, generating females of disparate sizes. Natal host was shown to change the ranking of perceived host quality with relation to host size. Parasitoids preferentially attacked hosts that corresponded to the size of the second instar of their natal host species. This resulted in optimal host selection behaviour when parasitoids were exposed to the same host species from which they emerged. Parasitoid size was positively correlated with host size preference, indicating that females use relative measurements when selecting suitable hosts. These coadapted gene complexes allow generalist parasitoids to effectively use multiple host species over several generations. However, the fixed nature of the behavioural response, within a parasitoid's lifetime, suggests that these traits may have evolved in a patchy host species environment. PMID:17015365

  6. Phenotypic plasticity with instantaneous but delayed switches.

    PubMed

    Utz, Margarete; Jeschke, Jonathan M; Loeschcke, Volker; Gabriel, Wilfried

    2014-01-07

    Phenotypic plasticity is a widespread phenomenon, allowing organisms to better adapt to changing environments. Most empirical and theoretical studies are restricted to irreversible plasticity where the expression of a specific phenotype is mostly determined during development. However, reversible plasticity is not uncommon; here, organisms are able to switch back and forth between phenotypes. We present two optimization models for the fitness of (i) non-plastic, (ii) irreversibly plastic, and (iii) reversibly plastic genotypes in a fluctuating environment. In one model, the fitness values of an organism during different life phases act together multiplicatively (so as to consider traits that are related to survival). The other model additionally considers additive effects (corresponding to traits related to fecundity). Both models yield qualitatively similar results. If the only costs of reversible plasticity are due to temporal maladaptation while switching between phenotypes, reversibility is virtually always advantageous over irreversibility, especially for slow environmental fluctuations. If reversibility implies an overall decreased fitness, then irreversibility is advantageous if the environment fluctuates quickly or if stress events last relatively short. Our results are supported by observations from different types of organisms and have implications for many basic and applied research questions, e.g., on invasive alien species.

  7. The ubiquity of phenotypic plasticity in plants: a synthesis.

    PubMed

    Palacio-López, Kattia; Beckage, Brian; Scheiner, Samuel; Molofsky, Jane

    2015-08-01

    Adaptation to heterogeneous environments can occur via phenotypic plasticity, but how often this occurs is unknown. Reciprocal transplant studies provide a rich dataset to address this issue in plant populations because they allow for a determination of the prevalence of plastic versus canalized responses. From 31 reciprocal transplant studies, we quantified the frequency of five possible evolutionary patterns: (1) canalized response-no differentiation: no plasticity, the mean phenotypes of the populations are not different; (2) canalized response-population differentiation: no plasticity, the mean phenotypes of the populations are different; (3) perfect adaptive plasticity: plastic responses with similar reaction norms between populations; (4) adaptive plasticity: plastic responses with parallel, but not congruent reaction norms between populations; and (5) nonadaptive plasticity: plastic responses with differences in the slope of the reaction norms. The analysis included 362 records: 50.8% life-history traits, 43.6% morphological traits, and 5.5% physiological traits. Across all traits, 52% of the trait records were not plastic, and either showed no difference in means across sites (17%) or differed among sites (83%). Among the 48% of trait records that showed some sort of plasticity, 49.4% showed perfect adaptive plasticity, 19.5% adaptive plasticity, and 31% nonadaptive plasticity. These results suggest that canalized responses are more common than adaptive plasticity as an evolutionary response to environmental heterogeneity.

  8. The ubiquity of phenotypic plasticity in plants: a synthesis

    PubMed Central

    Palacio-López, Kattia; Beckage, Brian; Scheiner, Samuel; Molofsky, Jane

    2015-01-01

    Adaptation to heterogeneous environments can occur via phenotypic plasticity, but how often this occurs is unknown. Reciprocal transplant studies provide a rich dataset to address this issue in plant populations because they allow for a determination of the prevalence of plastic versus canalized responses. From 31 reciprocal transplant studies, we quantified the frequency of five possible evolutionary patterns: (1) canalized response–no differentiation: no plasticity, the mean phenotypes of the populations are not different; (2) canalized response–population differentiation: no plasticity, the mean phenotypes of the populations are different; (3) perfect adaptive plasticity: plastic responses with similar reaction norms between populations; (4) adaptive plasticity: plastic responses with parallel, but not congruent reaction norms between populations; and (5) nonadaptive plasticity: plastic responses with differences in the slope of the reaction norms. The analysis included 362 records: 50.8% life-history traits, 43.6% morphological traits, and 5.5% physiological traits. Across all traits, 52% of the trait records were not plastic, and either showed no difference in means across sites (17%) or differed among sites (83%). Among the 48% of trait records that showed some sort of plasticity, 49.4% showed perfect adaptive plasticity, 19.5% adaptive plasticity, and 31% nonadaptive plasticity. These results suggest that canalized responses are more common than adaptive plasticity as an evolutionary response to environmental heterogeneity. PMID:26380672

  9. Phenotypic plasticity and divergence in gene expression.

    PubMed

    Healy, Timothy M; Schulte, Patricia M

    2015-07-01

    The extent to which phenotypic plasticity, or the ability of a single genotype to produce different phenotypes in different environments, impedes or promotes genetic divergence has been a matter of debate within evolutionary biology for many decades (see, for example, Ghalambor et al. ; Pfennig et al. ). Similarly, the role of evolution in shaping phenotypic plasticity remains poorly understood (Pigliucci ). In this issue of Molecular Ecology, Dayan et al. () provide empirical data relevant to these questions by assessing the extent of plasticity and divergence in the expression levels of 2272 genes in muscle tissue from killifish (genus Fundulus) exposed to different temperatures. F. heteroclitus (Fig. A) and F. grandis are minnows that inhabit estuarine marshes (Fig. B) along the coasts of the Atlantic Ocean and Gulf of Mexico in North America. These habitats undergo large variations in temperature both daily and seasonally, and these fish are known to demonstrate substantial phenotypic plasticity in response to temperature change (e.g. Fangue et al. ). Furthermore, the range of F. heteroclitus spans a large latitudinal gradient of temperatures, such that northern populations experience temperatures that are on average ~10°C colder than do southern populations (Schulte ). By comparing gene expression patterns between populations of these fish from different thermal habitats held in the laboratory at three different temperatures, Dayan et al. () address two important questions regarding the interacting effects of plasticity and evolution: (i) How does phenotypic plasticity affect adaptive divergence? and (ii) How does adaptive divergence affect plasticity?

  10. Genetic Regulation of Phenotypic Plasticity and Canalisation in Yeast Growth.

    PubMed

    Yadav, Anupama; Dhole, Kaustubh; Sinha, Himanshu

    2016-01-01

    The ability of a genotype to show diverse phenotypes in different environments is called phenotypic plasticity. Phenotypic plasticity helps populations to evade extinctions in novel environments, facilitates adaptation and fuels evolution. However, most studies focus on understanding the genetic basis of phenotypic regulation in specific environments. As a result, while it's evolutionary relevance is well established, genetic mechanisms regulating phenotypic plasticity and their overlap with the environment specific regulators is not well understood. Saccharomyces cerevisiae is highly sensitive to the environment, which acts as not just external stimulus but also as signalling cue for this unicellular, sessile organism. We used a previously published dataset of a biparental yeast population grown in 34 diverse environments and mapped genetic loci regulating variation in phenotypic plasticity, plasticity QTL, and compared them with environment-specific QTL. Plasticity QTL is one whose one allele exhibits high plasticity whereas the other shows a relatively canalised behaviour. We mapped phenotypic plasticity using two parameters-environmental variance, an environmental order-independent parameter and reaction norm (slope), an environmental order-dependent parameter. Our results show a partial overlap between pleiotropic QTL and plasticity QTL such that while some plasticity QTL are also pleiotropic, others have a significant effect on phenotypic plasticity without being significant in any environment independently. Furthermore, while some plasticity QTL are revealed only in specific environmental orders, we identify large effect plasticity QTL, which are order-independent such that whatever the order of the environments, one allele is always plastic and the other is canalised. Finally, we show that the environments can be divided into two categories based on the phenotypic diversity of the population within them and the two categories have differential regulators of

  11. Phenotypic plasticity of nest timing in a post-glacial landscape: how do reptiles adapt to seasonal time constraints?

    PubMed

    Edge, Christopher B; Rollinson, Njal; Brooks, Ronald J; Congdon, Justin D; Iverson, John B; Janzen, Fredric J; Litzgus, Jacqueline D

    2017-02-01

    Life histories evolve in response to constraints on the time available for growth and development. Nesting date and its plasticity in response to spring temperature may therefore be important components of fitness in oviparous ectotherms near their northern range limit, as reproducing early provides more time for embryos to complete development before winter. We used data collected over several decades to compare air temperature and nest date plasticity in populations of painted turtles and snapping turtles from a relatively warm environment (southeastern Michigan) near the southern extent of the last glacial maximum to a relatively cool environment (central Ontario) near the northern extent of post-glacial recolonization. For painted turtles, population-level differences in reaction norm elevation for two phenological traits were consistent with adaptation to time constraints, but no differences in reaction norm slopes were observed. For snapping turtle populations, the difference in reaction norm elevation for a single phenological trait was in the opposite direction of what was expected under adaptation to time constraints, and no difference in reaction norm slope was observed. Finally, among-individual variation in individual plasticity for nesting date was detected only in the northern population of snapping turtles, suggesting that reaction norms are less canalized in this northern population. Overall, we observed evidence of phenological adaptation, and possibly maladaptation, to time constraints in long-lived reptiles. Where present, (mal)adaptation occurred by virtue of differences in reaction norm elevation, not reaction norm slope. Glacial history, generation time, and genetic constraint may all play an important role in the evolution of phenological timing and its plasticity in long-lived reptiles.

  12. Evolution of phenotypic plasticity in colonizing species.

    PubMed

    Lande, Russell

    2015-05-01

    I elaborate an hypothesis to explain inconsistent empirical findings comparing phenotypic plasticity in colonizing populations or species with plasticity from their native or ancestral range. Quantitative genetic theory on the evolution of plasticity reveals that colonization of a novel environment can cause a transient increase in plasticity: a rapid initial increase in plasticity accelerates evolution of a new optimal phenotype, followed by slow genetic assimilation of the new phenotype and reduction of plasticity. An association of colonization with increased plasticity depends on the difference in the optimal phenotype between ancestral and colonized environments, the difference in mean, variance and predictability of the environment, the cost of plasticity, and the time elapsed since colonization. The relative importance of these parameters depends on whether a phenotypic character develops by one-shot plasticity to a constant adult phenotype or by labile plasticity involving continuous and reversible development throughout adult life.

  13. Endothelial Plasticity: Shifting Phenotypes through Force Feedback

    PubMed Central

    Krenning, Guido; Barauna, Valerio G.; Krieger, José E.; Harmsen, Martin C.; Moonen, Jan-Renier A. J.

    2016-01-01

    The endothelial lining of the vasculature is exposed to a large variety of biochemical and hemodynamic stimuli with different gradients throughout the vascular network. Adequate adaptation requires endothelial cells to be highly plastic, which is reflected by the remarkable heterogeneity of endothelial cells in tissues and organs. Hemodynamic forces such as fluid shear stress and cyclic strain are strong modulators of the endothelial phenotype and function. Although endothelial plasticity is essential during development and adult physiology, proatherogenic stimuli can induce adverse plasticity which contributes to disease. Endothelial-to-mesenchymal transition (EndMT), the hallmark of endothelial plasticity, was long thought to be restricted to embryonic development but has emerged as a pathologic process in a plethora of diseases. In this perspective we argue how shear stress and cyclic strain can modulate EndMT and discuss how this is reflected in atherosclerosis and pulmonary arterial hypertension. PMID:26904133

  14. Evolution and ecology meet molecular genetics: adaptive phenotypic plasticity in two isolated Negev desert populations of Acacia raddiana at either end of a rainfall gradient

    PubMed Central

    Ward, David; Shrestha, Madan K.; Golan-Goldhirsh, Avi

    2012-01-01

    Background and Aims The ecological, evolutionary and genetic bases of population differentiation in a variable environment are often related to the selection pressures that plants experience. We compared differences in several growth- and defence-related traits in two isolated populations of Acacia raddiana trees from sites at either end of an extreme environmental gradient in the Negev desert. Methods We used random amplified polymorphic DNA (RAPD) to determine the molecular differences between populations. We grew plants under two levels of water, three levels of nutrients and three levels of herbivory to test for phenotypic plasticity and adaptive phenotypic plasticity. Key Results The RAPD analyses showed that these populations are highly genetically differentiated. Phenotypic plasticity in various morphological traits in A. raddiana was related to patterns of population genetic differentiation between the two study sites. Although we did not test for maternal effects in these long-lived trees, significant genotype × environment (G × E) interactions in some of these traits indicated that such plasticity may be adaptive. Conclusions The main selection pressure in this desert environment, perhaps unsurprisingly, is water. Increased water availability resulted in greater growth in the southern population, which normally receives far less rain than the northern population. Even under the conditions that we defined as low water and/or nutrients, the performance of the seedlings from the southern population was significantly better, perhaps reflecting selection for these traits. Consistent with previous studies of this genus, there was no evidence of trade-offs between physical and chemical defences and plant growth parameters in this study. Rather, there appeared to be positive correlations between plant size and defence parameters. The great variation in several traits in both populations may result in a diverse potential for responding to selection pressures in

  15. Amphibious fishes: evolution and phenotypic plasticity.

    PubMed

    Wright, Patricia A; Turko, Andy J

    2016-08-01

    Amphibious fishes spend part of their life in terrestrial habitats. The ability to tolerate life on land has evolved independently many times, with more than 200 extant species of amphibious fishes spanning 17 orders now reported. Many adaptations for life out of water have been described in the literature, and adaptive phenotypic plasticity may play an equally important role in promoting favourable matches between the terrestrial habitat and behavioural, physiological, biochemical and morphological characteristics. Amphibious fishes living at the interface of two very different environments must respond to issues relating to buoyancy/gravity, hydration/desiccation, low/high O2 availability, low/high CO2 accumulation and high/low NH3 solubility each time they traverse the air-water interface. Here, we review the literature for examples of plastic traits associated with the response to each of these challenges. Because there is evidence that phenotypic plasticity can facilitate the evolution of fixed traits in general, we summarize the types of investigations needed to more fully determine whether plasticity in extant amphibious fishes can provide indications of the strategies used during the evolution of terrestriality in tetrapods.

  16. Unusual predator-prey dynamics under reciprocal phenotypic plasticity.

    PubMed

    Mougi, Akihiko

    2012-07-21

    Recent theories and experiments have shown that plasticity, such as an inducible defense or an inducible offense in predator-prey interactions, strongly influences the stability of the population dynamics. However, such plastic adaptation has not been expected to cause unusual dynamics such as antiphase cycles, which occur in experimental predator-prey systems with evolutionary adaptation in the defensive trait of prey. Here I show that antiphase cycles and cryptic cycles (a large population fluctuation in one species with almost no change in the population of the other species) can occur in a predator-prey system when both member species can change their phenotypes through adaptive plasticity (inducible defenses and offenses). I consider a familiar type of predator-prey system in which both species can change their morphology or behavior through phenotypic plasticity. The plasticity, that is, the ability to change between distinct phenotypes, is assumed to occur so as to maximize their fitness. I examined how the reciprocal adaptive plasticity influences the population dynamics. The results show that unusual dynamics such as antiphase population cycles and cryptic cycles can occur when both species show inducible plasticity. The unusual dynamics are particularly likely to occur when the carrying capacity of the prey is small (the density dependence of the prey's growth is strong). The unusual predator-prey dynamics may be induced by phenotypic plasticity as long as the phenotypic change occurs to maximize fitness.

  17. Ocean acidification challenges copepod phenotypic plasticity

    NASA Astrophysics Data System (ADS)

    Vehmaa, Anu; Almén, Anna-Karin; Brutemark, Andreas; Paul, Allanah; Riebesell, Ulf; Furuhagen, Sara; Engström-Öst, Jonna

    2016-11-01

    Ocean acidification is challenging phenotypic plasticity of individuals and populations. Calanoid copepods (zooplankton) are shown to be fairly plastic against altered pH conditions, and laboratory studies indicate that transgenerational effects are one mechanism behind this plasticity. We studied phenotypic plasticity of the copepod Acartia sp. in the course of a pelagic, large-volume mesocosm study that was conducted to investigate ecosystem and biogeochemical responses to ocean acidification. We measured copepod egg production rate, egg-hatching success, adult female size and adult female antioxidant capacity (ORAC) as a function of acidification (fCO2 ˜ 365-1231 µatm) and as a function of quantity and quality of their diet. We used an egg transplant experiment to reveal whether transgenerational effects can alleviate the possible negative effects of ocean acidification on offspring development. We found significant negative effects of ocean acidification on adult female size. In addition, we found signs of a possible threshold at high fCO2, above which adaptive maternal effects cannot alleviate the negative effects of acidification on egg-hatching and nauplii development. We did not find support for the hypothesis that insufficient food quantity (total particulate carbon < 55 µm) or quality (C : N) weakens the transgenerational effects. However, females with high-ORAC-produced eggs with high hatching success. Overall, these results indicate that Acartia sp. could be affected by projected near-future CO2 levels.

  18. Relaxed selection is a precursor to the evolution of phenotypic plasticity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phenotypic plasticity represents one of the most important ways that organisms adaptively respond to environmental variation. Alternate phenotypes produced through phenotypic plasiticity generally arise through conditional gene expression, which is predicted to result in relaxed selective constrain...

  19. Genetic adaptation and phenotypic plasticity contribute to greater leaf hydraulic tolerance in response to drought in warmer climates.

    PubMed

    Blackman, Chris J; Aspinwall, Michael J; Tissue, David T; Rymer, Paul D

    2017-02-09

    The ability of plants to maintain an intact water transport system in leaves under drought conditions is intimately linked to survival and can been be seen as adaptive in shaping species climatic limits. Large differences in leaf hydraulic vulnerability to drought are known among species from contrasting climates, yet whether this trait varies among populations within a single species and, furthermore, whether it is altered by changes in growth conditions, remain unclear. We examined intraspecific variation in both leaf water transport capacity (Kleaf) and leaf hydraulic vulnerability to drought (P50leaf) among eight populations of Corymbia calophylla (R. Br.) K.D. Hill & L.A.S. Johnson (Myrtaceae) from both cool and warm climatic regions grown reciprocally under two temperature treatments representing the cool and warm edge of the species distribution. Kleaf did not vary between cool and warm-climate populations, nor was it affected by variable growth temperature. In contrast, population origin and growth temperature independently altered P50leaf. Using data pooled across growth temperatures, cool-climate populations showed significantly higher leaf hydraulic vulnerability (P50leaf = -3.55 ± 0.18 MPa) than warm-climate populations (P50leaf = -3.78 ± 0.08 MPa). Across populations, P50leaf decreased as population home-climate temperature increased, but was unrelated to rainfall and aridity. For populations from both cool and warm climatic regions, P50leaf was lower under the warmer growth conditions. These results provide evidence of trait plasticity in leaf hydraulic vulnerability to drought in response to variable growth temperature. Furthermore, they suggest that climate, and in particular temperature, may be a strong selective force in shaping intraspecific variation in leaf hydraulic vulnerability to drought.

  20. Modeling phenotypic plasticity in growth trajectories: a statistical framework.

    PubMed

    Wang, Zhong; Pang, Xiaoming; Wu, Weimiao; Wang, Jianxin; Wang, Zuoheng; Wu, Rongling

    2014-01-01

    Phenotypic plasticity, that is multiple phenotypes produced by a single genotype in response to environmental change, has been thought to play an important role in evolution and speciation. Historically, knowledge about phenotypic plasticity has resulted from the analysis of static traits measured at a single time point. New insight into the adaptive nature of plasticity can be gained by an understanding of how organisms alter their developmental processes in a range of environments. Recent advances in statistical modeling of functional data and developmental genetics allow us to construct a dynamic framework of plastic response in developmental form and pattern. Under this framework, development, genetics, and evolution can be synthesized through statistical bridges to better address how evolution results from phenotypic variation in the process of development via genetic alterations.

  1. Phenotypic plasticity in freshwater picocyanobacteria.

    PubMed

    Huber, Paula; Diovisalvi, Nadia; Ferraro, Marcela; Metz, Sebastián; Lagomarsino, Leonardo; Llames, María Eugenia; Royo-Llonch, Marta; Bustingorry, José; Escaray, Roberto; Acinas, Silvia G; Gasol, Josep M; Unrein, Fernando

    2017-03-01

    Picocyanobacteria can occur as single-cell (Pcy) or as colonies (CPcy). Published evidence suggests that some Pcy strains have the capability to aggregate under certain culture conditions, however this has not been demonstrated to occur in natural environments. We investigated whether the Pcy and CPcy belong to the same species (i.e. phylotype), and the factors that determine their morphological and genetic variability in a hypertrophic shallow lake dominated by picocyanobacteria. Six main different morphologies and >30 phylotypes were observed. All sequences retrieved belonged to the 'Anathece + Cyanobium' clade (Synechococcales) that are known to have the capability of aggregation/disaggregation. The temporal variation of picocyanobacteria morphotype composition was weakly correlated with the DGGE temporal pattern, and could be explained by the composition of the zooplankton assemblage. Laboratory experiments confirmed that the small cladoceran Bosmina favoured the dominance of CPcy, i.e. Cyanodictyon doubled the size of the colonies when present, most likely through the aggregation of single-cell picocyanobacteria into colonies. Flow cytometry cell sorting and 16S rRNA + ITS sequencing of the Pcy and CPcy cytometrically-defined populations revealed that some phylotypes could be found in both sorted populations, suggesting phenotypic plasticity in which various Synechococcales phylotypes could be found in situ either as single-cells or as colonies.

  2. The Genetics of Phenotypic Plasticity. XIV. Coevolution.

    PubMed

    Scheiner, Samuel M; Gomulkiewicz, Richard; Holt, Robert D

    2015-05-01

    Plastic changes in organisms' phenotypes can result from either abiotic or biotic effectors. Biotic effectors create the potential for a coevolutionary dynamic. Through the use of individual-based simulations, we examined the coevolutionary dynamic of two species that are phenotypically plastic. We explored two modes of biotic and abiotic interactions: ecological interactions that determine the form of natural selection and developmental interactions that determine phenotypes. Overall, coevolution had a larger effect on the evolution of phenotypic plasticity than plasticity had on the outcome of coevolution. Effects on the evolution of plasticity were greater when the fitness-maximizing coevolutionary outcomes were antagonistic between the species pair (predator-prey interactions) than when those outcomes were augmenting (competitive or mutualistic). Overall, evolution in the context of biotic interactions reduced selection for plasticity even when trait development was responding to just the abiotic environment. Thus, the evolution of phenotypic plasticity must always be interpreted in the full context of a species' ecology. Our results show how the merging of two theory domains--coevolution and phenotypic plasticity--can deepen our understanding of both and point to new empirical research.

  3. Global change and the evolution of phenotypic plasticity in plants.

    PubMed

    Matesanz, Silvia; Gianoli, Ernesto; Valladares, Fernando

    2010-09-01

    Global change drivers create new environmental scenarios and selective pressures, affecting plant species in various interacting ways. Plants respond with changes in phenology, physiology, and reproduction, with consequences for biotic interactions and community composition. We review information on phenotypic plasticity, a primary means by which plants cope with global change scenarios, recommending promising approaches for investigating the evolution of plasticity and describing constraints to its evolution. We discuss the important but largely ignored role of phenotypic plasticity in range shifts and review the extensive literature on invasive species as models of evolutionary change in novel environments. Plasticity can play a role both in the short-term response of plant populations to global change as well as in their long-term fate through the maintenance of genetic variation. In new environmental conditions, plasticity of certain functional traits may be beneficial (i.e., the plastic response is accompanied by a fitness advantage) and thus selected for. Plasticity can also be relevant in the establishment and persistence of plants in novel environments that are crucial for populations at the colonizing edge in range shifts induced by climate change. Experimental studies show taxonomically widespread plastic responses to global change drivers in many functional traits, though there is a lack of empirical support for many theoretical models on the evolution of phenotypic plasticity. Future studies should assess the adaptive value and evolutionary potential of plasticity under complex, realistic global change scenarios. Promising tools include resurrection protocols and artificial selection experiments.

  4. Evolution of environmental cues for phenotypic plasticity.

    PubMed

    Chevin, Luis-Miguel; Lande, Russell

    2015-10-01

    Phenotypically plastic characters may respond to multiple variables in their environment, but the evolutionary consequences of this phenomenon have rarely been addressed theoretically. We model the evolution of linear reaction norms in response to several correlated environmental variables, in a population undergoing stationary environmental fluctuations. At evolutionary equilibrium, the linear combination of environmental variables that acts as a developmental cue for the plastic trait is the multivariate best linear predictor of changes in the optimum. However, the reaction norm with respect to any single environmental variable may exhibit nonintuitive patterns. Apparently maladaptive, or hyperadaptive plasticity can evolve with respect to single environmental variables, and costs of plasticity may increase, rather than reduce, plasticity in response to some variables. We also find conditions for the evolution of an indirect environmental indicator that affects expression of a plastic phenotype, despite not influencing natural selection on it.

  5. Phenotypic plasticity and diversity in insects

    PubMed Central

    Moczek, Armin P.

    2010-01-01

    Phenotypic plasticity in general and polyphenic development in particular are thought to play important roles in organismal diversification and evolutionary innovation. Focusing on the evolutionary developmental biology of insects, and specifically that of horned beetles, I explore the avenues by which phenotypic plasticity and polyphenic development have mediated the origins of novelty and diversity. Specifically, I argue that phenotypic plasticity generates novel targets for evolutionary processes to act on, as well as brings about trade-offs during development and evolution, thereby diversifying evolutionary trajectories available to natural populations. Lastly, I examine the notion that in those cases in which phenotypic plasticity is underlain by modularity in gene expression, it results in a fundamental trade-off between degree of plasticity and mutation accumulation. On one hand, this trade-off limits the extent of plasticity that can be accommodated by modularity of gene expression. On the other hand, it causes genes whose expression is specific to rare environments to accumulate greater variation within species, providing the opportunity for faster divergence and diversification between species, compared with genes expressed across environments. Phenotypic plasticity therefore contributes to organismal diversification on a variety of levels of biological organization, thereby facilitating the evolution of novel traits, new species and complex life cycles. PMID:20083635

  6. Constraints on the evolution of phenotypic plasticity: limits and costs of phenotype and plasticity.

    PubMed

    Murren, C J; Auld, J R; Callahan, H; Ghalambor, C K; Handelsman, C A; Heskel, M A; Kingsolver, J G; Maclean, H J; Masel, J; Maughan, H; Pfennig, D W; Relyea, R A; Seiter, S; Snell-Rood, E; Steiner, U K; Schlichting, C D

    2015-10-01

    Phenotypic plasticity is ubiquitous and generally regarded as a key mechanism for enabling organisms to survive in the face of environmental change. Because no organism is infinitely or ideally plastic, theory suggests that there must be limits (for example, the lack of ability to produce an optimal trait) to the evolution of phenotypic plasticity, or that plasticity may have inherent significant costs. Yet numerous experimental studies have not detected widespread costs. Explicitly differentiating plasticity costs from phenotype costs, we re-evaluate fundamental questions of the limits to the evolution of plasticity and of generalists vs specialists. We advocate for the view that relaxed selection and variable selection intensities are likely more important constraints to the evolution of plasticity than the costs of plasticity. Some forms of plasticity, such as learning, may be inherently costly. In addition, we examine opportunities to offset costs of phenotypes through ontogeny, amelioration of phenotypic costs across environments, and the condition-dependent hypothesis. We propose avenues of further inquiry in the limits of plasticity using new and classic methods of ecological parameterization, phylogenetics and omics in the context of answering questions on the constraints of plasticity. Given plasticity's key role in coping with environmental change, approaches spanning the spectrum from applied to basic will greatly enrich our understanding of the evolution of plasticity and resolve our understanding of limits.

  7. Phenotypic plasticity in sex pheromone production in Bicyclus anynana butterflies

    PubMed Central

    Dion, Emilie; Monteiro, Antónia; Yew, Joanne Y.

    2016-01-01

    Phenotypic plasticity refers to the environmental control of phenotypes. Cues experienced during development (developmental plasticity) or during adulthood (acclimatization) can both affect adult phenotypes. Phenotypic plasticity has been described in many traits but examples of developmental plasticity in physiological traits, in particular, remain scarce. We examined developmental plasticity and acclimatization in pheromone production in the butterfly Bicyclus anynana in response to rearing temperature. B. anynana lives in the African tropics where warm rearing temperatures of the wet season produce active males that court and females that choose, whereas cooler temperatures of the dry season lead to choosy less active males and courting females. We hypothesized that if male pheromone production is costly, it should be reduced in the dry season form. After describing the ultrastructure of pheromone producing cells, we showed that dry season males produced significantly less sex pheromones than wet season males, partly due to acclimatization and partly due to developmental plasticity. Variation in levels of one of the compounds is associated with differential regulation of a pheromone biosynthetic enzyme gene. This plasticity might be an adaptation to minimize pheromone production costs during the stressful dry season. PMID:27966579

  8. Phenotypic plasticity in sex pheromone production in Bicyclus anynana butterflies.

    PubMed

    Dion, Emilie; Monteiro, Antónia; Yew, Joanne Y

    2016-12-14

    Phenotypic plasticity refers to the environmental control of phenotypes. Cues experienced during development (developmental plasticity) or during adulthood (acclimatization) can both affect adult phenotypes. Phenotypic plasticity has been described in many traits but examples of developmental plasticity in physiological traits, in particular, remain scarce. We examined developmental plasticity and acclimatization in pheromone production in the butterfly Bicyclus anynana in response to rearing temperature. B. anynana lives in the African tropics where warm rearing temperatures of the wet season produce active males that court and females that choose, whereas cooler temperatures of the dry season lead to choosy less active males and courting females. We hypothesized that if male pheromone production is costly, it should be reduced in the dry season form. After describing the ultrastructure of pheromone producing cells, we showed that dry season males produced significantly less sex pheromones than wet season males, partly due to acclimatization and partly due to developmental plasticity. Variation in levels of one of the compounds is associated with differential regulation of a pheromone biosynthetic enzyme gene. This plasticity might be an adaptation to minimize pheromone production costs during the stressful dry season.

  9. Phenotypic plasticity and evolution by genetic assimilation.

    PubMed

    Pigliucci, Massimo; Murren, Courtney J; Schlichting, Carl D

    2006-06-01

    In addition to considerable debate in the recent evolutionary literature about the limits of the Modern Synthesis of the 1930s and 1940s, there has also been theoretical and empirical interest in a variety of new and not so new concepts such as phenotypic plasticity, genetic assimilation and phenotypic accommodation. Here we consider examples of the arguments and counter-arguments that have shaped this discussion. We suggest that much of the controversy hinges on several misunderstandings, including unwarranted fears of a general attempt at overthrowing the Modern Synthesis paradigm, and some fundamental conceptual confusion about the proper roles of phenotypic plasticity and natural selection within evolutionary theory.

  10. The genetics of phenotypic plasticity. X. Variation versus uncertainty

    PubMed Central

    Scheiner, Samuel M; Holt, Robert D

    2012-01-01

    Despite the apparent advantages of adaptive plasticity, it is not common. We examined the effects of variation and uncertainty on selection for plasticity using an individual-based computer simulation model. In the model, the environment consisted of a linear gradient of 50 demes with dispersal occurring either before or after selection. Individuals consisted of multiple loci whose phenotypic expression either are affected (plastic) or are not affected (nonplastic) by the environment. Typically, evolution occurred first as genetic differentiation, which was then replaced by the evolution of adaptive plasticity, opposite to the evolutionary trend that is often assumed. Increasing dispersal rates selected for plasticity, if selection occurred before dispersal. If selection occurred after dispersal, the highest plasticity was at intermediate dispersal rates. Temporal variation in the environment occurring after development, but before selection, favored the evolution of plasticity. With dispersal before selection, such temporal variation resulted in hyperplasticity, with a reaction norm much steeper than the optimum. This effect was enhanced with negative temporal autocorrelation and can be interpreted as representing a form of bet hedging. As the number of nonplastic loci increased, plasticity was disfavored due to an increase in the uncertainty of the genomic environment. This effect was reversed with temporal variation. Thus, variation and uncertainty affect whether or not plasticity is favored with different sources of variation—arising from the amount and timing of dispersal, from temporal variation, and even from the genetic architecture underlying the phenotype—having contrasting, interacting, and at times unexpected effects. PMID:22837824

  11. A heuristic model on the role of plasticity in adaptive evolution: plasticity increases adaptation, population viability and genetic variation.

    PubMed

    Gomez-Mestre, Ivan; Jovani, Roger

    2013-11-22

    An ongoing new synthesis in evolutionary theory is expanding our view of the sources of heritable variation beyond point mutations of fixed phenotypic effects to include environmentally sensitive changes in gene regulation. This expansion of the paradigm is necessary given ample evidence for a heritable ability to alter gene expression in response to environmental cues. In consequence, single genotypes are often capable of adaptively expressing different phenotypes in different environments, i.e. are adaptively plastic. We present an individual-based heuristic model to compare the adaptive dynamics of populations composed of plastic or non-plastic genotypes under a wide range of scenarios where we modify environmental variation, mutation rate and costs of plasticity. The model shows that adaptive plasticity contributes to the maintenance of genetic variation within populations, reduces bottlenecks when facing rapid environmental changes and confers an overall faster rate of adaptation. In fluctuating environments, plasticity is favoured by selection and maintained in the population. However, if the environment stabilizes and costs of plasticity are high, plasticity is reduced by selection, leading to genetic assimilation, which could result in species diversification. More broadly, our model shows that adaptive plasticity is a common consequence of selection under environmental heterogeneity, and hence a potentially common phenomenon in nature. Thus, taking adaptive plasticity into account substantially extends our view of adaptive evolution.

  12. Genome-Wide Association Mapping for Phenotypic Plasticity in Rice.

    PubMed

    Kikuchi, Shinji; Bheemanahalli, Raju; Jagadish, Krishna S V; Kumagai, Etsushi; Masuya, Yusuke; Kuroda, Eiki; Raghavan, Chitra; Dingkuhn, Michael; Abe, Akira; Shimono, Hiroyuki

    2017-03-31

    Phenotypic plasticity of plants in response to environmental changes is important for adapting to changing climate. Less attention has been paid to exploring the advantages of phenotypic plasticity in resource-rich environments to enhance the productivity of agricultural crops. Here, we examined genetic variation in phenotypic plasticity in indica rice (Oryza sativa L.) across two diverse panels: (i) a Phenomics of Rice Adaptation and Yield (PRAY) population comprising 301 accessions and (ii) a Multi-parent-Advanced-Generation-Inter-Cross (MAGIC) indica population comprising 151 accessions. Altered planting density was used as a proxy for elevated atmospheric CO2 response. Low planting density significantly increased panicle weight per plant compared with normal density, and the magnitude of the increase ranged from 1.10 to 2.78 times among accessions for the PRAY population and from 1.05 to 2.45 times for the MAGIC population. Genome-wide-association studies revealed three Environmental Responsiveness (ER) candidate alleles (qER1-3) that were associated with relative response of panicle weight to low density. Two of these alleles were tested in 13 genotypes to clarify their biomass responses during vegetative growth under elevated CO2 in Japan. Our study provides evidence for polymorphisms that control rice phenotypic plasticity in environments that are rich in resources such as light and CO2 .

  13. The genetics of phenotypic plasticity. XI. Joint evolution of plasticity and dispersal rate.

    PubMed

    Scheiner, Samuel M; Barfield, Michael; Holt, Robert D

    2012-08-01

    In a spatially heterogeneous environment, the rate at which individuals move among habitats affects whether selection favors phenotypic plasticity or genetic differentiation, with high dispersal rates favoring trait plasticity. Until now, in theoretical explorations of plasticity evolution, dispersal rate has been treated as a fixed, albeit probabilistic, characteristic of a population, raising the question of what happens when the propensity to disperse and trait plasticity are allowed to evolve jointly. We examined the effects of their joint evolution on selection for plasticity using an individual-based computer simulation model. In the model, the environment consisted of a linear gradient of 50 demes with dispersal occurring either before or after selection. Individuals consisted of loci whose phenotypic expression either are affected by the environment (plastic) or are not affected (nonplastic), plus a locus determining the propensity to disperse. When dispersal rate and trait plasticity evolve jointly, the system tends to dichotomous outcomes of either high trait plasticity and high dispersal, or low trait plasticity and low dispersal. The outcome strongly depended on starting conditions, with high trait plasticity and dispersal favored when the system started at high values for either trait plasticity or dispersal rate (or both). Adding a cost of plasticity tended to drive the system to genetic differentiation, although this effect also depended on initial conditions. Genetic linkage between trait plasticity loci and dispersal loci further enhanced this strong dichotomy in evolutionary outcomes. All of these effects depended on organismal life history pattern, and in particular whether selection occurred before or after dispersal. These results can explain why adaptive trait plasticity is less common than might be expected.

  14. Does plasticity enhance or dampen phenotypic parallelism? A test with three lake-stream stickleback pairs.

    PubMed

    Oke, K B; Bukhari, M; Kaeuffer, R; Rolshausen, G; Räsänen, K; Bolnick, D I; Peichel, C L; Hendry, A P

    2016-01-01

    Parallel (and convergent) phenotypic variation is most often studied in the wild, where it is difficult to disentangle genetic vs. environmentally induced effects. As a result, the potential contributions of phenotypic plasticity to parallelism (and nonparallelism) are rarely evaluated in a formal sense. Phenotypic parallelism could be enhanced by plasticity that causes stronger parallelism across populations in the wild than would be expected from genetic differences alone. Phenotypic parallelism could be dampened if site-specific plasticity induced differences between otherwise genetically parallel populations. We used a common-garden study of three independent lake-stream stickleback population pairs to evaluate the extent to which adaptive divergence has a genetic or plastic basis, and to investigate the enhancing vs. dampening effects of plasticity on phenotypic parallelism. We found that lake-stream differences in most traits had a genetic basis, but that several traits also showed contributions from plasticity. Moreover, plasticity was much more prevalent in one watershed than in the other two. In most cases, plasticity enhanced phenotypic parallelism, whereas in a few cases, plasticity had a dampening effect. Genetic and plastic contributions to divergence seem to play a complimentary, likely adaptive, role in phenotypic parallelism of lake-stream stickleback. These findings highlight the value of formally comparing wild-caught and laboratory-reared individuals in the study of phenotypic parallelism.

  15. Adaptive evolution of molecular phenotypes

    NASA Astrophysics Data System (ADS)

    Held, Torsten; Nourmohammad, Armita; Lässig, Michael

    2014-09-01

    Molecular phenotypes link genomic information with organismic functions, fitness, and evolution. Quantitative traits are complex phenotypes that depend on multiple genomic loci. In this paper, we study the adaptive evolution of a quantitative trait under time-dependent selection, which arises from environmental changes or through fitness interactions with other co-evolving phenotypes. We analyze a model of trait evolution under mutations and genetic drift in a single-peak fitness seascape. The fitness peak performs a constrained random walk in the trait amplitude, which determines the time-dependent trait optimum in a given population. We derive analytical expressions for the distribution of the time-dependent trait divergence between populations and of the trait diversity within populations. Based on this solution, we develop a method to infer adaptive evolution of quantitative traits. Specifically, we show that the ratio of the average trait divergence and the diversity is a universal function of evolutionary time, which predicts the stabilizing strength and the driving rate of the fitness seascape. From an information-theoretic point of view, this function measures the macro-evolutionary entropy in a population ensemble, which determines the predictability of the evolutionary process. Our solution also quantifies two key characteristics of adapting populations: the cumulative fitness flux, which measures the total amount of adaptation, and the adaptive load, which is the fitness cost due to a population's lag behind the fitness peak.

  16. Changes in Selection Regime Cause Loss of Phenotypic Plasticity in Planktonic Freshwater Copepods

    PubMed Central

    Sereda, Sergej Vital’evič; Wilke, Thomas; Schultheiß, Roland

    2014-01-01

    Rapid phenotypic adaptation is critical for populations facing environmental changes and can be facilitated by phenotypic plasticity in the selected traits. Whereas recurrent environmental fluctuations can favour the maintenance or de novo evolution of plasticity, strong selection is hypothesized to decrease plasticity or even fix the trait (genetic assimilation). Despite advances in the theoretical understanding of the impact of plasticity on diversification processes, comparatively little empirical data of populations undergoing diversification mediated by plasticity are available. Here we use the planktonic freshwater copepod Acanthodiaptomus denticornis from two lakes as model system to study UV stress responses of two phenotypically different populations under laboratory conditions. Our study reveals heritable lake- and sex-specific differences of behaviour, physiological plasticity, and mortality. We discuss specific selective scenarios causing these differences and argue that phenotypic plasticity will be higher when selection pressure is moderate, but will decrease or even be lost under stronger pressure. PMID:24587186

  17. Changes in selection regime cause loss of phenotypic plasticity in planktonic freshwater copepods.

    PubMed

    Sereda, Sergej Vital'evič; Wilke, Thomas; Schultheiß, Roland

    2014-01-01

    Rapid phenotypic adaptation is critical for populations facing environmental changes and can be facilitated by phenotypic plasticity in the selected traits. Whereas recurrent environmental fluctuations can favour the maintenance or de novo evolution of plasticity, strong selection is hypothesized to decrease plasticity or even fix the trait (genetic assimilation). Despite advances in the theoretical understanding of the impact of plasticity on diversification processes, comparatively little empirical data of populations undergoing diversification mediated by plasticity are available. Here we use the planktonic freshwater copepod Acanthodiaptomus denticornis from two lakes as model system to study UV stress responses of two phenotypically different populations under laboratory conditions. Our study reveals heritable lake- and sex-specific differences of behaviour, physiological plasticity, and mortality. We discuss specific selective scenarios causing these differences and argue that phenotypic plasticity will be higher when selection pressure is moderate, but will decrease or even be lost under stronger pressure.

  18. Comparing the effects of rapid evolution and phenotypic plasticity on predator-prey dynamics.

    PubMed

    Yamamichi, Masato; Yoshida, Takehito; Sasaki, Akira

    2011-09-01

    Ecologists have increasingly focused on how rapid adaptive trait changes can affect population dynamics. Rapid adaptation can result from either rapid evolution or phenotypic plasticity, but their effects on population dynamics are seldom compared directly. Here we examine theoretically the effects of rapid evolution and phenotypic plasticity of antipredatory defense on predator-prey dynamics. Our analyses reveal that phenotypic plasticity tends to stabilize population dynamics more strongly than rapid evolution. It is therefore important to know the mechanism by which phenotypic variation is generated for predicting the dynamics of rapidly adapting populations. We next examine an advantage of a phenotypically plastic prey genotype over the polymorphism of specialist prey genotypes. Numerical analyses reveal that the plastic genotype, if there is a small cost for maintaining it, cannot coexist with the pairs of specialist counterparts unless the system has a limit cycle. Furthermore, for the plastic genotype to replace specialist genotypes, a forced environmental fluctuation is critical in a broad parameter range. When these results are combined, the plastic genotype enjoys an advantage with population oscillations, but plasticity tends to lose its advantage by stabilizing the oscillations. This dilemma leads to an interesting intermittent limit cycle with the changing frequency of phenotypic plasticity.

  19. Functional genomics of physiological plasticity and local adaptation in killifish.

    PubMed

    Whitehead, Andrew; Galvez, Fernando; Zhang, Shujun; Williams, Larissa M; Oleksiak, Marjorie F

    2011-01-01

    Evolutionary solutions to the physiological challenges of life in highly variable habitats can span the continuum from evolution of a cosmopolitan plastic phenotype to the evolution of locally adapted phenotypes. Killifish (Fundulus sp.) have evolved both highly plastic and locally adapted phenotypes within different selective contexts, providing a comparative system in which to explore the genomic underpinnings of physiological plasticity and adaptive variation. Importantly, extensive variation exists among populations and species for tolerance to a variety of stressors, and we exploit this variation in comparative studies to yield insights into the genomic basis of evolved phenotypic variation. Notably, species of Fundulus occupy the continuum of osmotic habitats from freshwater to marine and populations within Fundulus heteroclitus span far greater variation in pollution tolerance than across all species of fish. Here, we explore how transcriptome regulation underpins extreme physiological plasticity on osmotic shock and how genomic and transcriptomic variation is associated with locally evolved pollution tolerance. We show that F. heteroclitus quickly acclimate to extreme osmotic shock by mounting a dramatic rapid transcriptomic response including an early crisis control phase followed by a tissue remodeling phase involving many regulatory pathways. We also show that convergent evolution of locally adapted pollution tolerance involves complex patterns of gene expression and genome sequence variation, which is confounded with body-weight dependence for some genes. Similarly, exploiting the natural phenotypic variation associated with other established and emerging model organisms is likely to greatly accelerate the pace of discovery of the genomic basis of phenotypic variation.

  20. Phenotypic Plasticity and Population Differentiation in an Ongoing Species Invasion

    PubMed Central

    Matesanz, Silvia; Horgan-Kobelski, Tim; Sultan, Sonia E.

    2012-01-01

    The ability to succeed in diverse conditions is a key factor allowing introduced species to successfully invade and spread across new areas. Two non-exclusive factors have been suggested to promote this ability: adaptive phenotypic plasticity of individuals, and the evolution of locally adapted populations in the new range. We investigated these individual and population-level factors in Polygonum cespitosum, an Asian annual that has recently become invasive in northeastern North America. We characterized individual fitness, life-history, and functional plasticity in response to two contrasting glasshouse habitat treatments (full sun/dry soil and understory shade/moist soil) in 165 genotypes sampled from nine geographically separate populations representing the range of light and soil moisture conditions the species inhabits in this region. Polygonum cespitosum genotypes from these introduced-range populations expressed broadly similar plasticity patterns. In response to full sun, dry conditions, genotypes from all populations increased photosynthetic rate, water use efficiency, and allocation to root tissues, dramatically increasing reproductive fitness compared to phenotypes expressed in simulated understory shade. Although there were subtle among-population differences in mean trait values as well as in the slope of plastic responses, these population differences did not reflect local adaptation to environmental conditions measured at the population sites of origin. Instead, certain populations expressed higher fitness in both glasshouse habitat treatments. We also compared the introduced-range populations to a single population from the native Asian range, and found that the native population had delayed phenology, limited functional plasticity, and lower fitness in both experimental environments compared with the introduced-range populations. Our results indicate that the future spread of P. cespitosum in its introduced range will likely be fueled by

  1. How plastic can phenotypic plasticity be? The branching coral Stylophora pistillata as a model system.

    PubMed

    Shaish, Lee; Abelson, Avigdor; Rinkevich, Baruch

    2007-07-25

    Phenotypic plasticity enables multicellular organisms to adjust morphologies and various life history traits to variable environmental challenges. Here, we elucidate fixed and plastic architectural rules for colony astogeny in multiple types of colonial ramets, propagated by cutting from genets of the branching coral Stylophora pistillata from Eilat, the Red Sea. We examined 16 morphometric parameters on 136 one-year old S. pistillata colonies (of seven genotypes), originating from small fragments belonging, each, to one of three single-branch types (single tips, start-up, and advanced bifurcating tips) or to structural preparative manipulations (representing a single or two growth axes). Experiments were guided by the rationale that in colonial forms, complexity of evolving phenotypic plasticity can be associated with a degree of structural modularity, where shapes are approached by erecting iterative growth patterns at different levels of coral-colony organization. Analyses revealed plastic morphometric characters at branch level, and predetermined morphometric traits at colony level (only single trait exhibited plasticity under extreme manipulation state). Therefore, under the experimental manipulations of this study, phenotypic plasticity in S. pistillata appears to be related to branch level of organization, whereas colony traits are controlled by predetermined genetic architectural rules. Each level of organization undergoes its own mode of astogeny. However, depending on the original ramet structure, the spherical 3-D colonial architecture in this species is orchestrated and assembled by both developmental trajectories at the branch level, and traits at the colony level of organization. In nature, branching colonial forms are often subjected to harsh environmental conditions that cause fragmentation of colony into ramets of different sizes and structures. Developmental traits that are plastic, responding to fragment structure and are not predetermine in

  2. Phenotypic plasticity and specialization in clonal versus non-clonal plants: A data synthesis

    NASA Astrophysics Data System (ADS)

    Fazlioglu, Fatih; Bonser, Stephen P.

    2016-11-01

    Reproductive strategies can be associated with ecological specialization and generalization. Clonal plants produce lineages adapted to the maternal habitat that can lead to specialization. However, clonal plants frequently display high phenotypic plasticity (e.g. clonal foraging for resources), factors linked to ecological generalization. Alternately, sexual reproduction can be associated with generalization via increasing genetic variation or specialization through rapid adaptive evolution. Moreover, specializing to high or low quality habitats can determine how phenotypic plasticity is expressed in plants. The specialization hypothesis predicts that specialization to good environments results in high performance trait plasticity and specialization to bad environments results in low performance trait plasticity. The interplay between reproductive strategies, phenotypic plasticity, and ecological specialization is important for understanding how plants adapt to variable environments. However, we currently have a poor understanding of these relationships. In this study, we addressed following questions: 1) Is there a relationship between phenotypic plasticity, specialization, and reproductive strategies in plants? 2) Do good habitat specialists express greater performance trait plasticity than bad habitat specialists? We searched the literature for studies examining plasticity for performance traits and functional traits in clonal and non-clonal plant species from different habitat types. We found that non-clonal (obligate sexual) plants expressed greater performance trait plasticity and functional trait plasticity than clonal plants. That is, non-clonal plants exhibited a specialist strategy where they perform well only in a limited range of habitats. Clonal plants expressed less performance loss across habitats and a more generalist strategy. In addition, specialization to good habitats did not result in greater performance trait plasticity. This result was

  3. Replicated evolution of integrated plastic responses during early adaptive divergence.

    PubMed

    Parsons, Kevin J; Robinson, Beren W

    2006-04-01

    Colonization of a novel environment is expected to result in adaptive divergence from the ancestral population when selection favors a new phenotypic optimum. Local adaptation in the new environment occurs through the accumulation and integration of character states that positively affect fitness. The role played by plastic traits in adaptation to a novel environment has generally been ignored, except for variable environments. We propose that if conditions in a relatively stable but novel environment induce phenotypically plastic responses in many traits, and if genetic variation exists in the form of those responses, then selection may initially favor the accumulation and integration of functionally useful plastic responses. Early divergence between ancestral and colonist forms will then occur with respect to their plastic responses across the gradient bounded by ancestral and novel environmental conditions. To test this, we compared the magnitude, integration, and pattern of plastic character responses in external body form induced by shallow versus open water conditions between two sunfish ecomorphs that coexist in four postglacial lakes. The novel sunfish ecomorph is present in the deeper open water habitat, whereas the ancestral ecomorph inhabits the shallow waters along the lake margin. Plastic responses by open water ecomorphs were more correlated than those of their local shallow water ecomorph in two of the populations, whereas equal levels of correlated plastic character responses occurred between ecomorphs in the other two populations. Small but persistent differences occurred between ecomorph pairs in the pattern of their character responses, suggesting a recent divergence. Open water ecomorphs shared some similarities in the covariance among plastic responses to rearing environment. Replication in the form of correlated plastic responses among populations of open water ecomorphs suggests that plastic character states may evolve under selection

  4. Phenotypic plasticity can potentiate rapid evolutionary change.

    PubMed

    Behera, Narayan; Nanjundiah, Vidyanand

    2004-01-21

    Using a computational model of string-like haploid genotypes, we verify the conjecture (J. Theor. Biol. 188 (1997) 153) that phenotypic plasticity can speed up evolution. The corresponding real-life situation was realized by Waddington in experiments carried out on the fruit fly Drosophila. Waddington found that after selecting for an environmentally induced trait over a number of generations, a new, true-breeding phenotype resulted that was absent in the starting population. The phenomenon, termed 'genetic assimilation', continues to attract interest because of the rapidity of the effect and because of its seemingly Lamarckian implications. By making use of a genetic algorithm-based approach developed previously, we show that conventional Darwinian selection acting on regulatory genes can account for genetic assimilation. The essential assumption in our model is that a structural gene can be in either of three allelic states. These correspond to its being (a) 'on' or 'off' constitutively or (b) in a plastic state in which the probability that it is 'on' or 'off' is influenced by regulatory loci in a dosage-dependent manner.

  5. Phenotypic and genomic plasticity of alternative male reproductive tactics in sailfin mollies

    PubMed Central

    Fraser, Bonnie A.; Janowitz, Ilana; Thairu, Margaret; Travis, Joseph; Hughes, Kimberly A.

    2014-01-01

    A major goal of modern evolutionary biology is to understand the causes and consequences of phenotypic plasticity, the ability of a single genotype to produce multiple phenotypes in response to variable environments. While ecological and quantitative genetic studies have evaluated models of the evolution of adaptive plasticity, some long-standing questions about plasticity require more mechanistic approaches. Here, we address two of those questions: does plasticity facilitate adaptive evolution? And do physiological costs place limits on plasticity? We examine these questions by comparing genetically and plastically regulated behavioural variation in sailfin mollies (Poecilia latipinna), which exhibit striking variation in plasticity for male mating behaviour. In this species, some genotypes respond plastically to a change in the social environment by switching between primarily courting and primarily sneaking behaviour. In contrast, other genotypes have fixed mating strategies (either courting or sneaking) and do not display plasticity. We found that genetic and plastic variation in behaviour were accompanied by partially, but not completely overlapping changes in brain gene expression, in partial support of models that predict that plasticity can facilitate adaptive evolution. We also found that behavioural plasticity was accompanied by broader and more robust changes in brain gene expression, suggesting a substantial physiological cost to plasticity. We also observed that sneaking behaviour, but not courting, was associated with upregulation of genes involved in learning and memory, suggesting that sneaking is more cognitively demanding than courtship. PMID:24573842

  6. Strong and parallel salinity-induced phenotypic plasticity in one generation of threespine stickleback.

    PubMed

    Mazzarella, A B; Voje, K L; Hansson, T H; Taugbøl, A; Fischer, B

    2015-03-01

    Phenotypic plasticity is a major factor contributing to variation of organisms in nature, yet its evolutionary significance is insufficiently understood. One example system where plasticity might have played an important role in an adaptive radiation is the threespine stickleback (Gasterosteus aculeatus), a fish that has diversified after invading freshwater lakes repeatedly from the marine habitat. The parallel phenotypic changes that occurred in this radiation were extremely rapid. This study evaluates phenotypic plasticity in stickleback body shape in response to salinity in fish stemming from a wild freshwater population. Using a split-clutch design, we detected surprisingly large phenotypically plastic changes in body shape after one generation. Fish raised in salt water developed shallower bodies and longer jaws, and these changes were consistent and parallel across families. Although this work highlights the effect of phenotypic plasticity, we also find indications that constraints may play a role in biasing the direction of possible phenotypic change. The slopes of the allometric relationship of individual linear traits did not change across treatments, indicating that plastic change does not affect the covariation of traits with overall size. We conclude that stickleback have a large capacity for plastic phenotypic change in response to salinity and that plasticity and evolutionary constraints have likely contributed to the phenotypic diversification of these fish.

  7. Hormones and phenotypic plasticity in an ecological context: linking physiological mechanisms to evolutionary processes.

    PubMed

    Lema, Sean C

    2014-11-01

    Hormones are chemical signaling molecules that regulate patterns of cellular physiology and gene expression underlying phenotypic traits. Hormone-signaling pathways respond to an organism's external environment to mediate developmental stage-specific malleability in phenotypes, so that environmental variation experienced at different stages of development has distinct effects on an organism's phenotype. Studies of hormone-signaling are therefore playing a central role in efforts to understand how plastic phenotypic responses to environmental variation are generated during development. But, how do adaptive, hormonally mediated phenotypes evolve if the individual signaling components (hormones, conversion enzymes, membrane transporters, and receptors) that comprise any hormone-signaling pathway show expressional flexibility in response to environmental variation? What relevance do these components hold as molecular targets for selection to couple or decouple correlated hormonally mediated traits? This article explores how studying the endocrine underpinnings of phenotypic plasticity in an ecologically relevant context can provide insights into these, and other, crucial questions into the role of phenotypic plasticity in evolution, including how plasticity itself evolves. These issues are discussed in the light of investigations into how thyroid hormones mediate morphological plasticity in Death Valley's clade of pupfishes (Cyprinodon spp.). Findings from this work with pupfish illustrate that the study of hormone-signaling from an ecological perspective can reveal how phenotypic plasticity contributes to the generation of phenotypic novelty, as well as how physiological mechanisms developmentally link an organism's phenotype to its environmental experiences.

  8. Introduction to the symposium-uniting evolutionary and physiological approaches to understanding phenotypic plasticity.

    PubMed

    Wada, Haruka; Sewall, Kendra B

    2014-11-01

    Diverse subfields of biology have addressed phenotypic plasticity, but have emphasized different aspects of the definition, thereby shaping the questions that are asked and the methodological approaches that are employed. A key difference between studies of plasticity in the fields of evolutionary biology and physiology is the degree of focus upon the contribution of genetic variance to plastic traits. Although evolutionary biology is generally focused on the heritability and adaptive value of plastic traits and therefore the potential for plasticity to impact changes in traits across generations, physiological studies have historically focused on the timing and reversibility of plastic change across seasons or ages and the mechanisms underlying traits' plasticity. In this review and the symposium from which it emerged, we aimed to highlight ways that integrative biologists can better communicate about their research and design better studies to address phenotypic plasticity. Evolutionary theory clarifies the need to assess fitness using reliable measures, such as survival and reproductive success, and to consider the heritability and genetic variance underlying plasticity. Reciprocally, physiological research demonstrates that understanding the mechanisms that permit, or limit, plasticity, whether through pleiotropic effects, developmental, or functional linkages between traits, or epigenetic modifications, will shed light on limitations to phenotypic plasticity. Uniting the fields of evolution and physiology to address all aspects of phenotypic plasticity will be increasingly important as the rate of anthropogenic environmental change increases and biologists must predict the responses of wild populations to novel environments, as well as determine the most effective conservation interventions.

  9. Molecular mechanisms of phenotypic plasticity in social insects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Polyphenism in insects, whereby a single genome expresses different phenotypes in response to environmental cues, is a fascinating biological phenomenon. Social insects are especially intriguing examples of phenotypic plasticity because division of labor results in the development of extreme morphol...

  10. Adaptive plasticity and genetic divergence in feeding efficiency during parallel adaptive radiation of whitefish (Coregonus spp.).

    PubMed

    Lundsgaard-Hansen, B; Matthews, B; Vonlanthen, P; Taverna, A; Seehausen, O

    2013-03-01

    Parallel phenotypic divergence in replicated adaptive radiations could either result from parallel genetic divergence in response to similar divergent selection regimes or from equivalent phenotypically plastic response to the repeated occurrence of contrasting environments. In post-glacial fish, replicated divergence in phenotypes along the benthic-limnetic habitat axis is commonly observed. Here, we use two benthic-limnetic species pairs of whitefish from two Swiss lakes, raised in a common garden design, with reciprocal food treatments in one species pair, to experimentally measure whether feeding efficiency on benthic prey has a genetic basis or whether it underlies phenotypic plasticity (or both). To do so, we offered experimental fish mosquito larvae, partially burried in sand, and measured multiple feeding efficiency variables. Our results reveal both, genetic divergence as well as phenotypically plastic divergence in feeding efficiency, with the phenotypically benthic species raised on benthic food being the most efficient forager on benthic prey. This indicates that both, divergent natural selection on genetically heritable traits and adaptive phenotypic plasticity, are likely important mechanisms driving phenotypic divergence in adaptive radiation.

  11. Molecular signatures of plastic phenotypes in two eusocial insect species with simple societies.

    PubMed

    Patalano, Solenn; Vlasova, Anna; Wyatt, Chris; Ewels, Philip; Camara, Francisco; Ferreira, Pedro G; Asher, Claire L; Jurkowski, Tomasz P; Segonds-Pichon, Anne; Bachman, Martin; González-Navarrete, Irene; Minoche, André E; Krueger, Felix; Lowy, Ernesto; Marcet-Houben, Marina; Rodriguez-Ales, Jose Luis; Nascimento, Fabio S; Balasubramanian, Shankar; Gabaldon, Toni; Tarver, James E; Andrews, Simon; Himmelbauer, Heinz; Hughes, William O H; Guigó, Roderic; Reik, Wolf; Sumner, Seirian

    2015-11-10

    Phenotypic plasticity is important in adaptation and shapes the evolution of organisms. However, we understand little about what aspects of the genome are important in facilitating plasticity. Eusocial insect societies produce plastic phenotypes from the same genome, as reproductives (queens) and nonreproductives (workers). The greatest plasticity is found in the simple eusocial insect societies in which individuals retain the ability to switch between reproductive and nonreproductive phenotypes as adults. We lack comprehensive data on the molecular basis of plastic phenotypes. Here, we sequenced genomes, microRNAs (miRNAs), and multiple transcriptomes and methylomes from individual brains in a wasp (Polistes canadensis) and an ant (Dinoponera quadriceps) that live in simple eusocial societies. In both species, we found few differences between phenotypes at the transcriptional level, with little functional specialization, and no evidence that phenotype-specific gene expression is driven by DNA methylation or miRNAs. Instead, phenotypic differentiation was defined more subtly by nonrandom transcriptional network organization, with roles in these networks for both conserved and taxon-restricted genes. The general lack of highly methylated regions or methylome patterning in both species may be an important mechanism for achieving plasticity among phenotypes during adulthood. These findings define previously unidentified hypotheses on the genomic processes that facilitate plasticity and suggest that the molecular hallmarks of social behavior are likely to differ with the level of social complexity.

  12. Molecular signatures of plastic phenotypes in two eusocial insect species with simple societies

    PubMed Central

    Patalano, Solenn; Vlasova, Anna; Wyatt, Chris; Ewels, Philip; Camara, Francisco; Ferreira, Pedro G.; Asher, Claire L.; Jurkowski, Tomasz P.; Segonds-Pichon, Anne; Bachman, Martin; González-Navarrete, Irene; Minoche, André E.; Krueger, Felix; Lowy, Ernesto; Marcet-Houben, Marina; Rodriguez-Ales, Jose Luis; Nascimento, Fabio S.; Balasubramanian, Shankar; Gabaldon, Toni; Tarver, James E.; Andrews, Simon; Himmelbauer, Heinz; Hughes, William O. H.; Guigó, Roderic; Reik, Wolf; Sumner, Seirian

    2015-01-01

    Phenotypic plasticity is important in adaptation and shapes the evolution of organisms. However, we understand little about what aspects of the genome are important in facilitating plasticity. Eusocial insect societies produce plastic phenotypes from the same genome, as reproductives (queens) and nonreproductives (workers). The greatest plasticity is found in the simple eusocial insect societies in which individuals retain the ability to switch between reproductive and nonreproductive phenotypes as adults. We lack comprehensive data on the molecular basis of plastic phenotypes. Here, we sequenced genomes, microRNAs (miRNAs), and multiple transcriptomes and methylomes from individual brains in a wasp (Polistes canadensis) and an ant (Dinoponera quadriceps) that live in simple eusocial societies. In both species, we found few differences between phenotypes at the transcriptional level, with little functional specialization, and no evidence that phenotype-specific gene expression is driven by DNA methylation or miRNAs. Instead, phenotypic differentiation was defined more subtly by nonrandom transcriptional network organization, with roles in these networks for both conserved and taxon-restricted genes. The general lack of highly methylated regions or methylome patterning in both species may be an important mechanism for achieving plasticity among phenotypes during adulthood. These findings define previously unidentified hypotheses on the genomic processes that facilitate plasticity and suggest that the molecular hallmarks of social behavior are likely to differ with the level of social complexity. PMID:26483466

  13. Adaptive plasticity in wild field cricket's acoustic signaling.

    PubMed

    Bertram, Susan M; Harrison, Sarah J; Thomson, Ian R; Fitzsimmons, Lauren P

    2013-01-01

    Phenotypic plasticity can be adaptive when phenotypes are closely matched to changes in the environment. In crickets, rhythmic fluctuations in the biotic and abiotic environment regularly result in diel rhythms in density of sexually active individuals. Given that density strongly influences the intensity of sexual selection, we asked whether crickets exhibit plasticity in signaling behavior that aligns with these rhythmic fluctuations in the socio-sexual environment. We quantified the acoustic mate signaling behavior of wild-caught males of two cricket species, Gryllus veletis and G. pennsylvanicus. Crickets exhibited phenotypically plastic mate signaling behavior, with most males signaling more often and more attractively during the times of day when mating activity is highest in the wild. Most male G. pennsylvanicus chirped more often and louder, with shorter interpulse durations, pulse periods, chirp durations, and interchirp durations, and at slightly higher carrier frequencies during the time of the day that mating activity is highest in the wild. Similarly, most male G. veletis chirped more often, with more pulses per chirp, longer interpulse durations, pulse periods, and chirp durations, shorter interchirp durations, and at lower carrier frequencies during the time of peak mating activity in the wild. Among-male variation in signaling plasticity was high, with some males signaling in an apparently maladaptive manner. Body size explained some of the among-male variation in G. pennsylvanicus plasticity but not G. veletis plasticity. Overall, our findings suggest that crickets exhibit phenotypically plastic mate attraction signals that closely match the fluctuating socio-sexual context they experience.

  14. Developmental sculpting of social phenotype and plasticity.

    PubMed

    Sakata, Jon T; Crews, David

    2004-04-01

    Early developmental variables engender behavioral and neural variation, especially in species in which embryonic environment determines gonadal sex. In the leopard gecko, Eublepharis macularius, the incubation temperature of the egg (IncT) determines gonadal sex. Moreover, IncT affects the sexual differentiation of the individual and, consequently, within-sex variation. Individuals hatched from eggs incubated at an IncT that produces predominantly males are more masculinized than same-sex counterparts from IncTs that produce predominantly females. Here we review how gonadal sex and IncT interact to affect behavioral, endocrinological, and neural phenotype in the leopard gecko and influence phenotypic plasticity following hormone administration or social experience. We discuss the hormonal dependence of sex- and IncT-dependent behavioral and neural morphological and metabolic differences and highlight the parallels between IncT effects in geckos and intrauterine position effects in rodents. We argue that the leopard gecko is an important model of how the process of sex determination can affect sexual differentiation and of selection forces underlying the evolution of sex ratios.

  15. The evolution of phenotypic plasticity: genealogy of a debate in genetics.

    PubMed

    Nicoglou, Antonine

    2015-04-01

    The paper describes the context and the origin of a particular debate that concerns the evolution of phenotypic plasticity. In 1965, British biologist A. D. Bradshaw proposed a widely cited model intended to explain the evolution of norms of reaction, based on his studies of plant populations. Bradshaw's model went beyond the notion of the "adaptive norm of reaction" discussed before him by Dobzhansky and Schmalhausen by suggesting that "plasticity"--the ability of a phenotype to be modified by the environment--should be genetically determined. To prove Bradshaw's hypothesis, it became necessary for some authors to identify the pressures exerted by natural selection on phenotypic plasticity in particular traits, and thus to model its evolution. In this paper, I contrast two different views, based on quantitative genetic models, proposed in the mid-1980s: Russell Lande and Sara Via's conception of phenotypic plasticity, which assumes that the evolution of plasticity is linked to the evolution of the plastic trait itself, and Samuel Scheiner and Richard Lyman's view, which assumes that the evolution of plasticity is independent from the evolution of the trait. I show how the origin of this specific debate, and different assumptions about the evolution of phenotypic plasticity, depended on Bradshaw's definition of plasticity and the context of quantitative genetics.

  16. The genetics of phenotypic plasticity in nematode feeding structures

    PubMed Central

    Dardiry, Mohannad; Lenuzzi, Masa; Namdeo, Suryesh; Renahan, Tess; Sieriebriennikov, Bogdan; Werner, Michael S.

    2017-01-01

    Phenotypic plasticity has been proposed as an ecological and evolutionary concept. Ecologically, it can help study how genes and the environment interact to produce robust phenotypes. Evolutionarily, as a facilitator it might contribute to phenotypic novelty and diversification. However, the discussion of phenotypic plasticity remains contentious in parts due to the absence of model systems and rigorous genetic studies. Here, we summarize recent work on the nematode Pristionchus pacificus, which exhibits a feeding plasticity allowing predatory or bacteriovorous feeding. We show feeding plasticity to be controlled by developmental switch genes that are themselves under epigenetic control. Phylogenetic and comparative studies support phenotypic plasticity and its role as a facilitator of morphological novelty and diversity. PMID:28298309

  17. The Genome of the Self-Fertilizing Mangrove Rivulus Fish, Kryptolebias marmoratus: A Model for Studying Phenotypic Plasticity and Adaptations to Extreme Environments.

    PubMed

    Kelley, Joanna L; Yee, Muh-Ching; Brown, Anthony P; Richardson, Rhea R; Tatarenkov, Andrey; Lee, Clarence C; Harkins, Timothy T; Bustamante, Carlos D; Earley, Ryan L

    2016-08-16

    The mangrove rivulus (Kryptolebias marmoratus) is one of two preferentially self-fertilizing hermaphroditic vertebrates. This mode of reproduction makes mangrove rivulus an important model for evolutionary and biomedical studies because long periods of self-fertilization result in naturally homozygous genotypes that can produce isogenic lineages without significant limitations associated with inbreeding depression. Over 400 isogenic lineages currently held in laboratories across the globe show considerable among-lineage variation in physiology, behavior, and life history traits that is maintained under common garden conditions. Temperature mediates the development of primary males and also sex change between hermaphrodites and secondary males, which makes the system ideal for the study of sex determination and sexual plasticity. Mangrove rivulus also exhibit remarkable adaptations to living in extreme environments, and the system has great promise to shed light on the evolution of terrestrial locomotion, aerial respiration, and broad tolerances to hypoxia, salinity, temperature, and environmental pollutants. Genome assembly of the mangrove rivulus allows the study of genes and gene families associated with the traits described above. Here we present a de novo assembled reference genome for the mangrove rivulus, with an approximately 900 Mb genome, including 27,328 annotated, predicted, protein-coding genes. Moreover, we are able to place more than 50% of the assembled genome onto a recently published linkage map. The genome provides an important addition to the linkage map and transcriptomic tools recently developed for this species that together provide critical resources for epigenetic, transcriptomic, and proteomic analyses. Moreover, the genome will serve as the foundation for addressing key questions in behavior, physiology, toxicology, and evolutionary biology.

  18. The Genome of the Self-Fertilizing Mangrove Rivulus Fish, Kryptolebias marmoratus: A Model for Studying Phenotypic Plasticity and Adaptations to Extreme Environments

    PubMed Central

    Kelley, Joanna L.; Yee, Muh-Ching; Brown, Anthony P.; Richardson, Rhea R.; Tatarenkov, Andrey; Lee, Clarence C.; Harkins, Timothy T.; Bustamante, Carlos D.; Earley, Ryan L.

    2016-01-01

    The mangrove rivulus (Kryptolebias marmoratus) is one of two preferentially self-fertilizing hermaphroditic vertebrates. This mode of reproduction makes mangrove rivulus an important model for evolutionary and biomedical studies because long periods of self-fertilization result in naturally homozygous genotypes that can produce isogenic lineages without significant limitations associated with inbreeding depression. Over 400 isogenic lineages currently held in laboratories across the globe show considerable among-lineage variation in physiology, behavior, and life history traits that is maintained under common garden conditions. Temperature mediates the development of primary males and also sex change between hermaphrodites and secondary males, which makes the system ideal for the study of sex determination and sexual plasticity. Mangrove rivulus also exhibit remarkable adaptations to living in extreme environments, and the system has great promise to shed light on the evolution of terrestrial locomotion, aerial respiration, and broad tolerances to hypoxia, salinity, temperature, and environmental pollutants. Genome assembly of the mangrove rivulus allows the study of genes and gene families associated with the traits described above. Here we present a de novo assembled reference genome for the mangrove rivulus, with an approximately 900 Mb genome, including 27,328 annotated, predicted, protein-coding genes. Moreover, we are able to place more than 50% of the assembled genome onto a recently published linkage map. The genome provides an important addition to the linkage map and transcriptomic tools recently developed for this species that together provide critical resources for epigenetic, transcriptomic, and proteomic analyses. Moreover, the genome will serve as the foundation for addressing key questions in behavior, physiology, toxicology, and evolutionary biology. PMID:27324916

  19. Increased phenotypic plasticity to climate may have boosted the invasion success of polyploid Centaurea stoebe.

    PubMed

    Hahn, Min A; van Kleunen, Mark; Müller-Schärer, Heinz

    2012-01-01

    Phenotypic plasticity may allow organisms to cope with altered environmental conditions as e.g. after the introduction into a new range. In particular polyploid organisms, containing more than two sets of chromosomes, may show high levels of plasticity, which could in turn increase their environmental tolerance and invasiveness. Here, we studied the role of phenotypic plasticity in the invasion of Centaurea stoebe (Asteraceae), which in the native range in Europe occurs as diploids and tetraploids, whereas in the introduced range in North America so far only tetraploids have been found. In a common garden experiment at two sites in the native range, we grew half-sibs of the three geo-cytotypes (native European diploids, European tetraploids and invasive North American tetraploids) from a representative sample of 27 populations. We measured the level and the adaptive significance of phenotypic plasticity in eco-physiological and life-history traits in response to the contrasting climatic conditions at the two study sites as well as three different soil conditions in pots, simulating the most crucial abiotic differences between the native and introduced range. European tetraploids showed increased levels of phenotypic plasticity as compared to diploids in response to the different climatic conditions in traits associated with rapid growth and fast phenological development. Moreover, we found evidence for adaptive plasticity in these traits, which suggests that increased plasticity may have contributed to the invasion success of tetraploid C. stoebe by providing an advantage under the novel climatic conditions. However, in invasive tetraploids phenotypic plasticity was similar to that of native tetraploids, indicating no evolution of increased plasticity during invasions. Our findings provide the first empirical support for increased phenotypic plasticity associated with polyploids, which may contribute to their success as invasive species in novel environments.

  20. Selection on phenotypic plasticity of morphological traits in response to flooding and competition in the clonal shore plant Ranunculus reptans.

    PubMed

    van Kleunen, M; Lenssen, J P M; Fischer, M; de Kroon, H

    2007-11-01

    Adaptive evolution of phenotypic plasticity requires that plastic genotypes have the highest global fitness. We studied selection by spatial heterogeneity of interspecific competition and flooding, and by temporal heterogeneity of flooding on morphological plasticity of 52 genotypes of the clonal shore plant Ranunculus reptans. Competition reduced clone size, rosette size, leaf length and stolon internode thickness. Flooding had similar effects and reduced competition. Differences in selection between environments imply potential for either local adaptation or for indirect evolution of phenotypic plasticity. We also detected direct selection for plastic reductions in internode length in response to flooding and for a plastic increase in internode length in response to competition. Plastic responses of some morphological traits to flooding were in line with selection thereon, suggesting that they indeed are adaptive and might have evolved in response to direct selection on plasticity.

  1. The alignment between phenotypic plasticity, the major axis of genetic variation and the response to selection

    PubMed Central

    Lind, Martin I.; Yarlett, Kylie; Reger, Julia; Carter, Mauricio J.; Beckerman, Andrew P.

    2015-01-01

    Phenotypic plasticity is the ability of a genotype to produce more than one phenotype in order to match the environment. Recent theory proposes that the major axis of genetic variation in a phenotypically plastic population can align with the direction of selection. Therefore, theory predicts that plasticity directly aids adaptation by increasing genetic variation in the direction favoured by selection and reflected in plasticity. We evaluated this theory in the freshwater crustacean Daphnia pulex, facing predation risk from two contrasting size-selective predators. We estimated plasticity in several life-history traits, the G matrix of these traits, the selection gradients on reproduction and survival, and the predicted responses to selection. Using these data, we tested whether the genetic lines of least resistance and the predicted response to selection aligned with plasticity. We found predator environment-specific G matrices, but shared genetic architecture across environments resulted in more constraint in the G matrix than in the plasticity of the traits, sometimes preventing alignment of the two. However, as the importance of survival selection increased, the difference between environments in their predicted response to selection increased and resulted in closer alignment between the plasticity and the predicted selection response. Therefore, plasticity may indeed aid adaptation to new environments. PMID:26423845

  2. The alignment between phenotypic plasticity, the major axis of genetic variation and the response to selection.

    PubMed

    Lind, Martin I; Yarlett, Kylie; Reger, Julia; Carter, Mauricio J; Beckerman, Andrew P

    2015-10-07

    Phenotypic plasticity is the ability of a genotype to produce more than one phenotype in order to match the environment. Recent theory proposes that the major axis of genetic variation in a phenotypically plastic population can align with the direction of selection. Therefore, theory predicts that plasticity directly aids adaptation by increasing genetic variation in the direction favoured by selection and reflected in plasticity. We evaluated this theory in the freshwater crustacean Daphnia pulex, facing predation risk from two contrasting size-selective predators. We estimated plasticity in several life-history traits, the G matrix of these traits, the selection gradients on reproduction and survival, and the predicted responses to selection. Using these data, we tested whether the genetic lines of least resistance and the predicted response to selection aligned with plasticity. We found predator environment-specific G matrices, but shared genetic architecture across environments resulted in more constraint in the G matrix than in the plasticity of the traits, sometimes preventing alignment of the two. However, as the importance of survival selection increased, the difference between environments in their predicted response to selection increased and resulted in closer alignment between the plasticity and the predicted selection response. Therefore, plasticity may indeed aid adaptation to new environments.

  3. Hormone signaling and phenotypic plasticity in nematode development and evolution.

    PubMed

    Sommer, Ralf J; Ogawa, Akira

    2011-09-27

    Phenotypic plasticity refers to the ability of an organism to adopt different phenotypes depending on environmental conditions. In animals and plants, the progression of juvenile development and the formation of dormant stages are often associated with phenotypic plasticity, indicating the importance of phenotypic plasticity for life-history theory. Phenotypic plasticity has long been emphasized as a crucial principle in ecology and as facilitator of phenotypic evolution. In nematodes, several examples of phenotypic plasticity have been studied at the genetic and developmental level. In addition, the influence of different environmental factors has been investigated under laboratory conditions. These studies have provided detailed insight into the molecular basis of phenotypic plasticity and its ecological and evolutionary implications. Here, we review recent studies on the formation of dauer larvae in Caenorhabditis elegans, the evolution of nematode parasitism and the generation of a novel feeding trait in Pristionchus pacificus. These examples reveal a conserved and co-opted role of an endocrine signaling module involving the steroid hormone dafachronic acid. We will discuss how hormone signaling might facilitate life-history and morphological evolution.

  4. Cancer cells exhibit clonal diversity in phenotypic plasticity

    PubMed Central

    2017-01-01

    Phenotypic heterogeneity in cancers is associated with invasive progression and drug resistance. This heterogeneity arises in part from the ability of cancer cells to switch between phenotypic states, but the dynamics of this cellular plasticity remain poorly understood. Here we apply DNA barcodes to quantify and track phenotypic plasticity across hundreds of clones in a population of cancer cells exhibiting epithelial or mesenchymal differentiation phenotypes. We find that the epithelial-to-mesenchymal cell ratio is highly variable across the different clones in cancer cell populations, but remains stable for many generations within the progeny of any single clone—with a heritability of 0.89. To estimate the effects of combination therapies on phenotypically heterogeneous tumours, we generated quantitative simulations incorporating empirical data from our barcoding experiments. These analyses indicated that combination therapies which alternate between epithelial- and mesenchymal-specific treatments eventually select for clones with increased phenotypic plasticity. However, this selection could be minimized by increasing the frequency of alternation between treatments, identifying designs that may minimize selection for increased phenotypic plasticity. These findings establish new insights into phenotypic plasticity in cancer, and suggest design principles for optimizing the effectiveness of combination therapies for phenotypically heterogeneous tumours. PMID:28202626

  5. Cancer cells exhibit clonal diversity in phenotypic plasticity.

    PubMed

    Mathis, Robert Austin; Sokol, Ethan S; Gupta, Piyush B

    2017-02-01

    Phenotypic heterogeneity in cancers is associated with invasive progression and drug resistance. This heterogeneity arises in part from the ability of cancer cells to switch between phenotypic states, but the dynamics of this cellular plasticity remain poorly understood. Here we apply DNA barcodes to quantify and track phenotypic plasticity across hundreds of clones in a population of cancer cells exhibiting epithelial or mesenchymal differentiation phenotypes. We find that the epithelial-to-mesenchymal cell ratio is highly variable across the different clones in cancer cell populations, but remains stable for many generations within the progeny of any single clone-with a heritability of 0.89. To estimate the effects of combination therapies on phenotypically heterogeneous tumours, we generated quantitative simulations incorporating empirical data from our barcoding experiments. These analyses indicated that combination therapies which alternate between epithelial- and mesenchymal-specific treatments eventually select for clones with increased phenotypic plasticity. However, this selection could be minimized by increasing the frequency of alternation between treatments, identifying designs that may minimize selection for increased phenotypic plasticity. These findings establish new insights into phenotypic plasticity in cancer, and suggest design principles for optimizing the effectiveness of combination therapies for phenotypically heterogeneous tumours.

  6. Key Questions on the Role of Phenotypic Plasticity in Eco-Evolutionary Dynamics.

    PubMed

    Hendry, Andrew P

    2016-01-01

    Ecology and evolution have long been recognized as reciprocally influencing each other, with recent research emphasizing how such interactions can occur even on very short (contemporary) time scales. Given that these interactions are mediated by organismal phenotypes, they can be variously shaped by genetic variation, phenotypic plasticity, or both. I here address 8 key questions relevant to the role of plasticity in eco-evolutionary dynamics. Focusing on empirical evidence, especially from natural populations, I offer the following conclusions. 1) Plasticity is--not surprisingly--sometimes adaptive, sometimes maladaptive, and sometimes neutral. 2) Plasticity has costs and limits but these constraints are highly variable, often weak, and hard to detect. 3) Variable environments favor the evolution of increased trait plasticity, which can then buffer fitness/performance (i.e., tolerance). 4) Plasticity sometimes aids colonization of new environments (Baldwin Effect) and responses to in situ environmental change. However, plastic responses are not always necessary or sufficient in these contexts. 5) Plasticity will sometimes promote and sometimes constrain genetic evolution. 6) Plasticity will sometimes help and sometimes hinder ecological speciation but, at present, empirical tests are limited. 7) Plasticity can show considerable evolutionary change in contemporary time, although the rates of this reaction norm evolution are highly variable among taxa and traits. 8) Plasticity appears to have considerable influences on ecological dynamics at the community and ecosystem levels, although many more studies are needed. In summary, plasticity needs to be an integral part of any conceptual framework and empirical investigation of eco-evolutionary dynamics.

  7. Multiple cues influence multiple traits in the phenotypically plastic melanization of the cabbage white butterfly.

    PubMed

    Stoehr, Andrew M; Wojan, Erin M

    2016-11-01

    Phenotypic plasticity, or the ability of organisms to produce different phenotypes depending upon environmental factors, may be adaptive in varying environments. However, because environments differ in many ways and organisms consist of many traits perfect phenotype-environment matches are unlikely. Studies that investigate multiple interacting environmental factors and the plastic responses of multiple traits should increase our understanding of the limits of adaptive plasticity. We experimentally examined the effects of variation in temperature and photoperiod on the seasonally plastic, and likely adaptive, melanization of a temperate butterfly, Pieris rapae. Although several melanin-based traits changed in response to temperature and photoperiodic variation, these traits tended to fall into two 'trait groups' consisting of traits covarying positively. However, these two trait groups responded to environmental factors, particularly temperature, in independent and sometimes opposing ways, with one increasing and the other decreasing in melanization with increased temperature. In some cases, plastic responses were complex and non-linear. Furthermore, when temperature and photoperiod were manipulated orthogonally, we sometimes detected interactive effects on melanization. These complex responses to two environmental cues may reflect sub-optimal responses or may occur if the two cues together provide more reliable information about future conditions than would either cue alone. Our results highlight the limits of studies of phenotypic plasticity that consider only single environmental factors and limit treatments to just two levels.

  8. A systematic review of phenotypic plasticity in marine invertebrate and plant systems.

    PubMed

    Padilla, Dianna K; Savedo, Monique M

    2013-01-01

    Marine organisms provide some of the most important examples of phenotypic plasticity to date. We conducted a systematic review to cast a wide net through the literature to examine general patterns among marine taxa and to identify gaps in our knowledge. Unlike terrestrial systems, most studies of plasticity are on animals and fewer on plants and algae. For invertebrates, twice as many studies are on mobile than sessile species and for both animals and plants most species are benthic intertidal zone taxa. For invertebrates, morphological plasticity is most common, while chemical plasticity is most common among algae. For algae, as expected, predators (inducible defences) are the primary cue for triggering plasticity. Surprisingly, for invertebrates the abiotic environment is the most common trigger for plasticity. Inducible defences in invertebrates have received great attention and predominate for a few well-studied species, which can bias perceptions; but, their predominance overall is not supported by the full data set. We also identified important research needs, including the need for data on non-temperate zone taxa, planned experiments to directly test the role of habitat variability and the prevalence of plasticity. We also need information on the lag time for induction of plastic traits, which is critical for determining the adaptive value of phenotypic plasticity. Studies of early life stages and studies that link plasticity to mechanisms that produce phenotypes are critically needed, as are phylogenetic comparative studies that can be used to examine responses of organisms to both short- and long-term change.

  9. Quantitative trait loci mapping of phenotypic plasticity and genotype-environment interactions in plant and insect performance.

    PubMed

    Tétard-Jones, C; Kertesz, M A; Preziosi, R F

    2011-05-12

    Community genetic studies generally ignore the plasticity of the functional traits through which the effect is passed from individuals to the associated community. However, the ability of organisms to be phenotypically plastic allows them to rapidly adapt to changing environments and plasticity is commonly observed across all taxa. Owing to the fitness benefits of phenotypic plasticity, evolutionary biologists are interested in its genetic basis, which could explain how phenotypic plasticity is involved in the evolution of species interactions. Two current ideas exist: (i) phenotypic plasticity is caused by environmentally sensitive loci associated with a phenotype; (ii) phenotypic plasticity is caused by regulatory genes that simply influence the plasticity of a phenotype. Here, we designed a quantitative trait loci (QTL) mapping experiment to locate QTL on the barley genome associated with barley performance when the environment varies in the presence of aphids, and the composition of the rhizosphere. We simultaneously mapped aphid performance across variable rhizosphere environments. We mapped main effects, QTL × environment interaction (QTL×E), and phenotypic plasticity (measured as the difference in mean trait values) for barley and aphid performance onto the barley genome using an interval mapping procedure. We found that QTL associated with phenotypic plasticity were co-located with main effect QTL and QTL×E. We also located phenotypic plasticity QTL that were located separately from main effect QTL. These results support both of the current ideas of how phenotypic plasticity is genetically based and provide an initial insight into the functional genetic basis of how phenotypically plastic traits may still be important sources of community genetic effects.

  10. Adaptive plasticity and niche expansion in an invasive thistle.

    PubMed

    Turner, Kathryn G; Fréville, Hélène; Rieseberg, Loren H

    2015-08-01

    Phenotypic differentiation in size and fecundity between native and invasive populations of a species has been suggested as a causal driver of invasion in plants. Local adaptation to novel environmental conditions through a micro-evolutionary response to natural selection may lead to phenotypic differentiation and fitness advantages in the invaded range. Local adaptation may occur along a stress tolerance trade-off, favoring individuals that, in benign conditions, shift resource allocation from stress tolerance to increased vigor and fecundity and, therefore, invasiveness. Alternately, the typically disturbed invaded range may select for a plastic, generalist strategy, making phenotypic plasticity the main driver of invasion success. To distinguish between these hypotheses, we performed a field common garden and tested for genetically based phenotypic differentiation, resource allocation shifts in response to water limitation, and local adaptation to the environmental gradient which describes the source locations for native and invasive populations of diffuse knapweed (Centaurea diffusa). Plants were grown in an experimental field in France (naturalized range) under water addition and limitation conditions. After accounting for phenotypic variation arising from environmental differences among collection locations, we found evidence of genetic variation between the invasive and native populations for most morphological and life-history traits under study. Invasive C. diffusa populations produced larger, later maturing, and therefore potentially fitter individuals than native populations. Evidence for local adaptation along a resource allocation trade-off for water limitation tolerance is equivocal. However, native populations do show evidence of local adaptation to an environmental gradient, a relationship which is typically not observed in the invaded range. Broader analysis of the climatic niche inhabited by the species in both ranges suggests that the

  11. Endocrine regulation of predator-induced phenotypic plasticity.

    PubMed

    Dennis, Stuart R; LeBlanc, Gerald A; Beckerman, Andrew P

    2014-11-01

    Elucidating the developmental and genetic control of phenotypic plasticity remains a central agenda in evolutionary ecology. Here, we investigate the physiological regulation of phenotypic plasticity induced by another organism, specifically predator-induced phenotypic plasticity in the model ecological and evolutionary organism Daphnia pulex. Our research centres on using molecular tools to test among alternative mechanisms of developmental control tied to hormone titres, receptors and their timing in the life cycle. First, we synthesize detail about predator-induced defenses and the physiological regulation of arthropod somatic growth and morphology, leading to a clear prediction that morphological defences are regulated by juvenile hormone and life-history plasticity by ecdysone and juvenile hormone. We then show how a small network of genes can differentiate phenotype expression between the two primary developmental control pathways in arthropods: juvenoid and ecdysteroid hormone signalling. Then, by applying an experimental gradient of predation risk, we show dose-dependent gene expression linking predator-induced plasticity to the juvenoid hormone pathway. Our data support three conclusions: (1) the juvenoid signalling pathway regulates predator-induced phenotypic plasticity; (2) the hormone titre (ligand), rather than receptor, regulates predator-induced developmental plasticity; (3) evolution has favoured the harnessing of a major, highly conserved endocrine pathway in arthropod development to regulate the response to cues about changing environments (risk) from another organism (predator).

  12. A QTL model to map the common genetic basis for correlative phenotypic plasticity.

    PubMed

    Zhou, Tao; Lyu, Yafei; Xu, Fang; Bo, Wenhao; Zhai, Yi; Zhang, Jian; Pang, Xiaoming; Zheng, Bingsong; Wu, Rongling

    2015-01-01

    As an important mechanism for adaptation to heterogeneous environment, plastic responses of correlated traits to environmental alteration may also be genetically correlated, but less is known about the underlying genetic basis. We describe a statistical model for mapping specific quantitative trait loci (QTLs) that control the interrelationship of phenotypic plasticity between different traits. The model is constructed by a bivariate mixture setting, implemented with the EM algorithm to estimate the genetic effects of QTLs on correlative plastic response. We provide a series of procedure that test (1) how a QTL controls the phenotypic plasticity of a single trait; and (2) how the QTL determines the correlation of environment-induced changes of different traits. The model is readily extended to test how epistatic interactions among QTLs play a part in the correlations of different plastic traits. The model was validated through computer simulation and used to analyse multi-environment data of genetic mapping in winter wheat, showing its utilization in practice.

  13. The genetics of phenotypic plasticity. XIII. Interactions with developmental instability.

    PubMed

    Scheiner, Samuel M

    2014-04-01

    In a heterogeneous environment, natural selection on a trait can lead to a variety of outcomes, including phenotypic plasticity and bet-hedging through developmental instability. These outcomes depend on the magnitude and pattern of that heterogeneity and the spatial and temporal distribution of individuals. However, we do not know if and how those two outcomes might interact with each other. I examined the joint evolution of plasticity and instability through the use of an individual-based simulation in which each could be genetically independent or pleiotropically linked. When plasticity and instability were determined by different loci, the only effect on the evolution of plasticity was the elimination of plasticity as a bet-hedging strategy. In contrast, the effects on the evolution of instability were more substantial. If conditions were such that the population was likely to evolve to the optimal reaction norm, then instability was disfavored. Instability was favored only when the lack of a reliable environmental cue disfavored plasticity. When plasticity and instability were determined by the same loci, instability acted as a strong limitation on the evolution of plasticity. Under some conditions, selection for instability resulted in maladaptive plasticity. Therefore, before testing any models of plasticity or instability evolution, or interpreting empirical patterns, it is important to know the ecological, life history, developmental, and genetic contexts of trait phenotypic plasticity and developmental instability.

  14. Adaptive Plasticity in Wild Field Cricket’s Acoustic Signaling

    PubMed Central

    Bertram, Susan M.; Harrison, Sarah J.; Thomson, Ian R.; Fitzsimmons, Lauren P.

    2013-01-01

    Phenotypic plasticity can be adaptive when phenotypes are closely matched to changes in the environment. In crickets, rhythmic fluctuations in the biotic and abiotic environment regularly result in diel rhythms in density of sexually active individuals. Given that density strongly influences the intensity of sexual selection, we asked whether crickets exhibit plasticity in signaling behavior that aligns with these rhythmic fluctuations in the socio-sexual environment. We quantified the acoustic mate signaling behavior of wild-caught males of two cricket species, Gryllus veletis and G. pennsylvanicus. Crickets exhibited phenotypically plastic mate signaling behavior, with most males signaling more often and more attractively during the times of day when mating activity is highest in the wild. Most male G. pennsylvanicus chirped more often and louder, with shorter interpulse durations, pulse periods, chirp durations, and interchirp durations, and at slightly higher carrier frequencies during the time of the day that mating activity is highest in the wild. Similarly, most male G. veletis chirped more often, with more pulses per chirp, longer interpulse durations, pulse periods, and chirp durations, shorter interchirp durations, and at lower carrier frequencies during the time of peak mating activity in the wild. Among-male variation in signaling plasticity was high, with some males signaling in an apparently maladaptive manner. Body size explained some of the among-male variation in G. pennsylvanicus plasticity but not G. veletis plasticity. Overall, our findings suggest that crickets exhibit phenotypically plastic mate attraction signals that closely match the fluctuating socio-sexual context they experience. PMID:23935965

  15. Shaping development through mechanical strain: the transcriptional basis of diet-induced phenotypic plasticity in a cichlid fish.

    PubMed

    Gunter, Helen M; Fan, Shaohua; Xiong, Fan; Franchini, Paolo; Fruciano, Carmelo; Meyer, Axel

    2013-09-01

    Adaptive phenotypic plasticity, the ability of an organism to change its phenotype to match local environments, is increasingly recognized for its contribution to evolution. However, few empirical studies have explored the molecular basis of plastic traits. The East African cichlid fish Astatoreochromis alluaudi displays adaptive phenotypic plasticity in its pharyngeal jaw apparatus, a structure that is widely seen as an evolutionary key innovation that has contributed to the remarkable diversity of cichlid fishes. It has previously been shown that in response to different diets, the pharyngeal jaws change their size, shape and dentition: hard diets induce an adaptive robust molariform tooth phenotype with short jaws and strong internal bone structures, while soft diets induce a gracile papilliform tooth phenotype with elongated jaws and slender internal bone structures. To gain insight into the molecular underpinnings of these adaptations and enable future investigations of the role that phenotypic plasticity plays during the formation of adaptive radiations, the transcriptomes of the two divergent jaw phenotypes were examined. Our study identified a total of 187 genes whose expression differs in response to hard and soft diets, including immediate early genes, extracellular matrix genes and inflammatory factors. Transcriptome results are interpreted in light of expression of candidate genes-markers for tooth size and shape, bone cells and mechanically sensitive pathways. This study opens up new avenues of research at new levels of biological organization into the roles of phenotypic plasticity during speciation and radiation of cichlid fishes.

  16. Human Maternal Brain Plasticity: Adaptation to Parenting

    ERIC Educational Resources Information Center

    Kim, Pilyoung

    2016-01-01

    New mothers undergo dynamic neural changes that support positive adaptation to parenting and the development of mother-infant relationships. In this article, I review important psychological adaptations that mothers experience during pregnancy and the early postpartum period. I then review evidence of structural and functional plasticity in human…

  17. The evolution of phenotypic plasticity in spatially structured environments: implications of intraspecific competition, plasticity costs and environmental characteristics.

    PubMed

    Ernande, B; Dieckmann, U

    2004-05-01

    We model the evolution of reaction norms focusing on three aspects: frequency-dependent selection arising from resource competition, maintenance and production costs of phenotypic plasticity, and three characteristics of environmental heterogeneity (frequency of environments, their intrinsic carrying capacity and the sensitivity to phenotypic maladaptation in these environments). We show that (i) reaction norms evolve so as to trade adaptation for acquiring resources against cost avoidance; (ii) maintenance costs cause reaction norms to better adapt to frequent rather than to infrequent environments, whereas production costs do not; and (iii) evolved reaction norms confer better adaptation to environments with low rather than with high intrinsic carrying capacity. The two previous findings contradict earlier theoretical results and originate from two previously unexplored features that are included in our model. First, production costs of phenotypic plasticity are only incurred when a given phenotype is actually produced. Therefore, they are proportional to the frequency of environments, and these frequencies thus affect the selection pressure to avoid costs just as much as the selection pressure to improve adaptation. This prevents the frequency of environments from affecting the evolving reaction norm. Secondly, our model describes the evolution of plasticity for a phenotype determining an individual's capability to acquire resources, and thus its realized carrying capacity. When individuals are distributed randomly across environments, they cannot avoid experiencing environments with intrinsically low carrying capacity. As selection pressures arising from the need to improve adaptation are stronger under such extreme conditions than under mild ones, better adaptation to environments with low rather than with high intrinsic carrying capacity results.

  18. Adaptive shaping of the behavioural and neuroendocrine phenotype during adolescence.

    PubMed

    Zimmermann, Tobias D; Kaiser, Sylvia; Hennessy, Michael B; Sachser, Norbert

    2017-02-22

    Environmental conditions during early life can adaptively shape the phenotype for the prevailing environment. Recently, it has been suggested that adolescence represents an additional temporal window for adaptive developmental plasticity, though supporting evidence is scarce. Previous work has shown that male guinea pigs living in large mixed-sex colonies develop a low-aggressive phenotype as part of a queuing strategy that is adaptive for integrating into large unfamiliar colonies. By contrast, males living in pairs during adolescence become highly aggressive towards strangers. Here, we tested whether the high-aggressive phenotype is adaptive under conditions of low population density, namely when directly competing with a single opponent for access to females. For that purpose, we established groups of one pair-housed male (PM), one colony-housed male (CM) and two females. PMs directed more aggression towards the male competitor and more courtship and mating towards females than did CMs. In consequence, PMs attained the dominant position in most cases and sired significantly more offspring. Moreover, they showed distinctly higher testosterone concentrations and elevated cortisol levels, which probably promoted enhanced aggressiveness while mobilizing necessary energy. Taken together, our results provide the clearest evidence to date for adaptive shaping of the phenotype by environmental influences during adolescence.

  19. Phenotypic plasticity changes correlations of traits following experimental introductions of Trinidadian guppies (Poecilia reticulata).

    PubMed

    Handelsman, Corey A; Ruell, Emily W; Torres-Dowdall, Julián; Ghalambor, Cameron K

    2014-11-01

    Colonization of novel environments can alter selective pressures and act as a catalyst for rapid evolution in nature. Theory and empirical studies suggest that the ability of a population to exhibit an adaptive evolutionary response to novel selection pressures should reflect the presence of sufficient additive genetic variance and covariance for individual and correlated traits. As correlated traits should not respond to selection independently, the structure of correlations of traits can bias or constrain adaptive evolution. Models of how multiple correlated traits respond to selection often assume spatial and temporal stability of trait-correlations within populations. Yet, trait-correlations can also be plastic in response to environmental variation. Phenotypic plasticity, the ability of a single genotype to produce different phenotypes across environments, is of particular interest because it can induce population-wide changes in the combination of traits exposed to selection and change the trajectory of evolutionary divergence. We tested the ability of phenotypic plasticity to modify trait-correlations by comparing phenotypic variance and covariance in the body-shapes of four experimental populations of Trinidadian guppies (Poecilia reticulata) to their ancestral population. We found that phenotypic plasticity produced both adaptive and novel aspects of body-shape, which was repeated in all four experimental populations. Further, phenotypic plasticity changed patterns of covariance among morphological characters. These findings suggest our ability to make inferences about patterns of divergence based on correlations of traits in extant populations may be limited if novel environments not only induce plasticity in multiple traits, but also change the correlations among the traits.

  20. Phenotypic plasticity confers multiple fitness benefits to a mimic.

    PubMed

    Cortesi, Fabio; Feeney, William E; Ferrari, Maud C O; Waldie, Peter A; Phillips, Genevieve A C; McClure, Eva C; Sköld, Helen N; Salzburger, Walter; Marshall, N Justin; Cheney, Karen L

    2015-03-30

    Animal communication is often deceptive; however, such dishonesty can become ineffective if it is used too often, is used out of context, or is too easy to detect [1-3]. Mimicry is a common form of deception, and most mimics gain the greatest fitness benefits when they are rare compared to their models [3, 4]. If mimics are encountered too frequently or if their model is absent, avoidance learning of noxious models is disrupted (Batesian mimicry [3]), or receivers become more vigilant and learn to avoid perilous mimics (aggressive mimicry [4]). Mimics can moderate this selective constraint by imperfectly resembling multiple models [5], through polymorphisms [6], or by opportunistically deploying mimetic signals [1, 7]. Here we uncover a novel mechanism to escape the constraints of deceptive signaling: phenotypic plasticity allows mimics to deceive targets using multiple guises. Using a combination of behavioral, cell histological, and molecular methods, we show that a coral reef fish, the dusky dottyback (Pseudochromis fuscus), flexibly adapts its body coloration to mimic differently colored reef fishes and in doing so gains multiple fitness benefits. We find that by matching the color of other reef fish, dottybacks increase their success of predation upon juvenile fish prey and are therefore able to deceive their victims by resembling multiple models. Furthermore, we demonstrate that changing color also increases habitat-associated crypsis that decreases the risk of being detected by predators. Hence, when mimics and models share common selective pressures, flexible imitation of models might inherently confer secondary benefits to mimics. Our results show that phenotypic plasticity can act as a mechanism to ease constraints that are typically associated with deception. VIDEO ABSTRACT.

  1. Phenotypic plasticity in heterotrophic marine microbial communities in continuous cultures

    PubMed Central

    Beier, Sara; Rivers, Adam R; Moran, Mary Ann; Obernosterer, Ingrid

    2015-01-01

    Phenotypic plasticity (PP) is the development of alternate phenotypes of a given taxon as an adaptation to environmental conditions. Methodological limitations have restricted the quantification of PP to the measurement of a few traits in single organisms. We used metatranscriptomic libraries to overcome these challenges and estimate PP using the expressed genes of multiple heterotrophic organisms as a proxy for traits in a microbial community. The metatranscriptomes captured the expression response of natural marine bacterial communities grown on differing carbon resource regimes in continuous cultures. We found that taxa with different magnitudes of PP coexisted in the same cultures, and that members of the order Rhodobacterales had the highest levels of PP. In agreement with previous studies, our results suggest that continuous culturing may have specifically selected for taxa featuring a rather high range of PP. On average, PP and abundance changes within a taxon contributed equally to the organism's change in functional gene abundance, implying that both PP and abundance mediated observed differences in community function. However, not all functional changes due to PP were directly reflected in the bulk community functional response: gene expression changes in individual taxa due to PP were partly masked by counterbalanced expression of the same gene in other taxa. This observation demonstrates that PP had a stabilizing effect on a community's functional response to environmental change. PMID:25397947

  2. Phenotypic plasticity in prostate cancer: role of intrinsically disordered proteins

    PubMed Central

    Mooney, Steven M; Jolly, Mohit Kumar; Levine, Herbert; Kulkarni, Prakash

    2016-01-01

    A striking characteristic of cancer cells is their remarkable phenotypic plasticity, which is the ability to switch states or phenotypes in response to environmental fluctuations. Phenotypic changes such as a partial or complete epithelial to mesenchymal transition (EMT) that play important roles in their survival and proliferation, and development of resistance to therapeutic treatments, are widely believed to arise due to somatic mutations in the genome. However, there is a growing concern that such a deterministic view is not entirely consistent with multiple lines of evidence, which indicate that stochasticity may also play an important role in driving phenotypic plasticity. Here, we discuss how stochasticity in protein interaction networks (PINs) may play a key role in determining phenotypic plasticity in prostate cancer (PCa). Specifically, we point out that the key players driving transitions among different phenotypes (epithelial, mesenchymal, and hybrid epithelial/mesenchymal), including ZEB1, SNAI1, OVOL1, and OVOL2, are intrinsically disordered proteins (IDPs) and discuss how plasticity at the molecular level may contribute to stochasticity in phenotypic switching by rewiring PINs. We conclude by suggesting that targeting IDPs implicated in EMT in PCa may be a new strategy to gain additional insights and develop novel treatments for this disease, which is the most common form of cancer in adult men. PMID:27427552

  3. Phenotypic plasticity in prostate cancer: role of intrinsically disordered proteins.

    PubMed

    Mooney, Steven M; Jolly, Mohit Kumar; Levine, Herbert; Kulkarni, Prakash

    2016-01-01

    A striking characteristic of cancer cells is their remarkable phenotypic plasticity, which is the ability to switch states or phenotypes in response to environmental fluctuations. Phenotypic changes such as a partial or complete epithelial to mesenchymal transition (EMT) that play important roles in their survival and proliferation, and development of resistance to therapeutic treatments, are widely believed to arise due to somatic mutations in the genome. However, there is a growing concern that such a deterministic view is not entirely consistent with multiple lines of evidence, which indicate that stochasticity may also play an important role in driving phenotypic plasticity. Here, we discuss how stochasticity in protein interaction networks (PINs) may play a key role in determining phenotypic plasticity in prostate cancer (PCa). Specifically, we point out that the key players driving transitions among different phenotypes (epithelial, mesenchymal, and hybrid epithelial/mesenchymal), including ZEB1, SNAI1, OVOL1, and OVOL2, are intrinsically disordered proteins (IDPs) and discuss how plasticity at the molecular level may contribute to stochasticity in phenotypic switching by rewiring PINs. We conclude by suggesting that targeting IDPs implicated in EMT in PCa may be a new strategy to gain additional insights and develop novel treatments for this disease, which is the most common form of cancer in adult men.

  4. A multi-phenotypic cancer model with cell plasticity.

    PubMed

    Zhou, Da; Wang, Yue; Wu, Bin

    2014-09-21

    The conventional cancer stem cell (CSC) theory indicates a hierarchy of CSCs and non-stem cancer cells (NSCCs), that is, CSCs can differentiate into NSCCs but not vice versa. However, an alternative paradigm of CSC theory with reversible cell plasticity among cancer cells has received much attention very recently. Here we present a generalized multi-phenotypic cancer model by integrating cell plasticity with the conventional hierarchical structure of cancer cells. We prove that under very weak assumption, the nonlinear dynamics of multi-phenotypic proportions in our model has only one stable steady state and no stable limit cycle. This result theoretically explains the phenotypic equilibrium phenomena reported in various cancer cell lines. Furthermore, according to the transient analysis of our model, it is found that cancer cell plasticity plays an essential role in maintaining the phenotypic diversity in cancer especially during the transient dynamics. Two biological examples with experimental data show that the phenotypic conversions from NCSSs to CSCs greatly contribute to the transient growth of CSCs proportion shortly after the drastic reduction of it. In particular, an interesting overshooting phenomenon of CSCs proportion arises in three-phenotypic example. Our work may pave the way for modeling and analyzing the multi-phenotypic cell population dynamics with cell plasticity.

  5. Climate change in the oceans: evolutionary versus phenotypically plastic responses of marine animals and plants

    PubMed Central

    Reusch, Thorsten B H

    2014-01-01

    I summarize marine studies on plastic versus adaptive responses to global change. Due to the lack of time series, this review focuses largely on the potential for adaptive evolution in marine animals and plants. The approaches were mainly synchronic comparisons of phenotypically divergent populations, substituting spatial contrasts in temperature or CO2 environments for temporal changes, or in assessments of adaptive genetic diversity within populations for traits important under global change. The available literature is biased towards gastropods, crustaceans, cnidarians and macroalgae. Focal traits were mostly environmental tolerances, which correspond to phenotypic buffering, a plasticity type that maintains a functional phenotype despite external disturbance. Almost all studies address coastal species that are already today exposed to fluctuations in temperature, pH and oxygen levels. Recommendations for future research include (i) initiation and analyses of observational and experimental temporal studies encompassing diverse phenotypic traits (including diapausing cues, dispersal traits, reproductive timing, morphology) (ii) quantification of nongenetic trans-generational effects along with components of additive genetic variance (iii) adaptive changes in microbe–host associations under the holobiont model in response to global change (iv) evolution of plasticity patterns under increasingly fluctuating environments and extreme conditions and (v) joint consideration of demography and evolutionary adaptation in evolutionary rescue approaches. PMID:24454551

  6. Climate change in the oceans: evolutionary versus phenotypically plastic responses of marine animals and plants.

    PubMed

    Reusch, Thorsten B H

    2014-01-01

    I summarize marine studies on plastic versus adaptive responses to global change. Due to the lack of time series, this review focuses largely on the potential for adaptive evolution in marine animals and plants. The approaches were mainly synchronic comparisons of phenotypically divergent populations, substituting spatial contrasts in temperature or CO2 environments for temporal changes, or in assessments of adaptive genetic diversity within populations for traits important under global change. The available literature is biased towards gastropods, crustaceans, cnidarians and macroalgae. Focal traits were mostly environmental tolerances, which correspond to phenotypic buffering, a plasticity type that maintains a functional phenotype despite external disturbance. Almost all studies address coastal species that are already today exposed to fluctuations in temperature, pH and oxygen levels. Recommendations for future research include (i) initiation and analyses of observational and experimental temporal studies encompassing diverse phenotypic traits (including diapausing cues, dispersal traits, reproductive timing, morphology) (ii) quantification of nongenetic trans-generational effects along with components of additive genetic variance (iii) adaptive changes in microbe-host associations under the holobiont model in response to global change (iv) evolution of plasticity patterns under increasingly fluctuating environments and extreme conditions and (v) joint consideration of demography and evolutionary adaptation in evolutionary rescue approaches.

  7. Lineage stability and phenotypic plasticity of Foxp3⁺ regulatory T cells.

    PubMed

    Hori, Shohei

    2014-05-01

    Regulatory T (Treg) cells expressing the transcription factor forkhead box protein 3 (Foxp3) constitute a unique T-cell lineage committed to suppressive functions. While their differentiation state is remarkably stable in the face of various perturbations from the extracellular environment, they are able to adapt to diverse and fluctuating tissue environments by changing their phenotype. The lineage stability and phenotypic plasticity of Treg cells thus ensure the robustness of self-tolerance and tissue homeostasis. Recent studies have suggested, however, that Treg cells may retain lineage plasticity, the ability to switch their cell fate to various effector T-cell types under certain circumstances such as inflammation, a notion that remains highly contentious. While accumulating evidence indicates that some Treg cells can downregulate Foxp3 expression and/or acquire effector T-helper cell-like phenotypes, results from my laboratory have shown that Treg cells retain epigenetic memory of, and thus remain committed to, Foxp3 expression and suppressive functions despite such phenotypic plasticity. It has also become evident that Foxp3 can be promiscuously and transiently expressed in activated T cells. Here, I argue that the current controversy stems partly from the lack of the lineage specificity of Foxp3 expression and also from the confusion between phenotypic plasticity and lineage plasticity, and discuss implications of our findings in Treg cell fate determination and maintenance.

  8. Jack-of-all-trades: phenotypic plasticity facilitates the invasion of an alien slug species

    PubMed Central

    Knop, Eva; Reusser, Nik

    2012-01-01

    Invasive alien species might benefit from phenotypic plasticity by being able to (i) maintain fitness in stressful environments (‘robust’), (ii) increase fitness in favourable environments (‘opportunistic’), or (iii) combine both abilities (‘robust and opportunistic’). Here, we applied this framework, for the first time, to an animal, the invasive slug, Arion lusitanicus, and tested (i) whether it has a more adaptive phenotypic plasticity compared with a congeneric native slug, Arion fuscus, and (ii) whether it is robust, opportunistic or both. During one year, we exposed specimens of both species to a range of temperatures along an altitudinal gradient (700–2400 m a.s.l.) and to high and low food levels, and we compared the responsiveness of two fitness traits: survival and egg production. During summer, the invasive species had a more adaptive phenotypic plasticity, and at high temperatures and low food levels, it survived better and produced more eggs than A. fuscus, representing the robust phenotype. During winter, A. lusitanicus displayed a less adaptive phenotype than A. fuscus. We show that the framework developed for plants is also very useful for a better mechanistic understanding of animal invasions. Warmer summers and milder winters might lead to an expansion of this invasive species to higher altitudes and enhance its spread in the lowlands, supporting the concern that global climate change will increase biological invasions. PMID:23015630

  9. Jack-of-all-trades: phenotypic plasticity facilitates the invasion of an alien slug species.

    PubMed

    Knop, Eva; Reusser, Nik

    2012-11-22

    Invasive alien species might benefit from phenotypic plasticity by being able to (i) maintain fitness in stressful environments ('robust'), (ii) increase fitness in favourable environments ('opportunistic'), or (iii) combine both abilities ('robust and opportunistic'). Here, we applied this framework, for the first time, to an animal, the invasive slug, Arion lusitanicus, and tested (i) whether it has a more adaptive phenotypic plasticity compared with a congeneric native slug, Arion fuscus, and (ii) whether it is robust, opportunistic or both. During one year, we exposed specimens of both species to a range of temperatures along an altitudinal gradient (700-2400 m a.s.l.) and to high and low food levels, and we compared the responsiveness of two fitness traits: survival and egg production. During summer, the invasive species had a more adaptive phenotypic plasticity, and at high temperatures and low food levels, it survived better and produced more eggs than A. fuscus, representing the robust phenotype. During winter, A. lusitanicus displayed a less adaptive phenotype than A. fuscus. We show that the framework developed for plants is also very useful for a better mechanistic understanding of animal invasions. Warmer summers and milder winters might lead to an expansion of this invasive species to higher altitudes and enhance its spread in the lowlands, supporting the concern that global climate change will increase biological invasions.

  10. Integrating biological invasions, climate change and phenotypic plasticity.

    PubMed

    Engel, Katharina; Tollrian, Ralph; Jeschke, Jonathan M

    2011-05-01

    Invasive species frequently change the ecosystems where they are introduced, e.g., by affecting species interactions and population densities of native species. We outline the connectedness of biological invasions, climate change and the phenomenon of phenotypic plasticity. Integrating these hot topics is important for understanding the biology of many species, their information transfer and general interactions with other organisms. One example where this is particularly true is the zooplankton species Daphnia lumholtzi, which has successfully invaded North America. The combination of a high thermal tolerance and a phenotypically plastic defense in D. lumholtzi might be responsible for its invasion success. Its morphological defense consists of rigid spines and is formed after sensory detecting the presence of native fish predators. The integration of biological invasions, climate change and phenotypic plasticity is an important goal for integrative biology.

  11. Phenotypic plasticity in response to food source in Triatoma infestans (Klug, 1834) (Hemiptera, Reduviidae: Triatominae).

    PubMed

    Nattero, Julieta; Malerba, Romina; Rodríguez, Claudia S; Crocco, Liliana

    2013-10-01

    In the Gran Chaco region of Argentina, Bolivia, and Paraguay, vector transmission of Trypanosoma cruzi, the etiological agent of Chagas disease, is still a severe problem because, among other causes, houses are reinfested with Triatoma infestans, the main vector of T. cruzi in southern South America. A better understanding of adaptation and evolution of T. infestans populations may contribute to the selection of appropriate vector control strategies in this region. Phenotypic plasticity is essential to understand development and maintenance of morphological variation. An experimental phenotypic plasticity study was conducted to assess if blood meal source induced head shape and size variation during development in T. infestans. Eighteen full-sib families were assigned to one of two food sources (pigeon and guinea pig) to examine the effect of food source on head shape and size in all nymph instars and adults. Data were analyzed using geometric morphometric tools and phenotypic plasticity analyses. Significant differences in head shape and size were observed between adults fed on different food sources. Allometric effects at the adult stage were observed. Head size showed significant food source × family interaction for fifth-instar nymphs and adults. For head size, significant differences between food sources were observed at stages and in ontogenetic trajectory. Phenotypic plasticity expression was found for head shape and size in adults; indeed, bugs fed on guinea pigs exhibited greater changes in head shape and larger heads than those fed on pigeon. Full-sib families exhibited different patterns of phenotypic expression in response to food source. Food source × family interaction may indicate that the observed variation in phenotypic plasticity may contribute to changes in head morphometry. These results may contribute to the selection of an appropriate control strategy for T. infestans in the Gran Chaco region, since they provide evidences of morphological

  12. The overshoot and phenotypic equilibrium in characterizing cancer dynamics of reversible phenotypic plasticity.

    PubMed

    Chen, Xiufang; Wang, Yue; Feng, Tianquan; Yi, Ming; Zhang, Xingan; Zhou, Da

    2016-02-07

    The paradigm of phenotypic plasticity indicates reversible relations of different cancer cell phenotypes, which extends the cellular hierarchy proposed by the classical cancer stem cell (CSC) theory. Since it is still questionable if the phenotypic plasticity is a crucial improvement to the hierarchical model or just a minor extension to it, it is worthwhile to explore the dynamic behavior characterizing the reversible phenotypic plasticity. In this study we compare the hierarchical model and the reversible model in predicting the cell-state dynamics observed in biological experiments. Our results show that the hierarchical model shows significant disadvantages over the reversible model in describing both long-term stability (phenotypic equilibrium) and short-term transient dynamics (overshoot) in cancer cell populations. In a very specific case in which the total growth of population due to each cell type is identical, the hierarchical model predicts neither phenotypic equilibrium nor overshoot, whereas the reversible model succeeds in predicting both of them. Even though the performance of the hierarchical model can be improved by relaxing the specific assumption, its prediction to the phenotypic equilibrium strongly depends on a precondition that may be unrealistic in biological experiments. Moreover, it still does not show as rich dynamics as the reversible model in capturing the overshoots of both CSCs and non-CSCs. By comparison, it is more likely for the reversible model to correctly predict the stability of the phenotypic mixture and various types of overshoot behavior.

  13. Developmental phenotypic plasticity in a marsupial.

    PubMed

    Riek, Alexander; Geiser, Fritz

    2012-05-01

    Climate change is likely to substantially affect the distribution ranges of species. However, little is known about how different mammalian taxa respond morphologically and physiologically to a rapid change of climate. Our objective was to provide the first quantitative data on the effect of continuous cold exposure during development on morphological and functional variables of a marsupial. Fat-tailed dunnarts (Sminthopsis crassicaudata, Dasyuridae) were reared at an ambient temperature (T(a)) of 16°C [cold-reared (CR)] or 22°C [warm-reared (WR)] until they reached adult age (>200 days). Body and head length of CR animals were significantly longer than in WR animals (mean ± s.e.m.; body: CR 80.8±6 mm, WR 76.4±5 mm; head: CR 29.4±3 mm, WR 27.5±2 mm), but other body attributes were not significantly different. Use of torpor was more frequent, torpor bout duration was longer and average daily metabolic rate and percentage of savings when using torpor were significantly higher (P<0.01) in CR than in WR animals at 16°C T(a) but not at 24°C. Furthermore, resting metabolic rates measured at 16°C T(a) were significantly lower in CR than WR animals; at 30°C T(a) values were similar. Our results do not conform to Allen's rule, but to some extent they do conform to Bergmann's rule. However, the data demonstrate that a relatively moderate cold exposure from birth until adulthood induces marked changes in the morphology and thermal energetics of small marsupials. Such short-term phenotypic responses without the need for long-term selection are likely important for the ability to cope with different climates over a wide range of distribution, but will also play a crucial role in enhancing the survival of species during climate change.

  14. Phenotyping maize for adaptation to drought

    PubMed Central

    Araus, Jose L.; Serret, María D.; Edmeades, Gregory O.

    2012-01-01

    The need of a better adaptation of crops to drought is an issue of increasing urgency. However, enhancing the tolerance of maize has, therefore, proved to be somewhat elusive in terms of plant breeding. In that context, proper phenotyping remains as one of the main factors limiting breeding advance. Topics covered by this review include the conceptual framework for identifying secondary traits associated with yield response to drought and how to measure these secondary traits in practice. PMID:22934056

  15. Phenotypic Plasticity through Transcriptional Regulation of the Evolutionary Hotspot Gene tan in Drosophila melanogaster

    PubMed Central

    Mouchel-Vielh, Emmanuèle; De Castro, Sandra; Peronnet, Frédérique

    2016-01-01

    Phenotypic plasticity is the ability of a given genotype to produce different phenotypes in response to distinct environmental conditions. Phenotypic plasticity can be adaptive. Furthermore, it is thought to facilitate evolution. Although phenotypic plasticity is a widespread phenomenon, its molecular mechanisms are only beginning to be unravelled. Environmental conditions can affect gene expression through modification of chromatin structure, mainly via histone modifications, nucleosome remodelling or DNA methylation, suggesting that phenotypic plasticity might partly be due to chromatin plasticity. As a model of phenotypic plasticity, we study abdominal pigmentation of Drosophila melanogaster females, which is temperature sensitive. Abdominal pigmentation is indeed darker in females grown at 18°C than at 29°C. This phenomenon is thought to be adaptive as the dark pigmentation produced at lower temperature increases body temperature. We show here that temperature modulates the expression of tan (t), a pigmentation gene involved in melanin production. t is expressed 7 times more at 18°C than at 29°C in female abdominal epidermis. Genetic experiments show that modulation of t expression by temperature is essential for female abdominal pigmentation plasticity. Temperature modulates the activity of an enhancer of t without modifying compaction of its chromatin or level of the active histone mark H3K27ac. By contrast, the active mark H3K4me3 on the t promoter is strongly modulated by temperature. The H3K4 methyl-transferase involved in this process is likely Trithorax, as we show that it regulates t expression and the H3K4me3 level on the t promoter and also participates in female pigmentation and its plasticity. Interestingly, t was previously shown to be involved in inter-individual variation of female abdominal pigmentation in Drosophila melanogaster, and in abdominal pigmentation divergence between Drosophila species. Sensitivity of t expression to

  16. Phenotypic Plasticity through Transcriptional Regulation of the Evolutionary Hotspot Gene tan in Drosophila melanogaster.

    PubMed

    Gibert, Jean-Michel; Mouchel-Vielh, Emmanuèle; De Castro, Sandra; Peronnet, Frédérique

    2016-08-01

    Phenotypic plasticity is the ability of a given genotype to produce different phenotypes in response to distinct environmental conditions. Phenotypic plasticity can be adaptive. Furthermore, it is thought to facilitate evolution. Although phenotypic plasticity is a widespread phenomenon, its molecular mechanisms are only beginning to be unravelled. Environmental conditions can affect gene expression through modification of chromatin structure, mainly via histone modifications, nucleosome remodelling or DNA methylation, suggesting that phenotypic plasticity might partly be due to chromatin plasticity. As a model of phenotypic plasticity, we study abdominal pigmentation of Drosophila melanogaster females, which is temperature sensitive. Abdominal pigmentation is indeed darker in females grown at 18°C than at 29°C. This phenomenon is thought to be adaptive as the dark pigmentation produced at lower temperature increases body temperature. We show here that temperature modulates the expression of tan (t), a pigmentation gene involved in melanin production. t is expressed 7 times more at 18°C than at 29°C in female abdominal epidermis. Genetic experiments show that modulation of t expression by temperature is essential for female abdominal pigmentation plasticity. Temperature modulates the activity of an enhancer of t without modifying compaction of its chromatin or level of the active histone mark H3K27ac. By contrast, the active mark H3K4me3 on the t promoter is strongly modulated by temperature. The H3K4 methyl-transferase involved in this process is likely Trithorax, as we show that it regulates t expression and the H3K4me3 level on the t promoter and also participates in female pigmentation and its plasticity. Interestingly, t was previously shown to be involved in inter-individual variation of female abdominal pigmentation in Drosophila melanogaster, and in abdominal pigmentation divergence between Drosophila species. Sensitivity of t expression to

  17. How plasticity, genetic assimilation and cryptic genetic variation may contribute to adaptive radiations.

    PubMed

    Schneider, Ralf F; Meyer, Axel

    2017-01-01

    There is increasing evidence that phenotypic plasticity can promote population divergence by facilitating phenotypic diversification and, eventually, genetic divergence. When a 'plastic' population colonizes a new habitat, it has the possibility to occupy multiple niches by expressing several distinct phenotypes. These initially reflect the population's plastic range but may later become genetically fixed by selection via the process of 'genetic assimilation' (GA). Through this process multiple specialized sister lineages can arise that share a common plastic ancestor - the 'flexible stem'. Here, we review possible molecular mechanisms through which natural selection could fix an initially plastic trait during GA. These mechanisms could also explain how GA may contribute to cryptic genetic variation that can subsequently be coopted into other phenotypes or traits, but also lead to nonadaptive responses. We outline the predicted patterns of genetic and transcriptional divergence accompanying flexible stem radiations. The analysis of such patterns of (retained) adaptive and nonadaptive plastic responses within and across radiating lineages can inform on the state of ongoing GA. We conclude that, depending on the stability of the environment, the molecular architecture underlying plastic traits can facilitate diversification, followed by fixation and consolidation of an adaptive phenotype and degeneration of nonadaptive ones. Additionally, the process of GA may increase the cryptic genetic variation of populations, which on one hand may serve as substrate for evolution, but on another may be responsible for nonadaptive responses that consolidate local allopatry and thus reproductive isolation.

  18. Evolution of Robustness and Plasticity under Environmental Fluctuation: Formulation in Terms of Phenotypic Variances

    NASA Astrophysics Data System (ADS)

    Kaneko, Kunihiko

    2012-09-01

    The characterization of plasticity, robustness, and evolvability, an important issue in biology, is studied in terms of phenotypic fluctuations. By numerically evolving gene regulatory networks, the proportionality between the phenotypic variances of epigenetic and genetic origins is confirmed. The former is given by the variance of the phenotypic fluctuation due to noise in the developmental process; and the latter, by the variance of the phenotypic fluctuation due to genetic mutation. The relationship suggests a link between robustness to noise and to mutation, since robustness can be defined by the sharpness of the distribution of the phenotype. Next, the proportionality between the variances is demonstrated to also hold over expressions of different genes (phenotypic traits) when the system acquires robustness through the evolution. Then, evolution under environmental variation is numerically investigated and it is found that both the adaptability to a novel environment and the robustness are made compatible when a certain degree of phenotypic fluctuations exists due to noise. The highest adaptability is achieved at a certain noise level at which the gene expression dynamics are near the critical state to lose the robustness. Based on our results, we revisit Waddington's canalization and genetic assimilation with regard to the two types of phenotypic fluctuations.

  19. Phenotypic plasticity in Drosophila cactophilic species: the effect of competition, density and breeding sites.

    PubMed

    Fanara, Juan Jose; Werenkraut, Victoria

    2016-04-09

    Changes in the environmental conditions experienced by naturally occurring populations are frequently accompanied by changes in adaptive traits allowing the organism to cope with environmental unpredictability. Phenotypic plasticity is a major aspect of adaptation and it has been involved in population dynamics of interacting species. In this study, phenotypic plasticity (i.e., environmental sensitivity) of morphological adaptive traits were analyzed in the cactophilic species Drosophila buzzatii and Drosophila koepferae (Diptera: Drosophilidae) considering the effect of crowding conditions (low and high density), type of competition (intraspecific and interspecific competition) and cacti hosts (Opuntia and Columnar cacti). All traits (wing length, wing width, thorax length, wing loading and wing aspect) showed significant variation for each environmental factor considered in both Drosophila species. The phenotypic plasticity pattern observed for each trait was different within and between these cactophilic Drosophila species depending on the environmental factor analyzed suggesting that body size-related traits respond almost independently to environmental heterogeneity. The effects of ecological factors analyzed in this study are discussed in order to elucidate the causal factors investigated (type of competition, crowding conditions and alternative host) affecting the election of the breeding site and/or the range of distribution of these cactophilic species. This article is protected by copyright. All rights reserved.

  20. RNA Directed Modulation of Phenotypic Plasticity in Human Cells

    PubMed Central

    Burdach, Jon; Morris, Kevin V.

    2016-01-01

    Natural selective processes have been known to drive phenotypic plasticity, which is the emergence of different phenotypes from one genome following environmental stimulation. Long non-coding RNAs (lncRNAs) have been observed to modulate transcriptional and epigenetic states of genes in human cells. We surmised that lncRNAs are governors of phenotypic plasticity and drive natural selective processes through epigenetic modulation of gene expression. Using heat shocked human cells as a model we find several differentially expressed transcripts with the top candidates being lncRNAs derived from retro-elements. One particular retro-element derived transcripts, Retro-EIF2S2, was found to be abundantly over-expressed in heat shocked cells. Over-expression of Retro-EIF2S2 significantly enhanced cell viability and modulated a predisposition for an adherent cellular phenotype upon heat shock. Mechanistically, we find that this retro-element derived transcript interacts directly with a network of proteins including 40S ribosomal protein S30 (FAU), Eukaryotic translation initiation factor 5A (EIF5A), and Ubiquitin-60S ribosomal protein L40 (UBA52) to affect protein modulated cell adhesion pathways. We find one motif in Retro-EIF2S2 that exhibits binding to FAU and modulates phenotypic cell transitions from adherent to suspension states. The observations presented here suggest that retroviral derived transcripts actively modulate phenotypic plasticity in human cells in response to environmental selective pressures and suggest that natural selection may play out through the action of retro-elements in human cells. PMID:27082860

  1. RNA Directed Modulation of Phenotypic Plasticity in Human Cells.

    PubMed

    Trakman, Laura; Hewson, Chris; Burdach, Jon; Morris, Kevin V

    2016-01-01

    Natural selective processes have been known to drive phenotypic plasticity, which is the emergence of different phenotypes from one genome following environmental stimulation. Long non-coding RNAs (lncRNAs) have been observed to modulate transcriptional and epigenetic states of genes in human cells. We surmised that lncRNAs are governors of phenotypic plasticity and drive natural selective processes through epigenetic modulation of gene expression. Using heat shocked human cells as a model we find several differentially expressed transcripts with the top candidates being lncRNAs derived from retro-elements. One particular retro-element derived transcripts, Retro-EIF2S2, was found to be abundantly over-expressed in heat shocked cells. Over-expression of Retro-EIF2S2 significantly enhanced cell viability and modulated a predisposition for an adherent cellular phenotype upon heat shock. Mechanistically, we find that this retro-element derived transcript interacts directly with a network of proteins including 40S ribosomal protein S30 (FAU), Eukaryotic translation initiation factor 5A (EIF5A), and Ubiquitin-60S ribosomal protein L40 (UBA52) to affect protein modulated cell adhesion pathways. We find one motif in Retro-EIF2S2 that exhibits binding to FAU and modulates phenotypic cell transitions from adherent to suspension states. The observations presented here suggest that retroviral derived transcripts actively modulate phenotypic plasticity in human cells in response to environmental selective pressures and suggest that natural selection may play out through the action of retro-elements in human cells.

  2. Phenological plasticity will not help all species adapt to climate change.

    PubMed

    Duputié, Anne; Rutschmann, Alexis; Ronce, Ophélie; Chuine, Isabelle

    2015-08-01

    Concerns are rising about the capacity of species to adapt quickly enough to climate change. In long-lived organisms such as trees, genetic adaptation is slow, and how much phenotypic plasticity can help them cope with climate change remains largely unknown. Here, we assess whether, where and when phenological plasticity is and will be adaptive in three major European tree species. We use a process-based species distribution model, parameterized with extensive ecological data, and manipulate plasticity to suppress phenological variations due to interannual, geographical and trend climate variability, under current and projected climatic conditions. We show that phenological plasticity is not always adaptive and mostly affects fitness at the margins of the species' distribution and climatic niche. Under current climatic conditions, phenological plasticity constrains the northern range limit of oak and beech and the southern range limit of pine. Under future climatic conditions, phenological plasticity becomes strongly adaptive towards the trailing edges of beech and oak, but severely constrains the range and niche of pine. Our results call for caution when interpreting geographical variation in trait means as adaptive, and strongly point towards species distribution models explicitly taking phenotypic plasticity into account when forecasting species distribution under climate change scenarios.

  3. Distinct subspecies or phenotypic plasticity? Genetic and morphological differentiation of mountain honey bees in East Africa

    PubMed Central

    Gruber, Karl; Schöning, Caspar; Otte, Marianne; Kinuthia, Wanja; Hasselmann, Martin

    2013-01-01

    Identifying the forces shaping intraspecific phenotypic and genotypic divergence are of key importance in evolutionary biology. Phenotypic divergence may result from local adaptation or, especially in species with strong gene flow, from pronounced phenotypic plasticity. Here, we examine morphological and genetic divergence among populations of the western honey bee Apis mellifera in the topographically heterogeneous East African region. The currently accepted “mountain refugia hypothesis” states that populations living in disjunct montane forests belong to a different lineage than those in savanna habitats surrounding these forests. We obtained microsatellite data, mitochondrial sequences, and morphometric data from worker honey bees collected from feral colonies in three montane forests and corresponding neighboring savanna regions in Kenya. Honey bee colonies from montane forests showed distinct worker morphology compared with colonies in savanna areas. Mitochondrial sequence data did not support the existence of the two currently accepted subspecies. Furthermore, analyses of the microsatellite data with a Bayesian clustering method did not support the existence of two source populations as it would be expected under the mountain refugia scenario. Our findings suggest that phenotypic plasticity rather than distinct ancestry is the leading cause behind the phenotypic divergence observed between montane forest and savanna honey bees. Our study thus corroborates the idea that high gene flow may select for increased plasticity. PMID:24223262

  4. Distinct subspecies or phenotypic plasticity? Genetic and morphological differentiation of mountain honey bees in East Africa.

    PubMed

    Gruber, Karl; Schöning, Caspar; Otte, Marianne; Kinuthia, Wanja; Hasselmann, Martin

    2013-09-01

    Identifying the forces shaping intraspecific phenotypic and genotypic divergence are of key importance in evolutionary biology. Phenotypic divergence may result from local adaptation or, especially in species with strong gene flow, from pronounced phenotypic plasticity. Here, we examine morphological and genetic divergence among populations of the western honey bee Apis mellifera in the topographically heterogeneous East African region. The currently accepted "mountain refugia hypothesis" states that populations living in disjunct montane forests belong to a different lineage than those in savanna habitats surrounding these forests. We obtained microsatellite data, mitochondrial sequences, and morphometric data from worker honey bees collected from feral colonies in three montane forests and corresponding neighboring savanna regions in Kenya. Honey bee colonies from montane forests showed distinct worker morphology compared with colonies in savanna areas. Mitochondrial sequence data did not support the existence of the two currently accepted subspecies. Furthermore, analyses of the microsatellite data with a Bayesian clustering method did not support the existence of two source populations as it would be expected under the mountain refugia scenario. Our findings suggest that phenotypic plasticity rather than distinct ancestry is the leading cause behind the phenotypic divergence observed between montane forest and savanna honey bees. Our study thus corroborates the idea that high gene flow may select for increased plasticity.

  5. Iterative development and the scope for plasticity: contrasts among trait categories in an adaptive radiation

    PubMed Central

    Foster, S A; Wund, M A; Graham, M A; Earley, R L; Gardiner, R; Kearns, T; Baker, J A

    2015-01-01

    Phenotypic plasticity can influence evolutionary change in a lineage, ranging from facilitation of population persistence in a novel environment to directing the patterns of evolutionary change. As the specific nature of plasticity can impact evolutionary consequences, it is essential to consider how plasticity is manifested if we are to understand the contribution of plasticity to phenotypic evolution. Most morphological traits are developmentally plastic, irreversible, and generally considered to be costly, at least when the resultant phenotype is mis-matched to the environment. At the other extreme, behavioral phenotypes are typically activational (modifiable on very short time scales), and not immediately costly as they are produced by constitutive neural networks. Although patterns of morphological and behavioral plasticity are often compared, patterns of plasticity of life history phenotypes are rarely considered. Here we review patterns of plasticity in these trait categories within and among populations, comprising the adaptive radiation of the threespine stickleback fish Gasterosteus aculeatus. We immediately found it necessary to consider the possibility of iterated development, the concept that behavioral and life history trajectories can be repeatedly reset on activational (usually behavior) or developmental (usually life history) time frames, offering fine tuning of the response to environmental context. Morphology in stickleback is primarily reset only in that developmental trajectories can be altered as environments change over the course of development. As anticipated, the boundaries between the trait categories are not clear and are likely to be linked by shared, underlying physiological and genetic systems. PMID:26243135

  6. Adaptation by Plasticity of Genetic Regulatory Networks

    NASA Astrophysics Data System (ADS)

    Brenner, Naama

    2007-03-01

    Genetic regulatory networks have an essential role in adaptation and evolution of cell populations. This role is strongly related to their dynamic properties over intermediate-to-long time scales. We have used the budding yeast as a model Eukaryote to study the long-term dynamics of the genetic regulatory system and its significance in evolution. A continuous cell growth technique (chemostat) allows us to monitor these systems over long times under controlled condition, enabling a quantitative characterization of dynamics: steady states and their stability, transients and relaxation. First, we have demonstrated adaptive dynamics in the GAL system, a classic model for a Eukaryotic genetic switch, induced and repressed by different carbon sources in the environment. We found that both induction and repression are only transient responses; over several generations, the system converges to a single robust steady state, independent of external conditions. Second, we explored the functional significance of such plasticity of the genetic regulatory network in evolution. We used genetic engineering to mimic the natural process of gene recruitment, placing the gene HIS3 under the regulation of the GAL system. Such genetic rewiring events are important in the evolution of gene regulation, but little is known about the physiological processes supporting them and the dynamics of their assimilation in a cell population. We have shown that cells carrying the rewired genome adapted to a demanding change of environment and stabilized a population, maintaining the adaptive state for hundreds of generations. Using genome-wide expression arrays we showed that underlying the observed adaptation is a global transcriptional programming that allowed tuning expression of the recruited gene to demands. Our results suggest that non-specific properties reflecting the natural plasticity of the regulatory network support adaptation of cells to novel challenges and enhance their evolvability.

  7. A synthetic framework for modeling the genetic basis of phenotypic plasticity and its costs.

    PubMed

    Zhai, Yi; Lv, Yafei; Li, Xin; Wu, Weimiao; Bo, Wenhao; Shen, Dengfeng; Xu, Fang; Pang, Xiaoming; Zheng, Bingsong; Wu, Rongling

    2014-01-01

    The phenotype of an individual is controlled not only by its genes, but also by the environment in which it grows. A growing body of evidence shows that the extent to which phenotypic changes are driven by the environment, known as phenotypic plasticity, is also under genetic control, but an overall picture of genetic variation for phenotypic plasticity remains elusive. Here, we develop a model for mapping quantitative trait loci (QTLs) that regulate environment-induced plastic response. This model enables geneticists to test whether there exist actual QTLs that determine phenotypic plasticity and, if there are, further test how plasticity QTLs control the costs of plastic response by dissecting the genetic correlation of phenotypic plasticity and trait value. The model was used to analyze real data for grain yield of winter wheat (Triticum aestivum), leading to the detection of pleiotropic QTLs and epistatic QTLs that affect phenotypic plasticity and its cost in this crop.

  8. Williams' paradox and the role of phenotypic plasticity in sexual systems.

    PubMed

    Leonard, Janet L

    2013-10-01

    As George Williams pointed out in 1975, although evolutionary explanations, based on selection acting on individuals, have been developed for the advantages of simultaneous hermaphroditism, sequential hermaphroditism and gonochorism, none of these evolutionary explanations adequately explains the current distribution of these sexual systems within the Metazoa (Williams' Paradox). As Williams further pointed out, the current distribution of sexual systems is explained largely by phylogeny. Since 1975, we have made a great deal of empirical and theoretical progress in understanding sexual systems. However, we still lack a theory that explains the current distribution of sexual systems in animals and we do not understand the evolutionary transitions between hermaphroditism and gonochorism. Empirical data, collected over the past 40 years, demonstrate that gender may have more phenotypic plasticity than was previously realized. We know that not only sequential hermaphrodites, but also simultaneous hermaphrodites have phenotypic plasticity that alters sex allocation in response to social and environmental conditions. A focus on phenotypic plasticity suggests that one sees a continuum in animals between genetically determined gonochorism on the one hand and simultaneous hermaphroditism on the other, with various types of sequential hermaphroditism and environmental sex determination as points along the spectrum. Here I suggest that perhaps the reason we have been unable to resolve Williams' Paradox is because the problem was not correctly framed. First, because, for example, simultaneous hermaphroditism provides reproductive assurance or dioecy ensures outcrossing does not mean that there are no other evolutionary paths that can provide adaptive responses to those selective pressures. Second, perhaps the question we need to ask is: What selective forces favor increased versus reduced phenotypic plasticity in gender expression? It is time to begin to look at the question

  9. Evidence of adaptive divergence in plasticity: density- and site-dependent selection on shade-avoidance responses in Impatiens capensis.

    PubMed

    Donohue, K; Messiqua, D; Pyle, E H; Heschel, M S; Schmitt, J

    2000-12-01

    We investigated the conditions under which plastic responses to density are adaptive in natural populations of Impatiens capensis and determined whether plasticity has evolved differently in different selective environments. Previous studies showed that a population that evolved in a sunny site exhibited greater plasticity in response to density than did a population that evolved in a woodland site. Using replicate inbred lines in a reciprocal transplant that included a density manipulation, we asked whether such population differentiation was consistent with the hypothesis of adaptive divergence. We hypothesized that plasticity would be more strongly favored in the sunny site than in the woodland site; consequently, we predicted that selection would be more strongly density dependent in the sunny site, favoring the phenotype that was expressed at each density. Selection on internode length and flowering date was consistent with the hypothesis of adaptive divergence in plasticity. Few costs or benefits of plasticity were detected independently from the expressed phenotype, so plasticity was selected primarily through selection on the phenotype. Correlations between phenotypes and their plasticity varied with the environment and would cause indirect selection on plasticity to be environment dependent. We showed that an appropriate plastic response even to a rare environment can greatly increase genotypic fitness when that environment is favorable. Selection on the measured characters contributed to local adaptation and fully accounted for fitness differences between populations in all treatments except the woodland site at natural density.

  10. Plasticity and genetic adaptation mediate amphibian and reptile responses to climate change.

    PubMed

    Urban, Mark C; Richardson, Jonathan L; Freidenfelds, Nicole A

    2014-01-01

    Phenotypic plasticity and genetic adaptation are predicted to mitigate some of the negative biotic consequences of climate change. Here, we evaluate evidence for plastic and evolutionary responses to climate variation in amphibians and reptiles via a literature review and meta-analysis. We included studies that either document phenotypic changes through time or space. Plasticity had a clear and ubiquitous role in promoting phenotypic changes in response to climate variation. For adaptive evolution, we found no direct evidence for evolution of amphibians or reptiles in response to climate change over time. However, we found many studies that documented adaptive responses to climate along spatial gradients. Plasticity provided a mixture of adaptive and maladaptive responses to climate change, highlighting that plasticity frequently, but not always, could ameliorate climate change. Based on our review, we advocate for more experiments that survey genetic changes through time in response to climate change. Overall, plastic and genetic variation in amphibians and reptiles could buffer some of the formidable threats from climate change, but large uncertainties remain owing to limited data.

  11. Plasticity and genetic adaptation mediate amphibian and reptile responses to climate change

    PubMed Central

    Urban, Mark C; Richardson, Jonathan L; Freidenfelds, Nicole A

    2014-01-01

    Phenotypic plasticity and genetic adaptation are predicted to mitigate some of the negative biotic consequences of climate change. Here, we evaluate evidence for plastic and evolutionary responses to climate variation in amphibians and reptiles via a literature review and meta-analysis. We included studies that either document phenotypic changes through time or space. Plasticity had a clear and ubiquitous role in promoting phenotypic changes in response to climate variation. For adaptive evolution, we found no direct evidence for evolution of amphibians or reptiles in response to climate change over time. However, we found many studies that documented adaptive responses to climate along spatial gradients. Plasticity provided a mixture of adaptive and maladaptive responses to climate change, highlighting that plasticity frequently, but not always, could ameliorate climate change. Based on our review, we advocate for more experiments that survey genetic changes through time in response to climate change. Overall, plastic and genetic variation in amphibians and reptiles could buffer some of the formidable threats from climate change, but large uncertainties remain owing to limited data. PMID:24454550

  12. Phenotypic plasticity is not affected by experimental evolution in constant, predictable or unpredictable fluctuating thermal environments.

    PubMed

    Manenti, T; Loeschcke, V; Moghadam, N N; Sørensen, J G

    2015-11-01

    The selective past of populations is presumed to affect the levels of phenotypic plasticity. Experimental evolution at constant temperatures is generally expected to lead to a decreased level of plasticity due to presumed costs associated with phenotypic plasticity when not needed. In this study, we investigated the effect of experimental evolution in constant, predictable and unpredictable daily fluctuating temperature regimes on the levels of phenotype plasticity in several life history and stress resistance traits in Drosophila simulans. Contrary to the expectation, evolution in the different regimes did not affect the levels of plasticity in any of the traits investigated even though the populations from the different thermal regimes had evolved different stress resistance and fitness trait means. Although costs associated with phenotypic plasticity are known, our results suggest that the maintenance of phenotypic plasticity might come at low and negligible costs, and thus, the potential of phenotypic plasticity to evolve in populations exposed to different environmental conditions might be limited.

  13. Adaptive plasticity of the penis in a simultaneous hermaphrodite.

    PubMed

    Hoch, J Matthew

    2009-08-01

    Acorn barnacles are important model organisms for the study of sex allocation. They are sessile, nonselfing hermaphrodites that copulate with penises that have been suggested to be phenotypically plastic. On wave-exposed shores, Semibalanus balanoides develop penises with relatively greater diameter whereas in wave-protected sites they are thinner. A reciprocal transplant experiment between wave-exposed and protected sites tested whether these exposure-specific morphologies have adaptive value. Mating success was compared over a range of distances to compare the ability of barnacles to reach mates. Barnacles that grew in the wave-protected site and mated in the wave-protected site fertilized more broods at increasing distances than those transplanted to the wave-exposed site. For barnacles that developed in the wave-exposed site, there was no difference in the ability to fertilize neighbors between sites of differing exposure. This study demonstrates the adaptive value of plasticity in penis morphology. The results suggest a trade-off between development of a penis adapted to wave exposure and the ability to fertilize distant mates. Barnacles in different physical environments are limited by different factors, which may limit numbers of potential mates, constrain optimal sex allocation strategies and alter reproductive behavior.

  14. Phenotyping Cowpeas for Adaptation to Drought

    PubMed Central

    Hall, Anthony E.

    2012-01-01

    Methods for phenotyping cowpeas for adaptation to drought are reviewed. Key factors involve achieving optimal time of flowering and cycle length, and appropriate morphology for different types of cultivars as they relate to their utilization for dry grain, hay, and fresh pea production. Strong resistance to vegetative-stage drought is available and should be incorporated. The extreme ability of extra-early erect cowpea cultivars to escape terminal drought should be exploited in zones with very short rainfall seasons. In zones with the possibility of limited rainfall in the middle of the growing season, resistance to mid-season drought, and the delayed-leaf-senescence trait can be valuable. Breeding for water-use efficiency, deeper rooting, and heat tolerance are discussed. Diseases and pests that influence adaptation to drought are considered. Resistance to the organism causing ashy stem blight disease should be incorporated because this disease can destroy cowpea seedlings under hot, dry soil conditions. The value of varietal intercrops with contrasting types of cowpea cultivars in enhancing adaptation to drought is described. Implications of cowpea/cereal rotations for cowpea breeding are discussed. Breeding strategies for enhancing cowpea adaptation to drought are described. PMID:22654769

  15. Phenotyping cowpeas for adaptation to drought.

    PubMed

    Hall, Anthony E

    2012-01-01

    Methods for phenotyping cowpeas for adaptation to drought are reviewed. Key factors involve achieving optimal time of flowering and cycle length, and appropriate morphology for different types of cultivars as they relate to their utilization for dry grain, hay, and fresh pea production. Strong resistance to vegetative-stage drought is available and should be incorporated. The extreme ability of extra-early erect cowpea cultivars to escape terminal drought should be exploited in zones with very short rainfall seasons. In zones with the possibility of limited rainfall in the middle of the growing season, resistance to mid-season drought, and the delayed-leaf-senescence trait can be valuable. Breeding for water-use efficiency, deeper rooting, and heat tolerance are discussed. Diseases and pests that influence adaptation to drought are considered. Resistance to the organism causing ashy stem blight disease should be incorporated because this disease can destroy cowpea seedlings under hot, dry soil conditions. The value of varietal intercrops with contrasting types of cowpea cultivars in enhancing adaptation to drought is described. Implications of cowpea/cereal rotations for cowpea breeding are discussed. Breeding strategies for enhancing cowpea adaptation to drought are described.

  16. Diet-induced co-variation between architectural and physicochemical plasticity in an extended phenotype.

    PubMed

    Blamires, Sean J; Hasemore, Matthew; Martens, Penny J; Kasumovic, Michael M

    2017-03-01

    The adaptive benefits of extended phenotypic plasticity are imprecisely defined due to a paucity of experiments examining traits that are manipulable and measurable across environments. Spider webs are often used as models to explore the adaptive benefits of variations in extended phenotypes across environments. Nonetheless, our understanding of the adaptive nature of the plastic responses of spider webs is impeded when web architectures and silk physicochemical properties appear to co-vary. An opportunity to examine this co-variation is presented by modifying prey items while measuring web architectures and silk physiochemical properties. Here, we performed two experiments to assess the nature of the association between web architectures and gluey silk properties when the orb web spider Argiope keyserlingi was fed a diet that varied in either mass and energy or prey size and feeding frequency. We found web architectures and gluey silk physicochemical properties to co-vary across treatments in both experiments. Specifically, web capture area co-varied with gluey droplet morphometrics, thread stickiness and salt concentrations when prey mass and energy were manipulated, and spiral spacing co-varied with gluey silk salt concentrations when prey size and feeding frequency were manipulated. We explained our results as A. keyserlingi plastically shifting its foraging strategy as multiple prey parameters simultaneously varied. We confirmed and extended previous work by showing that spiders use a variety of prey cues to concurrently adjust web and silk traits across different feeding regimes.

  17. Inbreeding and adaptive plasticity: an experimental analysis on predator-induced responses in the water flea Daphnia

    PubMed Central

    Swillen, Ine; Vanoverbeke, Joost; De Meester, Luc

    2015-01-01

    Several studies have emphasized that inbreeding depression (ID) is enhanced under stressful conditions. Additionally, one might imagine a loss of adaptively plastic responses which may further contribute to a reduction in fitness under environmental stress. Here, we quantified ID in inbred families of the cyclical parthenogen Daphnia magna in the absence and presence of fish predation risk. We test whether predator stress affects the degree of ID and if inbred families have a reduced capacity to respond to predator stress by adaptive phenotypic plasticity. We obtained two inbred families through clonal selfing within clones isolated from a fish pond. After mild purging under standardized conditions, we compared life history traits and adaptive plasticity between inbred and outbred lineages (directly hatched from the natural dormant egg bank of the same pond). Initial purging of lineages under standardized conditions differed among inbred families and exceeded that in outbreds. The least purged inbred family exhibited strong ID for most life history traits. Predator-induced stress hardly affected the severity of ID, but the degree to which the capacity for adaptive phenotypic plasticity was retained varied strongly among the inbred families. The least purged family overall lacked the capacity for adaptive phenotypic plasticity, whereas the family that suffered only mild purging exhibited a potential for adaptive plasticity that was comparable to the outbred population. We thus found that inbred offspring may retain the capacity to respond to the presence of fish by adaptive phenotypic plasticity, but this strongly depends on the parental clone engaging in selfing. PMID:26257883

  18. Disentangling the role of phenotypic plasticity and genetic divergence in contemporary ecotype formation during a biological invasion.

    PubMed

    Lucek, Kay; Sivasundar, Arjun; Seehausen, Ole

    2014-09-01

    The occurrence of contemporary ecotype formation through adaptive divergence of populations within the range of an invasive species typically requires standing genetic variation but can be facilitated by phenotypic plasticity. The relative contributions of both of these to adaptive trait differentiation have rarely been simultaneously quantified in recently diverging vertebrate populations. Here we study a case of intraspecific divergence into distinct lake and stream ecotypes of threespine stickleback that evolved in the past 140 years within the invasive range in Switzerland. Using a controlled laboratory experiment with full-sib crosses and treatments mimicking a key feature of ecotypic niche divergence, we test if the phenotypic divergence that we observe in the wild results from phenotypic plasticity or divergent genetic predisposition. Our experimental groups show qualitatively similar phenotypic divergence as those observed among wild adults. The relative contribution of plasticity and divergent genetic predisposition differs among the traits studied, with traits related to the biomechanics of feeding showing a stronger genetic predisposition, whereas traits related to locomotion are mainly plastic. These results implicate that phenotypic plasticity and standing genetic variation interacted during contemporary ecotype formation in this case.

  19. Snowshoe hares display limited phenotypic plasticity to mismatch in seasonal camouflage

    PubMed Central

    Zimova, Marketa; Mills, L. Scott; Lukacs, Paul M.; Mitchell, Michael S.

    2014-01-01

    As duration of snow cover decreases owing to climate change, species undergoing seasonal colour moults can become colour mismatched with their background. The immediate adaptive solution to this mismatch is phenotypic plasticity, either in phenology of seasonal colour moults or in behaviours that reduce mismatch or its consequences. We observed nearly 200 snowshoe hares across a wide range of snow conditions and two study sites in Montana, USA, and found minimal plasticity in response to mismatch between coat colour and background. We found that moult phenology varied between study sites, likely due to differences in photoperiod and climate, but was largely fixed within study sites with only minimal plasticity to snow conditions during the spring white-to-brown moult. We also found no evidence that hares modify their behaviour in response to colour mismatch. Hiding and fleeing behaviours and resting spot preference of hares were more affected by variables related to season, site and concealment by vegetation, than by colour mismatch. We conclude that plasticity in moult phenology and behaviours in snowshoe hares is insufficient for adaptation to camouflage mismatch, suggesting that any future adaptation to climate change will require natural selection on moult phenology or behaviour. PMID:24619446

  20. Snowshoe hares display limited phenotypic plasticity to mismatch in seasonal camouflage

    USGS Publications Warehouse

    Zimova, Marketa; Mills, L. Scott; Lukacs, Paul M.; Mitchell, Michael S.

    2014-01-01

    As duration of snow cover decreases owing to climate change, species undergoing seasonal colour moults can become colour mismatched with their background. The immediate adaptive solution to this mismatch is phenotypic plasticity, either in phenology of seasonal colour moults or in behaviours that reduce mismatch or its consequences. We observed nearly 200 snowshoe hares across a wide range of snow conditions and two study sites in Montana, USA, and found minimal plasticity in response to mismatch between coat colour and background. We found that moult phenology varied between study sites, likely due to differences in photoperiod and climate, but was largely fixed within study sites with only minimal plasticity to snow conditions during the spring white-to-brown moult. We also found no evidence that hares modify their behaviour in response to colour mismatch. Hiding and fleeing behaviours and resting spot preference of hares were more affected by variables related to season, site and concealment by vegetation, than by colour mismatch. We conclude that plasticity in moult phenology and behaviours in snowshoe hares is insufficient for adaptation to camouflage mismatch, suggesting that any future adaptation to climate change will require natural selection on moult phenology or behaviour.

  1. Snowshoe hares display limited phenotypic plasticity to mismatch in seasonal camouflage.

    PubMed

    Zimova, Marketa; Mills, L Scott; Lukacs, Paul M; Mitchell, Michael S

    2014-05-07

    As duration of snow cover decreases owing to climate change, species undergoing seasonal colour moults can become colour mismatched with their background. The immediate adaptive solution to this mismatch is phenotypic plasticity, either in phenology of seasonal colour moults or in behaviours that reduce mismatch or its consequences. We observed nearly 200 snowshoe hares across a wide range of snow conditions and two study sites in Montana, USA, and found minimal plasticity in response to mismatch between coat colour and background. We found that moult phenology varied between study sites, likely due to differences in photoperiod and climate, but was largely fixed within study sites with only minimal plasticity to snow conditions during the spring white-to-brown moult. We also found no evidence that hares modify their behaviour in response to colour mismatch. Hiding and fleeing behaviours and resting spot preference of hares were more affected by variables related to season, site and concealment by vegetation, than by colour mismatch. We conclude that plasticity in moult phenology and behaviours in snowshoe hares is insufficient for adaptation to camouflage mismatch, suggesting that any future adaptation to climate change will require natural selection on moult phenology or behaviour.

  2. Phenotyping common beans for adaptation to drought

    PubMed Central

    Beebe, Stephen E.; Rao, Idupulapati M.; Blair, Matthew W.; Acosta-Gallegos, Jorge A.

    2013-01-01

    Common beans (Phaseolus vulgaris L.) originated in the New World and are the grain legume of greatest production for direct human consumption. Common bean production is subject to frequent droughts in highland Mexico, in the Pacific coast of Central America, in northeast Brazil, and in eastern and southern Africa from Ethiopia to South Africa. This article reviews efforts to improve common bean for drought tolerance, referring to genetic diversity for drought response, the physiology of drought tolerance mechanisms, and breeding strategies. Different races of common bean respond differently to drought, with race Durango of highland Mexico being a major source of genes. Sister species of P. vulgaris likewise have unique traits, especially P. acutifolius which is well adapted to dryland conditions. Diverse sources of tolerance may have different mechanisms of plant response, implying the need for different methods of phenotyping to recognize the relevant traits. Practical considerations of field management are discussed including: trial planning; water management; and field preparation. PMID:23507928

  3. Ocean acidification influences host DNA methylation and phenotypic plasticity in environmentally susceptible corals.

    PubMed

    Putnam, Hollie M; Davidson, Jennifer M; Gates, Ruth D

    2016-10-01

    As climate change challenges organismal fitness by creating a phenotype-environment mismatch, phenotypic plasticity generated by epigenetic mechanisms (e.g., DNA methylation) can provide a temporal buffer for genetic adaptation. Epigenetic mechanisms may be crucial for sessile benthic marine organisms, such as reef-building corals, where ocean acidification (OA) and warming reflect in strong negative responses. We tested the potential for scleractinian corals to exhibit phenotypic plasticity associated with a change in DNA methylation in response to OA. Clonal coral fragments of the environmentally sensitive Pocillopora damicornis and more environmentally robust Montipora capitata were exposed to fluctuating ambient pH (7.9-7.65) and low pH (7.6-7.35) conditions in common garden tanks for ~6 weeks. M. capitata responded weakly, or acclimated more quickly, to OA, with no difference in calcification, minimal separation of metabolomic profiles, and no change in DNA methylation between treatments. Conversely, P. damicornis exhibited diminished calcification at low pH, stronger separation in metabolomic profiles, and responsiveness of DNA methylation to treatment. Our data suggest corals differ in their temporal dynamics and sensitivity for environmentally triggered real-time epigenetic reprogramming. The generation of potentially heritable plasticity via environmental induction of DNA methylation provides an avenue for assisted evolution applications in corals under rapid climate change.

  4. Reciprocal osmotic challenges reveal mechanisms of divergence in phenotypic plasticity in the killifish Fundulus heteroclitus.

    PubMed

    Brennan, Reid S; Galvez, Fernando; Whitehead, Andrew

    2015-04-15

    The killifish Fundulus heteroclitus is an estuarine species with broad physiological plasticity, enabling acclimation to diverse stressors. Previous work suggests that freshwater populations expanded their physiology to accommodate low salinity environments; however, it is unknown whether this compromises their tolerance to high salinity. We used a comparative approach to investigate the mechanisms of a derived freshwater phenotype and the fate of an ancestral euryhaline phenotype after invasion of a freshwater environment. We compared physiological and transcriptomic responses to high- and low-salinity stress in fresh and brackish water populations and found an enhanced plasticity to low salinity in the freshwater population coupled with a reduced ability to acclimate to high salinity. Transcriptomic data identified genes with a conserved common response, a conserved salinity-dependent response and responses associated with population divergence. Conserved common acclimation responses revealed stress responses and alterations in cell-cycle regulation as important mechanisms in the general osmotic response. Salinity-specific responses included the regulation of genes involved in ion transport, intracellular calcium, energetic processes and cellular remodeling. Genes diverged between populations were primarily those showing salinity-specific expression and included those regulating polyamine homeostasis and the cell cycle. Additionally, when populations were matched with their native salinity, expression patterns were consistent with the concept of 'transcriptomic resilience', suggesting local adaptation. These findings provide insight into the fate of a plastic phenotype after a shift in environmental salinity and help to reveal mechanisms allowing for euryhalinity.

  5. Adaptive developmental plasticity: what is it, how can we recognize it and when can it evolve?

    PubMed Central

    Nettle, Daniel; Bateson, Melissa

    2015-01-01

    Developmental plasticity describes situations where a specific input during an individual's development produces a lasting alteration in phenotype. Some instances of developmental plasticity may be adaptive, meaning that the tendency to produce the phenotype conditional on having experienced the developmental input has been under positive selection. We discuss the necessary assumptions and predictions of hypotheses concerning adaptive developmental plasticity (ADP) and develop guidelines for how to test empirically whether a particular example is adaptive. Central to our analysis is the distinction between two kinds of ADP: informational, where the developmental input provides information about the future environment, and somatic state-based, where the developmental input enduringly alters some aspect of the individual's somatic state. Both types are likely to exist in nature, but evolve under different conditions. In all cases of ADP, the expected fitness of individuals who experience the input and develop the phenotype should be higher than that of those who experience the input and do not develop the phenotype, while the expected fitness of those who do not experience the input and do not develop the phenotype should be higher than those who do not experience the input and do develop the phenotype. We describe ancillary predictions that are specific to just one of the two types of ADP and thus distinguish between them. PMID:26203000

  6. Genetic assimilation and the postcolonization erosion of phenotypic plasticity in island tiger snakes.

    PubMed

    Aubret, Fabien; Shine, Richard

    2009-12-01

    In 1942, C.H. Waddington [1] suggested that colonizing populations could initially succeed by flexibly altering their characteristics (phenotypic plasticity; [2-4]) in fitness-inducing traits, but selective forces would rapidly eliminate that plasticity to result in a canalized trait [1, 5, 6]. Waddington termed this process "genetic assimilation"[1, 7]. Despite the potential importance of genetic assimilation to evolutionary changes in founder populations [8-10], empirical evidence on this topic is rare, possibly because it happens on short timescales and is therefore difficult to detect except under unusual circumstances [11, 12]. We exploited a mosaic of snake populations isolated (or introduced) on islands from less than 30 years ago to more than 9000 years ago and exposed to selection for increased head size (i.e., ability to ingest large prey [13-16]). Here we show that a larger head size is achieved by plasticity in "young" populations and by genetic canalization in "older" populations. Island tiger snakes (Notechis scutatus) thus show clear empirical evidence of genetic assimilation, with the elaboration of an adaptive trait shifting from phenotypically plastic expression through to canalization within a few thousand years.

  7. Genetic Determinism vs. Phenotypic Plasticity in Protist Morphology.

    PubMed

    Mulot, Matthieu; Marcisz, Katarzyna; Grandgirard, Lara; Lara, Enrique; Kosakyan, Anush; Robroek, Bjorn J M; Lamentowicz, Mariusz; Payne, Richard J; Mitchell, Edward A D

    2017-02-23

    Untangling the relationships between morphology and phylogeny is key to building a reliable taxonomy, but is especially challenging for protists, where the existence of cryptic or pseudocryptic species makes finding relevant discriminant traits difficult. Here we use Hyalosphenia papilio (a testate amoeba) as a model species to investigate the contribution of phylogeny and phenotypic plasticity in its morphology. We study the response of H. papilio morphology (shape and pores number) to environmental variables in (i) a manipulative experiment with controlled conditions (water level), (ii) an observational study of a within-site natural ecological gradient (water level), and (iii) an observational study across 37 European peatlands (climate). We showed that H. papilio morphology is correlated to environmental conditions (climate and water depth) as well as geography, while no relationship between morphology and phylogeny was brought to light. The relative contribution of genetic inheritance and phenotypic plasticity in shaping morphology varies depending on the taxonomic group and the trait under consideration. Thus, our data call for a reassessment of taxonomy based on morphology alone. This clearly calls for a substantial increase in taxonomic research on these globally still under-studied organisms leading to a reassessment of estimates of global microbial eukaryotic diversity.

  8. Understanding the wide geographic range of a clonal perennial grass: plasticity versus local adaptation

    PubMed Central

    Liu, Yanjie; Zhang, Lirong; Xu, Xingliang; Niu, Haishan

    2016-01-01

    Both phenotypic plasticity and local adaptation may allow widely distributed plant species to either acclimate or adapt to environmental heterogeneity. Given the typically low genetic variation of clonal plants across their habitats, phenotypic plasticity may be the primary adaptive strategy allowing them to thrive across a wide range of habitats. In this study, the mechanism supporting the widespread distribution of the clonal plant Leymus chinensis was determined, i.e. phenotypic plasticity or local specialization in water use efficiency (WUE; reflected by foliar δ13C). To test whether plasticity is required for the species to thrive in different habitats, samples were collected across its distribution in the Mongolian steppe, and a controlled watering experiment was conducted with two populations at two different sites. Five populations were also transplanted from different sites into a control environment, and the foliar δ13C was compared between the control and original habitats, to test for local specialization in WUE. Results demonstrated decreased foliar δ13C with increasing precipitation during controlled watering experiments, with divergent responses between the two populations assessed. Change in foliar δ13C (−3.69 ‰) due to water addition was comparable to fluctuations of foliar δ13C observed in situ (−4.83 ‰). Foliar δ13C differed by −0.91 ‰ between two transplanted populations; however, this difference was not apparent between the two populations when growing in their original habitats. Findings provide evidence that local adaptation affects foliar δ13C much less than phenotypic plasticity. Thus, plasticity in WUE is more important than local adaptation in allowing the clonal plant L. chinensis to occupy a wide range of habitats in the Mongolian steppe. PMID:26644341

  9. Adaptive plasticity in mammalian masticatory joints

    NASA Astrophysics Data System (ADS)

    Ravosa, Matthew J.; Kunwar, Ravinder; Nicholson, Elisabeth K.; Klopp, Emily B.; Pinchoff, Jessie; Stock, Stuart R.; Stack, M. Sharon; Hamrick, Mark W.

    2006-08-01

    Genetically similar white rabbits raised on diets of different mechanical properties, as well as wild-type and myostatin-deficient mice raised on similar diets, were compared to assess the postweaning effects of elevated masticatory loads due to increased jaw-adductor muscle and bite forces on the proportions and properties of the mandibular symphysis and temporomandibular joint (TMJ). Microcomputed tomography (microCT) was used to quantify bone structure at a series of equidistant external and internal sites in coronal sections for a series of joint locations. Discriminant function analyses and non-parametric ANOVAs were used to characterize variation in biomineralization within and between loading cohorts. In both species, long-term excessive loading results in larger joint proportions, thicker articular and cortical bone, and increased biomineralization of hard tissues. Such adaptive plasticity appears designed to maintain the postnatal integrity of masticatory joint systems for a primary loading environment(s). This behavioral signal may be increasingly mitigated in older organisms by the interplay between adaptive and degradative joint tissue responses.

  10. Limited genetic variability and phenotypic plasticity detected for cavitation resistance in a Mediterranean pine.

    PubMed

    Lamy, Jean-Baptiste; Delzon, Sylvain; Bouche, Pauline S; Alia, Ricardo; Vendramin, Giovanni Giuseppe; Cochard, Hervé; Plomion, Christophe

    2014-02-01

    Resistance to cavitation is a major determinant of plant survival under severe drought and can be used to quantify species adaptive potential. Interspecific variation in this key trait is well defined in woody species, but intraspecific variation (level and structure) resulting from standing genetic variation and phenotypic plasticity has never been determined. Combining for the first time in situ characterization of natural populations and two reciprocal common gardens in dry and wet sites, we estimated variance components (phenotypic, genetic, environmental, and genetic × environmental) of cavitation resistance based on 513 genotypes of a Mediterranean pine, Pinus pinaster. Despite the selected populations being climatically contrasted, phenotypic plasticity in resistance to cavitation remained low and was essentially attributed to family level. Between-population variation in cavitation resistance for both phenotypic and genetic variation was limited. These results strongly suggest that cavitation resistance is buffered against genetic and to a lesser extent environmental variation (canalization) in maritime pine. Consequently, in a drier world, the increasing drought tolerance of Pinus species might be severely constrained by the low level of cavitation resistance variation, resulting in a large-scale loss of productivity.

  11. The nuclear phenotypic plasticity observed in fish during rRNA regulation entails Cajal bodies dynamics

    SciTech Connect

    Alvarez, Marco; Nardocci, Gino; Thiry, Marc; Alvarez, Rodrigo; Reyes, Mauricio; Molina, Alfredo; Vera, M. Ines . E-mail: mvera@unab.cl

    2007-08-17

    Cajal bodies (CBs) are small mobile organelles found throughout the nucleoplasm of animal and plant cells. The dynamics of these organelles involves interactions with the nucleolus. The later has been found to play a substantial role in the compensatory response that evolved in eurythermal fish to adapt to the cyclic seasonal habitat changes, i.e., temperature and photoperiod. Contrary to being constitutive, rRNA synthesis is dramatically regulated between summer and winter, thus affecting ribosomal biogenesis which plays a central role in the acclimatization process. To examine whether CBs, up to now, never described in fish, were also sustaining the phenotypic plasticity observed in nuclei of fish undergoing seasonal acclimatization, we identified these organelles both, by transmission electronic microscopy and immunodetection with the marker protein p80-coilin. We found transcripts in all tissues analyzed. Furthermore we assessed that p80-coilin gene expression was always higher in summer-acclimatized fish when compared to that adapted to the cold season, indicating that p80-coilin expression is modulated upon seasonal acclimatization. Concurrently, CBs were more frequently found in summer-acclimatized carp which suggests that the organization of CBs is involved in adaptive processes and contribute to the phenotypic plasticity of fish cell nuclei observed concomitantly with profound reprogramming of nucleolar components and regulation of ribosomal rRNAs.

  12. Adaptive plasticity and epigenetic variation in response to warming in an Alpine plant

    PubMed Central

    Nicotra, Adrienne B; Segal, Deborah L; Hoyle, Gemma L; Schrey, Aaron W; Verhoeven, Koen J F; Richards, Christina L

    2015-01-01

    Environmentally induced phenotypic plasticity may be a critical component of response to changing environments. We examined local differentiation and adaptive phenotypic plasticity in response to elevated temperature in half-sib lines collected across an elevation gradient for the alpine herb, Wahlenbergia ceracea. Using Amplified Fragment Length Polymorphism (AFLP), we found low but significant genetic differentiation between low- and high-elevation seedlings, and seedlings originating from low elevations grew faster and showed stronger temperature responses (more plasticity) than those from medium and high elevations. Furthermore, plasticity was more often adaptive for plants of low-elevation origin and maladaptive for plants of high elevation. With methylation sensitive-AFLP (MS-AFLP), we revealed an increase in epigenetic variation in response to temperature in low-elevation seedlings. Although we did not find significant direct correlations between MS-AFLP loci and phenotypes, our results demonstrate that adaptive plasticity in temperature response to warming varies over fine spatial scales and suggest the involvement of epigenetic mechanisms in this response. PMID:25691987

  13. Experimental evolution of phenotypic plasticity: how predictive are cross-environment genetic correlations?

    PubMed

    Czesak, Mary Ellen; Fox, Charles W; Wolf, Jason B

    2006-09-01

    Genetic correlations are often predictive of correlated responses of one trait to selection on another trait. There are examples, however, in which genetic correlations are not predictive of correlated responses. We examine how well a cross-environment genetic correlation predicts correlated responses to selection and the evolution of phenotypic plasticity in the seed beetle Stator limbatus. This beetle exhibits adaptive plasticity in egg size by laying large eggs on a resistant host and small eggs on a high-quality host. From a half-sib analysis, the cross-environment genetic correlation estimate was large and positive (rA=0.99). However, an artificial-selection experiment on egg size found that the realized genetic correlations were positive but asymmetrical; that is, they depended on both the host on which selection was imposed and the direction of selection. The half-sib estimate poorly predicted the evolution of egg size plasticity; plasticity evolved when selection was imposed on one host but did not evolve when selection was imposed on the other host. We use a simple two-locus additive genetic model to explore the conditions that can generate the observed realized genetic correlation and the observed pattern of plasticity evolution. Our model and experimental results indicate that the ability of genetic correlations to predict correlated responses to selection depends on the underlying genetic architecture producing the genetic correlation.

  14. Is plasticity across seasons adaptive in the annual cleistogamous plant Lamium amplexicaule?

    PubMed Central

    Stojanova, B.; Maurice, S.; Cheptou, P.-O.

    2016-01-01

    Background and aims Many angiosperms exhibit cleistogamy, the production of both cleistogamous flowers (CL), which remain closed and obligately self-pollinated, and chasmogamous flowers (CH), which are potentially open-pollinated. The CH proportion can be plastic. Plasticity is adaptive if environmental changes can be reliably assessed and responded to with an appropriate phenotype and if plastic genotypes have higher fitness in variable environments than non-plastic ones. Methods We studied the plastic response of four natural populations from northern and southern France of an annual cleistogamous plant, Lamium amplexicaule, to predictable seasonal variation. Plants were grown in a semi-controlled environment in spring and in autumn. We assessed the variation in flower number, phenology and cleistogamy-related traits, which were all plastic with respect to season. The CH proportion was higher in spring than in autumn in all four populations. Key Results We showed significant stabilizing selection for cleistogamy traits, with higher optimal CH proportions and more pronounced stabilizing selection in spring than in autumn. Observed CH proportions were close to the predicted optimal CH proportions in each season except in autumn for southern populations, which do not experience the autumnal growing season in nature. Conclusions These results are consistent with adaptive plasticity across seasons of cleistogamy in L. amplexicaule. We propose that adaptive plasticity of cleistogamy could be driven by pollination environment variation, with CL flowers providing reproductive assurance when pollinators are scarce and CH flowers reducing the inbreeding depression in offspring when pollinators are abundant. PMID:26995537

  15. Kidney morphology and candidate gene expression shows plasticity in sticklebacks adapted to divergent osmotic environments.

    PubMed

    Hasan, M Mehedi; DeFaveri, Jacquelin; Kuure, Satu; Dash, Surjya N; Lehtonen, Sanna; Merilä, Juha; McCairns, R J Scott

    2017-04-03

    Novel physiological challenges in different environments can promote the evolution of divergent phenotypes, either through plastic or genetic changes. Environmental salinity serves as a key barrier to the distribution of nearly all aquatic organisms, and species diversification is likely to be enabled by adaptation to alternative osmotic environments. The threespine stickleback (Gasterosteus aculeatus) is a euryhaline species with populations found both in marine and freshwater environments. It has evolved both highly plastic and locally adapted phenotypes due to salinity-derived selection, but the physiological and genetic basis of adaptation to salinity is not fully understood. We integrated comparative cellular morphology of the kidney, a key organ for osmoregulation, and candidate gene expression to explore the underpinnings of evolved variation in osmotic plasticity within two populations of sticklebacks from distinct salinity zones in the Baltic Sea: the high salinity Kattegat, representative of the ancestral marine habitat, and the low salinity Bay of Bothnia. A common-garden experiment revealed that kidney morphology in the ancestral high salinity population had a highly plastic response to salinity conditions, whereas this plastic response was reduced in the low salinity population. Candidate gene expression in kidney tissue revealed a similar pattern of population-specific differences, with a higher degree of plasticity in the native high salinity population. Together these results suggest that renal cellular morphology has become canalized to low salinity, and that these structural differences may have functional implications for osmoregulation.

  16. Phenotypic plasticity in thermal tolerance in the Glanville fritillary butterfly.

    PubMed

    Luo, Shiqi; Chong Wong, Swee; Xu, Chongren; Hanski, Ilkka; Wang, Rongjiang; Lehtonen, Rainer

    2014-05-01

    Ambient temperature is an ubiquitous environmental factor affecting all organisms. Global climate change increases temperature variation and the frequency of extreme temperatures, which may pose challenges to ectotherms. Here, we examine phenotypic plasticity to temperature and genotypic effects on thermal tolerance in the Glanville fritillary butterfly (Melitaea cinxia). We found no significant difference in heat or cold tolerance in populations originating from a continental climate in China and from Finland with moderate temperature variation. Acclimation to large-amplitude temperature variation increased heat tolerance in both populations, but decreased cold tolerance and increased hsp70-2 expression in the Chinese population only. The latter result indicates a genotypic effect in the response to temperature variation. In the Finnish population, a non-synonymous SNP in the phosphoglucose isomerase (Pgi) gene was associated with heat knock-down time.

  17. Epigenetic Control of Phenotypic Plasticity in the Filamentous Fungus Neurospora crassa.

    PubMed

    Kronholm, Ilkka; Johannesson, Hanna; Ketola, Tarmo

    2016-12-07

    Phenotypic plasticity is the ability of a genotype to produce different phenotypes under different environmental or developmental conditions. Phenotypic plasticity is a ubiquitous feature of living organisms, and is typically based on variable patterns of gene expression. However, the mechanisms by which gene expression is influenced and regulated during plastic responses are poorly understood in most organisms. While modifications to DNA and histone proteins have been implicated as likely candidates for generating and regulating phenotypic plasticity, specific details of each modification and its mode of operation have remained largely unknown. In this study, we investigated how epigenetic mechanisms affect phenotypic plasticity in the filamentous fungus Neurospora crassa By measuring reaction norms of strains that are deficient in one of several key physiological processes, we show that epigenetic mechanisms play a role in homeostasis and phenotypic plasticity of the fungus across a range of controlled environments. In general, effects on plasticity are specific to an environment and mechanism, indicating that epigenetic regulation is context dependent and is not governed by general plasticity genes. Specifically, we found that, in Neurospora, histone methylation at H3K36 affected plastic response to high temperatures, H3K4 methylation affected plastic response to pH, but H3K27 methylation had no effect. Similarly, DNA methylation had only a small effect in response to sucrose. Histone deacetylation mainly decreased reaction norm elevation, as did genes involved in histone demethylation and acetylation. In contrast, the RNA interference pathway was involved in plastic responses to multiple environments.

  18. Epigenetic Control of Phenotypic Plasticity in the Filamentous Fungus Neurospora crassa

    PubMed Central

    Kronholm, Ilkka; Johannesson, Hanna; Ketola, Tarmo

    2016-01-01

    Phenotypic plasticity is the ability of a genotype to produce different phenotypes under different environmental or developmental conditions. Phenotypic plasticity is a ubiquitous feature of living organisms, and is typically based on variable patterns of gene expression. However, the mechanisms by which gene expression is influenced and regulated during plastic responses are poorly understood in most organisms. While modifications to DNA and histone proteins have been implicated as likely candidates for generating and regulating phenotypic plasticity, specific details of each modification and its mode of operation have remained largely unknown. In this study, we investigated how epigenetic mechanisms affect phenotypic plasticity in the filamentous fungus Neurospora crassa. By measuring reaction norms of strains that are deficient in one of several key physiological processes, we show that epigenetic mechanisms play a role in homeostasis and phenotypic plasticity of the fungus across a range of controlled environments. In general, effects on plasticity are specific to an environment and mechanism, indicating that epigenetic regulation is context dependent and is not governed by general plasticity genes. Specifically, we found that, in Neurospora, histone methylation at H3K36 affected plastic response to high temperatures, H3K4 methylation affected plastic response to pH, but H3K27 methylation had no effect. Similarly, DNA methylation had only a small effect in response to sucrose. Histone deacetylation mainly decreased reaction norm elevation, as did genes involved in histone demethylation and acetylation. In contrast, the RNA interference pathway was involved in plastic responses to multiple environments. PMID:27694114

  19. Playing smart vs. playing safe: the joint expression of phenotypic plasticity and potential bet hedging across and within thermal environments.

    PubMed

    Simons, A M

    2014-06-01

    Adaptive phenotypic plasticity evolves when cues reliably predict fitness consequences of life-history decisions, whereas bet hedging evolves when environments are unpredictable. These modes of response should be jointly expressed, because environmental variance is composed of both predictable and unpredictable components. However, little attention has been paid to the joint expression of plasticity and bet hedging. Here, I examine the simultaneous expression of plasticity in germination rate and two potential bet-hedging traits - germination fraction and within-season diversification in timing of germination - in seeds from multiple seed families of five geographically distant populations of Lobelia inflata (L.) subjected to a thermal gradient. Populations differ in germination plasticity to temperature, in total germination fraction and in the expression of potential diversification in the timing of germination. The observation of a negative partial correlation between the expression of plasticity and germination variance (potential diversification), and a positive correlation between plasticity and germination fraction is suggestive of a trade-off between modes of response to environmental variance. If the observed correlations are indicative of those between adaptive plasticity and bet hedging, we expect an optimal balance to exist and differ among populations. I discuss the challenges involved in testing whether the balance between plasticity and bet hedging depends on the relative predictability of environmental variance.

  20. Relaxed genetic constraint is ancestral to the evolution of phenotypic plasticity.

    PubMed

    Leichty, Aaron R; Pfennig, David W; Jones, Corbin D; Pfennig, Karin S

    2012-07-01

    Phenotypic plasticity--the capacity of a single genotype to produce different phenotypes in response to varying environmental conditions--is widespread. Yet, whether, and how, plasticity impacts evolutionary diversification is unclear. According to a widely discussed hypothesis, plasticity promotes rapid evolution because genes expressed differentially across different environments (i.e., genes with "biased" expression) experience relaxed genetic constraint and thereby accumulate variation faster than do genes with unbiased expression. Indeed, empirical studies confirm that biased genes evolve faster than unbiased genes in the same genome. An alternative hypothesis holds, however, that the relaxed constraint and faster evolutionary rates of biased genes may be a precondition for, rather than a consequence of, plasticity's evolution. Here, we evaluated these alternative hypotheses by characterizing evolutionary rates of biased and unbiased genes in two species of frogs that exhibit a striking form of phenotypic plasticity. We also characterized orthologs of these genes in four species of frogs that had diverged from the two plastic species before the plasticity evolved. We found that the faster evolutionary rates of biased genes predated the evolution of the plasticity. Furthermore, biased genes showed greater expression variance than did unbiased genes, suggesting that they may be more dispensable. Phenotypic plasticity may therefore evolve when dispensable genes are co-opted for novel function in environmentally induced phenotypes. Thus, relaxed genetic constraint may be a cause--not a consequence--of the evolution of phenotypic plasticity, and thereby contribute to the evolution of novel traits.

  1. Phenotypic Plasticity Promotes Balanced Polymorphism in Periodic Environments by a Genomic Storage Effect.

    PubMed

    Gulisija, Davorka; Kim, Yuseob; Plotkin, Joshua B

    2016-04-01

    Phenotypic plasticity is known to evolve in perturbed habitats, where it alleviates the deleterious effects of selection. But the effects of plasticity on levels of genetic polymorphism, an important precursor to adaptation in temporally varying environments, are unclear. Here we develop a haploid, two-locus population-genetic model to describe the interplay between a plasticity modifier locus and a target locus subject to periodically varying selection. We find that the interplay between these two loci can produce a "genomic storage effect" that promotes balanced polymorphism over a large range of parameters, in the absence of all other conditions known to maintain genetic variation. The genomic storage effect arises as recombination allows alleles at the two loci to escape more harmful genetic backgrounds and associate in haplotypes that persist until environmental conditions change. Using both Monte Carlo simulations and analytical approximations we quantify the strength of the genomic storage effect across a range of selection pressures, recombination rates, plasticity modifier effect sizes, and environmental periods.

  2. The Relative Importance of Genetic Diversity and Phenotypic Plasticity in Determining Invasion Success of a Clonal Weed in the USA and China.

    PubMed

    Geng, Yupeng; van Klinken, Rieks D; Sosa, Alejandro; Li, Bo; Chen, Jiakuan; Xu, Cheng-Yuan

    2016-01-01

    Phenotypic plasticity has been proposed as an important adaptive strategy for clonal plants in heterogeneous habitats. Increased phenotypic plasticity can be especially beneficial for invasive clonal plants, allowing them to colonize new environments even when genetic diversity is low. However, the relative importance of genetic diversity and phenotypic plasticity for invasion success remains largely unknown. Here, we performed molecular marker analyses and a common garden experiment to investigate the genetic diversity and phenotypic plasticity of the globally important weed Alternanthera philoxeroides in response to different water availability (terrestrial vs. aquatic habitats). This species relies predominantly on clonal propagation in introduced ranges. We therefore expected genetic diversity to be restricted in the two sampled introduced ranges (the USA and China) when compared to the native range (Argentina), but that phenotypic plasticity may allow the species' full niche range to nonetheless be exploited. We found clones from China had very low genetic diversity in terms of both marker diversity and quantitative variation when compared with those from the USA and Argentina, probably reflecting different introduction histories. In contrast, similar patterns of phenotypic plasticity were found for clones from all three regions. Furthermore, despite the different levels of genetic diversity, bioclimatic modeling suggested that the full potential bioclimatic distribution had been invaded in both China and USA. Phenotypic plasticity, not genetic diversity, was therefore critical in allowing A. philoxeroides to invade diverse habitats across broad geographic areas.

  3. The Relative Importance of Genetic Diversity and Phenotypic Plasticity in Determining Invasion Success of a Clonal Weed in the USA and China

    PubMed Central

    Geng, Yupeng; van Klinken, Rieks D.; Sosa, Alejandro; Li, Bo; Chen, Jiakuan; Xu, Cheng-Yuan

    2016-01-01

    Phenotypic plasticity has been proposed as an important adaptive strategy for clonal plants in heterogeneous habitats. Increased phenotypic plasticity can be especially beneficial for invasive clonal plants, allowing them to colonize new environments even when genetic diversity is low. However, the relative importance of genetic diversity and phenotypic plasticity for invasion success remains largely unknown. Here, we performed molecular marker analyses and a common garden experiment to investigate the genetic diversity and phenotypic plasticity of the globally important weed Alternanthera philoxeroides in response to different water availability (terrestrial vs. aquatic habitats). This species relies predominantly on clonal propagation in introduced ranges. We therefore expected genetic diversity to be restricted in the two sampled introduced ranges (the USA and China) when compared to the native range (Argentina), but that phenotypic plasticity may allow the species' full niche range to nonetheless be exploited. We found clones from China had very low genetic diversity in terms of both marker diversity and quantitative variation when compared with those from the USA and Argentina, probably reflecting different introduction histories. In contrast, similar patterns of phenotypic plasticity were found for clones from all three regions. Furthermore, despite the different levels of genetic diversity, bioclimatic modeling suggested that the full potential bioclimatic distribution had been invaded in both China and USA. Phenotypic plasticity, not genetic diversity, was therefore critical in allowing A. philoxeroides to invade diverse habitats across broad geographic areas. PMID:26941769

  4. The adaptive evolution of plasticity: phytochrome-mediated shade avoidance responses.

    PubMed

    Schmitt, Johanna; Stinchcombe, John R; Heschel, M Shane; Huber, Heidrun

    2003-07-01

    Many plants display a characteristic suite of developmental "shade avoidance" responses, such as stem elongation and accelerated reproduction, to the low ratio of red to far-red wavelengths (R:FR) reflected or transmitted from green vegetation. This R:FR cue of crowding and vegetation shade is perceived by the phytochrome family of photoreceptors. Phytochrome-mediated responses provide an ideal system for investigating the adaptive evolution of phenotypic plasticity in natural environments. The molecular and developmental mechanisms underlying shade avoidance responses are well studied, and testable ecological hypotheses exist for their adaptive significance. Experimental manipulation of phenotypes demonstrates that shade avoidance responses may be adaptive, resulting in phenotypes with high relative fitness in the environments that induce those phenotypes. The adaptive value of shade avoidance depends upon the competitive environment, resource availability, and the reliability of the R:FR cue for predicting the selective environment experienced by an induced phenotype. Comparative studies and a reciprocal transplant experiment with Impatiens capensis provide evidence of adaptive divergence in shade avoidance responses between woodland and clearing habitats, which may result from population differences in the frequency of selection on shade avoidance traits, as well as differences in the reliability of the R:FR cue. Recent rapid progress in elucidating phytochrome signaling pathways in the genetic model Arabidopsis thaliana and other species now provides the opportunity for studying how selection on shade avoidance traits in natural environments acts upon the molecular mechanisms underlying natural phenotypic variation.

  5. The impact of beneficial plant-associated microbes on plant phenotypic plasticity.

    PubMed

    Goh, Chooi-Hua; Veliz Vallejos, Debora F; Nicotra, Adrienne B; Mathesius, Ulrike

    2013-07-01

    Plants show phenotypic plasticity in response to changing or extreme abiotic environments; but over millions of years they also have co-evolved to respond to the presence of soil microbes. Studies on phenotypic plasticity in plants have focused mainly on the effects of the changing environments on plants' growth and survival. Evidence is now accumulating that the presence of microbes can alter plant phenotypic plasticity in a broad range of traits in response to a changing environment. In this review, we discuss the effects of microbes on plant phenotypic plasticity in response to changing environmental conditions, and how this may affect plant fitness. By using a range of specific plant-microbe interactions as examples, we demonstrate that one way that microbes can alleviate the effect of environmental stress on plants and thus increase plant fitness is to remove the stress, e.g., nutrient limitation, directly. Furthermore, microbes indirectly affect plant phenotypic plasticity and fitness through modulation of plant development and defense responses. In doing so, microbes affect fitness by both increasing or decreasing the degree of phenotypic plasticity, depending on the phenotype and the environmental stress studied, with no clear difference between the effect of prokaryotic and eukaryotic microbes in general. Additionally, plants have the ability to modulate microbial behaviors, suggesting that they manipulate bacteria, enhancing interactions that help them cope with stressful environments. Future challenges remain in the identification of the many microbial signals that modulate phenotypic plasticity, the characterization of plant genes, e.g. receptors, that mediate the microbial effects on plasticity, and the elucidation of the molecular mechanisms that link phenotypic plasticity with fitness. The characterization of plant and microbial mutants defective in signal synthesis or perception, together with carefully designed glasshouse or field experiments that

  6. Rethinking phenotypic plasticity and its consequences for individuals, populations and species.

    PubMed

    Forsman, A

    2015-10-01

    Much research has been devoted to identify the conditions under which selection favours flexible individuals or genotypes that are able to modify their growth, development and behaviour in response to environmental cues, to unravel the mechanisms of plasticity and to explore its influence on patterns of diversity among individuals, populations and species. The consequences of developmental plasticity and phenotypic flexibility for the performance and ecological success of populations and species have attracted a comparatively limited but currently growing interest. Here, I re-emphasize that an increased understanding of the roles of plasticity in these contexts requires a 'whole organism' (rather than 'single trait') approach, taking into consideration that organisms are integrated complex phenotypes. I further argue that plasticity and genetic polymorphism should be analysed and discussed within a common framework. I summarize predictions from theory on how phenotypic variation stemming from developmental plasticity and phenotypic flexibility may affect different aspects of population-level performance. I argue that it is important to distinguish between effects associated with greater interindividual phenotypic variation resulting from plasticity, and effects mediated by variation among individuals in the capacity to express plasticity and flexibility as such. Finally, I claim that rigorous testing of predictions requires methods that allow for quantifying and comparing whole organism plasticity, as well as the ability to experimentally manipulate the level of and capacity for developmental plasticity and phenotypic flexibility independent of genetic variation.

  7. Sperm competition risk generates phenotypic plasticity in ovum fertilizability

    PubMed Central

    Firman, Renée C.; Simmons, Leigh W.

    2013-01-01

    Theory predicts that sperm competition will generate sexual conflict that favours increased ovum defences against polyspermy. A recent study on house mice has shown that ovum resistance to fertilization coevolves in response to increased sperm fertilizing capacity. However, the capacity for the female gamete to adjust its fertilizability as a strategic response to sperm competition risk has never, to our knowledge, been studied. We sourced house mice (Mus domesticus) from natural populations that differ in the level of sperm competition and sperm fertilizing capacity, and manipulated the social experience of females during their sexual development to simulate conditions of either a future ‘risk’ or ‘no risk’ of sperm competition. Consistent with coevolutionary predictions, we found lower fertilization rates in ova produced by females from a high sperm competition population compared with ova from a low sperm competition population, indicating that these populations are divergent in the fertilizability of their ova. More importantly, females exposed to a ‘risk’ of sperm competition produced ova that had greater resistance to fertilization than ova produced by females reared in an environment with ‘no risk’. Consequently, we show that variation in sperm competition risk during development generates phenotypic plasticity in ova fertilizability, which allows females to prepare for prevailing conditions during their reproductive life. PMID:24132308

  8. Sperm competition risk generates phenotypic plasticity in ovum fertilizability.

    PubMed

    Firman, Renée C; Simmons, Leigh W

    2013-12-07

    Theory predicts that sperm competition will generate sexual conflict that favours increased ovum defences against polyspermy. A recent study on house mice has shown that ovum resistance to fertilization coevolves in response to increased sperm fertilizing capacity. However, the capacity for the female gamete to adjust its fertilizability as a strategic response to sperm competition risk has never, to our knowledge, been studied. We sourced house mice (Mus domesticus) from natural populations that differ in the level of sperm competition and sperm fertilizing capacity, and manipulated the social experience of females during their sexual development to simulate conditions of either a future 'risk' or 'no risk' of sperm competition. Consistent with coevolutionary predictions, we found lower fertilization rates in ova produced by females from a high sperm competition population compared with ova from a low sperm competition population, indicating that these populations are divergent in the fertilizability of their ova. More importantly, females exposed to a 'risk' of sperm competition produced ova that had greater resistance to fertilization than ova produced by females reared in an environment with 'no risk'. Consequently, we show that variation in sperm competition risk during development generates phenotypic plasticity in ova fertilizability, which allows females to prepare for prevailing conditions during their reproductive life.

  9. Phenotypic plasticity to light of two congeneric trees from contrasting habitats: Brazilian Atlantic Forest versus cerrado (savanna).

    PubMed

    Barros, F de V; Goulart, M F; Telles, S B Sá; Lovato, M B; Valladares, F; de Lemos-Filho, J P

    2012-01-01

    The Brazilian Atlantic Forest is a typically multi-layer tropical forest, while cerrado (savanna) is a patchy habitat with different physiognomy. Despite these differences, both habitats have high light heterogeneity. Functional traits of Dalbergia nigra and D. miscolobium from the Atlantic Forest and cerrado, respectively, were evaluated under shade (25% of full sunlight) and full sunlight in a nursery experiment. We hypothesised that both species should benefit from high phenotypic plasticity in relation to light. Plasticity was estimated using the relative distance phenotypic index (RDPI). D. miscolobium had lower shoot growth under both light conditions, suggesting it has low competitive capacity in the forest environment, which could explain its limited ability to expand over areas of Atlantic Forest. The studied species exhibited photoprotection strategies under high light and improved light capture under low light. Stomatal conductance, ETR(max) (maximum electron transport rate), PPFD(sat) (saturating photosynthetically active photon flux density), chlorophyll and carotenoid content had higher RDPI than stem morphological traits. Although both species showed considerable phenotypic plasticity, D. miscolobium had higher RDPI for eight of 11 evaluated traits. This high plasticity could be one of the factors that explain the occurrence of this species in a wide range of environmental conditions, from open grassland to dense woodlands, and it could also reflect its adaptation to high light. D. nigra also had considerable plasticity and good growth performance in both shade and full sunlight, but its absence in areas of cerrado suggests that factors other than light limit its occurrence in these habitats.

  10. Candida albicans the chameleon: Transitions and interactions between multiple phenotypic states confer phenotypic plasticity

    PubMed Central

    Scaduto, Christine M.

    2015-01-01

    The ability of microbial cells to exist in multiple states is a ubiquitous property that promotes adaptation and survival. This phenomenon has been extensively studied in the opportunistic pathogen Candida albicans, which can transition between multiple phenotypic states in response to environmental signals. C. albicans normally exists as a commensal in the human body, but can also cause debilitating mucosal infections or life-threatening systemic infections. The ability to switch between cellular forms contributes to C. albicans’ capacity to infect different host niches, and strictly regulates the program of sexual mating. We review the unique properties associated with different phenotypic states, as well as how interactions between cells in different states can further augment microbial behavior. PMID:26189047

  11. Phenotypic integration plasticity in Daphnia magna: an integral facet of G × E interactions.

    PubMed

    Plaistow, S J; Collin, H

    2014-09-01

    Phenotypic integration can be defined as the network of multivariate relationships among behavioural, physiological and morphological traits that describe the organism. Phenotypic integration plasticity refers to the change in patterns of phenotypic integration across environments or ontogeny. Because studies of phenotypic plasticity have predominantly focussed on single traits, a G × E interaction is typically perceived as differences in the magnitude of trait expression across two or more environments. However, many plastic responses involve coordinated responses in multiple traits, raising the possibility that relative differences in trait expression in different environments are an important, but often overlooked, source of G × E interaction. Here, we use phenotypic change vectors to statistically compare the multivariate life-history plasticity of six Daphnia magna clones collected from four disparate European populations. Differences in the magnitude of plastic responses were statistically distinguishable for two of the six clones studied. However, differences in phenotypic integration plasticity were statistically distinguishable for all six of the clones studied, suggesting that phenotypic integration plasticity is an important component of G × E interactions that may be missed unless appropriate multivariate analyses are used.

  12. Evidence for phenotypic plasticity in the Antarctic extremophile Chlamydomonas raudensis Ettl. UWO 241.

    PubMed

    Pocock, Tessa; Vetterli, Adrien; Falk, Stefan

    2011-01-01

    Life in extreme environments poses unique challenges to photosynthetic organisms. The ability for an extremophilic green alga and its genetic and mesophilic equivalent to acclimate to changes in their environment was examined to determine the extent of their phenotypic plasticities. The Antarctic extremophile Chlamydomonas raudensis Ettl. UWO 241 (UWO) was isolated from an ice-covered lake in Antarctica, whereas its mesophilic counterpart C. raudensis Ettl. SAG 49.72 (SAG) was isolated from a meadow pool in the Czech Republic. The effects of changes in temperature and salinity on growth, morphology, and photochemistry were examined in the two strains. Differential acclimative responses were observed in UWO which include a wider salinity range for growth, and broader temperature- and salt-induced fluctuations in F(v)/F(m), relative to SAG. Furthermore, the redox state of the photosynthetic electron transport chain, measured as 1-q(P), was modulated in the extremophile whereas this was not observed in the mesophile. Interestingly, it is shown for the first time that SAG is similar to UWO in that it is unable to undergo state transitions. The different natural histories of these two strains exert different evolutionary pressures and, consequently, different abilities for acclimation, an important component of phenotypic plasticity. In contrast to SAG, UWO relied on a redox sensing and signalling system under the growth conditions used in this study. It is proposed that growth and adaptation of UWO under a stressful and extreme environment poises this extremophile for better success under changing environmental conditions.

  13. Non-swarming grasshoppers exhibit density-dependent phenotypic plasticity reminiscent of swarming locusts.

    PubMed

    Gotham, Steven; Song, Hojun

    2013-11-01

    those on the desert locust and other relevant studies. We attribute the presence of density-dependent phenotypic plasticity in the non-swarming Schistocerca species to phylogenetic conservatism, but there may be a possible role of local adaptation in further shaping the ultimate expressions of plasticity.

  14. Evolution of phenotypic plasticity and environmental tolerance of a labile quantitative character in a fluctuating environment.

    PubMed

    Lande, R

    2014-05-01

    Quantitative genetic models of evolution of phenotypic plasticity are used to derive environmental tolerance curves for a population in a changing environment, providing a theoretical foundation for integrating physiological and community ecology with evolutionary genetics of plasticity and norms of reaction. Plasticity is modelled for a labile quantitative character undergoing continuous reversible development and selection in a fluctuating environment. If there is no cost of plasticity, a labile character evolves expected plasticity equalling the slope of the optimal phenotype as a function of the environment. This contrasts with previous theory for plasticity influenced by the environment at a critical stage of early development determining a constant adult phenotype on which selection acts, for which the expected plasticity is reduced by the environmental predictability over the discrete time lag between development and selection. With a cost of plasticity in a labile character, the expected plasticity depends on the cost and on the environmental variance and predictability averaged over the continuous developmental time lag. Environmental tolerance curves derived from this model confirm traditional assumptions in physiological ecology and provide new insights. Tolerance curve width increases with larger environmental variance, but can only evolve within a limited range. The strength of the trade-off between tolerance curve height and width depends on the cost of plasticity. Asymmetric tolerance curves caused by male sterility at high temperature are illustrated. A simple condition is given for a large transient increase in plasticity and tolerance curve width following a sudden change in average environment.

  15. [Genome, environment and plasticity of the brain underlying individual adaptation].

    PubMed

    Paunio, Tiina

    2011-01-01

    Epigenetic mechanisms mediate the interaction between environment and genome. On molecular level, these mechanisms are active in plastic processes of the brain and influence brain function and the person's ability to adapt to the environment. Genomic variations provide individual options for this adaptation, and a spectrum of behavioral patterns necessary for species preservation. Adaptation processes may also be harmful in respect of individual health, leading even to psychiatric illnesses, but are still meaningful as seen through the person's inner experience, genome or environment.

  16. Drought responses, phenotypic plasticity and survival of Mediterranean species in two different microclimatic sites.

    PubMed

    Bongers, F J; Olmo, M; Lopez-Iglesias, B; Anten, N P R; Villar, R

    2017-01-05

    Climate models predict a further drying of the Mediterranean summer. One way for plant species to persist during such climate changes is through acclimation. Here, we determine the extent to which trait plasticity in response to drought differs between species and between sites, and address the question whether there is a trade-off between drought survival and phenotypic plasticity. Throughout the summer we measured physiological traits (photosynthesis - Amax , stomatal conductance - gs , transpiration - E, leaf water potential - ψl) and structural traits (specific leaf area - SLA, leaf density - LD, leaf dry matter content - LDMC, leaf relative water content - LRWC) of leaves of eight woody species in two sites with slightly different microclimate (north- versus south-facing slopes) in southern Spain. Plant recovery and survival was estimated after the summer drought period. We found high trait variability between species. In most variables, phenotypic plasticity was lower in the drier site. Phenotypic plasticity of SLA and LDMC correlated negatively with drought survival, which suggests a trade-off between them. On the other hand, high phenotypic plasticity of SLA and LDMC was positively related to traits associated with rapid recovery and growth after the drought period. Although phenotypic plasticity is generally seen as favourable during stress conditions, here it seemed beneficial for favourable conditions. We propose that in environments with fluctuating drought periods there can be a trade-off between drought survival and growth during favourable conditions. When climate become drier, species with high drought survival but low phenotypic plasticity might be selected for.

  17. Reciprocal phenotypic plasticity in a predator-prey interaction between larval amphibians.

    PubMed

    Kishida, Osamu; Mizuta, Yuuki; Nishimura, Kinya

    2006-06-01

    In biological interactions, phenotypic change in interacting organisms induced by their interaction partners causes a substantial shift in some environmental factor of the partners, which may subsequently change their phenotype in response to that modified environmental factor. Few examples of such arms-race-like plastic responses, known as reciprocal phenotypic plasticity, have been identified in predator-prey interactions. We experimentally identified a reciprocal defensive plastic response of a prey species against a predator with a predaceous phenotype using a model system of close predator-prey interaction. Rana pirica tadpoles (the prey species) were reared with larvae of the salamander Hynobius retardatus (the predator species) having either a predaceous or a typical, nonpredaceous phenotype. The H. retardatus larvae with the predaceous phenotype, which is known to be induced by the presence of R. pirica tadpoles, induced a more defensive phenotype in the tadpoles than did larvae with the typical phenotype. The result suggests that the reciprocal phenotypic plasticity of R. pirica tadpoles is in response to a phenotype-specific signal under a close-signal recognition process.

  18. Phenotypic lability and the evolution of predator-induced plasticity in tadpoles.

    PubMed

    Van Buskirk, J

    2002-02-01

    The hypothesis that predator-induced defenses in anuran larvae are maintained by divergent selection across multiple predation environments has not been fully supported by empirical results. One reason may be that traits that respond slowly to environmental variation experience a fitness cost not incorporated in the standard adaptive model, due to a time lag between detecting the state of the environment and expressing the phenotypic response. I measured the rate at which behavior and morphology of Rana temporaria tadpoles change when confronted with a switch in the predation environment at two points in development. Hatchling tadpoles that had been exposed during the egg stage to Aeshna dragonfly larvae were not phenotypically different from those exposed as eggs to predator-free conditions, and both responded similarly to post-hatching predator treatments. When 25-day-old tadpoles from treatments with and without dragonflies were subjected to a switch in the environment, their activity budgets reversed completely within 24-36 h, and their body and tail shape began changing significantly within 4 days. The behavioral response was conservative: Tadpoles switched from high-risk to predator-free treatments were slower to adjust their activity. The study confirmed that behavioral traits are relatively labile and exhibit strong plasticity, but it did not reveal such a pattern at the level of individual traits: Morphological traits that developed slowly did not show the least plasticity. Thus, I found that differences in lability of traits were useful for predicting the magnitude of plasticity only for fundamentally different kinds of characters.

  19. Inbreeding depression in adaptive plasticity under predation risk in a freshwater snail.

    PubMed

    Auld, Josh R; Relyea, Rick A

    2010-04-23

    While much attention has been paid to the effects of inbreeding on fitness, this has mostly come from a genetic perspective. Consequently, the interaction between inbreeding and the environment is less well understood. To understand the effects of inbreeding in natural populations where environmental conditions are variable, we need to examine not only how the effects of inbreeding change among environments but also how inbreeding may affect the ability to respond to environmental conditions (i.e. phenotypic plasticity). We reared selfed and outcrossed hermaphroditic snails (Physa acuta) in the presence and absence of chemical cues from predatory crayfish and quantified expression of an inducible defence, an adaptively plastic response to predation risk. Overall, inbred snails exhibited reduced defences, but more importantly, inbreeding reduced the expression of predator-induced adaptive plasticity. Inbreeding depression in defensive morphology was 26 per cent and inbreeding depression in the plasticity of this trait was 48 per cent. Inbreeding depression in adaptive plasticity may be important to understanding the effects of inbreeding in nature.

  20. Neuronal plasticity: adaptation and readaptation to the environment of space

    NASA Technical Reports Server (NTRS)

    Correia, M. J.

    1998-01-01

    While there have been few documented permanent neurological changes resulting from space travel, there is a growing literature which suggests that neural plasticity sometimes occurs within peripheral and central vestibular pathways during and following spaceflight. This plasticity probably has adaptive value within the context of the space environment, but it can be maladaptive upon return to the terrestrial environment. Fortunately, the maladaptive responses resulting from neuronal plasticity diminish following return to earth. However, the literature suggests that the longer the space travel, the more difficult the readaptation. With the possibility of extended space voyages and extended stays on board the international space station, it seems worthwhile to review examples of plastic vestibular responses and changes in the underlying neural substrates. Studies and facilities needed for space station investigation of plastic changes in the neural substrates are suggested. Copyright 1998 Elsevier Science B.V.

  1. Neuronal plasticity: adaptation and readaptation to the environment of space.

    PubMed

    Correia, M J

    1998-11-01

    While there have been few documented permanent neurological changes resulting from space travel, there is a growing literature which suggests that neural plasticity sometimes occurs within peripheral and central vestibular pathways during and following spaceflight. This plasticity probably has adaptive value within the context of the space environment, but it can be maladaptive upon return to the terrestrial environment. Fortunately, the maladaptive responses resulting from neuronal plasticity diminish following return to earth. However, the literature suggests that the longer the space travel, the more difficult the readaptation. With the possibility of extended space voyages and extended stays on board the international space station, it seems worthwhile to review examples of plastic vestibular responses and changes in the underlying neural substrates. Studies and facilities needed for space station investigation of plastic changes in the neural substrates are suggested.

  2. Stress relief may promote the evolution of greater phenotypic plasticity in exotic invasive species: a hypothesis.

    PubMed

    Huang, Qiao Q; Pan, Xiao Y; Fan, Zhi W; Peng, Shao L

    2015-03-01

    Invasion ecologists have often found that exotic invaders evolve to be more plastic than conspecific populations from their native range. However, an open question is why some exotic invaders can even evolve to be more plastic given that there may be costs to being plastic. Investigation into the benefits and costs of plasticity suggests that stress may constrain the expression of plasticity (thereby reducing the benefits of plasticity) and exacerbate the costs of plasticity (although this possibility might not be generally applicable). Therefore, evolution of adaptive plasticity is more likely to be constrained in stressful environments. Upon introduction to a new range, exotic species may experience more favorable growth conditions (e.g., because of release from natural enemies). Therefore, we hypothesize that any factors mitigating stress in the introduced range may promote exotic invaders to evolve increased adaptive plasticity by reducing the costs and increasing the benefits of plasticity. Empirical evidence is largely consistent with this hypothesis. This hypothesis contributes to our understanding of why invasive species are often found to be more competitive in a subset of environments. Tests of this hypothesis may not only help us understand what caused increased plasticity in some exotic invaders, but could also tell us if costs (unless very small) are more likely to inhibit the evolution of adaptive plasticity in stressful environments in general.

  3. Stress relief may promote the evolution of greater phenotypic plasticity in exotic invasive species: a hypothesis

    PubMed Central

    Huang, Qiao Q; Pan, Xiao Y; Fan, Zhi W; Peng, Shao L

    2015-01-01

    Invasion ecologists have often found that exotic invaders evolve to be more plastic than conspecific populations from their native range. However, an open question is why some exotic invaders can even evolve to be more plastic given that there may be costs to being plastic. Investigation into the benefits and costs of plasticity suggests that stress may constrain the expression of plasticity (thereby reducing the benefits of plasticity) and exacerbate the costs of plasticity (although this possibility might not be generally applicable). Therefore, evolution of adaptive plasticity is more likely to be constrained in stressful environments. Upon introduction to a new range, exotic species may experience more favorable growth conditions (e.g., because of release from natural enemies). Therefore, we hypothesize that any factors mitigating stress in the introduced range may promote exotic invaders to evolve increased adaptive plasticity by reducing the costs and increasing the benefits of plasticity. Empirical evidence is largely consistent with this hypothesis. This hypothesis contributes to our understanding of why invasive species are often found to be more competitive in a subset of environments. Tests of this hypothesis may not only help us understand what caused increased plasticity in some exotic invaders, but could also tell us if costs (unless very small) are more likely to inhibit the evolution of adaptive plasticity in stressful environments in general. PMID:25859323

  4. The biology of developmental plasticity and the Predictive Adaptive Response hypothesis.

    PubMed

    Bateson, Patrick; Gluckman, Peter; Hanson, Mark

    2014-06-01

    Many forms of developmental plasticity have been observed and these are usually beneficial to the organism. The Predictive Adaptive Response (PAR) hypothesis refers to a form of developmental plasticity in which cues received in early life influence the development of a phenotype that is normally adapted to the environmental conditions of later life. When the predicted and actual environments differ, the mismatch between the individual's phenotype and the conditions in which it finds itself can have adverse consequences for Darwinian fitness and, later, for health. Numerous examples exist of the long-term effects of cues indicating a threatening environment affecting the subsequent phenotype of the individual organism. Other examples consist of the long-term effects of variations in environment within a normal range, particularly in the individual's nutritional environment. In mammals the cues to developing offspring are often provided by the mother's plane of nutrition, her body composition or stress levels. This hypothetical effect in humans is thought to be important by some scientists and controversial by others. In resolving the conflict, distinctions should be drawn between PARs induced by normative variations in the developmental environment and the ill effects on development of extremes in environment such as a very poor or very rich nutritional environment. Tests to distinguish between different developmental processes impacting on adult characteristics are proposed. Many of the mechanisms underlying developmental plasticity involve molecular epigenetic processes, and their elucidation in the context of PARs and more widely has implications for the revision of classical evolutionary theory.

  5. The biology of developmental plasticity and the Predictive Adaptive Response hypothesis

    PubMed Central

    Bateson, Patrick; Gluckman, Peter; Hanson, Mark

    2014-01-01

    Many forms of developmental plasticity have been observed and these are usually beneficial to the organism. The Predictive Adaptive Response (PAR) hypothesis refers to a form of developmental plasticity in which cues received in early life influence the development of a phenotype that is normally adapted to the environmental conditions of later life. When the predicted and actual environments differ, the mismatch between the individual's phenotype and the conditions in which it finds itself can have adverse consequences for Darwinian fitness and, later, for health. Numerous examples exist of the long-term effects of cues indicating a threatening environment affecting the subsequent phenotype of the individual organism. Other examples consist of the long-term effects of variations in environment within a normal range, particularly in the individual's nutritional environment. In mammals the cues to developing offspring are often provided by the mother's plane of nutrition, her body composition or stress levels. This hypothetical effect in humans is thought to be important by some scientists and controversial by others. In resolving the conflict, distinctions should be drawn between PARs induced by normative variations in the developmental environment and the ill effects on development of extremes in environment such as a very poor or very rich nutritional environment. Tests to distinguish between different developmental processes impacting on adult characteristics are proposed. Many of the mechanisms underlying developmental plasticity involve molecular epigenetic processes, and their elucidation in the context of PARs and more widely has implications for the revision of classical evolutionary theory. PMID:24882817

  6. Evidence of selection on phenotypic plasticity and cost of plasticity in response to host-feeding sources in the major Chagas disease vector Triatoma infestans.

    PubMed

    Nattero, Julieta; Leonhard, Gustavo; Gürtler, Ricardo E; Crocco, Liliana B

    2015-12-01

    Phenotypic plasticity is the ability of a genotype to display alternative phenotypes in different environments. Understanding how plasticity evolves and the factors that favor and constrain its evolution have attracted great interest. We investigated whether selection on phenotypic plasticity and costs of plasticity affect head and wing morphology in response to host-feeding sources in the major Chagas disease vector Triatoma infestans. Full-sib families were assigned to blood-feeding on either live pigeons or guinea pigs throughout their lives. We measured diet-induced phenotypic plasticity on wing and head size and shape; characterized selection on phenotypic plasticity for female and male fecundity rates, and evaluated costs of plasticity. Wing size and shape variables exhibited significant differences in phenotypic plasticity associated with host-feeding source in female and male bugs. Evidence of selection on phenotypic plasticity was detected in head size and shape for guinea pig-fed females. A lower female fecundity rate was detected in more plastic families for traits that showed selection on plasticity. These results provide insights into the morphological phenotypic plasticity of T. infestans, documenting fitness advantages of head size and shape for females fed on guinea pigs. This vector species showed measurable benefits of responding plastically to environmental variation rather than adopting a fixed development plan. The presence of cost of plasticity suggests constraints on the evolution of plasticity. Our study indicates that females fed on guinea pigs (and perhaps on other suitable mammalian hosts) have greater chances of evolving under selection on phenotypic plasticity subject to some constraints.

  7. Independent genetic control of maize (Zea mays L.) kernel weight determination and its phenotypic plasticity.

    PubMed

    Alvarez Prado, Santiago; Sadras, Víctor O; Borrás, Lucas

    2014-08-01

    Maize kernel weight (KW) is associated with the duration of the grain-filling period (GFD) and the rate of kernel biomass accumulation (KGR). It is also related to the dynamics of water and hence is physiologically linked to the maximum kernel water content (MWC), kernel desiccation rate (KDR), and moisture concentration at physiological maturity (MCPM). This work proposed that principles of phenotypic plasticity can help to consolidated the understanding of the environmental modulation and genetic control of these traits. For that purpose, a maize population of 245 recombinant inbred lines (RILs) was grown under different environmental conditions. Trait plasticity was calculated as the ratio of the variance of each RIL to the overall phenotypic variance of the population of RILs. This work found a hierarchy of plasticities: KDR ≈ GFD > MCPM > KGR > KW > MWC. There was no phenotypic and genetic correlation between traits per se and trait plasticities. MWC, the trait with the lowest plasticity, was the exception because common quantitative trait loci were found for the trait and its plasticity. Independent genetic control of a trait per se and genetic control of its plasticity is a condition for the independent evolution of traits and their plasticities. This allows breeders potentially to select for high or low plasticity in combination with high or low values of economically relevant traits.

  8. Unimpaired Neuro-Adaptive Plasticity in an Elderly Astronaut

    NASA Technical Reports Server (NTRS)

    Paloski, William H.; Black, F. Owen; Metter, E. Jeffrey; Dawson, David L. (Technical Monitor)

    1999-01-01

    Quantitative analyses of a 77 year old astronaut's balance control performances on a standardized test battery revealed few differences between his neuro-adaptive responses to space flight and those of a group of younger astronauts tested following missions of similar duration. This finding suggests that the physiological changes associated with age do not necessarily impair adaptive plasticity in the human following removal and subsequent reintroduction of gravity.

  9. Whole chromosome aneuploidy: big mutations drive adaptation by phenotypic leap

    PubMed Central

    Chen, Guangbo; Rubinstein, Boris; Li, Rong

    2012-01-01

    Despite its wide existence, the adaptive role of aneuploidy (the abnormal state of having unequal number of different chromosomes) has been a subject of debate. Cellular aneuploidy has been associated with enhanced resistance to stress, whereas on the organismal level it is detrimental to multi-cellular species. Certain aneuploid karyotypes are deleterious for specific environments, but karyotype diversity in a population potentiates adaptive evolution. To reconcile these paradoxical observations, this review distinguishes the role of aneuploidy in cellular versus organismal evolution. Further, it proposes a population genetics perspective to examine the behavior of aneuploidy on a populational versus individual level. By altering the copy number of a significant portion of the genome, aneuploidy introduces large phenotypic leap that enables small cell populations to explore a wide phenotypic landscape, from which adaptive traits can be selected. The production of chromosome number variation can be further increased by stress- or mutation-induced chromosomal instability, fueling rapid cellular adaptation. PMID:22926916

  10. Transcriptome analysis of predator- and prey-induced phenotypic plasticity in the Hokkaido salamander (Hynobius retardatus).

    PubMed

    Matsunami, Masatoshi; Kitano, Jun; Kishida, Osamu; Michimae, Hirofumi; Miura, Toru; Nishimura, Kinya

    2015-06-01

    Predator- and prey-induced phenotypic plasticity is widely observed among amphibian species. Although ecological factors inducing diverse phenotypic responses have been extensively characterized, we know little about the molecular bases of variation in phenotypic plasticity. Larvae of the Hokkaido salamander, Hynobius retardatus, exhibit two distinct morphs: the presence of their prey, Rana pirica tadpoles, induces a broad-headed attack morph, and the presence of predatory dragonfly nymphs (Aeshna nigroflava) induces a defence morph with enlarged external gills and a high tail. To compare the genes involved in predator- and prey-induced phenotypic plasticity, we carried out a de novo transcriptome analysis of Hokkaido salamander larvae exposed to either prey or predator individuals. First, we found that the number of genes involved in the expression of the defence morph was approximately five times the number involved in the expression of the attack morph. This result is consistent with the fact that the predator-induced plasticity involves more drastic morphological changes than the prey-induced plasticity. Second, we found that particular sets of genes were upregulated during the induction of both the attack and defence morphs, but others were specific to the expression of one or the other morph. Because both shared and unique molecular mechanisms were used in the expression of each morph, the evolution of a new plastic phenotype might involve both the co-option of pre-existing molecular mechanisms and the acquisition of novel regulatory mechanisms.

  11. The contribution of phenotypic plasticity to complementary light capture in plant mixtures.

    PubMed

    Zhu, Junqi; van der Werf, Wopke; Anten, Niels P R; Vos, Jan; Evers, Jochem B

    2015-09-01

    Interspecific differences in functional traits are a key factor for explaining the positive diversity-productivity relationship in plant communities. However, the role of intraspecific variation attributable to phenotypic plasticity in diversity-productivity relationships has largely been overlooked. By taking a wheat (Triticum aestivum)-maize (Zea mays) intercrop as an elementary example of mixed vegetation, we show that plasticity in plant traits is an important factor contributing to complementary light capture in species mixtures. We conceptually separated net biodiversity effect into the effect attributable to interspecific trait differences and species distribution (community structure effect), and the effect attributable to phenotypic plasticity. Using a novel plant architectural modelling approach, whole-vegetation light capture was simulated for scenarios with and without plasticity based on empirical plant trait data. Light capture was 23% higher in the intercrop with plasticity than the expected value from monocultures, of which 36% was attributable to community structure and 64% was attributable to plasticity. For wheat, plasticity in tillering was the main reason for increased light capture, whereas for intercropped maize, plasticity induced a major reduction in light capture. The results illustrate the potential of plasticity for enhancing resource acquisition in mixed stands, and indicate the importance of plasticity in the performance of species-diverse plant communities.

  12. Adaptive responses and invasion: the role of plasticity and evolution in snail shell morphology.

    PubMed

    Kistner, Erica J; Dybdahl, Mark F

    2013-02-01

    Invasive species often exhibit either evolved or plastic adaptations in response to spatially varying environmental conditions. We investigated whether evolved or plastic adaptation was driving variation in shell morphology among invasive populations of the New Zealand mud snail (Potamopyrgus antipodarum) in the western United States. We found that invasive populations exhibit considerable shell shape variation and inhabit a variety of flow velocity habitats. We investigated the importance of evolution and plasticity by examining variation in shell morphological traits 1) between the parental and F1 generations for each population and 2) among populations of the first lab generation (F1) in a common garden, full-sib design using Canonical Variate Analyses (CVA). We compared the F1 generation to the parental lineages and found significant differences in overall shell shape indicating a plastic response. However, when examining differences among the F1 populations, we found that they maintained among-population shell shape differences, indicating a genetic response. The F1 generation exhibited a smaller shell morph more suited to the low-flow common garden environment within a single generation. Our results suggest that phenotypic plasticity in conjunction with evolution may be driving variation in shell morphology of this widespread invasive snail.

  13. Adaptive responses and invasion: the role of plasticity and evolution in snail shell morphology

    PubMed Central

    Kistner, Erica J; Dybdahl, Mark F

    2013-01-01

    Invasive species often exhibit either evolved or plastic adaptations in response to spatially varying environmental conditions. We investigated whether evolved or plastic adaptation was driving variation in shell morphology among invasive populations of the New Zealand mud snail (Potamopyrgus antipodarum) in the western United States. We found that invasive populations exhibit considerable shell shape variation and inhabit a variety of flow velocity habitats. We investigated the importance of evolution and plasticity by examining variation in shell morphological traits 1) between the parental and F1 generations for each population and 2) among populations of the first lab generation (F1) in a common garden, full-sib design using Canonical Variate Analyses (CVA). We compared the F1 generation to the parental lineages and found significant differences in overall shell shape indicating a plastic response. However, when examining differences among the F1 populations, we found that they maintained among-population shell shape differences, indicating a genetic response. The F1 generation exhibited a smaller shell morph more suited to the low-flow common garden environment within a single generation. Our results suggest that phenotypic plasticity in conjunction with evolution may be driving variation in shell morphology of this widespread invasive snail. PMID:23467920

  14. What can aquatic gastropods tell us about phenotypic plasticity? A review and meta-analysis.

    PubMed

    Bourdeau, P E; Butlin, R K; Brönmark, C; Edgell, T C; Hoverman, J T; Hollander, J

    2015-10-01

    There have been few attempts to synthesise the growing body of literature on phenotypic plasticity to reveal patterns and generalities about the extent and magnitude of plastic responses. Here, we conduct a review and meta-analysis of published literature on phenotypic plasticity in aquatic (marine and freshwater) gastropods, a common system for studying plasticity. We identified 96 studies, using pre-determined search terms, published between 1985 and November 2013. The literature was dominated by studies of predator-induced shell form, snail growth rates and life history parameters of a few model taxa, accounting for 67% of all studies reviewed. Meta-analyses indicated average plastic responses in shell thickness, shell shape, and growth and fecundity of freshwater species was at least three times larger than in marine species. Within marine gastropods, species with planktonic development had similar average plastic responses to species with benthic development. We discuss these findings in the context of the role of costs and limits of phenotypic plasticity and environmental heterogeneity as important constraints on the evolution of plasticity. We also consider potential publication biases and discuss areas for future research, indicating well-studied areas and important knowledge gaps.

  15. What can aquatic gastropods tell us about phenotypic plasticity? A review and meta-analysis

    PubMed Central

    Bourdeau, P E; Butlin, R K; Brönmark, C; Edgell, T C; Hoverman, J T; Hollander, J

    2015-01-01

    There have been few attempts to synthesise the growing body of literature on phenotypic plasticity to reveal patterns and generalities about the extent and magnitude of plastic responses. Here, we conduct a review and meta-analysis of published literature on phenotypic plasticity in aquatic (marine and freshwater) gastropods, a common system for studying plasticity. We identified 96 studies, using pre-determined search terms, published between 1985 and November 2013. The literature was dominated by studies of predator-induced shell form, snail growth rates and life history parameters of a few model taxa, accounting for 67% of all studies reviewed. Meta-analyses indicated average plastic responses in shell thickness, shell shape, and growth and fecundity of freshwater species was at least three times larger than in marine species. Within marine gastropods, species with planktonic development had similar average plastic responses to species with benthic development. We discuss these findings in the context of the role of costs and limits of phenotypic plasticity and environmental heterogeneity as important constraints on the evolution of plasticity. We also consider potential publication biases and discuss areas for future research, indicating well-studied areas and important knowledge gaps. PMID:26219231

  16. Phenotypic plasticity alone cannot explain climate-induced change in avian migration timing.

    PubMed

    Buskirk, Josh; Mulvihill, Robert S; Leberman, Robert C

    2012-10-01

    Recent climate change has been linked to shifts in the timing of life-cycle events in many organisms, but there is debate over the degree to which phenological changes are caused by evolved genetic responses of populations or by phenotypic plasticity of individuals. We estimated plasticity of spring arrival date in 27 species of bird that breed in the vicinity of an observatory in eastern North America. For 2441 individuals detected in multiple years, arrival occurred earlier during warm years, especially in species that migrate short distances. Phenotypic plasticity averaged -0.93 days °C(-1) ± 0.70 (95% CI). However, plasticity accounted for only 13-25% of the climate-induced trend in phenology observed over 46 years. Although our approach probably underestimates the full scope of plasticity, the data suggest that part of the response to environmental change has been caused by microevolution. The estimated evolutionary rates are plausible (0.016 haldanes).

  17. Phenotypic plasticity or speciation? A case from a clonal marine organism

    PubMed Central

    2008-01-01

    adaptational responses of each lineage to the environmental demands of each habitat. Conclusion The extensive distribution and ample morphological variation of Eunicea flexuosa corresponds to two distinct genetic lineages with narrower distributions and more rigid phenotypic plasticity than the original description. The accepted description sensu Bayer (1961) of E. flexuosa is a complex of at least two distinct genetic lineages, adapted to different habitats and do not exchange genetic material despite living in sympatry. The present study highlights the importance of correctly defining species, because the unknowingly use of species complexes can overestimate geographical distribution, population abundance, and physiological tolerance. PMID:18271961

  18. Phenotypic plasticity and its genetic regulation for yield, nitrogen fixation and δ13C in chickpea crops under varying water regimes.

    PubMed

    Sadras, Victor O; Lake, Lachlan; Li, Yongle; Farquharson, Elizabeth A; Sutton, Tim

    2016-07-01

    We measured yield components, nitrogen fixation, soil nitrogen uptake and carbon isotope composition (δ(13)C) in a collection of chickpea genotypes grown in environments where water availability was the main source of yield variation. We aimed to quantify the phenotypic plasticity of these traits using variance ratios, and to explore their genetic basis using FST genome scan. Fifty-five genes in three genomic regions were found to be under selection for plasticity of yield; 54 genes in four genomic regions for the plasticity of seeds per m(2); 48 genes in four genomic regions for the plasticity of δ(13)C; 54 genes in two genomic regions for plasticity of flowering time; 48 genes in five genomic regions for plasticity of nitrogen fixation and 49 genes in three genomic regions for plasticity of nitrogen uptake from soil. Plasticity of yield was related to plasticity of nitrogen uptake from soil, and unrelated to plasticity of nitrogen fixation, highlighting the need for closer attention to nitrogen uptake in legumes. Whereas the theoretical link between δ(13)C and transpiration efficiency is strong, the actual link with yield is erratic due to trade-offs and scaling issues. Genes associated with plasticity of δ(13)C were identified that may help to untangle the δ(13)C-yield relationship. Combining a plasticity perspective to deal with complex G×E interactions with FST genome scan may help understand and improve both crop adaptation to stress and yield potential.

  19. Phenotypic plasticity of winter wheat heading date and grain yield across the U.S. Great Plains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phenotypic plasticity describes the range of phenotypes produced by a single genotype under varying environmental conditions. We evaluated the extent of phenotypic variation and plasticity in thermal time to heading and grain yield in 299 hard winter wheat (Triticum aestivum L.) genotypes representa...

  20. Latitudinal and longitudinal clines of phenotypic plasticity in the invasive herb Solidago canadensis in China.

    PubMed

    Li, Junmin; Du, Leshan; Guan, Wenbin; Yu, Fei-Hai; van Kleunen, Mark

    2016-11-01

    Phenotypic plasticity is thought to be important for plants in variable environments. The climatic variability hypothesis poses that populations at higher latitudes, due to the stronger variation in temperature, there should be more plastic in response to temperature than populations at lower latitudes. Similarly, populations at locations with stronger precipitation fluctuations should be more plastic in response to water availability than populations at locations with less variable precipitation. We sampled seven and nine populations of Solidago canadensis, a North American native that is invasive in China, along a latitudinal (temperature variability) and a longitudinal (precipitation variability) gradient, respectively, in China, and grew them under two temperature treatments and two water-availability treatments, respectively. Among the four traits with significant variation in plasticity among populations in response to temperature, plasticity of leaf length-to-width ratio was significantly positively correlated with latitude and temperature seasonality of the populations. In addition, root/shoot ratio and water-use efficiency showed significant variation in plasticity among populations in response to water availability, and plasticities of these two traits were significantly negatively correlated with longitude and positively correlated with precipitation seasonality. The observed geographic clines in plasticity suggest that phenotypic plasticity of S. canadensis may have evolved rapidly in regions with different climatic conditions, and this may have contributed to the spread of this invasive species.

  1. Evolution of phenotype-environment associations by genetic responses to selection and phenotypic plasticity in a temporally autocorrelated environment.

    PubMed

    Michel, Matt J; Chevin, Luis-Miguel; Knouft, Jason H

    2014-05-01

    Covariation between population-mean phenotypes and environmental variables, sometimes termed a "phenotype-environment association" (PEA), can result from phenotypic plasticity, genetic responses to natural selection, or both. PEAs can potentially provide information on the evolutionary dynamics of a particular set of populations, but this requires a full theoretical characterization of PEAs and their evolution. Here, we derive formulas for the expected PEA in a temporally fluctuating environment for a quantitative trait with a linear reaction norm. We compare several biologically relevant scenarios, including constant versus evolving plasticity, and the situation in which an environment affects both development and selection but at different time periods. We find that PEAs are determined not only by biological factors (e.g., magnitude of plasticity, genetic variation), but also environmental factors, such as the association between the environments of development and of selection, and in some cases the level of temporal autocorrelation. We also describe how a PEA can be used to estimate the relationship between an optimum phenotype and an environmental variable (i.e., the environmental sensitivity of selection), an important parameter for determining the extinction risk of populations experiencing environmental change. We illustrate this ability using published data on the predator-induced morphological responses of tadpoles to predation risk.

  2. Utilizing intraspecific variation in phenotypic plasticity to bolster agricultural and forest productivity under climate change.

    PubMed

    Aspinwall, Michael J; Loik, Michael E; Resco de Dios, Victor; Tjoelker, Mark G; Payton, Paxton R; Tissue, David T

    2015-09-01

    Climate change threatens the ability of agriculture and forestry to meet growing global demands for food, fibre and wood products. Information gathered from genotype-by-environment interactions (G × E), which demonstrate intraspecific variation in phenotypic plasticity (the ability of a genotype to alter its phenotype in response to environmental change), may prove important for bolstering agricultural and forest productivity under climate change. Nonetheless, very few studies have explicitly quantified genotype plasticity-productivity relationships in agriculture or forestry. Here, we conceptualize the importance of intraspecific variation in agricultural and forest species plasticity, and discuss the physiological and genetic factors contributing to intraspecific variation in phenotypic plasticity. Our discussion highlights the need for an integrated understanding of the mechanisms of G × E, more extensive assessments of genotypic responses to climate change under field conditions, and explicit testing of genotype plasticity-productivity relationships. Ultimately, further investigation of intraspecific variation in phenotypic plasticity in agriculture and forestry may prove important for identifying genotypes capable of increasing or sustaining productivity under more extreme climatic conditions.

  3. The ecology and evolution of animal medication: genetically fixed response versus phenotypic plasticity.

    PubMed

    Choisy, Marc; de Roode, Jacobus C

    2014-08-01

    Animal medication against parasites can occur either as a genetically fixed (constitutive) or phenotypically plastic (induced) behavior. Taking the tritrophic interaction between the monarch butterfly Danaus plexippus, its protozoan parasite Ophryocystis elektroscirrha, and its food plant Asclepias spp. as a test case, we develop a game-theory model to identify the epidemiological (parasite prevalence and virulence) and environmental (plant toxicity and abundance) conditions that predict the evolution of genetically fixed versus phenotypically plastic forms of medication. Our model shows that the relative benefits (the antiparasitic properties of medicinal food) and costs (side effects of medicine, the costs of searching for medicine, and the costs of plasticity itself) crucially determine whether medication is genetically fixed or phenotypically plastic. Our model suggests that animals evolve phenotypic plasticity when parasite risk (a combination of virulence and prevalence and thus a measure of the strength of parasite-mediated selection) is relatively low to moderately high and genetically fixed medication when parasite risk becomes very high. The latter occurs because at high parasite risk, the costs of plasticity are outweighed by the benefits of medication. Our model provides a simple and general framework to study the conditions that drive the evolution of alternative forms of animal medication.

  4. Introduction: contexts and concepts of adaptability and plasticity in 20th-century plant science.

    PubMed

    Baranski, Marci; Peirson, B R Erick

    2015-04-01

    Nowhere is the problem of understanding the complex linkages between organisms and their environments more apparent than in the science of plants. Today, efforts by scientists to predict and manage the biological consequences of shifting global and regional climates depend on understanding how organisms respond morphologically, physiologically, and behaviorally to changes in their environments. Investigating organismal "adaptability" (or "plasticity") is rarely straightforward, prompting controversy and discourse among and between ecologists and agricultural scientists. Concepts like agro-climatic adaptation, phenotypic plasticity, and genotype-environment interaction (GxE) are key to those debates, and their complex histories have imbued them with assumptions and meanings that are consequential but often opaque. This special section explores the diverse ways in which organismal adaptability has been conceptualized and investigated in the second half of the 20th century, and the multifarious political, economic, environmental, and intellectual contexts in which those conceptions have emerged and evolved. The papers in this section bring together perspectives from the histories of agriculture, population ecology, evolutionary theory, and plant physiology, cutting across Asian, North American, and British contexts. As a whole, this section highlights not only the diversity of meanings of "adaptability" and "plasticity," but also the complex linkages between those meanings, the scientific practices and technologies in which they are embedded, and the ends toward which those practices and technologies are employed.

  5. Coevolution of phenotypic plasticity in predator and prey: why are inducible offenses rarer than inducible defenses?

    PubMed

    Mougi, Akihiko; Kishida, Osamu; Iwasa, Yoh

    2011-04-01

    Inducible defenses of prey and inducible offenses of predators are drastic phenotypic changes activated by the interaction between a prey and predator. Inducible defenses occur in many taxa and occur more frequently than inducible offenses. Recent empirical studies have reported reciprocal phenotypic changes in both predator and prey. Here, we model the coevolution of inducible plasticity in both prey and predator, and examine how the evolutionary dynamics of inducible plasticity affect the population dynamics of a predator-prey system. Under a broad range of parameter values, the proportion of predators with an offensive phenotype is smaller than the proportion of prey with a defensive phenotype, and the offense level is relatively lower than the defense level at evolutionary end points. Our model also predicts that inducible plasticity evolves in both species when predation success depends sensitively on the difference in the inducible trait value between the two species. Reciprocal phenotypic plasticity may be widespread in nature but may have been overlooked by field studies because offensive phenotypes are rare and inconspicuous.

  6. Plasticity in reproduction and growth among 52 range-wide populations of a Mediterranean conifer: adaptive responses to environmental stress.

    PubMed

    Santos-Del-Blanco, L; Bonser, S P; Valladares, F; Chambel, M R; Climent, J

    2013-09-01

    A plastic response towards enhanced reproduction is expected in stressful environments, but it is assumed to trade off against vegetative growth and efficiency in the use of available resources deployed in reproduction [reproductive efficiency (RE)]. Evidence supporting this expectation is scarce for plants, particularly for long-lived species. Forest trees such as Mediterranean pines provide ideal models to study the adaptive value of allocation to reproduction vs. vegetative growth given their among-population differentiation for adaptive traits and their remarkable capacity to cope with dry and low-fertility environments. We studied 52 range-wide Pinus halepensis populations planted into two environmentally contrasting sites during their initial reproductive stage. We investigated the effect of site, population and their interaction on vegetative growth, threshold size for female reproduction, reproductive-vegetative size relationships and RE. We quantified correlations among traits and environmental variables to identify allocation trade-offs and ecotypic trends. Genetic variation for plasticity was high for vegetative growth, whereas it was nonsignificant for reproduction. Size-corrected reproduction was enhanced in the more stressful site supporting the expectation for adverse conditions to elicit plastic responses in reproductive allometry. However, RE was unrelated with early reproductive investment. Our results followed theoretical predictions and support that phenotypic plasticity for reproduction is adaptive under stressful environments. Considering expectations of increased drought in the Mediterranean, we hypothesize that phenotypic plasticity together with natural selection on reproductive traits will play a relevant role in the future adaptation of forest tree species.

  7. Testing adaptive plasticity to UV: costs and benefits of stem elongation and light-induced phenolics.

    PubMed

    Weinig, Cynthia; Gravuer, Kelly A; Kane, Nolan C; Schmitt, Johanna

    2004-12-01

    On exposure to ultraviolet radiation (UV), many plant species both reduce stem elongation and increase production of phenolic compounds that absorb in the UV region of the spectrum. To demonstrate that such developmental plasticity to UV is adaptive, it is necessary to show that the induced phenotype is both beneficial in inductive environments and maladaptive in non-inductive environments. We measured selection on stem elongation and phenolic content of seedlings of Impatiens capensis transplanted into ambient-UV and UV-removal treatments. We extended the range of phenotypes expressed, and thus the opportunity for selection in each UV treatment, by pretreating seedlings with either a low ratio of red:far-red wavelengths (R:FR), which induced stem elongation and reduced phenolic concentrations, or high R:FR, which had the opposite effect on these two phenotypic traits. Reduced stem length relative to biomass was advantageous for elongated plants under ambient UV, whereas increased elongation was favored in the UV-removal treatment. Selection favored an increase in the level of phenolics induced by UV in the ambient-UV treatment, but a decrease in phenolics in the absence of UV. These results are consistent with the hypotheses that reduced elongation and increased phenolic concentrations serve a UV-protective function and provide the first explicit demonstration in a wild species that plasticity of these traits to UV is adaptive. The observed cost to phenolics in the absence of UV may explain why many species plastically upregulate phenolic production when exposed to UV, rather than evolve constitutively high levels of these compounds. Finally, pretreatment with low R:FR simulating foliar shade did not exacerbate the fitness impact of UV exposure when plants had several weeks to acclimate to UV. This observation suggests that the evolution of adaptive shade avoidance responses to low R:FR in crowded stands will not be constrained by increased sensitivity to UV in

  8. Selection in a fluctuating environment leads to decreased genetic variation and facilitates the evolution of phenotypic plasticity.

    PubMed

    Hallsson, L R; Björklund, M

    2012-07-01

    Changes in the environment are expected to induce changes in the quantitative genetic variation, which influences the ability of a population to adapt to environmental change. Furthermore, environmental changes are not constant in time, but fluctuate. Here, we investigate the effect of rapid, continuous and/or fluctuating temperature changes in the seed beetle Callosobruchus maculatus, using an evolution experiment followed by a split-brood experiment. In line with expectations, individuals responded in a plastic way and had an overall higher potential to respond to selection after a rapid change in the environment. After selection in an environment with increasing temperature, plasticity remained unchanged (or decreased) and environmental variation decreased, especially when fluctuations were added; these results were unexpected. As expected, the genetic variation decreased after fluctuating selection. Our results suggest that fluctuations in the environment have major impact on the response of a population to environmental change; in a highly variable environment with low predictability, a plastic response might not be beneficial and the response is genetically and environmentally canalized resulting in a low potential to respond to selection and low environmental sensitivity. Interestingly, we found greater variation for phenotypic plasticity after selection, suggesting that the potential for plasticity to evolve is facilitated after exposure to environmental fluctuations. Our study highlights that environmental fluctuations should be considered when investigating the response of a population to environmental change.

  9. Phenotypic Plasticity of Southern Ocean Diatoms: Key to Success in the Sea Ice Habitat?

    PubMed Central

    Sackett, Olivia; Petrou, Katherina; Reedy, Brian; De Grazia, Adrian; Hill, Ross; Doblin, Martina; Beardall, John; Ralph, Peter; Heraud, Philip

    2013-01-01

    Diatoms are the primary source of nutrition and energy for the Southern Ocean ecosystem. Microalgae, including diatoms, synthesise biological macromolecules such as lipids, proteins and carbohydrates for growth, reproduction and acclimation to prevailing environmental conditions. Here we show that three key species of Southern Ocean diatom (Fragilariopsis cylindrus, Chaetoceros simplex and Pseudo-nitzschia subcurvata) exhibited phenotypic plasticity in response to salinity and temperature regimes experienced during the seasonal formation and decay of sea ice. The degree of phenotypic plasticity, in terms of changes in macromolecular composition, was highly species-specific and consistent with each species’ known distribution and abundance throughout sea ice, meltwater and pelagic habitats, suggesting that phenotypic plasticity may have been selected for by the extreme variability of the polar marine environment. We argue that changes in diatom macromolecular composition and shifts in species dominance in response to a changing climate have the potential to alter nutrient and energy fluxes throughout the Southern Ocean ecosystem. PMID:24363795

  10. Diet-induced phenotypic plasticity in European eel (Anguilla anguilla).

    PubMed

    De Meyer, Jens; Christiaens, Joachim; Adriaens, Dominique

    2016-02-01

    Two phenotypes are present within the European eel population: broad-heads and narrow-heads. The expression of these phenotypes has been linked to several factors, such as diet and differential growth. The exact factors causing this dimorphism, however, are still unknown. In this study, we performed a feeding experiment on glass eels from the moment they start to feed. Eels were either fed a hard diet, which required biting and spinning behavior, or a soft diet, which required suction feeding. We found that the hard feeders develop a broader head and a larger adductor mandibulae region than eels that were fed a soft diet, implying that the hard feeders are capable of larger bite forces. Next to this, soft feeders develop a sharper and narrower head, which could reduce hydrodynamic drag, allowing more rapid strikes towards their prey. Both phenotypes were found in a control group, which were given a combination of both diets. These phenotypes were, however, not as extreme as the hard or the soft feeding group, indicating that some specimens are more likely to consume hard prey and others soft prey, but that they do not selectively eat one of both diets. In conclusion, we found that diet is a major factor influencing head shape in European eel and this ability to specialize in feeding on hard or soft prey could decrease intra-specific competition in European eel populations.

  11. Cooperation between phenotypic plasticity and genetic mutations can account for the cumulative selection in evolution

    PubMed Central

    Nishikawa, Ken; Kinjo, Akira R.

    2014-01-01

    We propose the cooperative model of phenotype-driven evolution, in which natural selection operates on a phenotype caused by both genetic and epigenetic factors. The conventional theory of evolutionary synthesis assumes that a phenotypic value (P) is the sum of genotypic value (G) and environmental deviation (E), P=G+E, where E is the fluctuations of the phenotype among individuals in the absence of environmental changes. In contrast, the cooperative model assumes that an evolution is triggered by an environmental change and individuals respond to the change by phenotypic plasticity (epigenetic changes). The phenotypic plasticity, while essentially qualitative, is denoted by a quantitative value F which is modeled as a normal random variable like E, but with a much larger variance. Thus, the fundamental equation of the cooperative model is given as P=G+F where F includes the effect of E. Computer simulations using a genetic algorithm demonstrated that the cooperative model realized much faster evolution than the evolutionary synthesis. This accelerated evolution was found to be due to the cumulative evolution made possible by a ratchet mechanism due to the epigenetic contribution to the phenotypic value. The cooperative model can well account for the phenomenon of genetic assimilation, which, in turn, suggests the mechanism of cumulative selection. The cooperative model may also serve as a theoretical basis to understand various ideas and phenomena of the phenotype-driven evolution such as genetic assimilation, the theory of facilitated phenotypic variation, and epigenetic inheritance over generations. PMID:27493504

  12. Adaptive divergence in plasticity in natural populations of Impatiens capensis and its consequences for performance in novel habitats.

    PubMed

    Donohue, K; Pyle, E H; Messiqua, D; Heschel, M S; Schmitt, J

    2001-04-01

    We tested for adaptive differentiation between two natural populations of Impatiens capensis from sites known to differ in selection on plasticity to density. We also determined the degree to which plasticity to density within a site was correlated with plastic responses of experimental immigrants to foreign sites. Inbred lines, derived from natural populations in an open-canopy site and a woodland site, were planted reciprocally in both original sites at naturally occurring high densities and at low density. The density manipulation represents environmental variation typically experienced within the site of a given population, and the transplant manipulation represents environmental differences between sites of different populations. Internode elongation, meristem allocation, leaf length, flowering date, and total lifetime fitness were measured. Genotypes originating in the open site, where selection favored plasticity of first internode length and flowering time (Donohue et al. 2000a), were more plastic in those characters than genotypes originating from the woodland site, where plasticity was maladaptive. Therefore, these two populations appear to have responded to divergent selection on plasticity. Plasticity to density strongly resembled plasticity to site differences for many characters, suggesting that similar environmental factors elicit plasticity both to density and to overhead canopy. Thus, plasticity that evolved in response to density variation within a site influenced phenotypic expression in the foreign site. Plastic responses to site caused immigrants from foreign populations to resemble native genotypes more closely. In particular, immigrants from the open site converged toward the selectively favored early-flowering phenotype of native genotypes in the woodland site, thereby reducing potential fitness differences between foreign and native genotypes. However, because genotypes from the woods population were less plastic than genotypes from the sun

  13. Differential Expression of Ecdysone Receptor Leads to Variation in Phenotypic Plasticity across Serial Homologs

    PubMed Central

    Tong, Xiaoling; Bear, Ashley; Liew, Seng Fatt; Bhardwaj, Shivam; Wasik, Bethany R.; Dinwiddie, April; Bastianelli, Carole; Cheong, Wei Fun; Wenk, Markus R.; Cao, Hui

    2015-01-01

    Bodies are often made of repeated units, or serial homologs, that develop using the same core gene regulatory network. Local inputs and modifications to this network allow serial homologs to evolve different morphologies, but currently we do not understand which modifications allow these repeated traits to evolve different levels of phenotypic plasticity. Here we describe variation in phenotypic plasticity across serial homologous eyespots of the butterfly Bicyclus anynana, hypothesized to be under selection for similar or different functions in the wet and dry seasonal forms. Specifically, we document the presence of eyespot size and scale brightness plasticity in hindwing eyespots hypothesized to vary in function across seasons, and reduced size plasticity and absence of brightness plasticity in forewing eyespots hypothesized to have the same function across seasons. By exploring the molecular and physiological causes of this variation in plasticity across fore and hindwing serial homologs we discover that: 1) temperature experienced during the wandering stages of larval development alters titers of an ecdysteroid hormone, 20-hydroxyecdysone (20E), in the hemolymph of wet and dry seasonal forms at that stage; 2) the 20E receptor (EcR) is differentially expressed in the forewing and hindwing eyespot centers of both seasonal forms during this critical developmental stage; and 3) manipulations of EcR signaling disproportionately affected hindwing eyespots relative to forewing eyespots. We propose that differential EcR expression across forewing and hindwing eyespots at a critical stage of development explains the variation in levels of phenotypic plasticity across these serial homologues. This finding provides a novel signaling pathway, 20E, and a novel molecular candidate, EcR, for the regulation of levels of phenotypic plasticity across body parts or serial homologs. PMID:26405828

  14. Differential Expression of Ecdysone Receptor Leads to Variation in Phenotypic Plasticity across Serial Homologs.

    PubMed

    Monteiro, Antónia; Tong, Xiaoling; Bear, Ashley; Liew, Seng Fatt; Bhardwaj, Shivam; Wasik, Bethany R; Dinwiddie, April; Bastianelli, Carole; Cheong, Wei Fun; Wenk, Markus R; Cao, Hui; Prudic, Kathleen L

    2015-01-01

    Bodies are often made of repeated units, or serial homologs, that develop using the same core gene regulatory network. Local inputs and modifications to this network allow serial homologs to evolve different morphologies, but currently we do not understand which modifications allow these repeated traits to evolve different levels of phenotypic plasticity. Here we describe variation in phenotypic plasticity across serial homologous eyespots of the butterfly Bicyclus anynana, hypothesized to be under selection for similar or different functions in the wet and dry seasonal forms. Specifically, we document the presence of eyespot size and scale brightness plasticity in hindwing eyespots hypothesized to vary in function across seasons, and reduced size plasticity and absence of brightness plasticity in forewing eyespots hypothesized to have the same function across seasons. By exploring the molecular and physiological causes of this variation in plasticity across fore and hindwing serial homologs we discover that: 1) temperature experienced during the wandering stages of larval development alters titers of an ecdysteroid hormone, 20-hydroxyecdysone (20E), in the hemolymph of wet and dry seasonal forms at that stage; 2) the 20E receptor (EcR) is differentially expressed in the forewing and hindwing eyespot centers of both seasonal forms during this critical developmental stage; and 3) manipulations of EcR signaling disproportionately affected hindwing eyespots relative to forewing eyespots. We propose that differential EcR expression across forewing and hindwing eyespots at a critical stage of development explains the variation in levels of phenotypic plasticity across these serial homologues. This finding provides a novel signaling pathway, 20E, and a novel molecular candidate, EcR, for the regulation of levels of phenotypic plasticity across body parts or serial homologs.

  15. Ecological insights from assessments of phenotypic plasticity in a Neotropical species of Drosophila.

    PubMed

    Przybylska, Maria Stefania; Brito, Felipe Alves de; Tidon, Rosana

    2016-12-01

    Several authors have called attention to the evolutionary importance of phenotypic plasticity and niche construction, because such phenomena require a new status and a new perspective. Drosophila species are traditionally used as models in investigations of phenotypic plasticity, although the majority of such research has been conducted with species of the subgenus Sophophora, primarily Drosophila melanogaster. In this study, we investigated the phenotypic plasticity of Drosophila cardini, a Neotropical species of the subgenus Drosophila, and focused on the wing size, wing shape, thorax length and wing: thorax ratio of lines that were collected in the Brazilian savanna and exposed to different temperatures during growth. All of the analyzed traits presented plasticity to temperature, and the reaction norms were similar to those previously found in other drosophilid species; in addition, the maximum values were consistent with the temperature variations at the collection sites. The specimens that emerged at low temperatures were larger and had more rounded wings compared with those that emerged at high temperatures, which were smaller and had narrower wings. We hypothesized that the differences observed in the shape of the wings might be associated with flight performance. Nevertheless, further investigation of the relationships among wing shape, wing loading and flight performance is required. Investigations on phenotypic plasticity using species with diverse ecologies should help us to better understand how this phenomenon operates in nature, and studies of this type must be encouraged.

  16. Adaptive variability in the duration of critical windows of plasticity

    PubMed Central

    Wells, Jonathan C. K.

    2014-01-01

    Developmental plasticity underlies widespread associations between early-life exposures and many components of adult phenotype, including the risk of chronic diseases. Humans take almost two decades to reach reproductive maturity, and yet the ‘critical windows’ of physiological sensitivity that confer developmental plasticity tend to close during fetal life or infancy. While several explanations for lengthy human maturation have been offered, the brevity of physiological plasticity has received less attention. I argue that offspring plasticity is only viable within the niche of maternal care, and that as this protection is withdrawn, the offspring is obliged to canalize many developmental traits in order to minimize environmental disruptions. The schedule of maternal care may therefore shape the duration of critical windows, and since the duration of this care is subject to parent–offspring conflict, the resolution of this conflict may shape the duration of critical windows. This perspective may help understand (i) why windows close at different times for different traits, and (ii) why the duration of critical windows may vary across human populations. The issue is explored in relation to population differences in the association between infant weight gain and later body composition. The occupation of more stable environments by western populations may have favoured earlier closure of the critical window during which growth in lean mass is sensitive to nutritional intake. This may paradoxically have elevated the risk of obesity following rapid infant weight gain in such populations. PMID:25095791

  17. Phenotype-environment correlations in a putative whitefish adaptive radiation.

    PubMed

    Harrod, Chris; Mallela, Jennie; Kahilainen, Kimmo K

    2010-09-01

    1. The adaptive radiation of fishes into benthic (littoral) and pelagic (lentic) morphs in post-glacial lakes has become an important model system for speciation. Although these systems are well studied, there is little evidence of the existence of morphs that have diverged to utilize resources in the remaining principal lake habitat, the profundal zone. 2. Here, we tested phenotype-environment correlations of three whitefish (Coregonus lavaretus) morphs that have radiated into littoral, pelagic and profundal niches in northern Scandinavian lakes. We hypothesized that morphs in such trimorphic systems would have a morphology adapted to one of the principal lake habitats (littoral, pelagic or profundal niches). Most whitefish populations in the study area are formed by a single (monomorphic) whitefish morph, and we further hypothesized that these populations should display intermediate morphotypes and niche utilization. We used a combination of traditional (stomach content, habitat use, gill raker counts) and more recently developed (stable isotopes, geometric morphometrics) techniques to evaluate phenotype-environment correlations in two lakes with trimorphic and two lakes with monomorphic whitefish. 3. Distinct phenotype-environment correlations were evident for each principal niche in whitefish morphs inhabiting trimorphic lakes. Monomorphic whitefish exploited multiple habitats, had intermediate morphology, displayed increased variance in gillraker-counts, and relied significantly on zooplankton, most likely due to relaxed resource competition. 4. We suggest that the ecological processes acting in the trimorphic lakes are similar to each other, and are driving the adaptive evolution of whitefish morphs, possibly leading to the formation of new species.

  18. Will phenotypic plasticity affecting flowering phenology keep pace with climate change?

    PubMed

    Richardson, Bryce A; Chaney, Lindsay; Shaw, Nancy L; Still, Shannon M

    2016-10-14

    Rising temperatures have begun to shift flowering time, but it is unclear whether phenotypic plasticity can accommodate projected temperature change for this century. Evaluating clines in phenological traits and the extent and variation in plasticity can provide key information on assessing risk of maladaptation and developing strategies to mitigate climate change. In this study, flower phenology was examined in 52 populations of big sagebrush (Artemisia tridentata) growing in three common gardens. Flowering date (anthesis) varied 91 days from late July to late November among gardens. Mixed-effects modeling explained 79% of variation in flowering date, of which 46% could be assigned to plasticity and genetic variation in plasticity and 33% to genetics (conditional R(2) = 0.79, marginal R(2) = 0.33). Two environmental variables that explained the genetic variation were photoperiod and the onset of spring, the Julian date of accumulating degree days > 5°C reaching 100. The genetic variation was mapped for contemporary and future climates (decades 2060 and 2090), showing flower date change varies considerably across the landscape. Plasticity was estimated to accommodate, on average, a +/- 13-day change in flowering date. However, the examination of genetic variation in plasticity suggests that the magnitude of plasticity could be affected by variation in the sensitivity to photoperiod and temperature. In a warmer common garden, lower latitude populations have greater plasticity (+16 days) compared to higher latitude populations (+10 days). Mapped climatypes of flowering date for contemporary and future climates illustrate the wide breadth of plasticity and large geographic overlap. Our research highlights the importance of integrating information on genetic variation, phenotypic plasticity and climatic niche modeling to evaluate plant responses and elucidate vulnerabilities to climate change. This article is protected by copyright. All rights reserved.

  19. Phenotypic plasticity of sun and shade ecotypes of Stellaria longipes in response to light quality signaling, gibberellins and auxin.

    PubMed

    Kurepin, Leonid V; Pharis, Richard P; Neil Emery, R J; Reid, David M; Chinnappa, C C

    2015-09-01

    Stellaria longipes plant communities (ecotypes) occur in several environmentally distinct habitats along the eastern slopes of southern Alberta's Rocky Mountains. One ecotype occurs in a prairie habitat at ∼1000 m elevation where Stellaria plants grow in an environment in which the light is filtered by taller neighbouring vegetation, i.e. sunlight with a low red to far-red (R/FR) ratio. This ecotype exhibits a high degree of phenotypic plasticity by increasing stem elongation in response to the low R/FR ratio light signal. Another Stellaria ecotype occurs nearby at ∼2400 m elevation in a much cooler alpine habitat, one where plants rarely experience low R/FR ratio shade light. Stem elongation of plants is largely regulated by gibberellins (GAs) and auxin, indole-3-acetic acid (IAA). Shoots of the prairie ecotype plants show increased IAA levels under low R/FR ratio light and they also increase their stem growth in response to applied IAA. The alpine ecotype plants show neither response. Plants from both ecotypes produce high levels of growth-active GA1 under low R/FR ratio light, though they differ appreciably in their catabolism of GA1. The alpine ecotype plants exhibit very high levels of GA8, the inactive product of GA1 metabolism, under both normal and low R/FR ratio light. Alpine origin plants may de-activate GA1 by conversion to GA8 via a constitutively high level of expression of the GA2ox gene, thereby maintaining their dwarf phenotype and exhibiting a reduced phenotypic plasticity in terms of shoot elongation. In contrast, prairie plants exhibit a high degree of phenotypic plasticity, using low R/FR ratio light-mediated changes in GA and IAA concentrations to increase shoot elongation, thereby accessing direct sunlight to optimize photosynthesis. There thus appear to be complex adaptation strategies for the two ecotypes, ones which involve modifications in the homeostasis of endogenous hormones.

  20. Phenotypically plastic traits regulate caste formation and soldier function in polyembryonic wasps

    PubMed Central

    Smith, Margaret S.; Milton, Ian; Strand, Michael R.

    2011-01-01

    Polyembryonic encyrtid wasps are parasitoids that have evolved a clonal form of embryogenesis and a caste system where some progeny become reproducing wasps while others develop into a sterile soldier caste. Theory based on the biology of Copidosoma floridanum predicts the primary role of soldier larvae is to mediate conflict over sex ratio, which also favours female-biased soldier production. Other data, however, suggest female-biased soldier production reflects a developmental constraint. Here we assessed whether female-biased soldier function by polyembryonic wasps reflects sex specific adaptation or constraint by conducting comparative studies with Copidosma bakeri; a species that produces clutch sizes similar to C. floridanum yet rarely produces broods associated with sex ratio conflict. Our results indicate the oviposition behaviour of adults, development of progeny, and function of soldier larvae differs greatly between C. bakeri and C. floridanum. These findings indicate that caste formation and soldier function in polyembryonic encyrtid wasps are regulated by phenotypically plastic traits. Our results further suggest the primary function of the soldier caste in some species is defence of host resources from competitors while in others it is resolution of sex ratio conflict. PMID:21040070

  1. Phenotypically plastic traits regulate caste formation and soldier function in polyembryonic wasps.

    PubMed

    Smith, M S; Milton, I; Strand, M R

    2010-12-01

    Polyembryonic encyrtid wasps are parasitoids that have evolved a clonal form of embryogenesis and a caste system where some progeny become reproducing wasps whereas others develop into a sterile soldier caste. Theory based on the biology of Copidosoma floridanum predicts that the primary role of soldier larvae is to mediate conflict over sex ratio, which also favours female-biased soldier production. Other data, however, suggest that female-biased soldier production reflects a developmental constraint. Here, we assessed whether female-biased soldier function by polyembryonic wasps reflects sex-specific adaptation or constraint by conducting comparative studies with Copidosoma bakeri, a species that produces clutch sizes similar to C. floridanum yet rarely produces broods associated with sex ratio conflict. Our results indicate that the oviposition behaviour of adults, development of progeny and function of soldier larvae differ greatly between C. bakeri and C. floridanum. These findings indicate that caste formation and soldier function in polyembryonic encyrtid wasps are regulated by phenotypically plastic traits. Our results further suggest that the primary function of the soldier caste in some species is defence of host resources from competitors whereas in others it is the resolution of sex ratio conflict.

  2. Parallel ionoregulatory adjustments underlie phenotypic plasticity and evolution of Drosophila cold tolerance.

    PubMed

    MacMillan, Heath A; Ferguson, Laura V; Nicolai, Annegret; Donini, Andrew; Staples, James F; Sinclair, Brent J

    2015-02-01

    Low temperature tolerance is the main predictor of variation in the global distribution and performance of insects, yet the molecular mechanisms underlying cold tolerance variation are poorly known, and it is unclear whether the mechanisms that improve cold tolerance within the lifetime of an individual insect are similar to those that underlie evolved differences among species. The accumulation of cold-induced injuries by hemimetabolous insects is associated with loss of Na(+) and K(+) homeostasis. Here we show that this model holds true for Drosophila; cold exposure increases haemolymph [K(+)] in D. melanogaster, and cold-acclimated flies maintain low haemolymph [Na(+)] and [K(+)], both at rest and during a cold exposure. This pattern holds across 24 species of the Drosophila phylogeny, where improvements in cold tolerance have been consistently paired with reductions in haemolymph [Na(+)] and [K(+)]. Cold-acclimated D. melanogaster have low activity of Na(+)/K(+)-ATPase, which may contribute to the maintenance of low haemolymph [Na(+)] and underlie improvements in cold tolerance. Modifications to ion balance are associated with both phenotypic plasticity within D. melanogaster and evolutionary differences in cold tolerance across the Drosophila phylogeny, which suggests that adaptation and acclimation of cold tolerance in insects may occur through similar mechanisms. Cold-tolerant flies maintain haemolymph osmolality despite low haemolymph [Na(+)] and [K(+)], possibly through modest accumulations of organic osmolytes. We propose that this could have served as an evolutionary route by which chill-susceptible insects developed more extreme cold tolerance strategies.

  3. Life-history trait plasticity and its relationships with plant adaptation and insect fitness: a case study on the aphid Sitobion avenae

    PubMed Central

    Dai, Peng; Shi, Xiaoqin; Liu, Deguang; Ge, Zhaohong; Wang, Da; Dai, Xinjia; Yi, Zhihao; Meng, Xiuxiang

    2016-01-01

    Phenotypic plasticity has recently been considered a powerful means of adaptation, but its relationships with corresponding life-history characters and plant specialization levels of insects have been controversial. To address the issues, Sitobion avenae clones from three plants in two areas were compared. Varying amounts of life-history trait plasticity were found among S. avenae clones on barley, oat and wheat. In most cases, developmental durations and their corresponding plasticities were found to be independent, and fecundities and their plasticities were correlated characters instead. The developmental time of first instar nymphs for oat and wheat clones, but not for barley clones, was found to be independent from its plasticity, showing environment-specific effects. All correlations between environments were found to be positive, which could contribute to low plasticity in S. avenae. Negative correlations between trait plasticities and fitness of test clones suggest that lower plasticity could have higher adaptive value. Correlations between plasticity and specialization indices were identified for all clones, suggesting that plasticity might evolve as a by-product of adaptation to certain environments. The divergence patterns of life-history plasticities in S. avenae, as well as the relationships among plasticity, specialization and fitness, could have significant implications for evolutionary ecology of this aphid. PMID:27426961

  4. Phenotypic plasticity stimulated by cooperation fosters pattern diversity of bacterial colonies

    NASA Astrophysics Data System (ADS)

    Juanico, Dranreb Earl

    2012-07-01

    Colonies of flagellated bacteria on agar plates are known to take on diverse morphologies. A diffusion-reaction model is proposed for bacterial-colony pattern formation on a surface due to time scale separation between the slow mass migration of bacteria from the point of inoculation, and the fast, but localized, dynamics of bacterial phenotypic plasticity stimulated by public-goods cooperation and phenotypic switching. By considering two switchable phenotypes in the population, the model generates pattern diversity typifying those reported by experimental studies.

  5. Heritability, evolvability, phenotypic plasticity and temporal variation in sperm-competition success of Drosophila melanogaster.

    PubMed

    Dobler, R; Reinhardt, K

    2016-05-01

    Sperm-competition success (SCS) is seen as centrally important for evolutionary change: superior fathers sire superior sons and thereby inherit the traits that make them superior. Additional hypotheses, that phenotypic plasticity in SCS and sperm ageing explain variation in paternity, are less considered. Even though various alleles have individually been shown to be correlated with variation in SCS, few studies have addressed the heritability, or evolvability, of overall SCS. Those studies that have addressed found low or no heritability and have not examined evolvability. They have further not excluded phenotypic plasticity, and temporal effects on SCS, despite their known dramatic effects on sperm function. In Drosophila melanogaster, we found that both standard components of sperm competition, sperm defence and sperm offence, showed nonsignificant heritability across several offspring cohorts. Instead, our analysis revealed, for the first time, the existence of phenotypic plasticity in SCS across an extreme environment (5% CO2 ), and an influence of sperm ageing. Evolvability of SCS was substantial for sperm defence but weak for sperm offence. Our results suggest that the paradigm of explaining evolution by sperm competition is more complex and will benefit from further experimental work on the heritability or evolvability of SCS, measuring phenotypic plasticity, and separating the effects of sperm competition and sperm ageing.

  6. Hunting increases adaptive auditory map plasticity in adult barn owls.

    PubMed

    Bergan, Joseph F; Ro, Peter; Ro, Daniel; Knudsen, Eric I

    2005-10-19

    The optic tectum (OT) of barn owls contains topographic maps of auditory and visual space. Barn owls reared with horizontally displacing prismatic spectacles (prisms) acquire a novel auditory space map in the OT that restores alignment with the prismatically displaced visual map. Although juvenile owls readily acquire alternative maps of auditory space as a result of experience, this plasticity is reduced greatly in adults. We tested whether hunting live prey, a natural and critically important behavior for barn owls, increases auditory map plasticity in adult owls. Two groups of naive adult owls were fit with prisms. The first group was fed dead mice during 10 weeks of prism experience, while the second group was required to hunt live prey for an identical period of time. When the owls hunted live prey, auditory maps shifted substantially farther (five times farther, on average) and the consistency of tuning curve shifts within each map increased. Only a short period of time in each day, during which the two groups experienced different conditions, accounts for this effect. In addition, increased map plasticity correlated with behavioral improvements in the owls' ability to strike and capture prey. These results indicate that the experience of hunting dramatically increases adult adaptive plasticity in this pathway.

  7. Synaptic Plasticity Enables Adaptive Self-Tuning Critical Networks

    PubMed Central

    Stepp, Nigel; Plenz, Dietmar; Srinivasa, Narayan

    2015-01-01

    During rest, the mammalian cortex displays spontaneous neural activity. Spiking of single neurons during rest has been described as irregular and asynchronous. In contrast, recent in vivo and in vitro population measures of spontaneous activity, using the LFP, EEG, MEG or fMRI suggest that the default state of the cortex is critical, manifested by spontaneous, scale-invariant, cascades of activity known as neuronal avalanches. Criticality keeps a network poised for optimal information processing, but this view seems to be difficult to reconcile with apparently irregular single neuron spiking. Here, we simulate a 10,000 neuron, deterministic, plastic network of spiking neurons. We show that a combination of short- and long-term synaptic plasticity enables these networks to exhibit criticality in the face of intrinsic, i.e. self-sustained, asynchronous spiking. Brief external perturbations lead to adaptive, long-term modification of intrinsic network connectivity through long-term excitatory plasticity, whereas long-term inhibitory plasticity enables rapid self-tuning of the network back to a critical state. The critical state is characterized by a branching parameter oscillating around unity, a critical exponent close to -3/2 and a long tail distribution of a self-similarity parameter between 0.5 and 1. PMID:25590427

  8. Plastic and Heritable Components of Phenotypic Variation in Nucella lapillus: An Assessment Using Reciprocal Transplant and Common Garden Experiments

    PubMed Central

    Pascoal, Sonia; Carvalho, Gary; Creer, Simon; Rock, Jenny; Kawaii, Kei; Mendo, Sonia; Hughes, Roger

    2012-01-01

    Assessment of plastic and heritable components of phenotypic variation is crucial for understanding the evolution of adaptive character traits in heterogeneous environments. We assessed the above in relation to adaptive shell morphology of the rocky intertidal snail Nucella lapillus by reciprocal transplantation of snails between two shores differing in wave action and rearing snails of the same provenance in a common garden. Results were compared with those reported for similar experiments conducted elsewhere. Microsatellite variation indicated limited gene flow between the populations. Intrinsic growth rate was greater in exposed-site than sheltered-site snails, but the reverse was true of absolute growth rate, suggesting heritable compensation for reduced foraging opportunity at the exposed site. Shell morphology of reciprocal transplants partially converged through plasticity toward that of native snails. Shell morphology of F2s in the common garden partially retained characteristics of the P-generation, suggesting genetic control. A maternal effect was revealed by greater resemblance of F1s than F2s to the P-generation. The observed synergistic effects of plastic, maternal and genetic control of shell-shape may be expected to maximise fitness when environmental characteristics become unpredictable through dispersal. PMID:22299035

  9. Phenotypic plasticity and longevity in plants and animals: cause and effect?

    PubMed

    Borges, Renee M

    2009-10-01

    Immobile plants and immobile modular animals outlive unitary animals. This paper discusses competing but not necessarily mutually exclusive theories to explain this extreme longevity, especially from the perspective of phenotypic plasticity. Stem cell immortality, vascular autonomy, and epicormic branching are some important features of the phenotypic plasticity of plants that contribute to their longevity. Monocarpy versus polycarpy can also influence the kind of senescent processes experienced by plants. How density-dependent phenomena affecting the establishment of juveniles in these immobile organisms can influence the evolution of senescence, and consequently longevity, is reviewed and discussed. Whether climate change scenarios will favour long-lived or short-lived organisms, with their attendant levels of plasticity, is also presented.

  10. Phenotypic plasticity and epigenetic marking: an assessment of evidence for genetic accommodation.

    PubMed

    Schlichting, Carl D; Wund, Matthew A

    2014-03-01

    The relationship between genotype (which is inherited) and phenotype (the target of selection) is mediated by environmental inputs on gene expression, trait development, and phenotypic integration. Phenotypic plasticity or epigenetic modification might influence evolution in two general ways: (1) by stimulating evolutionary responses to environmental change via population persistence or by revealing cryptic genetic variation to selection, and (2) through the process of genetic accommodation, whereby natural selection acts to improve the form, regulation, and phenotypic integration of novel phenotypic variants. We provide an overview of models and mechanisms for how such evolutionary influences may be manifested both for plasticity and epigenetic marking. We point to promising avenues of research, identifying systems that can best be used to address the role of plasticity in evolution, as well as the need to apply our expanding knowledge of genetic and epigenetic mechanisms to our understanding of how genetic accommodation occurs in nature. Our review of a wide variety of studies finds widespread evidence for evolution by genetic accommodation.

  11. Phenotypic plasticity in normal breast derived epithelial cells

    PubMed Central

    2014-01-01

    Background Normal, healthy human breast tissue from a variety of volunteer donors has become available for research thanks to the establishment of the Susan G. Komen for the Cure® Tissue Bank at the IU Simon Cancer Center (KTB). Multiple epithelial (K-HME) and stromal cells (K-HMS) were established from the donated tissue. Explant culture was utilized to isolate the cells from pieces of breast tissue. Selective media and trypsinization were employed to select either epithelial cells or stromal cells. The primary, non-transformed epithelial cells, the focus of this study, were characterized by immunohistochemistry, flow cytometry, and in vitro cell culture. Results All of the primary, non-transformed epithelial cells tested have the ability to differentiate in vitro into a variety of cell types when plated in or on biologic matrices. Cells identified include stratified squamous epithelial, osteoclasts, chondrocytes, adipocytes, neural progenitors/neurons, immature muscle and melanocytes. The cells also express markers of embryonic stem cells. Conclusions The cell culture conditions employed select an epithelial cell that is pluri/multipotent. The plasticity of the epithelial cells developed mimics that seen in metaplastic carcinoma of the breast (MCB), a subtype of triple negative breast cancer; and may provide clues to the origin of this particularly aggressive type of breast cancer. The KTB is a unique biorepository, and the normal breast epithelial cells isolated from donated tissue have significant potential as new research tools. PMID:24915897

  12. Flood induced phenotypic plasticity in amphibious genus Elatine (Elatinaceae)

    PubMed Central

    Sramkó, Gábor; Horváth, Orsolya; Popiela, Agnieszka; Mesterházy, Attila; Lukács, Balázs András

    2015-01-01

    Vegetative characters are widely used in the taxonomy of the amphibious genus Elatine L. However, these usually show great variation not just between species but between their aquatic and terrestrial forms. In the present study we examine the variation of seed and vegetative characters in nine Elatine species (E. brachysperma, E. californica, E. gussonei, E. hexandra, E. hungarica, E. hydropiper, E. macropoda, E. orthosperma and E. triandra) to reveal the extension of plasticity induced by the amphibious environment, and to test character reliability for species identification. Cultivated plant clones were kept under controlled conditions exposed to either aquatic or terrestrial environmental conditions. Six vegetative characters (length of stem, length of internodium, length of lamina, width of lamina, length of petioles, length of pedicel) and four seed characters (curvature, number of pits / lateral row, 1st and 2nd dimension) were measured on 50 fruiting stems of the aquatic and on 50 stems of the terrestrial form of the same clone. MDA, NPMANOVA Random Forest classification and cluster analysis were used to unravel the morphological differences between aquatic and terrestrial forms. The results of MDA cross-validated and Random Forest classification clearly indicated that only seed traits are stable within species (i.e., different forms of the same species keep similar morphology). Consequently, only seed morphology is valuable for taxonomic purposes since vegetative traits are highly influenced by environmental factors. PMID:26713235

  13. Genotypic and phenotypic diversity of the noncapsulated Haemophilus influenzae: adaptation and pathogenesis in the human airways.

    PubMed

    Garmendia, Junkal; Martí-Lliteras, Pau; Moleres, Javier; Puig, Carmen; Bengoechea, José A

    2012-12-01

    The human respiratory tract contains a highly adapted microbiota including commensal and opportunistic pathogens. Noncapsulated or nontypable Haemophilus influenzae (NTHi) is a human-restricted member of the normal airway microbiota in healthy carriers and an opportunistic pathogen in immunocompromised individuals. The duality of NTHi as a colonizer and as a symptomatic infectious agent is closely related to its adaptation to the host, which in turn greatly relies on the genetic plasticity of the bacterium and is facilitated by its condition as a natural competent. The variable genotype of NTHi accounts for its heterogeneous gene expression and variable phenotype, leading to differential host-pathogen interplay among isolates. Here we review our current knowledge of NTHi diversity in terms of genotype, gene expression, antigenic variation, and the phenotypes associated with colonization and pathogenesis. The potential benefits of NTHi diversity studies discussed herein include the unraveling of pathogenicity clues, the generation of tools to predict virulence from genomic data, and the exploitation of a unique natural system for the continuous monitoring of long-term bacterial evolution in human airways exposed to noxious agents. Finally, we highlight the challenge of monitoring both the pathogen and the host in longitudinal studies, and of applying comparative genomics to clarify the meaning of the vast NTHi genetic diversity and its translation to virulence phenotypes.

  14. Life history as a constraint on plasticity: developmental timing is correlated with phenotypic variation in birds

    PubMed Central

    Snell-Rood, E C; Swanson, E M; Young, R L

    2015-01-01

    Understanding why organisms vary in developmental plasticity has implications for predicting population responses to changing environments and the maintenance of intraspecific variation. The epiphenotype hypothesis posits that the timing of development can constrain plasticity—the earlier alternate phenotypes begin to develop, the greater the difference that can result amongst the final traits. This research extends this idea by considering how life history timing shapes the opportunity for the environment to influence trait development. We test the prediction that the earlier an individual begins to actively interact with and explore their environment, the greater the opportunity for plasticity and thus variation in foraging traits. This research focuses on life history variation across four groups of birds using museum specimens and measurements from the literature. We reasoned that greater phenotypic plasticity, through either environmental effects or genotype-by-environment interactions in development, would be manifest in larger trait ranges (bills and tarsi) within species. Among shorebirds and ducks, we found that species with relatively shorter incubation times tended to show greater phenotypic variation. Across warblers and sparrows, we found little support linking timing of flight and trait variation. Overall, our results also suggest a pattern between body size and trait variation, consistent with constraints on egg size that might result in larger species having more environmental influences on development. Taken together, our results provide some support for the hypothesis that variation in life histories affects how the environment shapes development, through either the expression of plasticity or the release of cryptic genetic variation. PMID:26039409

  15. Exploring phenotypic plasticity and biogeography in emerald moths: A phylogeny of the genus Nemoria (Lepidoptera: Geometridae).

    PubMed

    Canfield, Michael R; Greene, Erick; Moreau, Corrie S; Chen, Nancy; Pierce, Naomi E

    2008-11-01

    The moth genus Nemoria (Lepidoptera: Geometridae) includes 134 described species whose larvae and adults display a considerable range of phenotypic plasticity in coloration and morphology. We reconstructed the phylogeny of 54 species of Nemoria and seven outgroups using characters from the mitochondrial genes, Cytochrome Oxidase I and II (COI and COII), and the nuclear gene, Elongation Factor-alpha (EF-1alpha). Maximum parsimony, maximum likelihood and Bayesian inference were used to infer the phylogeny. The 54 ingroup species represented 13 of the 15 recognized species groups of Nemoria [Ferguson, D.C., 1985. Fasc. 18.1, Geometroidea: Geometridae (in part). In: Dominick, R.B. (Ed.), The Moths of America North of Mexico, Fasc. 18.1. Wedge Entomological Research Foundation, Washington; Pitkin, L.M., 1993. Neotropical emerald moths of the genera Nemoria, Lissochlora and Chavarriella, with particular reference to the species of Costa Rica (Lepidoptera: Geometridae, Geometrinae). Bull. Br. Mus. Nat. Hist. 62, 39-159], and the seven outgroups came from four tribes of Geometrinae. These data support Nemoria as a monophyletic group and largely recover the species groupings proposed in previous taxonomic analyses using morphological characters. Phenotypic plasticity of larvae is not correlated with plasticity of adults among those species of Nemoria where life histories are known, and appears to be evolutionarily labile for both life history stages: Species exhibiting larval phenotypic plasticity, such as N. arizonaria and N. outina, are placed in several distinct clades, suggesting that this trait has evolved multiple times, and species displaying adult phenotypic plasticity are likewise distributed throughout the phylogeny. A comparative analysis of the biogeographic history of Nemoria supports a South American origin for the genus with multiple introductions into North America, and an application of published substitution rates to the phylogram provides an age estimate

  16. Phenotypic plasticity alone cannot explain climate-induced change in avian migration timing

    PubMed Central

    Buskirk, Josh; Mulvihill, Robert S; Leberman, Robert C

    2012-01-01

    Recent climate change has been linked to shifts in the timing of life-cycle events in many organisms, but there is debate over the degree to which phenological changes are caused by evolved genetic responses of populations or by phenotypic plasticity of individuals. We estimated plasticity of spring arrival date in 27 species of bird that breed in the vicinity of an observatory in eastern North America. For 2441 individuals detected in multiple years, arrival occurred earlier during warm years, especially in species that migrate short distances. Phenotypic plasticity averaged −0.93 days °C−1 ± 0.70 (95% CI). However, plasticity accounted for only 13–25% of the climate-induced trend in phenology observed over 46 years. Although our approach probably underestimates the full scope of plasticity, the data suggest that part of the response to environmental change has been caused by microevolution. The estimated evolutionary rates are plausible (0.016 haldanes). PMID:23145329

  17. Echinoderms display morphological and behavioural phenotypic plasticity in response to their trophic environment.

    PubMed

    Hughes, Adam D; Brunner, Lars; Cook, Elizabeth J; Kelly, Maeve S; Wilson, Ben

    2012-01-01

    The trophic interactions of sea urchins are known to be the agents of phase shifts in benthic marine habitats such as tropical and temperate reefs. In temperate reefs, the grazing activity of sea urchins has been responsible for the destruction of kelp forests and the formation of 'urchin barrens', a rocky habitat dominated by crustose algae and encrusting invertebrates. Once formed, these urchin barrens can persist for decades. Trophic plasticity in the sea urchin may contribute to the stability and resilience of this alternate stable state by increasing diet breadth in sea urchins. This plasticity promotes ecological connectivity and weakens species interactions and so increases ecosystem stability. We test the hypothesis that sea urchins exhibit trophic plasticity using an approach that controls for other typically confounding environmental and genetic factors. To do this, we exposed a genetically homogenous population of sea urchins to two very different trophic environments over a period of two years. The sea urchins exhibited a wide degree of phenotypic trophic plasticity when exposed to contrasting trophic environments. The two populations developed differences in their gross morphology and the test microstructure. In addition, when challenged with unfamiliar prey, the response of each group was different. We show that sea urchins exhibit significant morphological and behavioural phenotypic plasticity independent of their environment or their nutritional status.

  18. A conceptual review of mate choice: stochastic demography, within-sex phenotypic plasticity, and individual flexibility.

    PubMed

    Ah-King, Malin; Gowaty, Patricia Adair

    2016-07-01

    Mate choice hypotheses usually focus on trait variation of chosen individuals. Recently, mate choice studies have increasingly attended to the environmental circumstances affecting variation in choosers' behavior and choosers' traits. We reviewed the literature on phenotypic plasticity in mate choice with the goal of exploring whether phenotypic plasticity can be interpreted as individual flexibility in the context of the switch point theorem, SPT (Gowaty and Hubbell 2009). We found >3000 studies; 198 were empirical studies of within-sex phenotypic plasticity, and sixteen showed no evidence of mate choice plasticity. Most studies reported changes from choosy to indiscriminate behavior of subjects. Investigators attributed changes to one or more causes including operational sex ratio, adult sex ratio, potential reproductive rate, predation risk, disease risk, chooser's mating experience, chooser's age, chooser's condition, or chooser's resources. The studies together indicate that "choosiness" of potential mates is environmentally and socially labile, that is, induced - not fixed - in "the choosy sex" with results consistent with choosers' intrinsic characteristics or their ecological circumstances mattering more to mate choice than the traits of potential mates. We show that plasticity-associated variables factor into the simpler SPT variables. We propose that it is time to complete the move from questions about within-sex plasticity in the choosy sex to between- and within-individual flexibility in reproductive decision-making of both sexes simultaneously. Currently, unanswered empirical questions are about the force of alternative constraints and opportunities as inducers of individual flexibility in reproductive decision-making, and the ecological, social, and developmental sources of similarities and differences between individuals. To make progress, we need studies (1) of simultaneous and symmetric attention to individual mate preferences and subsequent

  19. The effects of phenotypic plasticity on photosynthetic performance in winter rye, winter wheat and Brassica napus.

    PubMed

    Dahal, Keshav; Kane, Khalil; Gadapati, Winona; Webb, Elizabeth; Savitch, Leonid V; Singh, Jasbir; Sharma, Pooja; Sarhan, Fathey; Longstaffe, Fred J; Grodzinski, Bernard; Hüner, Norman P A

    2012-02-01

    The contributions of phenotypic plasticity to photosynthetic performance in winter (cv Musketeer, cv Norstar) and spring (cv SR4A, cv Katepwa) rye (Secale cereale) and wheat (Triticum aestivum) cultivars grown at either 20°C [non-acclimated (NA)] or 5°C [cold acclimated (CA)] were assessed. The 22-40% increase in light-saturated rates of CO₂ assimilation in CA vs NA winter cereals were accounted for by phenotypic plasticity as indicated by the dwarf phenotype and increased specific leaf weight. However, phenotypic plasticity could not account for (1) the differential temperature sensitivity of CO₂ assimilation and photosynthetic electron transport, (2) the increased efficiency and light-saturated rates of photosynthetic electron transport or (3) the decreased light sensitivity of excitation pressure and non-photochemical quenching between NA and NA winter cultivars. Cold acclimation decreased photosynthetic performance of spring relative to winter cultivars. However, the differences in photosynthetic performances between CA winter and spring cultivars were dependent upon the basis on which photosynthetic performance was expressed. Overexpression of BNCBF17 in Brassica napus generally decreased the low temperature sensitivity (Q₁₀) of CO₂ assimilation and photosynthetic electron transport even though the latter had not been exposed to low temperature. Photosynthetic performance in wild type compared to the BNCBF17-overexpressing transgenic B. napus indicated that CBFs/DREBs regulate not only freezing tolerance but also govern plant architecture, leaf anatomy and photosynthetic performance. The apparent positive and negative effects of cold acclimation on photosynthetic performance are discussed in terms of the apparent costs and benefits of phenotypic plasticity, winter survival and reproductive fitness.

  20. Adaptive plasticity in vestibular influences on cardiovascular control

    NASA Technical Reports Server (NTRS)

    Yates, B. J.; Holmes, M. J.; Jian, B. J.

    2000-01-01

    Data collected in both human subjects and animal models indicate that the vestibular system influences the control of blood pressure. In animals, peripheral vestibular lesions diminish the capacity to rapidly and accurately make cardiovascular adjustments to changes in posture. Thus, one role of vestibulo-cardiovascular influences is to elicit changes in blood distribution in the body so that stable blood pressure is maintained during movement. However, deficits in correcting blood pressure following vestibular lesions diminish over time, and are less severe when non-labyrinthine sensory cues regarding body position in space are provided. These observations show that pathways that mediate vestibulo-sympathetic reflexes can be subject to plastic changes. This review considers the adaptive plasticity in cardiovascular responses elicited by the central vestibular system. Recent data indicate that the posterior cerebellar vermis may play an important role in adaptation of these responses, such that ablation of the posterior vermis impairs recovery of orthostatic tolerance following subsequent vestibular lesions. Furthermore, recent experiments suggest that non-labyrinthine inputs to the central vestibular system may be important in controlling blood pressure during movement, particularly following vestibular dysfunction. A number of sensory inputs appear to be integrated to produce cardiovascular adjustments during changes in posture. Although loss of any one of these inputs does not induce lability in blood pressure, it is likely that maximal blood pressure stability is achieved by the integration of a variety of sensory cues signaling body position in space.

  1. Phenotyping for drought adaptation in wheat using physiological traits

    PubMed Central

    Monneveux, Philippe; Jing, Ruilian; Misra, Satish C.

    2012-01-01

    Wheat (Triticum spp) is one of the first domesticated food crops. It represents the first source of calories (after rice) and an important source of proteins in developing countries. As a result of the Green Revolution, wheat yield sharply increased due to the use of improved varieties, irrigation, pesticides, and fertilizers. The rate of increase in world wheat production, however, slowed after 1980, except in China, India, and Pakistan. Being adapted to a wide range of moisture conditions, wheat is grown on more land area worldwide than any other crop, including in drought prone areas. In these marginal rain-fed environments where at least 60 m ha of wheat is grown, amount and distribution of rainfall are the predominant factors influencing yield variability. Intensive work has been carried out in the area of drought adaptation over the last decades. Breeding strategies for drought tolerance improvement include: definition of the target environment, choice and characterization of the testing environment, water stress management and characterization, and use of phenotyping traits with high heritability. The use of integrative traits, facilitated by the development and application of new technologies (thermal imaging, spectral reflectance, stable isotopes) is facilitating high throughput phenotyping and indirect selection, consequently favoring yield improvement in drought prone environments. PMID:23181021

  2. Phenotyping for drought adaptation in wheat using physiological traits.

    PubMed

    Monneveux, Philippe; Jing, Ruilian; Misra, Satish C

    2012-01-01

    Wheat (Triticum spp) is one of the first domesticated food crops. It represents the first source of calories (after rice) and an important source of proteins in developing countries. As a result of the Green Revolution, wheat yield sharply increased due to the use of improved varieties, irrigation, pesticides, and fertilizers. The rate of increase in world wheat production, however, slowed after 1980, except in China, India, and Pakistan. Being adapted to a wide range of moisture conditions, wheat is grown on more land area worldwide than any other crop, including in drought prone areas. In these marginal rain-fed environments where at least 60 m ha of wheat is grown, amount and distribution of rainfall are the predominant factors influencing yield variability. Intensive work has been carried out in the area of drought adaptation over the last decades. Breeding strategies for drought tolerance improvement include: definition of the target environment, choice and characterization of the testing environment, water stress management and characterization, and use of phenotyping traits with high heritability. The use of integrative traits, facilitated by the development and application of new technologies (thermal imaging, spectral reflectance, stable isotopes) is facilitating high throughput phenotyping and indirect selection, consequently favoring yield improvement in drought prone environments.

  3. Plasticity as Phenotype: G x E Interaction in a Freshwater Snail

    NASA Astrophysics Data System (ADS)

    Brunkow, P. E.; Calloway, S. A.

    2005-05-01

    Plasticity in morphological development allows species to accommodate environmental variation experienced during growth; however, genetic variation for phenotypic plasticity per se has been relatively under-studied. We utilized the well-documented plastic response of shell development to predator cues in a freshwater snail to quantify genetic variation for plasticity in growth rate and shell shape. Field-caught pairs of snails reproduced in the laboratory to create families of full siblings, which were then divided and allowed to grow in control and predator cue treatments. Predator (crayfish) cues had significant effects on both size-corrected growth rate and shell shape; family identity also significantly affected both final shell shape and growth rate. The interaction between predator treatment and family identity significantly affected snail growth rate but not final shell shape, suggesting genetic variation in the plastic response to predator cues for a physiological variable (growth rate) but not for a variable known to mechanically reduce the risk of predation (shell shape), at least in this population of snails. The possibility that risk of multiple modes of predation (i.e., both fish and crayfish) in some populations might maintain genetic variation in morphological plasticity is discussed.

  4. Absence of Transgenerational Phenotypic Plasticity in Fecundity in the Parasitoid Anagrus erythroneurae (Hymenoptera: Mymaridae)

    PubMed Central

    Andreazza, Felipe; Rosenheim, Jay A.

    2015-01-01

    To improve biological pest control, we would like to understand the main factors that limit the reproductive success of key biological control agents, including parasitoid wasps. Previous research with proovigenic parasitoids in the genus Anagrus collected from multiple field sites revealed positive correlations between parasitoid fecundity and local host density. In this article, we test whether this variation in fecundity is a reflection of transgenerational phenotypic plasticity. We exposed females in laboratory microcosms to either low or high host densities and then quantified the fecundity of their adult daughters. Mean fecundity of daughters did not differ across host density treatments, arguing against the operation of phenotypic plasticity. Significant variation in mean fecundity across different families instead suggested the possibility that genetic variation may underlie the observed fecundity differences.

  5. Phenotypic plasticity and epithelial-to-mesenchymal transition in the behaviour and therapeutic response of oral squamous cell carcinoma.

    PubMed

    Vig, Navin; Mackenzie, Ian C; Biddle, Adrian

    2015-10-01

    It is increasingly recognised that phenotypic plasticity, apparently driven by epigenetic mechanisms, plays a key role in tumour behaviour and markedly influences the important processes of therapeutic survival and metastasis. An important source of plasticity in malignancy is epithelial-to-mesenchymal transition (EMT), a common epigenetically controlled event that results in transition of malignant cells between different phenotypic states that confer motility and enhance survival. In this review, we discuss the importance of phenotypic plasticity and its contribution to cellular heterogeneity in oral squamous cell carcinoma with emphasis on aspects of drug resistance and EMT.

  6. Rapid Evolution of Phenotypic Plasticity and Shifting Thresholds of Genetic Assimilation in the Nematode Caenorhabditis remanei

    PubMed Central

    Sikkink, Kristin L.; Reynolds, Rose M.; Ituarte, Catherine M.; Cresko, William A.; Phillips, Patrick C.

    2014-01-01

    Many organisms can acclimate to new environments through phenotypic plasticity, a complex trait that can be heritable, subject to selection, and evolve. However, the rate and genetic basis of plasticity evolution remain largely unknown. We experimentally evolved outbred populations of the nematode Caenorhabditis remanei under an acute heat shock during early larval development. When raised in a nonstressful environment, ancestral populations were highly sensitive to a 36.8° heat shock and exhibited high mortality. However, initial exposure to a nonlethal high temperature environment resulted in significantly reduced mortality during heat shock (hormesis). Lines selected for heat shock resistance rapidly evolved the capacity to withstand heat shock in the native environment without any initial exposure to high temperatures, and early exposure to high temperatures did not lead to further increases in heat resistance. This loss of plasticity would appear to have resulted from the genetic assimilation of the heat induction response in the noninducing environment. However, analyses of transcriptional variation via RNA-sequencing from the selected populations revealed no global changes in gene regulation correlated with the observed changes in heat stress resistance. Instead, assays of the phenotypic response across a broader range of temperatures revealed that the induced plasticity was not fixed across environments, but rather the threshold for the response was shifted to higher temperatures over evolutionary time. These results demonstrate that apparent genetic assimilation can result from shifting thresholds of induction across environments and that analysis of the broader environmental context is critically important for understanding the evolution of phenotypic plasticity. PMID:24727288

  7. Ecological opportunity and phenotypic plasticity interact to promote character displacement and species coexistence.

    PubMed

    Pfennig, David W; Rice, Amber M; Martin, Ryan A

    2006-03-01

    We investigated the roles of resource availability and phenotypic plasticity in promoting ecological character displacement (i.e., trait evolution stemming from resource competition between species). Because ecological character displacement generates new populations that differ in resource use, this process should only occur when exploitable resources are available. We tested this hypothesis in two species of spadefoot toads (Spea bombifrons and S. multiplicata) whose tadpoles use phenotypic plasticity to develop into either an omnivore morph, which specializes on detritus, or a physically distinctive carnivore morph, which specializes on shrimp. Both species grow best on shrimp, but when reared together, S. bombifrons outcompetes S. multiplicata for shrimp and S. multiplicata outcompetes S. bombifrons for detritus. We found that when each species occurred alone in the field, they produced similar proportions of omnivores and carnivores. When the two species occurred together, however, they underwent ecological character displacement in larval development, with S. multiplicata producing mostly omnivores, and S. bombifrons producing mostly carnivores. We combined observations of natural populations with experiments to evaluate whether such character displacement was only possible when both shrimp and detritus were relatively abundant. Mixed-species ponds contained abundant detritus and shrimp, in contrast with nearby pure-species ponds, which were deficient in one resource. Experiments revealed that S. multiplicata competed poorly when detritus was rare and that S. bombifrons competed poorly when shrimp was rare. In nature, when one of these two resources was scarce, one species was missing, perhaps through competitive exclusion by the species that was the superior competitor for the remaining resource. Thus, ecological character displacement and, therefore, coexistence of close competitors, was only possible when diverse resources were available. Finally, even if

  8. Complex Small-Molecule Architectures Regulate Phenotypic Plasticity in a Nematode**

    PubMed Central

    Bose, Neelanjan; Ogawa, Akira; von Reuss, Stephan H.; Yim, Joshua J.; Ragsdale, Erik J.; Sommer, Ralf J.; Schroeder, Frank C.

    2013-01-01

    Microorganisms and plants produce a large diversity of secondary metabolites, whereas analyses of metazoan metabolomes have yielded comparatively few types of small molecules. We show that the nematode Pristionchus pacificus constructs elaborate molecular architectures from modified building blocks of primary metabolism, including an unusual xylopyranose-based nucleoside. These compounds act as signaling molecules controlling adult phenotypic plasticity and development and provide striking examples for modular generation of structural diversity in metazoans. PMID:23161728

  9. Phenotypic plasticity in reproductive traits: Evidence from a viviparous snake. [Thamnophis marcianus

    SciTech Connect

    Ford, N.B.; Seigel, R.A. )

    1989-12-01

    A number of recent studies have indicated that life history characteristics (e.g., number of offspring, offspring size, age at sexual maturity) are strongly affected by proximate environmental factors such as prey availability. Evaluating this phenotypic plasticity will be crucial to a complete understanding of the evolution of life history traits, because the occurrence of such variability casts doubt on the common assumption that the values of life history characteristics expressed in nature are the outcome of long-term natural selection. In this study, the authors manipulated the diets of a captive-bred colony of the viviparous snake Thamnophis marcianus to determine to what degree the reproductive characteristics of this species were determined by food intake. They found that both number of offspring and clutch mass were significantly affected by prey availability, but that relative clutch mass and offspring size were fixed relative to diet. The data suggest that like other organisms, T. marcianus shows a gradient in phenotypic plasticity, with some traits more canalized than others. Therefore, intraspecific comparisons of life history characteristics should not be made without information on which traits are subject to phenotypic plasticity.

  10. Phenotypic Plasticity of Leaf Shape along a Temperature Gradient in Acer rubrum

    PubMed Central

    Royer, Dana L.; Meyerson, Laura A.; Robertson, Kevin M.; Adams, Jonathan M.

    2009-01-01

    Both phenotypic plasticity and genetic determination can be important for understanding how plants respond to environmental change. However, little is known about the plastic response of leaf teeth and leaf dissection to temperature. This gap is critical because these leaf traits are commonly used to reconstruct paleoclimate from fossils, and such studies tacitly assume that traits measured from fossils reflect the environment at the time of their deposition, even during periods of rapid climate change. We measured leaf size and shape in Acer rubrum derived from four seed sources with a broad temperature range and grown for two years in two gardens with contrasting climates (Rhode Island and Florida). Leaves in the Rhode Island garden have more teeth and are more highly dissected than leaves in Florida from the same seed source. Plasticity in these variables accounts for at least 6–19 % of the total variance, while genetic differences among ecotypes probably account for at most 69–87 %. This study highlights the role of phenotypic plasticity in leaf-climate relationships. We suggest that variables related to tooth count and leaf dissection in A. rubrum can respond quickly to climate change, which increases confidence in paleoclimate methods that use these variables. PMID:19893620

  11. The Genome of Pseudomonas fluorescens Strain R124 Demonstrates Phenotypic Adaptation to the Mineral Environment

    PubMed Central

    Barton, Michael D.; Petronio, Michael; Giarrizzo, Juan G.; Bowling, Bethany V.

    2013-01-01

    Microbial adaptation to environmental conditions is a complex process, including acquisition of positive traits through horizontal gene transfer or the modification of existing genes through duplication and/or mutation. In this study, we examined the adaptation of a Pseudomonas fluorescens isolate (R124) from the nutrient-limited mineral environment of a silica cave in comparison with P. fluorescens isolates from surface soil and the rhizosphere. Examination of metal homeostasis gene pathways demonstrated a high degree of conservation, suggesting that such systems remain functionally similar across chemical environments. The examination of genomic islands unique to our strain revealed the presence of genes involved in carbohydrate metabolism, aromatic carbon metabolism, and carbon turnover, confirmed through phenotypic assays, suggesting the acquisition of potentially novel mechanisms for energy metabolism in this strain. We also identified a twitching motility phenotype active at low-nutrient concentrations that may allow alternative exploratory mechanisms for this organism in a geochemical environment. Two sets of candidate twitching motility genes are present within the genome, one on the chromosome and one on a plasmid; however, a plasmid knockout identified the functional gene as being present on the chromosome. This work highlights the plasticity of the Pseudomonas genome, allowing the acquisition of novel nutrient-scavenging pathways across diverse geochemical environments while maintaining a core of functional stress response genes. PMID:23995634

  12. Phenotypic plasticity as an index of drought tolerance in three Patagonian steppe grasses

    PubMed Central

    Couso, L. L.; Fernández, R. J.

    2012-01-01

    Background and Aims Despite general agreement regarding the adaptive importance of plasticity, evidence for the role of environmental resource availability in plants is scarce. In arid and semi-arid environments, the persistence and dominance of perennial species depends on their capacity to tolerate drought: tolerance could be given on one extreme by fixed traits and, on the other, by plastic traits. To understand drought tolerance of species it is necessary to know the plasticity of their water economy-related traits, i.e. the position in the fixed–plastic continuum. Methods Three conspicuous co-existing perennial grasses from a Patagonian steppe were grown under controlled conditions with four levels of steady-state water availability. Evaluated traits were divided into two groups. The first was associated with potential plant performance and correlated with fitness, and included above-ground biomass, total biomass, tillering and tiller density at harvest. The second group consisted of traits associated with mechanisms of plant adjustment to environmental changes and included root biomass, shoot/root ratio, tiller biomass, length of total elongated leaf, length of yellow tissue divided by time and final length divided by the time taken to reach final length. Key Results and Conclusions The most plastic species along this drought gradient was the most sensitive to drought, whereas the least plastic and slowest growing was the most tolerant. This negative relationship between tolerance and plasticity was true for fitness-related traits but was trait-dependent for underlying traits. Remarkably, the most tolerant species had the highest positive plasticity (i.e. opposite to the default response to stress) in an underlying trait, directly explaining its drought resistance: it increased absolute root biomass. The niche differentiation axis that allows the coexistence of species in this group of perennial dryland grasses, all limited by soil surface moisture, would

  13. When to rely on maternal effects and when on phenotypic plasticity?

    PubMed Central

    Kuijper, Bram; Hoyle, Rebecca B.

    2015-01-01

    Existing insight suggests that maternal effects have a substantial impact on evolution, yet these predictions assume that maternal effects themselves are evolutionarily constant. Hence, it is poorly understood how natural selection shapes maternal effects in different ecological circumstances. To overcome this, the current study derives an evolutionary model of maternal effects in a quantitative genetics context. In constant environments, we show that maternal effects evolve to slight negative values that result in a reduction of the phenotypic variance (canalization). By contrast, in populations experiencing abrupt change, maternal effects transiently evolve to positive values for many generations, facilitating the transmission of beneficial maternal phenotypes to offspring. In periodically fluctuating environments, maternal effects evolve according to the autocorrelation between maternal and offspring environments, favoring positive maternal effects when change is slow, and negative maternal effects when change is rapid. Generally, the strongest maternal effects occur for traits that experience very strong selection and for which plasticity is severely constrained. By contrast, for traits experiencing weak selection, phenotypic plasticity enhances the evolutionary scope of maternal effects, although maternal effects attain much smaller values throughout. As weak selection is common, finding substantial maternal influences on offspring phenotypes may be more challenging than anticipated. PMID:25809121

  14. Matrix-dependent Plasticity of the Malignant Phenotype of Bladder Cancer Cells

    PubMed Central

    Hurst, Robert E.; Kyker, Kimberly D.; Bonner, Rebecca B.; Bowditch, Ron D.; Hemstreet, George P.

    2008-01-01

    The purpose of this study was to investigate the effect of cancer- and normal basement membrane-derived extracellular matrix to modulate the phenotype of bladder cancer cell lines. Five lines, varying in malignancy from papilloma to highly undifferentiated and invasive and immortalized human urothelial cells, were grown on two extracellular matrix preparations, Matrigel and SISgel. Matrigel represents matrix remodeled by malignancy while SISgel, obtained from small intestine submucosa (SIS), represents the normal matrix supporting differentiated cell growth. On Matrigel, regardless of the content of growth factors, the invasive lines displayed an invasive phenotype, while the low grade lines grew as papillary structures. In contrast, when the same cells were grown on SISgel, they grew as a layer of cells one to 5 cells thick, failed to invade, and expressed cell-surface E-cadherin. Unlike breast cancer cells, neutralization of β1, β4 and α6 integrins altered cell-cell and cell-matrix adhesiveness but did not alter the phenotype. When invasive cells were grown on mixtures of SISgel and Matrigel, the phenotype changed gradually, not abruptly, indicating that factors within the gel reversibly alter the phenotypic expression of invasion. In summary, the phenotype of bladder cancer cells growing in tissue-like 3-dimensional culture is highly plastic, and malignant properties such as invasion and papillary growth can be suppressed by the matrix. PMID:12926044

  15. Parallel adaptive mesh refinement techniques for plasticity problems

    SciTech Connect

    Barry, W.J.; Jones, M.T. |; Plassmann, P.E.

    1997-12-31

    The accurate modeling of the nonlinear properties of materials can be computationally expensive. Parallel computing offers an attractive way for solving such problems; however, the efficient use of these systems requires the vertical integration of a number of very different software components, we explore the solution of two- and three-dimensional, small-strain plasticity problems. We consider a finite-element formulation of the problem with adaptive refinement of an unstructured mesh to accurately model plastic transition zones. We present a framework for the parallel implementation of such complex algorithms. This framework, using libraries from the SUMAA3d project, allows a user to build a parallel finite-element application without writing any parallel code. To demonstrate the effectiveness of this approach on widely varying parallel architectures, we present experimental results from an IBM SP parallel computer and an ATM-connected network of Sun UltraSparc workstations. The results detail the parallel performance of the computational phases of the application during the process while the material is incrementally loaded.

  16. Parallel adaptive mesh refinement techniques for plasticity problems

    NASA Technical Reports Server (NTRS)

    Barry, W. J.; Jones, M. T.; Plassmann, P. E.

    1997-01-01

    The accurate modeling of the nonlinear properties of materials can be computationally expensive. Parallel computing offers an attractive way for solving such problems; however, the efficient use of these systems requires the vertical integration of a number of very different software components, we explore the solution of two- and three-dimensional, small-strain plasticity problems. We consider a finite-element formulation of the problem with adaptive refinement of an unstructured mesh to accurately model plastic transition zones. We present a framework for the parallel implementation of such complex algorithms. This framework, using libraries from the SUMAA3d project, allows a user to build a parallel finite-element application without writing any parallel code. To demonstrate the effectiveness of this approach on widely varying parallel architectures, we present experimental results from an IBM SP parallel computer and an ATM-connected network of Sun UltraSparc workstations. The results detail the parallel performance of the computational phases of the application during the process while the material is incrementally loaded.

  17. Neuromorphic adaptive plastic scalable electronics: analog learning systems.

    PubMed

    Srinivasa, Narayan; Cruz-Albrecht, Jose

    2012-01-01

    Decades of research to build programmable intelligent machines have demonstrated limited utility in complex, real-world environments. Comparing their performance with biological systems, these machines are less efficient by a factor of 1 million1 billion in complex, real-world environments. The Systems of Neuromorphic Adaptive Plastic Scalable Electronics (SyNAPSE) program is a multifaceted Defense Advanced Research Projects Agency (DARPA) project that seeks to break the programmable machine paradigm and define a new path for creating useful, intelligent machines. Since real-world systems exhibit infinite combinatorial complexity, electronic neuromorphic machine technology would be preferable in a host of applications, but useful and practical implementations still do not exist. HRL Laboratories LLC has embarked on addressing these challenges, and, in this article, we provide an overview of our project and progress made thus far.

  18. Predator-induced phenotypic plasticity within- and across-generations: a challenge for theory?

    PubMed Central

    Walsh, Matthew R.; Cooley, Frank; Biles, Kelsey; Munch, Stephan B.

    2015-01-01

    Much work has shown that the environment can induce non-genetic changes in phenotype that span multiple generations. Theory predicts that predictable environmental variation selects for both increased within- and across-generation responses. Yet, to the best of our knowledge, there are no empirical tests of this prediction. We explored the relationship between within- versus across-generation plasticity by evaluating the influence of predator cues on the life-history traits of Daphnia ambigua. We measured the duration of predator-induced transgenerational effects, determined when transgenerational responses are induced, and quantified the cues that activate transgenerational plasticity. We show that predator exposure during embryonic development causes earlier maturation and increased reproductive output. Such effects are detectable two generations removed from predator exposure and are similar in magnitude in response to exposure to cues emitted by injured conspecifics. Moreover, all experimental contexts and traits yielded a negative correlation between within- versus across-generation responses. That is, responses to predator cues within- and across-generations were opposite in sign and magnitude. Although many models address transgenerational plasticity, none of them explain this apparent negative relationship between within- and across-generation plasticities. Our results highlight the need to refine the theory of transgenerational plasticity. PMID:25392477

  19. Evolutionary Influences of Plastic Behavioral Responses Upon Environmental Challenges in an Adaptive Radiation

    PubMed Central

    Foster, Susan A.; Wund, Matthew A.; Baker, John A.

    2015-01-01

    At the end of the 19th century, the suggestion was made by several scientists, including J. M. Baldwin, that behavioral responses to environmental change could both rescue populations from extinction (Baldwin Effect) and influence the course of subsequent evolution. Here we provide the historical and theoretical background for this argument and offer evidence of the importance of these ideas for understanding how animals (and other organisms that exhibit behavior) will respond to the rapid environmental changes caused by human activity. We offer examples from long-term research on the evolution of behavioral and other phenotypes in the adaptive radiation of the threespine stickleback fish (Gasterosteus aculeatus), a radiation in which it is possible to infer ancestral patterns of behavioral plasticity relative to the post-glacial freshwater radiation in northwestern North America, and to use patterns of parallelism and contemporary evolution to understand adaptive causes of responses to environmental modification. Our work offers insights into the complexity of cognitive responses to environmental change, and into the importance of examining multiple aspects of the phenotype simultaneously, if we are to understand how behavioral shifts contribute to the persistence of populations and to subsequent evolution. We conclude by discussing the origins of apparent novelties induced by environmental shifts, and the importance of accounting for geographic variation within species if we are to accurately anticipate the effects of anthropogenic environmental modification on the persistence and evolution of animals. PMID:26163679

  20. Evolutionary Influences of Plastic Behavioral Responses Upon Environmental Challenges in an Adaptive Radiation.

    PubMed

    Foster, Susan A; Wund, Matthew A; Baker, John A

    2015-09-01

    At the end of the 19th century, the suggestion was made by several scientists, including J. M. Baldwin, that behavioral responses to environmental change could both rescue populations from extinction (Baldwin Effect) and influence the course of subsequent evolution. Here we provide the historical and theoretical background for this argument and offer evidence of the importance of these ideas for understanding how animals (and other organisms that exhibit behavior) will respond to the rapid environmental changes caused by human activity. We offer examples from long-term research on the evolution of behavioral and other phenotypes in the adaptive radiation of the threespine stickleback fish (Gasterosteus aculeatus), a radiation in which it is possible to infer ancestral patterns of behavioral plasticity relative to the post-glacial freshwater radiation in northwestern North America, and to use patterns of parallelism and contemporary evolution to understand adaptive causes of responses to environmental modification. Our work offers insights into the complexity of cognitive responses to environmental change, and into the importance of examining multiple aspects of the phenotype simultaneously, if we are to understand how behavioral shifts contribute to the persistence of populations and to subsequent evolution. We conclude by discussing the origins of apparent novelties induced by environmental shifts, and the importance of accounting for geographic variation within species if we are to accurately anticipate the effects of anthropogenic environmental modification on the persistence and evolution of animals.

  1. Phenotypic plasticity of stem water potential correlates with crop load in horticultural trees.

    PubMed

    Sadras, Victor O; Trentacoste, Eduardo R

    2011-05-01

    Conceptual models accounting for the influence of source:sink ratio on water relations of trees are theoretically relevant from a physiological perspective and practically important for irrigation scheduling. Midday stem water potential of horticultural trees often declines with increasing crop load but the actual response depends on environmental, management and plant factors. Here we advance a quantitative synthesis of the response of stem water potential to crop load from the perspective of phenotypic plasticity, defined as 'the amount by which the expression of individual characteristics of a genotype are changed by different environments'. Data sets of stem water potential for contrasting crop loads were compiled for apple (Malus domestica L. Borkh.), olive (Olea europea L.), peach (Prunus persica L.), pear (Pyrus communis L.) and plum (Prunus domestica L.). Phenotypic plasticity of stem water potential was calculated as the slope of the linear regression between stem water potential for each crop load and the environmental mean of stem water potential across crop loads. Regression lines for trees with different crop load diverged with decreasing environmental mean stem water potential. For the pooled data, plasticity of stem water potential was a linear function of relative crop load. This represents a significant shift in perspective: the effect of crop load on the trait per se (stem water potential) is environmentally contingent, but the effect of crop load on the plasticity of the trait is not. We conclude that research on the effects of crop load on tree water relations would return more robust results if plant traits are considered from the dual perspective of the trait per se and its plasticity.

  2. Contribution of phenotypic heterogeneity to adaptive antibiotic resistance

    PubMed Central

    Sánchez-Romero, María Antonia; Casadesús, Josep

    2014-01-01

    Antibiotic-resistant isolates of Salmonella enterica were selected on plates containing lethal concentrations of rifampicin, kanamycin, and nalidixic acid. The stability of the resistance phenotype was scored after nonselective growth. Rifampicin-resistant (Rifr) isolates were stable, suggesting that they had arisen by mutation. Mutations in the rpoB gene were detected indeed in Rifr mutants. In contrast, a fraction of kanamycin-resistant (Kmr) and nalidixic acid-resistant (Nalr) isolates showed reduced resistance after nonselective growth, suggesting that mechanisms other than mutation had contributed to bacterial survival upon lethal selection. Single-cell analysis revealed heterogeneity in expression of the porin gene ompC, and subpopulation separation provided evidence that reduced ompC expression confers adaptive resistance to kanamycin. In the case of Nalr isolates, mutations in the gyrA gene were present in most nalidixic acid-resistant isolates. However, the efflux pump inhibitor Phe-Arg-β-naphtylamide (PAβN) reduced the level of resistance in Nalr mutants, indicating that active efflux contributes to the overall level of nalidixic acid resistance. Heterogeneous efflux pump activity was detected in single cells and colonies, and a correlation between high efflux and increased resistance to nalidixic acid was found. These observations suggest that fluctuations in the expression and the activity of critical functions of the bacterial cell, alone or combined with mutations, can contribute to adaptive resistance to antibiotics. PMID:24351930

  3. Contribution of phenotypic heterogeneity to adaptive antibiotic resistance.

    PubMed

    Sánchez-Romero, María Antonia; Casadesús, Josep

    2014-01-07

    Antibiotic-resistant isolates of Salmonella enterica were selected on plates containing lethal concentrations of rifampicin, kanamycin, and nalidixic acid. The stability of the resistance phenotype was scored after nonselective growth. Rifampicin-resistant (Rif(r)) isolates were stable, suggesting that they had arisen by mutation. Mutations in the rpoB gene were detected indeed in Rif(r) mutants. In contrast, a fraction of kanamycin-resistant (Km(r)) and nalidixic acid-resistant (Nal(r)) isolates showed reduced resistance after nonselective growth, suggesting that mechanisms other than mutation had contributed to bacterial survival upon lethal selection. Single-cell analysis revealed heterogeneity in expression of the porin gene ompC, and subpopulation separation provided evidence that reduced ompC expression confers adaptive resistance to kanamycin. In the case of Nal(r) isolates, mutations in the gyrA gene were present in most nalidixic acid-resistant isolates. However, the efflux pump inhibitor Phe-Arg-β-naphtylamide (PAβN) reduced the level of resistance in Nal(r) mutants, indicating that active efflux contributes to the overall level of nalidixic acid resistance. Heterogeneous efflux pump activity was detected in single cells and colonies, and a correlation between high efflux and increased resistance to nalidixic acid was found. These observations suggest that fluctuations in the expression and the activity of critical functions of the bacterial cell, alone or combined with mutations, can contribute to adaptive resistance to antibiotics.

  4. Plasticity-Based Adaptive Cognitive Remediation (PACR) for OIF/OEF Veterans: A Randomized Controlled Trial

    DTIC Science & Technology

    2015-10-01

    Page 1 of 3 Award Number: W81XWH-11-2-0231 TITLE: Plasticity-Based Adaptive Cognitive Remediation (PACR) for OIF/OEF Veterans: A Randomized...DATES COVERED 30Sep2014 - 29Sep2015 4. TITLE AND SUBTITLE Plasticity-Based Adaptive Cognitive Remediation (PACR) for OIF/OEF Veterans: A Randomized

  5. Phenotypic Plasticity of the Introduced New Zealand Mud Snail, Potamopyrgus antipodarum, Compared to Sympatric Native Snails

    PubMed Central

    Levri, Edward P.; Krist, Amy C.; Bilka, Rachel; Dybdahl, Mark F.

    2014-01-01

    Phenotypic plasticity is likely to be important in determining the invasive potential of a species, especially if invasive species show greater plasticity or tolerance compared to sympatric native species. Here in two separate experiments we compare reaction norms in response to two environmental variables of two clones of the New Zealand mud snail, Potamopyrgus antipodarum, isolated from the United States, (one invasive and one not yet invasive) with those of two species of native snails that are sympatric with the invader, Fossaria bulimoides group and Physella gyrina group. We placed juvenile snails in environments with high and low conductivity (300 and 800 mS) in one experiment, and raised them at two different temperatures (16°C and 22°C) in a second experiment. Growth rate and mortality were measured over the course of 8 weeks. Mortality rates were higher in the native snails compared to P. antipodarum across all treatments, and variation in conductivity influenced mortality. In both experiments, reaction norms did not vary significantly between species. There was little evidence that the success of the introduced species is a result of greater phenotypic plasticity to these variables compared to the sympatric native species. PMID:24699685

  6. Phenotypic plasticity of the introduced New Zealand mud snail, Potamopyrgus antipodarum, compared to sympatric native snails.

    PubMed

    Levri, Edward P; Krist, Amy C; Bilka, Rachel; Dybdahl, Mark F

    2014-01-01

    Phenotypic plasticity is likely to be important in determining the invasive potential of a species, especially if invasive species show greater plasticity or tolerance compared to sympatric native species. Here in two separate experiments we compare reaction norms in response to two environmental variables of two clones of the New Zealand mud snail, Potamopyrgus antipodarum, isolated from the United States, (one invasive and one not yet invasive) with those of two species of native snails that are sympatric with the invader, Fossaria bulimoides group and Physella gyrina group. We placed juvenile snails in environments with high and low conductivity (300 and 800 mS) in one experiment, and raised them at two different temperatures (16 °C and 22 °C) in a second experiment. Growth rate and mortality were measured over the course of 8 weeks. Mortality rates were higher in the native snails compared to P. antipodarum across all treatments, and variation in conductivity influenced mortality. In both experiments, reaction norms did not vary significantly between species. There was little evidence that the success of the introduced species is a result of greater phenotypic plasticity to these variables compared to the sympatric native species.

  7. The Baldwin effect and genetic assimilation: revisiting two mechanisms of evolutionary change mediated by phenotypic plasticity.

    PubMed

    Crispo, Erika

    2007-11-01

    Two different, but related, evolutionary theories pertaining to phenotypic plasticity were proposed by James Mark Baldwin and Conrad Hal Waddington. Unfortunately, these theories are often confused with one another. Baldwin's notion of organic selection posits that plasticity influences whether an individual will survive in a new environment, thus dictating the course of future evolution. Heritable variations can then be selected upon to direct phenotypic evolution (i.e., "orthoplasy"). The combination of these two processes (organic selection and orthoplasy) is now commonly referred to as the "Baldwin effect." Alternately, Waddington's genetic assimilation is a process whereby an environmentally induced phenotype, or "acquired character," becomes canalized through selection acting upon the developmental system. Genetic accommodation is a modern term used to describe the process of heritable changes that occur in response to a novel induction. Genetic accommodation is a key component of the Baldwin effect, and genetic assimilation is a type of genetic accommodation. I here define both the Baldwin effect and genetic assimilation in terms of genetic accommodation, describe cases in which either should occur in nature, and propose that each could play a role in evolutionary diversification.

  8. Variation in phenotypic plasticity and selection patterns in blue tit breeding time: between- and within-population comparisons.

    PubMed

    Porlier, Melody; Charmantier, Anne; Bourgault, Patrice; Perret, Philippe; Blondel, Jacques; Garant, Dany

    2012-09-01

    1. Phenotypic plasticity, the response of individual phenotypes to their environment, can allow organisms to cope with spatio-temporal variation in environmental conditions. Recent studies have shown that variation exists among individuals in their capacity to adjust their traits to environmental changes and that this individual plasticity can be under strong selection. Yet, little is known on the extent and ultimate causes of variation between populations and individuals in plasticity patterns. 2. In passerines, timing of breeding is a key life-history trait strongly related to fitness and is known to vary with the environment, but few studies have investigated the within-species variation in individual plasticity. 3. Here, we studied between- and within-population variation in breeding time, phenotypic plasticity and selection patterns for this trait in four Mediterranean populations of blue tits (Cyanistes caeruleus) breeding in habitats varying in structure and quality. 4. Although there was no significant warming over the course of the study, we found evidence for earlier onset of breeding in warmer years in all populations, with reduced plasticity in the less predictable environment. In two of four populations, there was significant inter-individual variation in plasticity for laying date. Interestingly, selection for earlier laying date was significant only in populations where there was no inter-individual differences in plasticity. 5. Our results show that generalization of plasticity patterns among populations of the same species might be challenging even at a small spatial scale and that the amount of within-individual variation in phenotypic plasticity may be linked to selective pressures acting on these phenotypic traits.

  9. Proteomics to assess the role of phenotypic plasticity in aquatic organisms exposed to pollution and global warming.

    PubMed

    Silvestre, Frédéric; Gillardin, Virginie; Dorts, Jennifer

    2012-11-01

    Nowadays, the unprecedented rates of anthropogenic changes in ecosystems suggest that organisms have to migrate to new distributional ranges or to adapt commensurately quickly to new conditions to avoid becoming extinct. Pollution and global warming are two of the most important threats aquatic organisms will have to face in the near future. If genetic changes in a population in response to natural selection are extensively studied, the role of acclimation through phenotypic plasticity (the property of a given genotype to produce different phenotypes in response to particular environmental conditions) in a species to deal with new environmental conditions remains largely unknown. Proteomics is the extensive study of the protein complement of a genome. It is dynamic and depends on the specific tissue, developmental stage, and environmental conditions. As the final product of gene expression, it is subjected to several regulatory steps from gene transcription to the functional protein. Consequently, there is a discrepancy between the abundance of mRNA and the abundance of the corresponding protein. Moreover, proteomics is closer to physiology and gives a more functional knowledge of the regulation of gene expression than does transcriptomics. The study of protein-expression profiles, however, gives a better portrayal of the cellular phenotype and is considered as a key link between the genotype and the organismal phenotype. Under new environmental conditions, we can observe a shift of the protein-expression pattern defining a new cellular phenotype that can possibly improve the fitness of the organism. It is now necessary to define a proteomic norm of reaction for organisms acclimating to environmental stressors. Its link to fitness will give new insights into how organisms can evolve in a changing environment. The proteomic literature bearing on chronic exposure to pollutants and on acclimation to heat stress in aquatic organisms, as well as potential application of

  10. Intraspecific variation of a desert shrub species in phenotypic plasticity in response to sand burial.

    PubMed

    Xu, Liang; Huber, Heidrun; During, Heinjo J; Dong, Ming; Anten, Niels P R

    2013-09-01

    Shoot elongation is one of the main plastic responses of plants to burial, a ubiquitous stress factor in dry ecosystems. Yet, intraspecific variation in this response to burial and the extent to which this variation is functionally coordinated with variation in other trait responses are largely unknown. We subjected seedlings of the shrub Caragana intermedia from 18 maternal parents (i.e. different half-sib families) to repeated partial burial to investigate how burial affects shoot growth, stem mechanical traits and associated plasticity. Burial increased both stem elongation and diameter growth of plants, but decreased biomass production. Half-sib families had different rates of shoot elongation, and differed in their response to burial with respect to biomechanical stem properties. Across half-sib families, the magnitude of these responses in mechanical traits was positively correlated with the magnitude of the stem elongation response. These results indicate that plasticity in different stem traits in response to sand burial and intraspecific variation therein are functionally coordinated with respect to mechanical stability. The results emphasize the importance of considering functionally coordinated traits when analyzing phenotypic plasticity in plants.

  11. Phenotypic plasticity in age at first reproduction of female northern sea otters (Enhydra lutris kenyoni)

    USGS Publications Warehouse

    Von Biela, V.R.; Gill, V.A.; Bodkin, J.L.; Burns, Jennifer M.

    2009-01-01

    Life-history theory predicts that within a species, reproduction and survival rates will differ among populations that differ in resource availability or predation rates through phenotypic plasticity. When populations are near carrying capacity (K) or when they are declining due to reduced prey resources, the average age at 1st reproduction (average AFR) is predicted to be older than in populations below K. Differences between the trajectories of northern sea otter (Enhydra lutris kenyoni) populations in Alaska provides an opportunity to examine phenotypic plasticity. Using premolar teeth or reproductive tracts, we estimated average AFR from demographically distinct populations of sea otters in Alaska. We obtained samples from 2 populations near K, Prince William Sound (PWS) and the Aleutian Archipelago (archived samples), and from 2populations below K, the Kodiak Archipelago and Sitka. The average AFR was lower in populations below K (3.60 years ??0.16 SD)compared to those near K (4.21 ?? 0.13 years, P <0.001), and differed among all populations, with the Aleutian population possessing the oldest average AFR (4.29 ?? 0.09 years) followed by PWS (4.05 ?? 0.24 years), Sitka (3.80 ?? 0.21 years), and Kodiak (3.19 ?? 0.37 years). The difference in average AFR among populations supports life-history theory and provides evidence of phenotypic plasticity in sea otters. Our findings highlight the value of using average AFR as a tool for monitoring mammalian populations. ?? 2009 American Society of Mammalogists.

  12. Morphological change and phenotypic plasticity in native and non-native pumpkinseed sunfish in response to sustained water velocities.

    PubMed

    Yavno, S; Fox, M G

    2013-11-01

    Phenotypic plasticity can contribute to the proliferation and invasion success of nonindigenous species by promoting phenotypic changes that increase fitness, facilitate range expansion and improve survival. In this study, differences in phenotypic plasticity were investigated using young-of-year pumpkinseed sunfish from colonies established with lentic and lotic populations originating in Canada (native) and Spain (non-native). Individuals were subjected to static and flowing water treatments for 80 days. Inter- and intra-population differences were tested using ancova and discriminant function analysis, and differences in phenotypic plasticity were tested through a manova of discriminant function scores. Differences between Iberian and North American populations were observed in dorsal fin length, pectoral fin position and caudal peduncle length. Phenotypic plasticity had less influence on morphology than genetic factors, regardless of population origin. Contrary to predictions, Iberian pumpkinseed exhibited lower levels of phenotypic plasticity than native populations, suggesting that canalization may have occurred in the non-native populations during the processes of introduction and range expansion.

  13. Phenotypic Plasticity and Integration in the Mangrove Rivulus (Kryptolebias marmoratus): A Prospectus

    PubMed Central

    Earley, Ryan L.; Hanninen, Amanda F.; Fuller, Adam; Garcia, Mark J.; Lee, Elizabeth A.

    2012-01-01

    The mangrove rivulus (Kryptolebias marmoratus) is a small fish native to mangrove ecosystems in Florida, the Caribbean, Central America, and South America. This species is one of only two self-fertilizing, hermaphroditic vertebrates capable of producing offspring that are genetically identical to both the parent and all siblings. Long bouts of selfing result in individuals with completely homozygous genotypes, effectively allowing for the production of “clones.” Rivulus is also extremely sensitive to environmental change, both during development and adulthood. Life-history traits, behavior, physiology, morphology, and even sexual phenotype are shaped to a large extent by the interaction of genes with the environment, and many of these traits appear to co-vary. True reaction norms can be generated for this species in much the same way as has been done for clonally reproducing invertebrates and plants that have contributed immensely to our understanding of the evolution of phenotypic plasticity. That is, rivulus provides the opportunity to place individuals with identical genotypes in many different environments at any point during ontogeny or adulthood. In addition, rivulus populations are characterized by high genotypic diversity, a luxury not afforded by many clonal vertebrates, which allows us to evaluate variation among genotypes in the shape of reaction norms and in patterns of covariance among traits. We provide background information on phenotypic plasticity and phenotypic integration, coupled with a description of characteristics that we feel qualify rivulus as a potentially powerful model in which to study the evolution of reaction norms and covariance among traits. PMID:22990587

  14. Leaf damage decreases fitness and constrains phenotypic plasticity to drought of a perennial herb

    NASA Astrophysics Data System (ADS)

    Gianoli, Ernesto; Quezada, Iván M.; Suárez, Lorena H.

    2009-09-01

    Mediterranean-type ecosystems are increasingly prone to drought stress. Herbivory might limit plant functional responses to water shortage. This may occur as a result of plant resource depletion or due to the fact that leaf damage and drought may elicit opposite phenotypic responses. We evaluated the impact of herbivory on plant fitness in the field, and the effects of leaf damage on phenotypic plasticity to reduced soil moisture in a greenhouse. The study species was Convolvulus demissus, a perennial herb endemic to central Chile, which has a Mediterranean-type climate. Controlled herbivory by chrysomelid beetles (natural herbivores) in the field had a negative impact on plant fitness, estimated as number of fruits. Whereas reduced soil moisture alone did not affect seedling survival, damaged seedlings (simulated herbivory) had greater mortality when growing under water shortage. The hypothesis that herbivory would constrain phenotypic plasticity was supported by significant statistical interactions between leaf damage and soil moisture, followed by inspections of reaction norms. This was verified both overall (all phenotypic traits taken together, MANOVA) and in four of the six traits evaluated (ANOVAs). When plants were damaged, the reaction norms in response to low soil moisture of water use efficiency, root:shoot ratio and xylem water potential showed reduced slopes. While undamaged plants increased root biomass in response to low moisture, the opposite trend was found for damaged plants. The simultaneous occurrence of herbivory and drought events might curtail recruitment in plant populations of central Chile and other Mediterranean-type ecosystems due to the inability of damaged seedlings to show functional responses to low soil moisture. This finding is of ecological significance in view of current and projected trends of increased aridity in these ecosystems.

  15. The role of adaptive trans-generational plasticity in biological invasions of plants.

    PubMed

    Dyer, Andrew R; Brown, Cynthia S; Espeland, Erin K; McKay, John K; Meimberg, Harald; Rice, Kevin J

    2010-03-01

    High-impact biological invasions often involve establishment and spread in disturbed, high-resource patches followed by establishment and spread in biotically or abiotically stressful areas. Evolutionary change may be required for the second phase of invasion (establishment and spread in stressful areas) to occur. When species have low genetic diversity and short selection history, within-generation phenotypic plasticity is often cited as the mechanism through which spread across multiple habitat types can occur. We show that trans-generational plasticity (TGP) can result in pre-adapted progeny that exhibit traits associated with increased fitness both in high-resource patches and in stressful conditions. In the invasive sedge, Cyperus esculentus, maternal plants growing in nutrient-poor patches can place disproportional number of propagules into nutrient-rich patches. Using the invasive annual grass, Aegilops triuncialis, we show that maternal response to soil conditions can confer greater stress tolerance in seedlings in the form of greater photosynthetic efficiency. We also show TGP for a phenological shift in a low resource environment that results in greater stress tolerance in progeny. These lines of evidence suggest that the maternal environment can have profound effects on offspring success and that TGP may play a significant role in some plant invasions.

  16. Insult-induced adaptive plasticity of the auditory system

    PubMed Central

    Gold, Joshua R.; Bajo, Victoria M.

    2014-01-01

    The brain displays a remarkable capacity for both widespread and region-specific modifications in response to environmental challenges, with adaptive processes bringing about the reweighing of connections in neural networks putatively required for optimizing performance and behavior. As an avenue for investigation, studies centered around changes in the mammalian auditory system, extending from the brainstem to the cortex, have revealed a plethora of mechanisms that operate in the context of sensory disruption after insult, be it lesion-, noise trauma, drug-, or age-related. Of particular interest in recent work are those aspects of auditory processing which, after sensory disruption, change at multiple—if not all—levels of the auditory hierarchy. These include changes in excitatory, inhibitory and neuromodulatory networks, consistent with theories of homeostatic plasticity; functional alterations in gene expression and in protein levels; as well as broader network processing effects with cognitive and behavioral implications. Nevertheless, there abounds substantial debate regarding which of these processes may only be sequelae of the original insult, and which may, in fact, be maladaptively compelling further degradation of the organism's competence to cope with its disrupted sensory context. In this review, we aim to examine how the mammalian auditory system responds in the wake of particular insults, and to disambiguate how the changes that develop might underlie a correlated class of phantom disorders, including tinnitus and hyperacusis, which putatively are brought about through maladaptive neuroplastic disruptions to auditory networks governing the spatial and temporal processing of acoustic sensory information. PMID:24904256

  17. Simulated herbivory does not constrain phenotypic plasticity to shade through ontogeny in a relict tree.

    PubMed

    Pardo, A; García, F M; Valladares, F; Pulido, F

    2016-07-01

    Ecological limits to phenotypic plasticity (PP), induced by simultaneous biotic and abiotic factors, can prevent organisms from exhibiting optimal plasticity, and in turn lead to decreased fitness. Herbivory is an important biotic stressor and may limit plant functional responses to challenging environmental conditions such as shading. In this study we investigated whether plant functional responses and PP to shade are constrained by herbivory, and whether such constraints are due to direct effects based on resource limitation by considering ontogeny. We used as a model system the relict tree Prunus lusitanica and implemented an indoor experiment to quantify the response of saplings of different ages to shade and herbivory. We measured five functional traits and quantitatively calculated PP. Results showed that herbivory did not constrain functional responses or PP to shade except for shoot:root ratio (SR), which, despite showing a high PP in damaged saplings, decreased under shade instead of increasing. Damaged saplings of older age did not exhibit reduced constraints on functional responses to shade and generally presented a lower PP than damaged saplings of younger age. Our findings suggest that herbivory-mediated constraints on plant plasticity to shade may not be as widespread as previously thought. Nonetheless, the negative effect of herbivory on SR plastic expression to shade could be detrimental for plant fitness. Finally, our results suggest a secondary role of direct effects (resource-based) on P. lusitanica plasticity limitation. Further studies should quantify plant resources in order to gain a better understanding of this seldom-explored subject.

  18. The influence of abiotic stress and phenotypic plasticity on the distribution of invasive Alternanthera philoxeroides along a riparian zone

    NASA Astrophysics Data System (ADS)

    Pan, Xiaoyun; Geng, Yupeng; Zhang, Wenju; Li, Bo; Chen, Jiakuan

    2006-11-01

    Relatively few studies have compared invasibility and species invasiveness among microhabitats within communities, synchronously. We surveyed the abundance and performance of non-native Alternanthera philoxeroides (Mart.) Griseb. (alligator weed), its co-occurring native congener, Alternanthera sessilis (L.) DC. (sessile joyweed), and other species in a wetland community along a riparian zone in southeast China to test the hypotheses that: i) degree of invasion differs between different types of microhabitats within the community; and ii) microhabitat types that differ in invasibility also differ in soil resource availability or in sediment characteristics likely to affect resource availability; iii) phenotypic plasticity of A. philoxeroides may play a key role in its adaptation to diverse habitats as can be concluded from its extremely low genetic diversity in China. The study riparian zone comprises different types of microhabitats including wet abandoned field, swamp, marsh dunes and gravel dunes. Consistent with these hypotheses, cover of A. philoxeroides was high in abandoned fields (73 ± 2.9%) and swamps (94 ± 1.3%), which had high soil nutrients and water availability. On the contrary, cover of native A. sessilis was relatively high in marsh dunes and grave dunes, which had coarse gravel surfaces, low soil nutrients and low water availability. A. philoxeroides showed greater morphological plasticity in response to habitat variation. In abiotically harsh habitats, stems had limited growth, and were prostrate with weak adventitious roots at nodes, forming thin, scattered patches. In the two richer habitats, the highly branched plants spread over the water or soil surface, supporting dense stronger leaf-bearing stems which grew vertically. The growth pattern of A. sessilis among microhabitats did not exhibit significant variations. These results suggest that morphological plasticity and microhabitat types with high soil resources may facilitate invasions of A

  19. Patterns of phenotypic plasticity in common and rare environments: a study of host use and color learning in the cabbage white butterfly Pieris rapae.

    PubMed

    Snell-Rood, Emilie C; Papaj, Daniel R

    2009-05-01

    Phenotypic plasticity is adaptive in variable environments but, given its costs, may be disfavored if only one environment is commonly encountered. Yet species in relatively constant environments often adjust phenotypes successfully in rare or novel environments. Developmental biases may reduce the costs of plasticity in common environments, favoring the maintenance of plasticity. We explored this proposition by studying the flexibility of visually guided host-selection behavior in cabbage white butterflies (Pieris rapae), wherein common and rare environments consisted of green and red host types, respectively. We demonstrated in greenhouse assays that adult females display an innate bias toward green color during host search but alter that bias through learning in red-host assemblages such that, after several hours of experience, red hosts are located as efficiently as green hosts. Full-sib analyses suggested there was genetic variation in host and color choice that was more pronounced in the red-host environment. We found no evidence of genetic correlations in behavior across host environments or of fitness costs of plasticity in color choice. Our results support the idea that learning may persist in less variable environments through the evolution of innate biases that reduce operating costs in common environments.

  20. Low temperature-induced necrosis shows phenotypic plasticity in wheat triploid hybrids.

    PubMed

    Takumi, Shigeo; Mizuno, Nobuyuki

    2011-10-01

    Hybrid necrosis sometimes appears in triploid hybrids between tetraploid wheat and Aegilops tauschii Coss. Two types of hybrid necrosis (type II and type III) were observed when cultivar Langdon was used as female parent for hybrid production. Type II necrosis symptoms occurred only under low temperature conditions, whereas bushy and dwarf phenotypes were observed under normal temperature conditions. The developmental plasticity might be related to a temperature-responsive alteration of meristematic activity at the crown tissue of triploid hybrids. Epistatic interaction between the AB and D genomes induced not only upregulation of a number of defense-related genes, but also extensive changes in plant architecture in the type II necrosis hybrids. Such phenotypic plasticity was also observed in other cross combinations between cultivated tetraploid wheat and type II necrosis-induced Ae. tauschii accessions. Wild tetraploid wheat, Triticum turgidum subspecies dicoccoides, did not induce type II necrosis in the triploid hybrids, indicating the possibility of identifying the chromosomal location of a causal gene for type II necrosis in the AB genome.

  1. The therapeutic potential of skeletal muscle plasticity in Duchenne muscular dystrophy: phenotypic modifiers as pharmacologic targets.

    PubMed

    Ljubicic, Vladimir; Burt, Matthew; Jasmin, Bernard J

    2014-02-01

    Duchenne muscular dystrophy (DMD) is a life-limiting, neuromuscular disorder that causes progressive, severe muscle wasting in boys and young men. Although there is no cure, scientists and clinicians can leverage the fact that slower, more oxidative skeletal muscle fibers possess an enhanced degree of resistance to the dystrophic pathology relative to their faster, more glycolytic counterparts, and can thus use this knowledge when investigating novel therapeutic avenues. Several factors have been identified as powerful regulators of muscle plasticity. Some proteins, such as calcineurin, peroxisome proliferator-activated receptor (PPAR) γ coactivator 1α (PGC-1α), PPARβ/δ, and AMP-activated protein kinase (AMPK), when chronically stimulated in animal models, remodel skeletal muscle toward the slow, oxidative myogenic program, whereas others, such as receptor-interacting protein 140 (RIP140) and E2F transcription factor 1 (E2F1), repress this phenotype. Recent studies demonstrating that pharmacologic and physiological activation of targets that shift dystrophic muscle toward the slow, oxidative myogenic program provide appreciable molecular and functional benefits. This review surveys the rationale behind, and evidence for, the study of skeletal muscle plasticity in preclinical models of DMD and highlights the potential therapeutic opportunities in advancing a strategy focused on remodeling skeletal muscle in patients with DMD toward the slow, oxidative phenotype.

  2. Extensive phenotypic plasticity of a Red Sea coral over a strong latitudinal temperature gradient suggests limited acclimatization potential to warming

    NASA Astrophysics Data System (ADS)

    Sawall, Yvonne; Al-Sofyani, Abdulmoshin; Hohn, Sönke; Banguera-Hinestroza, Eulalia; Voolstra, Christian R.; Wahl, Martin

    2015-03-01

    Global warming was reported to cause growth reductions in tropical shallow water corals in both, cooler and warmer, regions of the coral species range. This suggests regional adaptation with less heat-tolerant populations in cooler and more thermo-tolerant populations in warmer regions. Here, we investigated seasonal changes in the in situ metabolic performance of the widely distributed hermatypic coral Pocillopora verrucosa along 12° latitudes featuring a steep temperature gradient between the northern (28.5°N, 21-27°C) and southern (16.5°N, 28-33°C) reaches of the Red Sea. Surprisingly, we found little indication for regional adaptation, but strong indications for high phenotypic plasticity: Calcification rates in two seasons (winter, summer) were found to be highest at 28-29°C throughout all populations independent of their geographic location. Mucus release increased with temperature and nutrient supply, both being highest in the south. Genetic characterization of the coral host revealed low inter-regional variation and differences in the Symbiodinium clade composition only at the most northern and most southern region. This suggests variable acclimatization potential to ocean warming of coral populations across the Red Sea: high acclimatization potential in northern populations, but limited ability to cope with ocean warming in southern populations already existing at the upper thermal margin for corals.

  3. Extensive phenotypic plasticity of a Red Sea coral over a strong latitudinal temperature gradient suggests limited acclimatization potential to warming.

    PubMed

    Sawall, Yvonne; Al-Sofyani, Abdulmoshin; Hohn, Sönke; Banguera-Hinestroza, Eulalia; Voolstra, Christian R; Wahl, Martin

    2015-03-10

    Global warming was reported to cause growth reductions in tropical shallow water corals in both, cooler and warmer, regions of the coral species range. This suggests regional adaptation with less heat-tolerant populations in cooler and more thermo-tolerant populations in warmer regions. Here, we investigated seasonal changes in the in situ metabolic performance of the widely distributed hermatypic coral Pocillopora verrucosa along 12° latitudes featuring a steep temperature gradient between the northern (28.5°N, 21-27°C) and southern (16.5°N, 28-33°C) reaches of the Red Sea. Surprisingly, we found little indication for regional adaptation, but strong indications for high phenotypic plasticity: Calcification rates in two seasons (winter, summer) were found to be highest at 28-29°C throughout all populations independent of their geographic location. Mucus release increased with temperature and nutrient supply, both being highest in the south. Genetic characterization of the coral host revealed low inter-regional variation and differences in the Symbiodinium clade composition only at the most northern and most southern region. This suggests variable acclimatization potential to ocean warming of coral populations across the Red Sea: high acclimatization potential in northern populations, but limited ability to cope with ocean warming in southern populations already existing at the upper thermal margin for corals.

  4. Natural selection for grazer resistance to toxic cyanobacteria: evolution of phenotypic plasticity?

    PubMed

    Hairston, N G; Holtmeier, C L; Lampert, W; Weider, L J; Post, D M; Fischer, J M; Cáceres, C E; Fox, J A; Gaedke, U

    2001-11-11

    We studied the selection response of the freshwater grazing zooplankter, Daphnia galeata, to increased abundance of cyanobacteria in its environment. Cyanobacteria are a poor-quality and often toxic food. Distinct genotypes of D. galeata were hatched from diapausing eggs extracted from three time horizons in the sediments of Lake Constance, Europe, covering the period 1962 to 1997, a time of change in both the prevalence of planktonic cyanobacteria and levels of phosphorus pollution. We assessed whether the grazers evolved to become more resistant to dietary cyanobacteria by exposing genetically distinct clones to two diets, one composed only of the nutritious green alga, Scenedesmus obliquus (good food), and the other a mixture of S. obliquus and the toxic cyanobacterium Microcvstis aeruginosa (poor food). Genotype performance was measured as the specific rate of weight gain from neonate to maturity (gj). We evaluated evolutionary change in the Daphnia population using an analysis of reaction norms based on relative (log-transformed) changes in gj. Log(gj) is a measure of the proportional effect of dietary cyanobacteria on other fitness components of the Daphnia phenotype. For comparison, we also analyze absolute (i.e., nontransformed) changes in gj and discuss the interpretations of the two approaches. Statistical results using a general linear model demonstrate a significant effect of genotype (showing differences in gj among genotypes), a significant genotype x food-type interaction (showing differences in phenotypic plasticity among genotypes), and, in the case of log-transformed data, a significant sediment-genotype-age x food-type interaction. The latter shows that phenotypic plasticity evolved over the period studied. Two constraints act on response to selection in the D. galeata-Lake Constance system. First, gj on a diet containing poor food is highly correlated with gj on a diet of good food, thus evolving resistance also meant evolving an increase in gj

  5. Antarctic climate change: extreme events disrupt plastic phenotypic response in Adélie penguins.

    PubMed

    Lescroël, Amélie; Ballard, Grant; Grémillet, David; Authier, Matthieu; Ainley, David G

    2014-01-01

    In the context of predicted alteration of sea ice cover and increased frequency of extreme events, it is especially timely to investigate plasticity within Antarctic species responding to a key environmental aspect of their ecology: sea ice variability. Using 13 years of longitudinal data, we investigated the effect of sea ice concentration (SIC) on the foraging efficiency of Adélie penguins (Pygoscelis adeliae) breeding in the Ross Sea. A 'natural experiment' brought by the exceptional presence of giant icebergs during 5 consecutive years provided unprecedented habitat variation for testing the effects of extreme events on the relationship between SIC and foraging efficiency in this sea-ice dependent species. Significant levels of phenotypic plasticity were evident in response to changes in SIC in normal environmental conditions. Maximum foraging efficiency occurred at relatively low SIC, peaking at 6.1% and decreasing with higher SIC. The 'natural experiment' uncoupled efficiency levels from SIC variations. Our study suggests that lower summer SIC than currently observed would benefit the foraging performance of Adélie penguins in their southernmost breeding area. Importantly, it also provides evidence that extreme climatic events can disrupt response plasticity in a wild seabird population. This questions the predictive power of relationships built on past observations, when not only the average climatic conditions are changing but the frequency of extreme climatic anomalies is also on the rise.

  6. Phenotypic plasticity in the spawning traits of bigheaded carp (Hypophthalmichthys spp.) in novel ecosystems

    USGS Publications Warehouse

    Coulter, Alison A.; Keller, Doug; Amberg, Jon J.; Bailey, Elizabeth J.; Goforth, Reuben R.

    2013-01-01

    1. Bigheaded carp, including both silver (Hypophthalmichthys molitrix) and bighead (H. nobilis) carp, are successful invasive fishes that threaten global freshwater biodiversity. High phenotypic plasticity probably contributes to their success in novel ecosystems, although evidence of plasticity in several spawning traits has hitherto been largely anecdotal or speculative. 2. We collected drifting eggs from a Midwestern U.S.A. river from June to September 2011 and from April to June 2012 to investigate the spawning traits of bigheaded carp in novel ecosystems. 3. Unlike reports from the native range, the presence of drifting bigheaded carp eggs was not related to changes in hydrological regime or mean daily water temperature. Bigheaded carp also exhibited protracted spawning, since we found drifting eggs throughout the summer and as late as 1 September 2011. Finally, we detected bigheaded carp eggs in a river reach where the channel is c. 30 m wide with a catchment area of 4579 km2, the smallest stream in which spawning has yet been documented. 4. Taken with previous observations of spawning traits that depart from those observed within the native ranges of both bighead and silver carp, our findings provide direct evidence that bigheaded carp exhibit plastic spawning traits in novel ecosystems that may facilitate invasion and establishment in a wider range of river conditions than previously envisaged.

  7. Antarctic Climate Change: Extreme Events Disrupt Plastic Phenotypic Response in Adélie Penguins

    PubMed Central

    Lescroël, Amélie; Ballard, Grant; Grémillet, David; Authier, Matthieu; Ainley, David G.

    2014-01-01

    In the context of predicted alteration of sea ice cover and increased frequency of extreme events, it is especially timely to investigate plasticity within Antarctic species responding to a key environmental aspect of their ecology: sea ice variability. Using 13 years of longitudinal data, we investigated the effect of sea ice concentration (SIC) on the foraging efficiency of Adélie penguins (Pygoscelis adeliae) breeding in the Ross Sea. A ‘natural experiment’ brought by the exceptional presence of giant icebergs during 5 consecutive years provided unprecedented habitat variation for testing the effects of extreme events on the relationship between SIC and foraging efficiency in this sea-ice dependent species. Significant levels of phenotypic plasticity were evident in response to changes in SIC in normal environmental conditions. Maximum foraging efficiency occurred at relatively low SIC, peaking at 6.1% and decreasing with higher SIC. The ‘natural experiment’ uncoupled efficiency levels from SIC variations. Our study suggests that lower summer SIC than currently observed would benefit the foraging performance of Adélie penguins in their southernmost breeding area. Importantly, it also provides evidence that extreme climatic events can disrupt response plasticity in a wild seabird population. This questions the predictive power of relationships built on past observations, when not only the average climatic conditions are changing but the frequency of extreme climatic anomalies is also on the rise. PMID:24489657

  8. Extraordinary Adaptive Plasticity of Colorado Potato Beetle: "Ten-Striped Spearman" in the Era of Biotechnological Warfare.

    PubMed

    Cingel, Aleksandar; Savić, Jelena; Lazarević, Jelica; Ćosić, Tatjana; Raspor, Martin; Smigocki, Ann; Ninković, Slavica

    2016-09-13

    Expanding from remote areas of Mexico to a worldwide scale, the ten-striped insect, the Colorado potato beetle (CPB, Leptinotarsa decemlineata Say), has risen from being an innocuous beetle to a prominent global pest. A diverse life cycle, phenotypic plasticity, adaptation to adverse conditions, and capability to detoxify or tolerate toxins make this insect appear to be virtually "indestructible". With increasing advances in molecular biology, tools of biotechnological warfare were deployed to combat CPB. In the last three decades, genetically modified potato has created a new challenge for the beetle. After reviewing hundreds of scientific papers dealing with CPB control, it became clear that even biotechnological means of control, if used alone, would not defeat the Colorado potato beetle. This control measure once again appears to be provoking the potato beetle to exhibit its remarkable adaptability. Nonetheless, the potential for adaptation to these techniques has increased our knowledge of this pest and thus opened possibilities for devising more sustainable CPB management programs.

  9. Inter- and intraspecific phenotypic plasticity of three phytoplankton species in response to ocean acidification.

    PubMed

    Hattich, Giannina S I; Listmann, Luisa; Raab, Julia; Ozod-Seradj, Dorthe; Reusch, Thorsten B H; Matthiessen, Birte

    2017-02-01

    Phenotypic plasticity describes the phenotypic adjustment of the same genotype to different environmental conditions and is best described by a reaction norm. We focus on the effect of ocean acidification on inter- and intraspecific reaction norms of three globally important phytoplankton species (Emiliania huxleyi, Gephyrocapsa oceanica and Chaetoceros affinis). Despite significant differences in growth rates between the species, they all showed a high potential for phenotypic buffering (similar growth rates between ambient and high CO2 conditions). Only three coccolithophore genotypes showed a reduced growth in high CO2 Diverging responses to high CO2 of single coccolithophore genotypes compared with the respective mean species responses, however, raise the question of whether an extrapolation to the population level is possible from single-genotype experiments. We therefore compared the mean response of all tested genotypes with a total species response comprising the same genotypes, which was not significantly different in the coccolithophores. Assessing species reaction norms to different environmental conditions on short time scale in a genotype-mix could thus reduce sampling effort while increasing predictive power.

  10. Inter- and intraspecific phenotypic plasticity of three phytoplankton species in response to ocean acidification

    PubMed Central

    Raab, Julia; Ozod-Seradj, Dorthe; Reusch, Thorsten B. H.; Matthiessen, Birte

    2017-01-01

    Phenotypic plasticity describes the phenotypic adjustment of the same genotype to different environmental conditions and is best described by a reaction norm. We focus on the effect of ocean acidification on inter- and intraspecific reaction norms of three globally important phytoplankton species (Emiliania huxleyi, Gephyrocapsa oceanica and Chaetoceros affinis). Despite significant differences in growth rates between the species, they all showed a high potential for phenotypic buffering (similar growth rates between ambient and high CO2 conditions). Only three coccolithophore genotypes showed a reduced growth in high CO2. Diverging responses to high CO2 of single coccolithophore genotypes compared with the respective mean species responses, however, raise the question of whether an extrapolation to the population level is possible from single-genotype experiments. We therefore compared the mean response of all tested genotypes with a total species response comprising the same genotypes, which was not significantly different in the coccolithophores. Assessing species reaction norms to different environmental conditions on short time scale in a genotype-mix could thus reduce sampling effort while increasing predictive power. PMID:28148833

  11. Phenotypic plasticity and integration in response to flooded conditions in natural accessions of Arabidopsis thaliana (L.) Heynh (Brassicaceae).

    PubMed

    Pigliucci, Massimo; Kolodynska, Anna

    2002-08-01

    Flood response is a crucial component of the life strategy of many plants, but it is seldom studied in non-flooded tolerant species, even though they may be subjected to stressful environmental conditions. Phenotypic plasticity in reaction to environmental stress affects the whole plant phenotype and can alter the character correlations that constitute the phenotypic architecture of the individual, yet few studies have investigated the lability of phenotypic integration to water regime. Moreover, little has been done to date to quantify the sort of selective pressures that different components of a plant's phenotype may be experiencing under contrasting water regimes. Genetic differentiation and phenotypic plasticity at the single-trait and multivariate levels were investigated in 47 accessions of the weedy plant Arabidopsis thaliana, and the relationship of plastic characters to reproductive fitness was quantified. Results indicate that these plants tend to be highly genetically differentiated for all traits, in agreement with predictions made on the basis of environmental variation and mating system. Varied patterns of apparent selection under flooded and non-flooded conditions were also uncovered, suggesting trade-offs in allocation between roots and above-ground biomass, as well as between leaves and reproductive structures. While the major components of the plants' multivariate phenotypic architecture were not significantly affected by environmental changes, many of the details were different under flooded and non-flooded conditions.

  12. Thermal plasticity of skeletal muscle phenotype in ectothermic vertebrates and its significance for locomotory behaviour.

    PubMed

    Johnston, Ian A; Temple, Genevieve K

    2002-08-01

    Seasonal cooling can modify the thermal preferenda of ectothermic vertebrates and elicit a variety of physiological responses ranging from winter dormancy to an acclimation response that partially compensates for the effects of low temperature on activity. Partial compensation of activity levels is particularly common in aquatic species for which seasonal temperature changes provide a stable cue for initiating the response. Thermal plasticity of locomotory performance has evolved independently on numerous occasions, and there is considerable phylogenetic diversity with respect to the mechanisms at the physiological and molecular levels. In teleosts, neuromuscular variables that can be modified include the duration of motor nerve stimulation, muscle activation and relaxation times, maximum force and unloaded shortening velocity (V(max)), although not all are modified in every species. Thermal plasticity in V(max) has been associated with changes in myosin ATPase activity and myosin heavy chain (MyHC) composition and/or with a change in the ratio of myosin light chain isoforms. In common carp (Cyprinus carpio), there are continuous changes in phenotype with acclimation temperature at lower levels of organisation, such as MyHC composition and V(max), but a distinct threshold for an effect in terms of locomotory performance. Thus, there is no simple relationship between whole-animal performance and muscle phenotype. The nature and magnitude of temperature acclimation responses also vary during ontogeny. For example, common carp acquire the ability to modify MyHC composition with changes in acclimation temperature during the juvenile stage. In contrast, the thermal plasticity of swimming performance observed in tadpoles of the frog Limnodynastes peronii is lost in the terrestrial adult stage. Although it is often assumed that the adjustments in locomotory performance associated with temperature acclimation enhance fitness, this has rarely been tested experimentally

  13. How flexible is phenotypic plasticity? Developmental windows for trait induction and reversal.

    PubMed

    Hoverman, Jason T; Relyea, Rick A

    2007-03-01

    Inducible defenses allow prey to modulate their phenotypic responses to the level of predation risk in the environment and reduce the cost of constitutive defenses. Inherent in this statement is that prey must alter their phenotypes during development in order to form these defenses. This has lead many ecologists and evolutionary biologists to call for studies that examine developmental plasticity to provide insights into the importance of development in controlling the trajectories of trait formation, the integration of phenotypes over ontogeny, and the establishment of developmental windows for trait formation and reversal. By moving away from studies that focus on a single point in development, we can obtain a more complete understanding of the phenotypic decisions and limitations of prey. We exposed freshwater snails (Helisoma trivolvis) to environments in which predatory water bugs (Belostoma flumineum) were always absent, always present, or added and removed at different points in development. We discovered that snails formed morphological defenses against water bugs. Importantly, after the initial induction of defenses, snails showed similar developmental trajectories as snails reared without predators. Further, the snails possessed wide developmental windows for inducible defenses that extended past sexual maturity. However, being induced later in development appeared to have an associated cost (i.e., decreased shell thickness) that was not found when water bugs were always present. This epiphenotype (i.e., new shell formation as an extension of the current shell) suggests that resource limitation plays an important role in responses to temporal variation in predation risk and may have critical ecological costs that limit the benefits of the inducible defense. Lastly, the ability of snails to completely reverse their defenses was limited to early in ontogeny due to the constraints associated with modular growth of shell material. In sum, we demonstrate that

  14. Inherent phenotypic plasticity facilitates progression of head and neck cancer: Endotheliod characteristics enable angiogenesis and invasion

    SciTech Connect

    Tong, Meng; Han, Byungdo B.; Holpuch, Andrew S.; Pei, Ping; He, Lingli; Mallery, Susan R.

    2013-04-15

    The presence of the EMT (epithelial-mesenchymal transition), EndMT (endothelial-mesenchymal transition) and VM (vasculogenic mimicry) demonstrates the multidirectional extent of phenotypic plasticity in cancers. Previous findings demonstrating the crosstalk between head and neck squamous cell carcinoma (HNSCC) and vascular endothelial growth factor (VEGF) imply that HNSCC cells share some functional commonalities with endothelial cells. Our current results reveal that cultured HNSCC cells not only possess endothelial-specific markers, but also display endotheliod functional features including low density lipoprotein uptake, formation of tube-like structures on Matrigel and growth state responsiveness to VEGF and endostatin. HNSCC cell subpopulations are also highly responsive to transforming growth factor-β1 and express its auxiliary receptor, endoglin. Furthermore, the endotheliod characteristics observed in vitro recapitulate phenotypic features observed in human HNSCC tumors. Conversely, cultured normal human oral keratinocytes and intact or ulcerated human oral epithelia do not express comparable endotheliod characteristics, which imply that assumption of endotheliod features is restricted to transformed keratinocytes. In addition, this phenotypic state reciprocity facilitates HNSCC progression by increasing production of factors that are concurrently pro-proliferative and pro-angiogenic, conserving cell energy stores by LDL internalization and enhancing cell mobility. Finally, recognition of this endotheliod phenotypic transition provides a solid rationale to evaluate the antitumorigenic potential of therapeutic agents formerly regarded as exclusively angiostatic in scope. - Highlights: ► HNSCC tumor cells express endothelial specific markers VE-cadherin, CD31 and vimentin. ► Similarly, cultured HNSCC cells retain expression of these markers. ► HNSCC cells demonstrate functional endotheliod characteristics i.e. AcLDL uptake. ► HNSCC cell

  15. Rice Root Architectural Plasticity Traits and Genetic Regions for Adaptability to Variable Cultivation and Stress Conditions.

    PubMed

    Sandhu, Nitika; Raman, K Anitha; Torres, Rolando O; Audebert, Alain; Dardou, Audrey; Kumar, Arvind; Henry, Amelia

    2016-08-01

    Future rice (Oryza sativa) crops will likely experience a range of growth conditions, and root architectural plasticity will be an important characteristic to confer adaptability across variable environments. In this study, the relationship between root architectural plasticity and adaptability (i.e. yield stability) was evaluated in two traditional × improved rice populations (Aus 276 × MTU1010 and Kali Aus × MTU1010). Forty contrasting genotypes were grown in direct-seeded upland and transplanted lowland conditions with drought and drought + rewatered stress treatments in lysimeter and field studies and a low-phosphorus stress treatment in a Rhizoscope study. Relationships among root architectural plasticity for root dry weight, root length density, and percentage lateral roots with yield stability were identified. Selected genotypes that showed high yield stability also showed a high degree of root plasticity in response to both drought and low phosphorus. The two populations varied in the soil depth effect on root architectural plasticity traits, none of which resulted in reduced grain yield. Root architectural plasticity traits were related to 13 (Aus 276 population) and 21 (Kali Aus population) genetic loci, which were contributed by both the traditional donor parents and MTU1010. Three genomic loci were identified as hot spots with multiple root architectural plasticity traits in both populations, and one locus for both root architectural plasticity and grain yield was detected. These results suggest an important role of root architectural plasticity across future rice crop conditions and provide a starting point for marker-assisted selection for plasticity.

  16. Phenotypic plasticity of invasive Alternanthera philoxeroides in relation to different water availability, compared to its native congener

    NASA Astrophysics Data System (ADS)

    Geng, Yu-Peng; Pan, Xiao-Yun; Xu, Cheng-Yuan; Zhang, Wen-Ju; Li, Bo; Chen, Jia-Kuan

    2006-11-01

    Phenotypic plasticity and genetic differentiation are two possible mechanisms that plants use to cope with varying environments. Although alligator weed ( Alternanthera philoxeroides) possesses very low genetic diversity, this alien weed has successfully invaded diverse habitats with considerably varying water availability (from swamps to dry lands) in China. In contrast, its native congener ( Alternanthera sessilis) has a much narrower ecological breadth, and is usually found in moist habitats. To understand the mechanisms underlying the contrasting pattern, we performed a greenhouse experiment to compare the reaction norms of alligator weed with those of its native congener, in which water availability was manipulated. Our results revealed that the two congeners had similar direction of phenotypic plasticity. However, A. philoxeroides showed greater plasticity in amount than did A. sessilis in many traits examined during the switch from wet to drought treatment. Nearly all of the phenotypic variance in A. philoxeroides could be ascribed to plasticity, while A. sessilis had a much higher fraction of phenotypic variance that could be explained by genotypic variation. These interspecific differences in plastic responses to variable water availability partially explained the difference in spatial distribution of the two congeners.

  17. Sex Differences in Phenotypic Plasticity Affect Variation in Sexual Size Dimorphism in Insects: From Physiology to Evolution

    PubMed Central

    Stillwell, R. Craig; Blanckenhorn, Wolf U.; Teder, Tiit; Davidowitz, Goggy; Fox, Charles W.

    2015-01-01

    Males and females of nearly all animals differ in their body size, a phenomenon called sexual size dimorphism (SSD). The degree and direction of SSD vary considerably among taxa, including among populations within species. A considerable amount of this variation is due to sex differences in body size plasticity. We examine how variation in these sex differences is generated by exploring sex differences in plasticity in growth rate and development time and the physiological regulation of these differences (e.g., sex differences in regulation by the endocrine system). We explore adaptive hypotheses proposed to explain sex differences in plasticity, including those that predict that plasticity will be lowest for traits under strong selection (adaptive canalization) or greatest for traits under strong directional selection (condition dependence), but few studies have tested these hypotheses. Studies that combine proximate and ultimate mechanisms offer great promise for understanding variation in SSD and sex differences in body size plasticity in insects. PMID:19728836

  18. Phenotypic plasticity in sex allocation for a simultaneously hermaphroditic coral reef fish

    NASA Astrophysics Data System (ADS)

    Hart, M. K.; Svoboda, A.; Mancilla Cortez, D.

    2011-06-01

    Phenotypic plasticity can facilitate reproductive strategies that maximize mating success in variable environments and lead to differences in sex allocation among populations. For simultaneous hermaphrodites with sperm competition, including Serranus tortugarum a small coral reef fish, proportional male allocation (testis in total gonad) is often greater where local density or mating group size is higher. We tested whether S. tortugarum reduced male allocation when transplanted from a higher density site to a lower density site. After 4 months, transplants mirrored the sex-allocation patterns of the resident population on their new reef. Transplants had significantly lower male allocation than representatives from their source population, largely as a result of reduced testis mass relative to body size.

  19. Phenotypic plasticity in Caryophyllaeus brachycollis Janiszewska, 1953 (Cestoda: Caryophyllidea): does fish host play a role?

    PubMed

    Barčák, Daniel; Oros, Mikuláš; Hanzelová, Vladimíra; Scholz, Tomáš

    2014-06-01

    Recent molecular phylogenetic studies on fish tapeworms of the genus Caryophyllaeus Gmelin, 1790 (Cestoda: Caryophyllidea), parasites of cyprinid fishes in the Palaearctic Region, have revealed unexpected phenotypic plasticity that seems to be related to definitive hosts. In the present paper, Caryophyllaeus brachycollis Janiszewska, 1953 is redescribed and its two morphotypes are circumscribed on the basis of newly-collected specimens. Morphotype 1 from barbels [Barbus spp. including the type-host Barbus barbus (L.); Barbinae] and chubs (Squalius spp.; Leuciscinae) is characterised by a more robust body with spatulate scolex, which is only slightly wider than a very short neck region, and the anterior position of the testes and vitelline follicles, which begin immediately posterior to the scolex. Specimens of Morphotype 2 from breams (Abramis spp., Ballerus spp. and Blicca spp.; Abraminae), which have been previously misidentifed as Caryophyllaeus laticeps (Pallas, 1781), possess a more slender body with a flabellate scolex, which is much wider than a long neck, and the first testes begin at a considerable distance posterior to the first vitelline follicles. Despite conspicuous differences in the scolex morphology and the anterior extent of the testes and vitelline follicles, both morphotypes are identical in the morphology of the posterior end of the body, in particular that of the cirrus-sac, which is large, thick-walled, elongate-pyriform, and contains a long cirrus, and in the distribution of the vitelline follicles, which surround medially vas deferens near the cirrus-sac. A specimen of Morphotype 1 from B. barbus from the Argens River, France, is designated as neotype of C. brachycollis. The presence of phenotypic plasticity in morphological characteristics previously used for differentiation of species of Caryophyllaeus may confound species identification, which is crucial for biodiversity, ecological and evolutionary studies. To avoid these potential

  20. Ecology and Evolution of Phenotypic Plasticity in the Penis and Cirri of Barnacles.

    PubMed

    Hoch, J Matthew; Schneck, Daniel T; Neufeld, Christopher J

    2016-10-01

    Most barnacles are sessile, simultaneous hermaphrodites that reproduce by copulation. This is achieved through the extension of a muscular penis, famous for being the proportionally largest in the animal kingdom. The penis is a long cylindrical or conical organ, composed of a series of folded rings, allowing it to stretch to great lengths. The penises are covered with chemosensory setae allowing them to seek out receptive neighbors. For many species, the condition of the penis changes seasonally. In the most extreme circumstances, it degenerates and is shed during the first post-mating molt and is re-grown for the next mating season. Barnacle penises have been shown to exhibit phenotypic plasticity in response to many different challenges. When exposed to heavy waves, diameter is increased by thickening both the cuticle and muscles. When mates are far, length increases by adding ringed annulations. Experiments have shown that these plastic traits are modular, capable of changing independently from each other and that they improve mating ability. Alternate strategies to increase reproductive ability by barnacles include the production of dwarf and complemental males, sperm casting and sperm leakage, and aerial copulation. All of these mating strategies may have important implications for the study of reproductive biology, life history, and sex allocation theory.

  1. The senescence-associated secretory phenotype induces cellular plasticity and tissue regeneration

    PubMed Central

    Ritschka, Birgit; Storer, Mekayla; Mas, Alba; Heinzmann, Florian; Ortells, Mari Carmen; Morton, Jennifer P.; Sansom, Owen J.; Zender, Lars; Keyes, William M.

    2017-01-01

    Senescence is a form of cell cycle arrest induced by stress such as DNA damage and oncogenes. However, while arrested, senescent cells secrete a variety of proteins collectively known as the senescence-associated secretory phenotype (SASP), which can reinforce the arrest and induce senescence in a paracrine manner. However, the SASP has also been shown to favor embryonic development, wound healing, and even tumor growth, suggesting more complex physiological roles than currently understood. Here we uncover timely new functions of the SASP in promoting a proregenerative response through the induction of cell plasticity and stemness. We show that primary mouse keratinocytes transiently exposed to the SASP exhibit increased expression of stem cell markers and regenerative capacity in vivo. However, prolonged exposure to the SASP causes a subsequent cell-intrinsic senescence arrest to counter the continued regenerative stimuli. Finally, by inducing senescence in single cells in vivo in the liver, we demonstrate that this activates tissue-specific expression of stem cell markers. Together, this work uncovers a primary and beneficial role for the SASP in promoting cell plasticity and tissue regeneration and introduces the concept that transient therapeutic delivery of senescent cells could be harnessed to drive tissue regeneration. PMID:28143833

  2. Genetic variability and phenotypic plasticity of metric thoracic traits in an invasive drosophilid in America.

    PubMed

    Bitner-Mathé, Blanche Christine; David, Jean Robert

    2015-08-01

    Thermal phenotypic plasticity of 5 metric thoracic traits (3 related to size and 2 to pigmentation) was investigated in Zaprionus indianus with an isofemale line design. Three of these traits are investigated for the first time in a drosophilid, i.e. thorax width and width of pigmented longitudinal white and black stripes. The reaction norms of white and black stripes were completely different: white stripes were insensitive to growth temperature while the black stripes exhibited a strong linear decrease with increasing temperatures. Thorax width exhibited a concave reaction norm, analogous but not identical to those of wing length and thorax length: the temperatures of maximum value were different, the highest being for thorax width. All traits exhibited a significant heritable variability and a low evolvability. Sexual dimorphism was very variable among traits, being nil for white stripes and thorax width, and around 1.13 for black stripes. The ratio thorax length to thorax width (an elongation index) was always >1, showing that males have a more rounded thorax at all temperatures. Black stripes revealed a significant increase of sexual dimorphism with increasing temperature. Shape indices, i.e. ratios between size traits all exhibited a linear decrease with temperature, the least sensitive being the elongation index. All these results illustrate the complexity of developmental processes but also the analytical strength of biometrical plasticity studies in an eco-devo perspective.

  3. Histone deacetylases control module-specific phenotypic plasticity in beetle weapons

    PubMed Central

    Ozawa, Takane; Mizuhara, Tomoko; Arata, Masataka; Shimada, Masakazu; Niimi, Teruyuki; Okada, Kensuke; Okada, Yasukazu; Ohta, Kunihiro

    2016-01-01

    Nutritional conditions during early development influence the plastic expression of adult phenotypes. Among several body modules of animals, the development of sexually selected exaggerated traits exhibits striking nutrition sensitivity, resulting in positive allometry and hypervariability distinct from other traits. Using de novo RNA sequencing and comprehensive RNA interference (RNAi) for epigenetic modifying factors, we found that histone deacetylases (HDACs) and polycomb group (PcG) proteins preferentially influence the size of mandibles (exaggerated male weapon) and demonstrate nutrition-dependent hypervariability in the broad-horned flour beetle, Gnatocerus cornutus. RNAi-mediated HDAC1 knockdown (KD) in G. cornutus larvae caused specific curtailment of mandibles in adults, whereas HDAC3 KD led to hypertrophy. Notably, these KDs conferred opposite effects on wing size, but little effect on the size of the core body and genital modules. PcG RNAi also reduced adult mandible size. These results suggest that the plastic development of exaggerated traits is controlled in a module-specific manner by HDACs. PMID:27956627

  4. Shade tolerance, photoinhibition sensitivity and phenotypic plasticity of Ilex aquifolium in continental Mediterranean sites.

    PubMed

    Valladares, Fernando; Arrieta, Sagrario; Aranda, Ismael; Lorenzo, David; Sánchez-Gómez, David; Tena, David; Suárez, Francisco; Alberto Pardos, José

    2005-08-01

    Shade tolerance, plastic phenotypic response to light and sensitivity to photoinhibition were studied in holly (Ilex aquifolium L.) seedlings transported from the field to a greenhouse and in adult trees in the field. All plants were growing in, or originated from, continental Mediterranean sites in central Spain. Seedlings tolerated moderate but not deep shade. Mortality was high and growth reduced in 1% sunlight. Survival was maximal in 12% sunlight and minimal in full sunlight, although the relative growth rate of the seedlings surviving in high light was similar to that of plants in moderate shade. Maximum photochemical efficiency at predawn was significantly lower in sun plants than in shade plants in the field, revealing chronic photoinhibition that was most pronounced in winter. Plasticity in response to available light varied according to the variable studied, being low for photosynthetic capacity and stomatal conductance, and high for specific leaf area, root:shoot ratio and leaf area ratio, particularly in seedlings. Differences in water relations and hydraulic features between sun and shade plants in the field were marginal. High water potential at the turgor loss point of field-grown plants suggested that holly is sensitive to drought during both the seedling and the adult stage. Low relative growth rates in both high and low light with low physiological plasticity in response to light indicate the existence of a stress-tolerance mechanism. We conclude that holly is a facultative understory plant in areas of oceanic and relatively mild climate, but an obligate understory plant in dry continental areas such as the study site. The impact of abandonment of traditional management practices and climate change on these Mediterranean populations is discussed.

  5. Clinal adaptation and adaptive plasticity in Artemisia californica: implications for the response of a foundation species to predicted climate change.

    PubMed

    Pratt, Jessica D; Mooney, Kailen A

    2013-08-01

    Local adaptation and plasticity pose significant obstacles to predicting plant responses to future climates. Although local adaptation and plasticity in plant functional traits have been documented for many species, less is known about population-level variation in plasticity and whether such variation is driven by adaptation to environmental variation. We examined clinal variation in traits and performance - and plastic responses to environmental change - for the shrub Artemisia californica along a 700 km gradient characterized (from south to north) by a fourfold increase in precipitation and a 61% decrease in interannual precipitation variation. Plants cloned from five populations along this gradient were grown for 3 years in treatments approximating the precipitation regimes of the north and south range margins. Most traits varying among populations did so clinally; northern populations (vs. southern) had higher water-use efficiencies and lower growth rates, C : N ratios and terpene concentrations. Notably, there was variation in plasticity for plant performance that was strongly correlated with source site interannual precipitation variability. The high-precipitation treatment (vs. low) increased growth and flower production more for plants from southern populations (181% and 279%, respectively) than northern populations (47% and 20%, respectively). Overall, precipitation variability at population source sites predicted 86% and 99% of variation in plasticity in growth and flowering, respectively. These striking, clinal patterns in plant traits and plasticity are indicative of adaptation to both the mean and variability of environmental conditions. Furthermore, our analysis of long-term coastal climate data in turn indicates an increase in interannual precipitation variation consistent with most global change models and, unexpectedly, this increased variation is especially pronounced at historically stable, northern sites. Our findings demonstrate the

  6. Phenotypic plasticity of the basidiomata of Thelephora sp. (Thelephoraceae) in tropical forest habitats.

    PubMed

    Ramirez-Lópezl, Itzel; Ríos, Margarita Villegas; Cano-Santana, Zenón

    2013-03-01

    Phenotypic plasticity in macroscopic fungi has been poorly studied in comparison to plants or animals and only general aspects of these changes have been described. In this work, the phenotypic variation in the basidiomata of Thelephora sp. (Thelephoraceae) was examined, as well as some aspects of its ecology and habitat, using 24 specimens collected in the tropical forests of the Chamela Biological Station, Jalisco, Mexico. Our observations showed that this taxon has clavarioid basidiomata that can become resupinate during development and growth if they are in contact with rocks, litter or live plants, establishing in the latter only an epiphytic relationship. This tropical species may form groups of up to 139 basidiomata over an area of 32.2m2, and in both types of vegetation (tropical sub-evergreen and deciduous forest) were primarily located on steep (>20 degree) South-facing slopes. It is found under closed canopy in both tropical forests, but its presence in sub-evergreen forests is greater than expected.

  7. Phenotypically plastic responses of green frog embryos to conflicting predation risk.

    PubMed

    Ireland, D H; Wirsing, A J; Murray, D L

    2007-05-01

    Predators have been shown to alter the timing of switch points between life history stages, but few studies have addressed switch point plasticity in prey exposed simultaneously to conflicting predation pressure. We tested hatching responses of green frog (Rana clamitans) embryos subject to perceived predation risk from chemical cues released by two stage-specific predators, predicting that these predators would elicit: (1) directional hatching responses when presented independently, and (2) intermediate phenotypic responses when presented simultaneously. R. clamitans embryos in outdoor exclosures were exposed to cues from an egg predator (freshwater leeches; Nephelopsis obscura), a larval predator (dragonfly nymphs, Aeschna canadensis), and both predators in a 2 x 2 factorial experiment, and changes in hatchling size, hatchling developmental stage, and hatching time were compared to those for control embryos. Leeches alone induced embryos to hatch at a smaller size and an earlier developmental stage than controls, while dragonfly nymphs elicited a delay in egg hatching time that was associated with larger size and later developmental stage at hatching. Embryos failed to respond to simultaneous exposure to both predators, implying that responses to each occurred concurrently and were therefore dampened. Our results indicate that prey under threat from conflicting predators may manifest intermediate defensive phenotypes. Such intermediate responses may result in elevated rates of prey mortality with possible consequences at the population level.

  8. Dynamic Microenvironment Induces Phenotypic Plasticity of Esophageal Cancer Cells Under Flow

    NASA Astrophysics Data System (ADS)

    Calibasi Kocal, Gizem; Güven, Sinan; Foygel, Kira; Goldman, Aaron; Chen, Pu; Sengupta, Shiladitya; Paulmurugan, Ramasamy; Baskin, Yasemin; Demirci, Utkan

    2016-12-01

    Cancer microenvironment is a remarkably heterogeneous composition of cellular and non-cellular components, regulated by both external and intrinsic physical and chemical stimuli. Physical alterations driven by increased proliferation of neoplastic cells and angiogenesis in the cancer microenvironment result in the exposure of the cancer cells to elevated levels of flow-based shear stress. We developed a dynamic microfluidic cell culture platform utilizing eshopagael cancer cells as model cells to investigate the phenotypic changes of cancer cells upon exposure to fluid shear stress. We report the epithelial to hybrid epithelial/mesenchymal transition as a result of decreasing E-Cadherin and increasing N-Cadherin and vimentin expressions, higher clonogenicity and ALDH positive expression of cancer cells cultured in a dynamic microfluidic chip under laminar flow compared to the static culture condition. We also sought regulation of chemotherapeutics in cancer microenvironment towards phenotypic control of cancer cells. Such in vitro microfluidic system could potentially be used to monitor how the interstitial fluid dynamics affect cancer microenvironment and plasticity on a simple, highly controllable and inexpensive bioengineered platform.

  9. Dynamic Microenvironment Induces Phenotypic Plasticity of Esophageal Cancer Cells Under Flow

    PubMed Central

    Calibasi Kocal, Gizem; Güven, Sinan; Foygel, Kira; Goldman, Aaron; Chen, Pu; Sengupta, Shiladitya; Paulmurugan, Ramasamy; Baskin, Yasemin; Demirci, Utkan

    2016-01-01

    Cancer microenvironment is a remarkably heterogeneous composition of cellular and non-cellular components, regulated by both external and intrinsic physical and chemical stimuli. Physical alterations driven by increased proliferation of neoplastic cells and angiogenesis in the cancer microenvironment result in the exposure of the cancer cells to elevated levels of flow-based shear stress. We developed a dynamic microfluidic cell culture platform utilizing eshopagael cancer cells as model cells to investigate the phenotypic changes of cancer cells upon exposure to fluid shear stress. We report the epithelial to hybrid epithelial/mesenchymal transition as a result of decreasing E-Cadherin and increasing N-Cadherin and vimentin expressions, higher clonogenicity and ALDH positive expression of cancer cells cultured in a dynamic microfluidic chip under laminar flow compared to the static culture condition. We also sought regulation of chemotherapeutics in cancer microenvironment towards phenotypic control of cancer cells. Such in vitro microfluidic system could potentially be used to monitor how the interstitial fluid dynamics affect cancer microenvironment and plasticity on a simple, highly controllable and inexpensive bioengineered platform. PMID:27910892

  10. Genetic Adaptation vs. Ecophysiological Plasticity of Photosynthetic-Related Traits in Young Picea glauca Trees along a Regional Climatic Gradient.

    PubMed

    Benomar, Lahcen; Lamhamedi, Mohammed S; Rainville, André; Beaulieu, Jean; Bousquet, Jean; Margolis, Hank A

    2016-01-01

    Assisted population migration (APM) is the intentional movement of populations within a species range to sites where future environmental conditions are projected to be more conducive to growth. APM has been proposed as a proactive adaptation strategy to maintain forest productivity and to reduce the vulnerability of forest ecosystems to projected climate change. The validity of such a strategy will depend on the adaptation capacity of populations, which can partially be evaluated by the ecophysiological response of different genetic sources along a climatic gradient. This adaptation capacity results from the compromise between (i) the degree of genetic adaptation of seed sources to their environment of origin and (ii) the phenotypic plasticity of functional trait which can make it possible for transferred seed sources to positively respond to new growing conditions. We examined phenotypic variation in morphophysiological traits of six seed sources of white spruce (Picea glauca [Moench] Voss) along a regional climatic gradient in Québec, Canada. Seedlings from the seed sources were planted at three forest sites representing a mean annual temperature (MAT) gradient of 2.2°C. During the second growing season, we measured height growth (H2014) and traits related to resources use efficiency and photosynthetic rate (A max). All functional traits showed an adaptive response to the climatic gradient. Traits such as H2014, A max, stomatal conductance (g s ), the ratio of mesophyll to stomatal conductance, water use efficiency, and photosynthetic nitrogen-use efficiency showed significant variation in both physiological plasticity due to the planting site and seed source variation related to local genetic adaptation. However, the amplitude of seed source variation was much less than that related to plantation sites in the area investigated. The six seed sources showed a similar level of physiological plasticity. H2014, A max and g s , but not carboxylation capacity (V

  11. Genetic Adaptation vs. Ecophysiological Plasticity of Photosynthetic-Related Traits in Young Picea glauca Trees along a Regional Climatic Gradient

    PubMed Central

    Benomar, Lahcen; Lamhamedi, Mohammed S.; Rainville, André; Beaulieu, Jean; Bousquet, Jean; Margolis, Hank A.

    2016-01-01

    Assisted population migration (APM) is the intentional movement of populations within a species range to sites where future environmental conditions are projected to be more conducive to growth. APM has been proposed as a proactive adaptation strategy to maintain forest productivity and to reduce the vulnerability of forest ecosystems to projected climate change. The validity of such a strategy will depend on the adaptation capacity of populations, which can partially be evaluated by the ecophysiological response of different genetic sources along a climatic gradient. This adaptation capacity results from the compromise between (i) the degree of genetic adaptation of seed sources to their environment of origin and (ii) the phenotypic plasticity of functional trait which can make it possible for transferred seed sources to positively respond to new growing conditions. We examined phenotypic variation in morphophysiological traits of six seed sources of white spruce (Picea glauca [Moench] Voss) along a regional climatic gradient in Québec, Canada. Seedlings from the seed sources were planted at three forest sites representing a mean annual temperature (MAT) gradient of 2.2°C. During the second growing season, we measured height growth (H2014) and traits related to resources use efficiency and photosynthetic rate (Amax). All functional traits showed an adaptive response to the climatic gradient. Traits such as H2014, Amax, stomatal conductance (gs), the ratio of mesophyll to stomatal conductance, water use efficiency, and photosynthetic nitrogen-use efficiency showed significant variation in both physiological plasticity due to the planting site and seed source variation related to local genetic adaptation. However, the amplitude of seed source variation was much less than that related to plantation sites in the area investigated. The six seed sources showed a similar level of physiological plasticity. H2014, Amax and gs, but not carboxylation capacity (Vcmax), were

  12. Phenotypic plasticity in Passiflora suberosa L.(Passifloraceae): induction and reversion of two morphs by variation in light intensity.

    PubMed

    Barp, E A; Soares, G L G; Gosmann, G; Machado, A M; Vecchi, C; Moreira, G R P

    2006-08-01

    Leaf morphology may vary considerably even within a branch of Passiflora suberosa plants. Leaves are of a typical green type in shaded areas, but in open fields turn into violet, and apparently have greater thickness and trichome density. The proximate causes and the adaptive meaning, if any, for the existence of the violet morph are still unknown. By cultivating P. suberosa clones under two light regimes (total and partial exposure to sunlight), we consecutively induced (first year) and then reversed (second year) the appearance of the violet morph. We evaluated the corresponding changes in morpho-anatomic and chemical leaf characteristics. Plants that were grown under partial sunlight had a greater size and did not alter their green color, but those grown under total sunlight changed into violet, were smaller in size and their leaves were tougher, thicker, and had a greater number of trichomes. The violet morph had increased anthocyanins and phenolic derivatives. It also showed cellular hypertrophy, a greater number of cell layers in the mesophyll, and a lignified pericycle. Since these morphs are interchangeable by changing light conditions, we inferred that they are not determined by genotypic diversity, but are mainly a result of a physiological response to light stress, and thus part of P. suberosa phenotypic plasticity.

  13. Host-Specific Phenotypic Plasticity of the Turtle Barnacle Chelonibia testudinaria: A Widespread Generalist Rather than a Specialist

    PubMed Central

    Chu, Ka Hou; Cheng, I-Jiunn; Chan, Benny K. K.

    2013-01-01

    Turtle barnacles are common epibionts on marine organisms. Chelonibia testudinaria is specific on marine turtles whereas C. patula is a host generalist, but rarely found on turtles. It has been questioned why C. patula, being abundant on a variety of live substrata, is almost absent from turtles. We evaluated the genetic (mitochondrial COI, 16S and 12S rRNA, and amplified fragment length polymorphism (AFLP)) and morphological differentiation of C. testudinaia and C. patula from different hosts, to determine the mode of adaptation exhibited by Chelonibia species on different hosts. The two taxa demonstrate clear differences in shell morphology and length of 4–6th cirri, but very similar in arthropodal characters. Moreover, we detected no genetic differentiation in mitochondrial DNA and AFLP analyses. Outlier detection infers insignificant selection across loci investigated. Based on combined morphological and molecular evidence, we proposed that C. testudinaria and C. patula are conspecific, and the two morphs with contrasting shell morphologies and cirral length found on different host are predominantly shaped by developmental plasticity in response to environmental setting on different hosts. Chelonibia testudinaria is, thus, a successful general epibiotic fouler and the phenotypic responses postulated can increase the fitness of the animals when they attach on hosts with contrasting life-styles. PMID:23469208

  14. Modeling the population dynamics and community impacts of Ambystoma tigrinum: A case study of phenotype plasticity.

    PubMed

    McCarthy, Maeve L; Wallace, Dorothy; Whiteman, Howard H; Rheingold, Evan T; Dunham, Ann M; Prosper, Olivia; Chen, Michelle; Hu-Wang, Eileen

    2017-02-24

    Phenotypic plasticity is the ability of an organism to change its phenotype in response to changes in the environment. General mathematical descriptions of the phenomenon rely on an abstract measure of "viability" that, in this study, is instantiated in the case of the Tiger Salamander, Ambystoma tigrinum. This organism has a point in its development when, upon maturing, it may take two very different forms. One is a terrestrial salamander (metamorph)that visits ponds to reproduce and eat, while the other is an aquatic form (paedomorph) that remains in the pond to breed and which consumes a variety of prey including its own offspring. A seven dimensional nonlinear system of ordinary differential equations is developed, incorporating small (Z) and large (B) invertebrates, Ambystoma young of the year (Y), juveniles (J), terrestrial metamorphs (A) and aquatic paedomorphs (P). One parameter in the model controls the proportion of juveniles maturing into A versus P. Solutions are shown to remain non-negative. Every effort was made to justify parameters biologically through studies reported in the literature. A sensitivity analysis and equilibrium analysis of model parameters demonstrate that morphological choice is critical to the overall composition of the Ambystoma population. Various population viability measures were used to select optimal percentages of juveniles maturing into metamorphs, with optimal choices differing considerably depending on the viability measure. The model suggests that the criteria for viability for this organism vary, both from location to location and also in time. Thus, optimal responses change with spatiotemporal variation, which is consistent with other phenotypically plastic systems. Two competing hypotheses for the conditions under which metamorphosis occurs are examined in light of the model and data from an Ambystoma tigrinum population at Mexican Cut, Colorado. The model clearly supports one of these over the other for this data set

  15. Morphological change and phenotypic plasticity in native and non-native pumpkinseed sunfish in response to competition

    NASA Astrophysics Data System (ADS)

    Yavno, Stan; Rooke, Anna C.; Fox, Michael G.

    2014-06-01

    Non-indigenous species are oftentimes exposed to ecosystems with unfamiliar species, and organisms that exhibit a high degree of phenotypic plasticity may be better able to contend with the novel competitors that they may encounter during range expansion. In this study, differences in morphological plasticity were investigated using young-of-year pumpkinseed sunfish ( Lepomis gibbosus) from native North American and non-native European populations. Two Canadian populations, isolated from bluegill sunfish ( L. macrochirus) since the last glaciation, and two Spanish populations, isolated from bluegill since their introduction in Europe, were reared in a common environment using artificial enclosures. Fish were subjected to allopatric (without bluegill) or sympatric (with bluegill) conditions, and differences in plasticity were tested through a MANOVA of discriminant function scores. All pumpkinseed populations exhibited dietary shifts towards more benthivorous prey when held with bluegill. Differences between North American and European populations were observed in body dimensions, gill raker length and pelvic fin position. Sympatric treatments induced an increase in body width and a decrease in caudal peduncle length in native fish; non-native fish exhibited longer caudal peduncle lengths when held in sympatry with bluegill. Overall, phenotypic plasticity influenced morphological divergence less than genetic factors, regardless of population. Contrary to predictions, pumpkinseeds from Europe exhibited lower levels of phenotypic plasticity than Canadian populations, suggesting that European pumpkinseeds are more canalized than their North American counterparts.

  16. Contrasting phenotypic plasticity in the photoprotective strategies of the invasive species Carpobrotus edulis and the coexisting native species Crithmum maritimum.

    PubMed

    Fenollosa, Erola; Munné-Bosch, Sergi; Pintó-Marijuan, Marta

    2017-01-05

    Photoprotective strategies vary greatly within the plant kingdom and reflect a plant's physiological status and capacity to cope with environment variations. The plasticity and intensity of these responses may determine plant success. Invasive species are reported to show increased vigor to displace native species. Describing the mechanisms that confer such vigor is essential to understanding the success of invasive species. We performed an experiment whereby two species were monitored: Carpobrotus edulis, an aggressive invasive species in the Mediterranean basin, and Crithmum maritimum, a coexisting native species in the Cap de Creus Natural Park (NE Spain). We analyzed their photoprotective responses to seasonal environmental dynamics by comparing the capacity of the invader to respond to the local environmental stresses throughout the year. Our study analyses ecophysiological markers and photoprotective strategies to gain an insight into the success of invaders. We found that both species showed completely different but effective photoprotective strategies: in summer, C. edulis took special advantage of the xanthophyll cycle, whereas the success of C. maritimum in summer stemmed from morphological changes and alterations on β-carotene content. Winter also presented differences between the species, as the native showed reduced Fv /Fm ratios. Our experimental design allowed us to introduce a new approach to compare phenotypic plasticity: the integrated phenotypic plasticity index (PPint ), defined as the maximum Euclidian distance between phenotypes, using a combination of different variables to describe them. This index revealed significantly greater phenotypic plasticity in the invasive species compared to the native species.

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

    PubMed Central

    2010-01-01

    Background 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. Results 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. Conclusion 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. Reviewers This article was reviewed by Rob Knight, Fyodor Kondrashov and Massimo Di Giulio (nominated by David H. Ardell). PMID:20067646

  18. Gene Expression Variability Underlies Adaptive Resistance in Phenotypically Heterogeneous Bacterial Populations.

    PubMed

    Erickson, Keesha E; Otoupal, Peter B; Chatterjee, Anushree

    2015-11-13

    The root cause of the antibiotic resistance crisis is the ability of bacteria to evolve resistance to a multitude of antibiotics and other environmental toxins. The regulation of adaptation is difficult to pinpoint due to extensive phenotypic heterogeneity arising during evolution. Here, we investigate the mechanisms underlying general bacterial adaptation by evolving wild-type Escherichia coli populations to dissimilar chemical toxins. We demonstrate the presence of extensive inter- and intrapopulation phenotypic heterogeneity across adapted populations in multiple traits, including minimum inhibitory concentration, growth rate, and lag time. To search for a common response across the heterogeneous adapted populations, we measured gene expression in three stress-response networks: the mar regulon, the general stress response, and the SOS response. While few genes were differentially expressed, clustering revealed that interpopulation gene expression variability in adapted populations was distinct from that of unadapted populations. Notably, we observed both increases and decreases in gene expression variability upon adaptation. Sequencing select genes revealed that the observed gene expression trends are not necessarily attributable to genetic changes. To further explore the connection between gene expression variability and adaptation, we propagated single-gene knockout and CRISPR (clustered regularly interspaced short palindromic repeats) interference strains and quantified impact on adaptation to antibiotics. We identified significant correlations that suggest genes with low expression variability have greater impact on adaptation. This study provides evidence that gene expression variability can be used as an indicator of bacterial adaptive resistance, even in the face of the pervasive phenotypic heterogeneity underlying adaptation.

  19. Optimality and adaptation of phenotypically switching cells in fluctuating environments

    NASA Astrophysics Data System (ADS)

    Belete, Merzu Kebede; Balázsi, Gábor

    2015-12-01

    Stochastic switching between alternative phenotypic states is a common cellular survival strategy during unforeseen environmental fluctuations. Cells can switch between different subpopulations that proliferate at different rates in different environments. Optimal population growth is typically assumed to occur when phenotypic switching rates match environmental switching rates. However, it is not well understood how this optimum behaves as a function of the growth rates of phenotypically different cells. In this study, we use mathematical and computational models to test how the actual parameters associated with optimal population growth differ from those assumed to be optimal. We find that the predicted optimum is practically always valid if the environmental durations are long. However, the regime of validity narrows as environmental durations shorten, especially if subpopulation growth rate differences differ from each other (are asymmetric) in two environments. Furthermore, we study the fate of mutants with switching rates previously predicted to be optimal. We find that mutants which match their phenotypic switching rates with the environmental ones can only sweep the population if the assumed optimum is valid, but not otherwise.

  20. Optimality and adaptation of phenotypically switching cells in fluctuating environments.

    PubMed

    Belete, Merzu Kebede; Balázsi, Gábor

    2015-12-01

    Stochastic switching between alternative phenotypic states is a common cellular survival strategy during unforeseen environmental fluctuations. Cells can switch between different subpopulations that proliferate at different rates in different environments. Optimal population growth is typically assumed to occur when phenotypic switching rates match environmental switching rates. However, it is not well understood how this optimum behaves as a function of the growth rates of phenotypically different cells. In this study, we use mathematical and computational models to test how the actual parameters associated with optimal population growth differ from those assumed to be optimal. We find that the predicted optimum is practically always valid if the environmental durations are long. However, the regime of validity narrows as environmental durations shorten, especially if subpopulation growth rate differences differ from each other (are asymmetric) in two environments. Furthermore, we study the fate of mutants with switching rates previously predicted to be optimal. We find that mutants which match their phenotypic switching rates with the environmental ones can only sweep the population if the assumed optimum is valid, but not otherwise.

  1. Skeletal muscle calcineurin: influence of phenotype adaptation and atrophy

    NASA Technical Reports Server (NTRS)

    Spangenburg, E. E.; Williams, J. H.; Roy, R. R.; Talmadge, R. J.; Spangenberg, E. E. (Principal Investigator)

    2001-01-01

    Calcineurin (CaN) has been implicated as a signaling molecule that can transduce physiological stimuli (e.g., contractile activity) into molecular signals that initiate slow-fiber phenotypic gene expression and muscle growth. To determine the influence of muscle phenotype and atrophy on CaN levels in muscle, the levels of soluble CaN in rat muscles of varying phenotype, as assessed by myosin heavy chain (MHC)-isoform proportions, were determined by Western blotting. CaN levels were significantly greater in the plantaris muscle containing predominantly fast (IIx and IIb) MHC isoforms, compared with the soleus (predominantly type I MHC) or vastus intermedius (VI, contains all 4 adult MHC isoforms). Three months after a complete spinal cord transection (ST), the CaN levels in the VI muscle were significantly reduced, despite a significant increase in fast MHC isoforms. Surprisingly, the levels of CaN in the VI were highly correlated with muscle mass but not MHC isoform proportions in ST and control rats. These data demonstrate that CaN levels in skeletal muscle are highly correlated to muscle mass and that the normal relationship with phenotype is lost after ST.

  2. RAD sequencing resolves fine-scale population structure in a benthic invertebrate: implications for understanding phenotypic plasticity

    PubMed Central

    Weigand, Hannah; Weiss, Martina; Fawcett, Katie; Lehman, Katrin; Clark, M. S.; Leese, Florian; McMinn, Carrie; Moore, Heather; Hoffman, Joseph I.

    2017-01-01

    The field of molecular ecology is transitioning from the use of small panels of classical genetic markers such as microsatellites to much larger panels of single nucleotide polymorphisms (SNPs) generated by approaches like RAD sequencing. However, few empirical studies have directly compared the ability of these methods to resolve population structure. This could have implications for understanding phenotypic plasticity, as many previous studies of natural populations may have lacked the power to detect genetic differences, especially over micro-geographic scales. We therefore compared the ability of microsatellites and RAD sequencing to resolve fine-scale population structure in a commercially important benthic invertebrate by genotyping great scallops (Pecten maximus) from nine populations around Northern Ireland at 13 microsatellites and 10 539 SNPs. The shells were then subjected to morphometric and colour analysis in order to compare patterns of phenotypic and genetic variation. We found that RAD sequencing was superior at resolving population structure, yielding higher Fst values and support for two distinct genetic clusters, whereas only one cluster could be detected in a Bayesian analysis of the microsatellite dataset. Furthermore, appreciable phenotypic variation was observed in size-independent shell shape and coloration, including among localities that could not be distinguished from one another genetically, providing support for the notion that these traits are phenotypically plastic. Taken together, our results suggest that RAD sequencing is a powerful approach for studying population structure and phenotypic plasticity in natural populations. PMID:28386419

  3. Morphological divergence and flow-induced phenotypic plasticity in a native fish from anthropogenically altered stream habitats.

    PubMed

    Franssen, Nathan R; Stewart, Laura K; Schaefer, Jacob F

    2013-11-01

    Understanding population-level responses to human-induced changes to habitats can elucidate the evolutionary consequences of rapid habitat alteration. Reservoirs constructed on streams expose stream fishes to novel selective pressures in these habitats. Assessing the drivers of trait divergence facilitated by these habitats will help identify evolutionary and ecological consequences of reservoir habitats. We tested for morphological divergence in a stream fish that occupies both stream and reservoir habitats. To assess contributions of genetic-level differences and phenotypic plasticity induced by flow variation, we spawned and reared individuals from both habitats types in flow and no flow conditions. Body shape significantly and consistently diverged in reservoir habitats compared with streams; individuals from reservoirs were shallower bodied with smaller heads compared with individuals from streams. Significant population-level differences in morphology persisted in offspring but morphological variation compared with field-collected individuals was limited to the head region. Populations demonstrated dissimilar flow-induced phenotypic plasticity when reared under flow, but phenotypic plasticity in response to flow variation was an unlikely explanation for observed phenotypic divergence in the field. Our results, together with previous investigations, suggest the environmental conditions currently thought to drive morphological change in reservoirs (i.e., predation and flow regimes) may not be the sole drivers of phenotypic change.

  4. Evidence for Cerebellar Contributions to Adaptive Plasticity in Speech Perception.

    PubMed

    Guediche, Sara; Holt, Lori L; Laurent, Patryk; Lim, Sung-Joo; Fiez, Julie A

    2015-07-01

    Human speech perception rapidly adapts to maintain comprehension under adverse listening conditions. For example, with exposure listeners can adapt to heavily accented speech produced by a non-native speaker. Outside the domain of speech perception, adaptive changes in sensory and motor processing have been attributed to cerebellar functions. The present functional magnetic resonance imaging study investigates whether adaptation in speech perception also involves the cerebellum. Acoustic stimuli were distorted using a vocoding plus spectral-shift manipulation and presented in a word recognition task. Regions in the cerebellum that showed differences before versus after adaptation were identified, and the relationship between activity during adaptation and subsequent behavioral improvements was examined. These analyses implicated the right Crus I region of the cerebellum in adaptive changes in speech perception. A functional correlation analysis with the right Crus I as a seed region probed for cerebral cortical regions with covarying hemodynamic responses during the adaptation period. The results provided evidence of a functional network between the cerebellum and language-related regions in the temporal and parietal lobes of the cerebral cortex. Consistent with known cerebellar contributions to sensorimotor adaptation, cerebro-cerebellar interactions may support supervised learning mechanisms that rely on sensory prediction error signals in speech perception.

  5. Catch Me if You Can: Adaptation from Standing Genetic Variation to a Moving Phenotypic Optimum.

    PubMed

    Matuszewski, Sebastian; Hermisson, Joachim; Kopp, Michael

    2015-08-01

    Adaptation lies at the heart of Darwinian evolution. Accordingly, numerous studies have tried to provide a formal framework for the description of the adaptive process. Of these, two complementary modeling approaches have emerged: While so-called adaptive-walk models consider adaptation from the successive fixation of de novo mutations only, quantitative genetic models assume that adaptation proceeds exclusively from preexisting standing genetic variation. The latter approach, however, has focused on short-term evolution of population means and variances rather than on the statistical properties of adaptive substitutions. Our aim is to combine these two approaches by describing the ecological and genetic factors that determine the genetic basis of adaptation from standing genetic variation in terms of the effect-size distribution of individual alleles. Specifically, we consider the evolution of a quantitative trait to a gradually changing environment. By means of analytical approximations, we derive the distribution of adaptive substitutions from standing genetic variation, that is, the distribution of the phenotypic effects of those alleles from the standing variation that become fixed during adaptation. Our results are checked against individual-based simulations. We find that, compared to adaptation from de novo mutations, (i) adaptation from standing variation proceeds by the fixation of more alleles of small effect and (ii) populations that adapt from standing genetic variation can traverse larger distances in phenotype space and, thus, have a higher potential for adaptation if the rate of environmental change is fast rather than slow.

  6. Beyond the Sensorimotor Plasticity: Cognitive Expansion of Prism Adaptation in Healthy Individuals

    PubMed Central

    Michel, Carine

    2016-01-01

    Sensorimotor plasticity allows us to maintain an efficient motor behavior in reaction to environmental changes. One of the classical models for the study of sensorimotor plasticity is prism adaptation. It consists of pointing to visual targets while wearing prismatic lenses that shift the visual field laterally. The conditions of the development of the plasticity and the sensorimotor after-effects have been extensively studied for more than a century. However, the interest taken in this phenomenon was considerably increased since the demonstration of neglect rehabilitation following prism adaptation by Rossetti et al. (1998). Mirror effects, i.e., simulation of neglect in healthy individuals, were observed for the first time by Colent et al. (2000). The present review focuses on the expansion of prism adaptation to cognitive functions in healthy individuals during the last 15 years. Cognitive after-effects have been shown in numerous tasks even in those that are not intrinsically spatial in nature. Altogether, these results suggest the existence of a strong link between low-level sensorimotor plasticity and high-level cognitive functions and raise important questions about the mechanisms involved in producing unexpected cognitive effects following prism adaptation. Implications for the functional mechanisms and neuroanatomical network of prism adaptation are discussed to explain how sensorimotor plasticity may affect cognitive processes. PMID:26779088

  7. Quantifying genetic variations and phenotypic plasticity of leaf phenology and growth for two temperate Fagaceae species (sessile oak and european beech)

    NASA Astrophysics Data System (ADS)

    Delzon, Sylvain; Vitasse, Yann; Alberto, Florian; Bresson, Caroline; Kremer, Antoine

    2010-05-01

    Under current climate change, research on inherent adaptive capacities of organisms is crucial to assess future evolutionary changes of natural populations. Genetic diversity and phenotypic plasticity constitute adaptative capacities that could allow populations to respond to new environmental conditions. The aim of the present study was (i) to determine whether there are genetic variations among populations from altitudinal gradients using a lowland common garden experiment and (ii) to assess the magnitude of phenotypic plasticity using a reciprocal transplant experiment (5 elevations from 100 to 1600 m asl.) for leaf phenology (flushing and senescence) and growth of two fagaceae species (Fagus sylvatica and Quercus petraea). We found significant differences in phenology among provenances for most species, and evidenced that these among-population differences in phenology were related to annual temperature of the provenance sites for both species. It's noteworthy that, along the same climatic gradient, the species exhibited opposite genetic clines: beech populations from high elevation flushed earlier than those of low elevation, whereas we observed an opposite trend for oak. Finally, we highlighted that both phenology timing and growth rate were highly consistent year to year. The results demonstrated that in spite of the proximity of the populations in their natural area, altitude led to genetic differentiations in their phenology and growth. Moreover, a high phenological plasticity was found for both species. We evidenced that reaction norms of flushing timing to temperature followed linear clinal trends for both species with an average shift of 5.7 days per degree increase. Timing of leaf senescence exhibited hyperbolic trends for beech and no or slight trends for oak. Furthermore, within species, there was no difference in magnitude of phenological plasticity among populations neither for flushing, nor for senescence. Consequently, for both species, the

  8. Phenotypic plasticity of composite beef cattle performance using reaction norms model with unknown covariate.

    PubMed

    Santana, M L; Eler, J P; Cardoso, F F; Albuquerque, L G; Ferraz, J B S

    2013-02-01

    The objective of the present study was to determine the presence of genotype by environment interaction (G × E) and to characterize the phenotypic plasticity of birth weight (BW), weaning weight (WW), postweaning weight gain (PWG) and yearling scrotal circumference (SC) in composite beef cattle using the reaction norms model with unknown covariate. The animals were born between 1995 and 2008 on 33 farms located throughout all Brazilian biomes between latitude -7° and -31°, longitude -40° and -63°. The contemporary group was chosen as the environmental descriptor, that is, the environmental covariate of the reaction norms. In general, higher estimates of direct heritability were observed in extreme favorable environments. The mean of direct heritability across the environmental gradient ranged from 0.05 to 0.51, 0.09 to 0.43, 0.01 to 0.43 and from 0.12 to 0.26 for BW, WW, PWG and SC, respectively. The variation in direct heritability observed indicates a different response to selection according to the environment in which the animals of the population are evaluated. The correlation between the level and slope of the reaction norm for BW and PWG was high, indicating that animals with higher average breeding values responded better to improvement in environmental conditions, a fact characterizing a scale of G × E. Low correlation between the intercept and slope was obtained for WW and SC, implying re-ranking of animals in different environments. Genetic variation exists in the sensitivity of animals to the environment, a fact that permits the selection of more plastic or robust genotypes in the population studied. Thus, the G × E is an important factor that should be considered in the genetic evaluation of the present population of composite beef cattle.

  9. Endocrine mechanisms, behavioral phenotypes and plasticity: known relationships and open questions

    PubMed Central

    2015-01-01

    Behavior of wild vertebrate individuals can vary in response to environmental or social factors. Such within-individual behavioral variation is often mediated by hormonal mechanisms. Hormones also serve as a basis for among-individual variations in behavior including animal personalities and the degree of responsiveness to environmental and social stimuli. How do relationships between hormones and behavioral traits evolve to produce such behavioral diversity within and among individuals? Answering questions about evolutionary processes generating among-individual variation requires characterizing how specific hormones are related to variation in specific behavioral traits, whether observed hormonal variation is related to individual fitness and, whether hormonal traits are consistent (repeatable) aspects of an individual's phenotype. With respect to within-individual variation, we need to improve our insight into the nature of the quantitative relationships between hormones and the traits they regulate, which in turn will determine how they may mediate behavioral plasticity of individuals. To address these questions, we review the actions of two steroid hormones, corticosterone and testosterone, in mediating changes in vertebrate behavior, focusing primarily on birds. In the first part, we concentrate on among-individual variation and present examples for how variation in corticosterone concentrations can relate to behaviors such as exploration of novel environments and parental care. We then review studies on correlations between corticosterone variation and fitness, and on the repeatability over time of corticosterone concentrations. At the end of this section, we suggest that further progress in our understanding of evolutionary patterns in the hormonal regulation of behavior may require, as one major tool, reaction norm approaches to characterize hormonal phenotypes as well as their responses to environments. In the second part, we discuss types of quantitative

  10. [Phenotypic and epigenetic adaptation of the moss clone to mercury].

    PubMed

    Khorkavtsiv, Ia D; Ripets'kyĭ, R T; Baïk, O L

    2009-01-01

    On agar-Knop medium containing 0.5 microM HgCl2 about one third of microregenerants of the clone from the individual gametophyte cell of the moss Pottia intermedia survived and gave rise to protonemal mats. The high survival percentage testifies to epigenetic nature of adaptation. The latter proved to be correlated to the increase of leaf cell number and of peroxidase activity as well as to intensification of activity zone of peroxidase isoform with MM in limits of 66 kD and to appearance of two isoforms of the enzyme on electrophoregrams. The increase of peroxidase activity, though considerably weaker expressed, has been stated at 0.2 microM HgCl2 when practically all regenerants survived and on the mercury-free medium epigenetically adapted regenerants differed from physiologically adapted ones only in intensification of activity zone of peroxidase isoform with 66 kD. This gives reason to regard the adaptation of the regenerants to 0.5 microM HgCl2 as intensified epigenocopy of modification and indicates the generality of mechanisms of both types of adaptation.

  11. Toward a nonhuman primate model of fetal programming: phenotypic plasticity of the common marmoset fetoplacental complex.

    PubMed

    Rutherford, Julienne N

    2012-11-01

    Nonhuman primates offer unique opportunities as animal models in the study of developmental programming and the role of the placenta in developmental processes. All primates share fundamental similarities in life history and reproductive biology. Thus, insights gleaned from studies of nonhuman primates have a higher degree of biological salience to human biology than do studies of rodents or agricultural animals. The common marmoset monkey is a small-bodied primate from South America that produces litters of dizygotic fetuses that share a single placental mass. This natural variation allows us to model different intrauterine conditions and associated fetoplacental phenotypes. The marmoset placenta is phenotypically plastic according to litter size. Triplet litters are characterized by low individual fetal weights and significantly more efficient placentas and attendant alterations to the microscopic architecture and endocrine function, thus modeling a nutrient restricted intrauterine environment. Consistent with this model, triplet neonates experience a higher risk of perinatal mortality and an increased likelihood of elevated adult weight. Recent evidence has shown that the intrauterine experience of females has an impact on their own pregnancy outcomes in adulthood: triplet females experience significantly greater pregnancy loss than do twin females. The marmoset monkey thus represents a potential powerful nonhuman primate model of multiple pregnancies, restrictive prenatal experiences, and differential reproductive outcomes in adulthood, which may have important implications for studying the impact of in vitro fertilization on adult reproductive health. It is still too early to determine exactly what developmental pathways lead to this disparity or what specific role the placenta plays; future work on this front will be critical to establish the marmoset as an important model of fetal programming of reproductive function in adulthood and across generations.

  12. Predicting adaptive phenotypes from multilocus genotypes in Sitka spruce (Picea sitchensis) using random forest.

    PubMed

    Holliday, Jason A; Wang, Tongli; Aitken, Sally

    2012-09-01

    Climate is the primary driver of the distribution of tree species worldwide, and the potential for adaptive evolution will be an important factor determining the response of forests to anthropogenic climate change. Although association mapping has the potential to improve our understanding of the genomic underpinnings of climatically relevant traits, the utility of adaptive polymorphisms uncovered by such studies would be greatly enhanced by the development of integrated models that account for the phenotypic effects of multiple single-nucleotide polymorphisms (SNPs) and their interactions simultaneously. We previously reported the results of association mapping in the widespread conifer Sitka spruce (Picea sitchensis). In the current study we used the recursive partitioning algorithm 'Random Forest' to identify optimized combinations of SNPs to predict adaptive phenotypes. After adjusting for population structure, we were able to explain 37% and 30% of the phenotypic variation, respectively, in two locally adaptive traits--autumn budset timing and cold hardiness. For each trait, the leading five SNPs captured much of the phenotypic variation. To determine the role of epistasis in shaping these phenotypes, we also used a novel approach to quantify the strength and direction of pairwise interactions between SNPs and found such interactions to be common. Our results demonstrate the power of Random Forest to identify subsets of markers that are most important to climatic adaptation, and suggest that interactions among these loci may be widespread.

  13. Flagellar phenotypic plasticity in volvocalean algae correlates with Péclet number.

    PubMed

    Solari, Cristian A; Drescher, Knut; Ganguly, Sujoy; Kessler, John O; Michod, Richard E; Goldstein, Raymond E

    2011-10-07

    Flagella-generated fluid stirring has been suggested to enhance nutrient uptake for sufficiently large micro-organisms, and to have played a role in evolutionary transitions to multicellularity. A corollary to this predicted size-dependent benefit is a propensity for phenotypic plasticity in the flow-generating mechanism to appear in large species under nutrient deprivation. We examined four species of volvocalean algae whose radii and flow speeds differ greatly, with Péclet numbers (Pe) separated by several orders of magnitude. Populations of unicellular Chlamydomonas reinhardtii and one- to eight-celled Gonium pectorale (Pe ∼ 0.1-1) and multicellular Volvox carteri and Volvox barberi (Pe ∼ 100) were grown in diluted and undiluted media. For C. reinhardtii and G. pectorale, decreasing the nutrient concentration resulted in smaller cells, but had no effect on flagellar length and propulsion force. In contrast, these conditions induced Volvox colonies to grow larger and increase their flagellar length, separating the somatic cells further. Detailed studies on V. carteri found that the opposing effects of increasing beating force and flagellar spacing balance, so the fluid speed across the colony surface remains unchanged between nutrient conditions. These results lend further support to the hypothesized link between the Péclet number, nutrient uptake and the evolution of biological complexity in the Volvocales.

  14. Ontogenetic loss of phenotypic plasticity of age at metamorphosis in tadpoles

    SciTech Connect

    Hensley, F.R. )

    1993-12-01

    Amphibian larvae exhibit phenotypic plasticity in size at metamorphosis and duration of the larval period. I used Pseudacris crucifer tadpoles to test two models for predicting tadpole age and size at metamorphosis under changing environmental conditions. The Wilbur-Collins model states that metamorphosis is initiated as a function of a tadpole's size and relative growth rate, and predicts that changes in growth rate throughout the larval period affect age and size at metamorphosis. An alternative model, the fixed-rate model, states that age at metamorphosis is fixed early in larval life, and subsequent changes in growth rate will have no effect on the length of the larval period. My results confirm that food supplies affect both age and size at metamorphosis, but developmental rates became fixed at approximately Gosner (1960) stages 35-37. Neither model completely predicted these results. I suggest that the generally accepted Wilbur-Collins model is improved by incorporating a point of fixed developmental timing. Growth trajectories predicted from this modified model fit the results of this study better than trajectories based on either of the original models. The results of this study suggests a constraint that limits the simultaneous optimization of age and size at metamorphosis. 32 refs., 5 figs., 1 tab.

  15. Plastic phenotypic resistance to predation by Bdellovibrio and like organisms in bacterial prey.

    PubMed

    Shemesh, Yair; Jurkevitch, Edouard

    2004-01-01

    Predation at the lowest trophic level, i.e. between bacteria, is poorly understood, hindering efforts to assess its impact on the structure of bacterial communities. The interaction of Bdellovibrio and Bacteriovorax (Bdellovibrio and like organisms, BLOs), a group of obligate, ubiquitous predatory bacteria, with their Gram-negative bacterial prey results in the multiplication of the predator and in the lysis, but not in the eradication, of the prey. We show that the residual, surviving populations of prey cells exposed to predation stress differ from the populations before exposure, as they exhibit increased resistance to predation. This resistance was demonstrated in a number of Gram-negative prey. Moreover, predation resistance is not specific for the BLO strain experienced by the prey. The phenomenon does not stem from a mutation but is a plastic response associated with a phenotypic change, and it disappears upon removal of the predator. As resistance to predation is not total, this mechanism can ensure survival of both predator and prey.

  16. Modeling the evolution of phenotypic plasticity in resource allocation in wing-dimorphic insects.

    PubMed

    King, Elizabeth G; Roff, Derek A

    2010-06-01

    In nature, resource availability varies spatially and temporally both within and across generations, leading to variation in the amount of energy available to individuals. The optimal allocation strategy can change, depending on the amount of resources available to allocate to life-history functions. If so, selection should favor the evolution of allocation strategies that can respond to variation in environmental resource levels. We address this issue by using two quantitative genetic simulation models in a model system for studying trade-offs, wing-dimorphic insects. Wing dimorphic insects typically exhibit a trade-off in the allocation of resources between migratory ability and reproduction. In our models, we focus on allocation as a genetic trait and model the evolution of phenotypic plasticity in this trait in response to spatiotemporal variation in resource availability. We show that the evolved allocation strategy depends on the predictability of resource levels across time. Specifically, selection favors higher investment in flight under poor conditions in predictable environments and lower investment in unpredictable environments.

  17. Does the white clover response to sulphur availability correspond to phenotypic or ontogenetic plasticity?

    NASA Astrophysics Data System (ADS)

    Varin, Sébastien; Leveel, Benjamen; Lemauviel-Lavenant, Servane; Cliquet, Jean-Bernard

    2009-05-01

    White clover ( Trifolium repens L.) is a key species in grasslands. Its performance in grassland communities is strongly linked to nitrogen (N) availability. A decrease in soil sulphur (S) content has appeared in the last few decades in grasslands in Northern Europe and this could change the behaviour of white clover. S is essential for plants and particularly for legumes through its effect upon nitrogen fixation. The aim of this study was to determine the effects of S deficiency on white clover fitness, analysing its plasticity in a time course of growth. Three concentrations of SO 42-, "Low S" (0.009 mM), "Medium S" (0.384 mM) and "High S" (1.509 mM), were used to grow plants in a hydroponic system. S availability modified biomasses significantly only at the end of the experiment (11 weeks). Medium S appeared optimal while Low S induced a lower aboveground dry mass. An appropriate S availability (Medium S) not only increased S content but also increased N content by stimulating N 2 fixation. Plant growth analysis using growth fitted curves and the calculation of RGR revealed that S effects on biomass corresponded to the production of different phenotypes and not to a growth delay. This work shows that the acceleration growth phase (49-56 days) is a key period for the nutritional needs of white clover and should be the best period for a sulphur fertilisation regime that aims to enhance white clover fitness.

  18. Extrafloral nectary phenotypic plasticity is damage- and resource-dependent in Vicia faba

    PubMed Central

    Mondor, Edward B; Tremblay, Michelle N; Messing, Russell H

    2006-01-01

    Phenotypic plasticity enables many damaged plants to increase nectar secretion rates from extrafloral nectaries (EFNs), or in the case of broad bean, Vicia faba L., to produce additional EFNs, to attract natural enemies of herbivores. While plants benefit greatly from these defensive mutualisms, the costs of producing EFNs are largely unknown. We hypothesized that if EFN production is costly, then damaged plants with high resource levels would be able to produce more EFNs than plants that are resource-limited. Here, we show that this indirect inducible defence does follow this general pattern. Vicia faba enriched with 6 or 12 g of 14 : 14 : 14 NPK fertilizer increased EFN numbers after leaf damage by 46 and 60%, respectively, compared with nutrient-poor plants. Thus, EFN production is both damage- and resource-dependent. Analogous to direct defences, production of EFNs may limit the overall loss of leaf tissue when risk of herbivory increases. PMID:17148294

  19. Fluctuations in population composition dampen the impact of phenotypic plasticity on trait dynamics in superb fairy-wrens.

    PubMed

    van de Pol, Martijn; Osmond, Helen L; Cockburn, Andrew

    2012-03-01

    1. In structured populations, phenotypic change can result from changes throughout an individual's lifetime (phenotypic plasticity, age-related changes), selection and changes in population composition (environment- or density-driven fluctuations in age-structure). 2. The contribution of population dynamics to phenotypic change has often been ignored. However, for understanding trait dynamics, it is important to identify both the individual- and population-level mechanisms responsible for trait change, because they potentially reinforce or counteract each other. 3. We use 22 years of field data to investigate the dynamics of a sexually selected phenological trait, the timing of nuptial moult in superb fairy-wrens Malurus cyaneus. 4. We show that trait expression is both climate- and age-dependent, but that phenotypic plasticity in response to climate variability also varies with age. Old males can acquire nuptial plumage very early after high rainfall, but 1- to 2-year-olds cannot. However, males of all ages that defer moult to later in the year acquire nuptial plumage earlier when conditions are warmer. 5. The underlying mechanism appears to be that old males may risk moulting in the most challenging period of the year: in autumn, when drought restricts food abundance and during the cold winter. By contrast, young males always moult during the spring transition to benign - warmer and generally wetter - conditions. Temperature changes dominate this transition that heralds the breeding season, thereby causing both young and late-moulting older birds to be temperature sensitive. 6. Climate and age also affect trait dynamics via a population dynamical pathway. The same high rainfall that triggers early moulting in old males concurrently increases offspring recruitment and thereby reduces the average age of males in the population. Consequently, effects of rainfall on trait dynamics through phenotypic plasticity of old males are dampened by synchronous rejuvenation of

  20. Morphological distinctness despite large-scale phenotypic plasticity--analysis of wild and pond-bred juveniles of allopatric populations of Tropheus moorii.

    PubMed

    Kerschbaumer, Michaela; Postl, Lisbeth; Koch, Martin; Wiedl, Thomas; Sturmbauer, Christian

    2011-02-01

    Cichlids are an excellent model to study explosive speciation and adaptive radiation. Their evolutionary success has been attributed to their ability to undergo rapid morphological changes related to diet, and their particular breeding biology. Relatively minor changes in morphology allow for exploitation of novel food resources. The importance of phenotypic plasticity and genetically based differences for diversification was long recognized, but their relationship and relative magnitude remained unclear. We compared morphology of individuals of four wild populations of the Lake Tanganyika cichlid Tropheus moorii with their pond-raised F(1) offspring. The magnitude of morphological change via phenotypic plasticity between wild and pond-bred F(1) fish exceeds pairwise population differences by a factor of 2.4 (mean Mahalanobis distances). The genetic and environmental effects responsible for among population differentiation in the wild could still be recognized in the pond-bred F(1) fish. All four pond populations showed the same trends in morphological change, mainly in mouth orientation, size and orientation of fins, and thickness of the caudal peduncle. As between population differentiation was lower in the wild than differentiation between pond-raised versus wild fish, we suggest the narrow ecological niche and intense interspecific competition in rock habitats is responsible for consistent shape similarity, even among long-term isolated populations.

  1. Mating system plasticity promotes persistence and adaptation of colonizing populations of hermaphroditic angiosperms.

    PubMed

    Peterson, Megan L; Kay, Kathleen M

    2015-01-01

    Persistence and adaptation in novel environments are limited by small population size, strong selection, and maladaptive gene flow. Mating system plasticity is common in angiosperms and may provide both demographic and genetic benefits that promote niche evolution, including reproductive assurance and isolation from maladaptive gene flow. Yet increased self-fertilization may also cause inbreeding depression, accumulation of deleterious mutations, and reduced adaptive potential. Here we use individual-based simulations to examine the consequences of mating system plasticity for persistence and adaptation in a novel environment that imposes selection on a quantitative trait. We examine the joint evolution of local adaptation, inbreeding depression, and genetic load. We find that a plastic shift to a mixed mating system generally promotes niche evolution by decreasing the risk of extinction, providing isolation from maladaptive gene flow, and temporarily increasing genetic variance in the trait under selection, whereas obligate self-fertilization reduces adaptive potential. These effects are most pronounced under conditions of mate limitation, strong selection, or maladaptive gene flow. Our results highlight the diverse demographic and genetic consequences of self-fertilization and support the potential role for plastic shifts in mating system to promote niche evolution in flowering plants.

  2. Crest evolution in newts: implications for reconstruction methods, sexual selection, phenotypic plasticity and the origin of novelties.

    PubMed

    Wiens, J J; Sparreboom, M; Arntzen, J W

    2011-10-01

    The dorsal crest of newts (Salamandridae) is a novel, phenotypically plastic, sexually selected trait that may evolve in association with complex courtship behaviours. We estimated a near-comprehensive, time-calibrated phylogeny for salamandrids and analysed the evolution of their crests and display behaviour. Different models give conflicting reconstructions for crest evolution, showing that likelihood can estimate incorrect ancestral states with strong statistical support. The best-fitting model suggests that crests evolved once and were lost repeatedly, supporting the hypothesis that sexually selected traits may be frequently lost. We demonstrate the correlated evolution of crests and courtship behaviour and show that species with larger numbers of crest-related traits have larger repertoires of behaviours. We also show that phenotypically plastic morphological traits can be maintained over long macroevolutionary timescales (∼25-48 Myr). Finally, we use salamandrids to address how novel structures may arise, and support a model involving the expansion and subdivision of pre-existing structures.

  3. Selection on outlier loci and their association with adaptive phenotypes in Littorina saxatilis contact zones.

    PubMed

    Hollander, J; Galindo, J; Butlin, R K

    2015-02-01

    A fundamental issue in speciation research is to evaluate phenotypic variation and the genomics driving the evolution of reproductive isolation between sister taxa. Above all, hybrid zones are excellent study systems for researchers to examine the association of genetic differentiation, phenotypic variation and the strength of selection. We investigated two contact zones in the marine gastropod Littorina saxatilis and utilized landmark-based geometric morphometric analysis together with amplified fragment length polymorphism (AFLP) markers to assess phenotypic and genomic divergence between ecotypes under divergent selection. From genetic markers, we calculated the cline width, linkage disequilibrium and the average effective selection on a locus. Additionally, we conducted an association analysis linking the outlier loci and phenotypic variation between ecotypes and show that a proportion of outlier loci are associated with key adaptive phenotypic traits.

  4. Phenotypic plasticity of Vaccinium meridionale (Ericaceae) in wild populations of mountain forests in Colombia.

    PubMed

    Ligarreto, Gustavo A; Patiño, Maria del Pilar; Magnitskiy, Stanislav V

    2011-06-01

    Vaccinium meridionale is a promising crop for the Andean region of South America and is currently available only in the wild. Spontaneous populations of this plant are found across the Colombian mountains, but very few published records on this plant morphology are available. A zonification study of V. meridionale was conducted in four principal areas of a low mountain forest of Colombia (Provinces of Boyacá, Cundinamarca, Santander and Nariño) in 2007. A total of 20 populations and 100 plants of V. meridionale were individually characterized and surveyed, using a list of 26 characters of morphological variables (9 quantitative and 17 qualitative characters). Our results indicated that natural populations of V. meridionale might be found in the tropical forest under a highly heterogeneous climate and microclimate conditions, at different mountain regions between 2 357 and 3 168masl. The shrubs of V. meridionale exhibited a high level of intra-population variation in several quantitative (plant height, stem diameter) and qualitative (growth habit, ramification density, presence of anthocyanins in stems) morphological characters, suggesting an environmentally induced phenotypic plasticity. Plant height, stem diameter and foliar density were the most variable morphological traits, with coefficients of variation higher than 50%. However, several quantitative characters of its reproductive potential, such as berry dimensions, rachis length and number of flowers per inflorescence, resulted with low plasticity with coefficients of variation lower than 30.2%, indicating that these characters were genetically determined. The highest correlation coefficients (p < 0.05) resulted to be between fruit length and fruit width (0.90), leaf length and leaf width (0.78), plant height and stem diameter (0.60), and inflorescence length and flowers number per inflorescence (0.57). The results suggest that an important genetic resource exists for this species in the wild. Low variation

  5. Phenotypic plasticity in cell walls of maize brown midrib mutants is limited by lignin composition

    PubMed Central

    Vermerris, Wilfred; Sherman, Debra M.; McIntyre, Lauren M.

    2010-01-01

    The hydrophobic cell wall polymer lignin is deposited in specialized cells to make them impermeable to water and prevent cell collapse as negative pressure or gravitational force is exerted. The variation in lignin subunit composition that exists among different species, and among different tissues within the same species suggests that lignin subunit composition varies depending on its precise function. In order to gain a better understanding of the relationship between lignin subunit composition and the physico-chemical properties of lignified tissues, detailed analyses were performed of near-isogenic brown midrib2 (bm2), bm4, bm2-bm4, and bm1-bm2-bm4 mutants of maize. This investigation was motivated by the fact that the bm2-bm4 double mutant is substantially shorter, displays drought symptoms even when well watered, and will often not develop reproductive organs, whereas the phenotypes of the individual bm single mutants and double mutant combinations other than bm2-bm4 are only subtly different from the wild-type control. Detailed cell wall compositional analyses revealed midrib-specific reductions in Klason lignin content in the bm2, bm4, and bm2-bm4 mutants relative to the wild-type control, with reductions in both guaiacyl (G)- and syringyl (S)-residues. The cellulose content was not different, but the reduction in lignin content was compensated by an increase in hemicellulosic polysaccharides. Linear discriminant analysis performed on the compositional data indicated that the bm2 and bm4 mutations act independently of each other on common cell wall biosynthetic steps. After quantitative analysis of scanning electron micrographs of midrib sections, the variation in chemical composition of the cell walls was shown to be correlated with the thickness of the sclerenchyma cell walls, but not with xylem vessel surface area. The bm2-bm4 double mutant represents the limit of phenotypic plasticity in cell wall composition, as the bm1-bm2-bm4 and bm2-bm3-bm4 mutants

  6. Hairstyle as an adaptive means of displaying phenotypic quality.

    PubMed

    Mesko, Norbert; Bereczkei, Tamas

    2004-09-01

    Although facial features that are considered beautiful have been investigated across cultures using the framework of sexual selection theory, the effects of head hair on esthetic evaluations have rarely been examined from an evolutionary perspective. In the present study the effects of six hair-styles (short, medium-length, long, disheveled, knot [hair bun], unkempt) on female facial attractiveness were examined in four dimensions (femininity, youth, health, sexiness) relative to faces without visible head hair ("basic face"). Three evolutionary hypotheses were tested (covering hypothesis, healthy mate theory, and good genes model); only the good genes model was supported by our data. According to this theory, individuals who can afford the high costs of long hair are those who have good phenotypic and genetic quality. In accordance with this hypothesis, we found that only long and medium-length hair had a significant positive effect on ratings of women's attractiveness; the other hairstyles did not influence the evaluation of their physical beauty. Furthermore, these two hairstyles caused a much larger change in the dimension of health than in the rest of the dimensions. Finally, male raters considered the longer-haired female subjects' health status better, especially if the subjects were less attractive women. The possible relationships between facial attractiveness and hair are discussed, and alternative explanations are presented.

  7. When three traits make a line: evolution of phenotypic plasticity and genetic assimilation through linear reaction norms in stochastic environments.

    PubMed

    Ergon, T; Ergon, R

    2017-03-01

    Genetic assimilation emerges from selection on phenotypic plasticity. Yet, commonly used quantitative genetics models of linear reaction norms considering intercept and slope as traits do not mimic the full process of genetic assimilation. We argue that intercept-slope reaction norm models are insufficient representations of genetic effects on linear reaction norms and that considering reaction norm intercept as a trait is unfortunate because the definition of this trait relates to a specific environmental value (zero) and confounds genetic effects on reaction norm elevation with genetic effects on environmental perception. Instead, we suggest a model with three traits representing genetic effects that, respectively, (i) are independent of the environment, (ii) alter the sensitivity of the phenotype to the environment and (iii) determine how the organism perceives the environment. The model predicts that, given sufficient additive genetic variation in environmental perception, the environmental value at which reaction norms tend to cross will respond rapidly to selection after an abrupt environmental change, and eventually becomes equal to the new mean environment. This readjustment of the zone of canalization becomes completed without changes in genetic correlations, genetic drift or imposing any fitness costs of maintaining plasticity. The asymptotic evolutionary outcome of this three-trait linear reaction norm generally entails a lower degree of phenotypic plasticity than the two-trait model, and maximum expected fitness does not occur at the mean trait values in the population.

  8. Does it pay to delay? Flesh flies show adaptive plasticity in reproductive timing.

    PubMed

    Wessels, Frank J; Kristal, Ross; Netter, Fleta; Hatle, John D; Hahn, Daniel A

    2011-02-01

    Life-history plasticity is widespread among organisms. However, an important question is whether it is adaptive. Most models for plasticity in life-history timing predict that animals, once they have reached the minimal nutritional threshold under poor conditions, will accelerate development or time to reproduction. Adaptive delays in reproduction are not common, especially in short-lived species. Examples of adaptive reproductive delays exist in mammalian populations experiencing strong interspecific (e.g., predation) and intraspecific (e.g., infanticide) competition. But are there other environmental factors that may trigger an adaptive delay in reproductive timing? We show that the short-lived flesh fly Sarcophaga crassipalpis will delay reproduction under nutrient-poor conditions, even though it has already met the minimal nutritional threshold for reproduction. We test whether this delay strategy is an adaptive response allowing the scavenger time to locate more resources by experimentally providing supplemental protein pulses (early, mid and late) throughout the reproductive delay period. Flies receiving additional protein produced more and larger eggs, demonstrating a benefit of the delay. In addition, by tracking the allocation of carbon from the pulses using stable isotopes, we show that flies receiving earlier pulses incorporated more carbon into eggs and somatic tissue than those given a later pulse. These results indicate that the reproductive delay in S. crassipalpis is consistent with adaptive post-threshold plasticity, a nutritionally linked reproductive strategy that has not been reported previously in an invertebrate species.

  9. Dissecting the proteome of pea mature seeds reveals the phenotypic plasticity of seed protein composition.

    PubMed

    Bourgeois, Michael; Jacquin, Françoise; Savois, Vincent; Sommerer, Nicolas; Labas, Valérie; Henry, Céline; Burstin, Judith

    2009-01-01

    Pea (Pisum sativum L.) is the most cultivated European pulse crop and the pea seeds mainly serve as a protein source for monogastric animals. Because the seed protein composition impacts on seed nutritional value, we aimed at identifying the determinants of its variability. This paper presents the first pea mature seed proteome reference map, which includes 156 identified proteins (http://www.inra.fr/legumbase/peaseedmap/). This map provides a fine dissection of the pea seed storage protein composition revealing a large diversity of storage proteins resulting both from gene diversity and post-translational processing. It gives new insights into the pea storage protein processing (especially 7S globulins) as a possible adaptation towards progressive mobilization of the proteins during germination. The nonstorage seed proteome revealed the presence of proteins involved in seed defense together with proteins preparing germination. The plasticity of the seed proteome was revealed for seeds produced in three successive years of cultivation, and 30% of the spots were affected by environmental variations. This work pinpoints seed proteins most affected by environment, highlighting new targets to stabilize storage protein composition that should be further analyzed.

  10. Norway maple displays greater seasonal growth and phenotypic plasticity to light than native sugar maple.

    PubMed

    Paquette, Alain; Fontaine, Bastien; Berninger, Frank; Dubois, Karine; Lechowicz, Martin J; Messier, Christian; Posada, Juan M; Valladares, Fernando; Brisson, Jacques

    2012-11-01

    Norway maple (Acer platanoides L), which is among the most invasive tree species in forests of eastern North America, is associated with reduced regeneration of the related native species, sugar maple (Acer saccharum Marsh) and other native flora. To identify traits conferring an advantage to Norway maple, we grew both species through an entire growing season under simulated light regimes mimicking a closed forest understorey vs. a canopy disturbance (gap). Dynamic shade-houses providing a succession of high-intensity direct-light events between longer periods of low, diffuse light were used to simulate the light regimes. We assessed seedling height growth three times in the season, as well as stem diameter, maximum photosynthetic capacity, biomass allocation above- and below-ground, seasonal phenology and phenotypic plasticity. Given the north European provenance of Norway maple, we also investigated the possibility that its growth in North America might be increased by delayed fall senescence. We found that Norway maple had significantly greater photosynthetic capacity in both light regimes and grew larger in stem diameter than sugar maple. The differences in below- and above-ground biomass, stem diameter, height and maximum photosynthesis were especially important in the simulated gap where Norway maple continued extension growth during the late fall. In the gap regime sugar maple had a significantly higher root : shoot ratio that could confer an advantage in the deepest shade of closed understorey and under water stress or browsing pressure. Norway maple is especially invasive following canopy disturbance where the opposite (low root : shoot ratio) could confer a competitive advantage. Considering the effects of global change in extending the potential growing season, we anticipate that the invasiveness of Norway maple will increase in the future.

  11. Urbanization and its effects on personality traits: a result of microevolution or phenotypic plasticity?

    PubMed

    Miranda, Ana Catarina; Schielzeth, Holger; Sonntag, Tanja; Partecke, Jesko

    2013-09-01

    Human-altered environmental conditions affect many species at the global scale. An extreme form of anthropogenic alteration is the existence and rapid increase of urban areas. A key question, then, is how species cope with urbanization. It has been suggested that rural and urban conspecifics show differences in behaviour and personality. However, (i) a generalization of this phenomenon has never been made; and (ii) it is still unclear whether differences in personality traits between rural and urban conspecifics are the result of phenotypic plasticity or of intrinsic differences. In a literature review, we show that behavioural differences between rural and urban conspecifics are common and taxonomically widespread among animals, suggesting a significant ecological impact of urbanization on animal behaviour. In order to gain insight into the mechanisms leading to behavioural differences in urban individuals, we hand-raised and kept European blackbirds (Turdus merula) from a rural and a nearby urban area under common-garden conditions. Using these birds, we investigated individual variation in two behavioural responses to the presence of novel objects: approach to an object in a familiar area (here defined as neophilia), and avoidance of an object in a familiar foraging context (defined as neophobia). Neophilic and neophobic behaviours were mildly correlated and repeatable even across a time period of one year, indicating stable individual behavioural strategies. Blackbirds from the urban population were more neophobic and seasonally less neophilic than blackbirds from the nearby rural area. These intrinsic differences in personality traits are likely the result of microevolutionary changes, although we cannot fully exclude early developmental influences.

  12. Phenotypical Temperature Adaptation of Protein Turnover in Desert Annuals 1

    PubMed Central

    Smrcka, Alan V.; Szarek, Stan R.

    1986-01-01

    Protein synthesis and protein degradation rates were measured in three desert annual species at four different experimental temperatures. The taxa chosen for this study were the C3 winter annuals, Bowlesia incana Ruiz & Pavon and Plantago insularis Eastw., and a C4 summer annual, Atriplex elegans (Moq.) D. Dietr. Peak rates of protein synthesis correlated well with the preferred habitat temperatures of B. incana and A. elegans; optima occurred at 25 and 35°C, respectively. Plants of P. insularis showed an optimum protein synthesis rate at 35°C; however, this optimum rate was considerably lower than for the other two species. Higher activation energies for protein synthesis tended to parallel adaptation to higher temperature habitats. Responses of protein degradation to temperature in A. elegans and B. incana were consistent with their natural thermal regimes, when evaluated for the transition from 25 to 35°C. Again, protein degradation in P. insularis shows an intermediate response to temperature during the 25 to 35°C transition. PMID:16664583

  13. Adaptive, convergent origins of the pygmy phenotype in African rainforest hunter-gatherers.

    PubMed

    Perry, George H; Foll, Matthieu; Grenier, Jean-Christophe; Patin, Etienne; Nédélec, Yohann; Pacis, Alain; Barakatt, Maxime; Gravel, Simon; Zhou, Xiang; Nsobya, Sam L; Excoffier, Laurent; Quintana-Murci, Lluis; Dominy, Nathaniel J; Barreiro, Luis B

    2014-09-02

    The evolutionary history of the human pygmy phenotype (small body size), a characteristic of African and Southeast Asian rainforest hunter-gatherers, is largely unknown. Here we use a genome-wide admixture mapping analysis to identify 16 genomic regions that are significantly associated with the pygmy phenotype in the Batwa, a rainforest hunter-gatherer population from Uganda (east central Africa). The identified genomic regions have multiple attributes that provide supporting evidence of genuine association with the pygmy phenotype, including enrichments for SNPs previously associated with stature variation in Europeans and for genes with growth hormone receptor and regulation functions. To test adaptive evolutionary hypotheses, we computed the haplotype-based integrated haplotype score (iHS) statistic and the level of population differentiation (FST) between the Batwa and their agricultural neighbors, the Bakiga, for each genomic SNP. Both |iHS| and FST values were significantly higher for SNPs within the Batwa pygmy phenotype-associated regions than the remainder of the genome, a signature of polygenic adaptation. In contrast, when we expanded our analysis to include Baka rainforest hunter-gatherers from Cameroon and Gabon (west central Africa) and Nzebi and Nzime neighboring agriculturalists, we did not observe elevated |iHS| or FST values in these genomic regions. Together, these results suggest adaptive and at least partially convergent origins of the pygmy phenotype even within Africa, supporting the hypothesis that small body size confers a selective advantage for tropical rainforest hunter-gatherers but raising questions about the antiquity of this behavior.

  14. Does it Pay to Delay? Flesh Flies Show Adaptive Plasticity in Reproductive Timing

    PubMed Central

    Kristal, Ross; Netter, Fleta; Hatle, John D.; Hahn, Daniel A.

    2013-01-01

    Life-history plasticity is widespread among organisms. However, an important question is whether this plasticity is adaptive, enhancing the organism’s fitness. Most models for plasticity in life-history timing predict that once they have reached the minimal nutritional threshold animals under poor conditions will accelerate timing to development or reproduction. Adaptive delays in reproductive timing are not common, especially in short-lived species. Examples of adaptive reproductive delays exist in mammalian populations experiencing strong interspecific (e.g. predation) and intraspecific (e.g. infanticide) competition. But are there other environmental factors that may trigger an adaptive delay in reproductive timing? We show that the short-lived flesh fly Sarcophaga crassipalpis will delay reproductive timing under nutrient poor conditions, even though it has already met the minimal nutritional threshold for reproduction. We test if this delay strategy is consistent with an adaptive response allowing the scavenger time to locate more resources by providing additional protein pulses (early, mid and late) throughout the reproductive delay period. Flies receiving additional protein produced more eggs and larger eggs, demonstrating a benefit of the delay. In addition, by tracking the allocation of carbon from the pulses using stable isotopes, we show that flies receiving earlier pulses incorporated more carbon into eggs and somatic tissue than those provided a later pulse. These results indicate that the reproductive delay in S. crassipalpis is consistent with adaptive post-threshold plasticity, a nutritionally-linked reproductive strategy that has not been previously reported in an invertebrate species. PMID:20953961

  15. Effects of Sowing Date on Phenotypic Plasticity of Fitness-Related Traits in Two Annual Weeds on the Songnen Plain of China

    PubMed Central

    Li, Haiyan; Lindquist, John L.; Yang, Yunfei

    2015-01-01

    Background Phenotypic plasticity of fitness-related traits is vital for plant species to adapt to variable environments. Chenopodium glaucum L. and Amaranthus retroflexus L. are two common weed species globally. Understanding the plasticity in life-history traits, especially in reproductive allocation, within and among these species is important for predicting their success and for managing them in different environments. Methodology/Principal Findings Seeds of the two plant species were sown every 10 days from 26 Jun to 15 Aug. Life-history and fitness-related traits of both phenology and morphology were measured, and dry biomass of roots, stems, leaves, and reproductive tissues was determined at physiological maturity. Length of reproductive and total life period of the two species differed among six sowing-date treatments. Later germinating plants led to relatively reduced total life period, size, and earlier reproduction than earlier germinating plants. The ratio of reproductive biomass to total plant biomass increased with later planting dates in C. glaucum but declined in A. retroflexus. Mature plant height, crown diameter, and reproductive tissue biomass, and seed production of C. glaucum and A. retroflexus increased with delayed reproductive period. Both species displayed true plasticity in reproductive allocation. However, the sowing date had a far greater effect on rate of vegetative growth than on allocation to reproduction. Conclusions/Significance The fitness of both C. glaucum and A. retroflexus populations have an apparent increase when the period between germination and seed production is much longer. However, C. glaucum appears better adapted to later sowing than A. retroflexus. Controlling seedlings prior to reproduction will alleviate the negative effect not only in the present year but also in future years. PMID:26023915

  16. Extraordinary Adaptive Plasticity of Colorado Potato Beetle: “Ten-Striped Spearman” in the Era of Biotechnological Warfare

    PubMed Central

    Cingel, Aleksandar; Savić, Jelena; Lazarević, Jelica; Ćosić, Tatjana; Raspor, Martin; Smigocki, Ann; Ninković, Slavica

    2016-01-01

    Expanding from remote areas of Mexico to a worldwide scale, the ten-striped insect, the Colorado potato beetle (CPB, Leptinotarsa decemlineata Say), has risen from being an innocuous beetle to a prominent global pest. A diverse life cycle, phenotypic plasticity, adaptation to adverse conditions, and capability to detoxify or tolerate toxins make this insect appear to be virtually “indestructible”. With increasing advances in molecular biology, tools of biotechnological warfare were deployed to combat CPB. In the last three decades, genetically modified potato has created a new challenge for the beetle. After reviewing hundreds of scientific papers dealing with CPB control, it became clear that even biotechnological means of control, if used alone, would not defeat the Colorado potato beetle. This control measure once again appears to be provoking the potato beetle to exhibit its remarkable adaptability. Nonetheless, the potential for adaptation to these techniques has increased our knowledge of this pest and thus opened possibilities for devising more sustainable CPB management programs. PMID:27649141

  17. Staphylococcus aureus metabolic adaptations during the transition from a daptomycin susceptibility phenotype to a daptomycin nonsusceptibility phenotype.

    PubMed

    Gaupp, Rosmarie; Lei, Shulei; Reed, Joseph M; Peisker, Henrik; Boyle-Vavra, Susan; Bayer, Arnold S; Bischoff, Markus; Herrmann, Mathias; Daum, Robert S; Powers, Robert; Somerville, Greg A

    2015-07-01

    Staphylococcus aureus is a major cause of nosocomial and community-acquired infections. The success of S. aureus as a pathogen is due in part to its many virulence determinants and resistance to antimicrobials. In particular, methicillin-resistant S. aureus has emerged as a major cause of infections and led to increased use of the antibiotics vancomycin and daptomycin, which has increased the isolation of vancomycin-intermediate S. aureus and daptomycin-nonsusceptible S. aureus strains. The most common mechanism by which S. aureus acquires intermediate resistance to antibiotics is by adapting its physiology and metabolism to permit growth in the presence of these antibiotics, a process known as adaptive resistance. To better understand the physiological and metabolic changes associated with adaptive resistance, six daptomycin-susceptible and -nonsusceptible isogenic strain pairs were examined for changes in growth, competitive fitness, and metabolic alterations. Interestingly, daptomycin nonsusceptibility coincides with a slightly delayed transition to the postexponential growth phase and alterations in metabolism. Specifically, daptomycin-nonsusceptible strains have decreased tricarboxylic acid cycle activity, which correlates with increased synthesis of pyrimidines and purines and increased carbon flow to pathways associated with wall teichoic acid and peptidoglycan biosynthesis. Importantly, these data provided an opportunity to alter the daptomycin nonsusceptibility phenotype by manipulating bacterial metabolism, a first step in developing compounds that target metabolic pathways that can be used in combination with daptomycin to reduce treatment failures.

  18. Staphylococcus aureus Metabolic Adaptations during the Transition from a Daptomycin Susceptibility Phenotype to a Daptomycin Nonsusceptibility Phenotype

    PubMed Central

    Gaupp, Rosmarie; Lei, Shulei; Reed, Joseph M.; Peisker, Henrik; Boyle-Vavra, Susan; Bayer, Arnold S.; Bischoff, Markus; Herrmann, Mathias; Daum, Robert S.

    2015-01-01

    Staphylococcus aureus is a major cause of nosocomial and community-acquired infections. The success of S. aureus as a pathogen is due in part to its many virulence determinants and resistance to antimicrobials. In particular, methicillin-resistant S. aureus has emerged as a major cause of infections and led to increased use of the antibiotics vancomycin and daptomycin, which has increased the isolation of vancomycin-intermediate S. aureus and daptomycin-nonsusceptible S. aureus strains. The most common mechanism by which S. aureus acquires intermediate resistance to antibiotics is by adapting its physiology and metabolism to permit growth in the presence of these antibiotics, a process known as adaptive resistance. To better understand the physiological and metabolic changes associated with adaptive resistance, six daptomycin-susceptible and -nonsusceptible isogenic strain pairs were examined for changes in growth, competitive fitness, and metabolic alterations. Interestingly, daptomycin nonsusceptibility coincides with a slightly delayed transition to the postexponential growth phase and alterations in metabolism. Specifically, daptomycin-nonsusceptible strains have decreased tricarboxylic acid cycle activity, which correlates with increased synthesis of pyrimidines and purines and increased carbon flow to pathways associated with wall teichoic acid and peptidoglycan biosynthesis. Importantly, these data provided an opportunity to alter the daptomycin nonsusceptibility phenotype by manipulating bacterial metabolism, a first step in developing compounds that target metabolic pathways that can be used in combination with daptomycin to reduce treatment failures. PMID:25963986

  19. Morphometric and genetic analysis of Arcella intermedia and Arcella intermedia laevis (Amoebozoa, Arcellinida) illuminate phenotypic plasticity in microbial eukaryotes.

    PubMed

    Porfírio-Sousa, Alfredo L; Ribeiro, Giulia M; Lahr, Daniel J G

    2016-11-25

    Testate amoebae are eukaryotic microorganisms characterized by the presence of an external shell (test). The shell morphology is used as a diagnostic character, but discordance between morphological and molecular data has been demonstrated in groups of arcellinids (Amoebozoa), one of the principal groups of testate amoebae. Morphology of the test is supposed to differentiate genera and species and it is applied in ecological, monitoring and paleontological studies. However, if phenotype does not reflect genotype, conclusions in these types of studies become severely impaired. The objective of this work is to evaluate the morphometrical and morphological variation of the closely related and morphologically similar taxa Arcella intermedia laevis Tsyganov and Mazei, 2006 and Arcella intermedia (Deflandre 1928) Tsyganov and Mazei, 2006 in nature and in cultured individuals and see how these are correlated with molecular data. Our results demonstrate that phenotypic plasticity in Arcella intermedia make morphological distinctions impossible in both taxa. Arcella intermedia and Arcella intermedia laevis are molecularly identical for SSU rDNA and a mitochondrial molecular marker (NAD9/7). We conclude that morphological techniques alone cannot identify phenotypic plasticity from natural populations. More work is clearly needed to better understand the morphological, morphometric and molecular variability in these organisms.

  20. Limited plasticity in the phenotypic variance-covariance matrix for male advertisement calls in the black field cricket, Teleogryllus commodus.

    PubMed

    Pitchers, W R; Brooks, R; Jennions, M D; Tregenza, T; Dworkin, I; Hunt, J

    2013-05-01

    Phenotypic integration and plasticity are central to our understanding of how complex phenotypic traits evolve. Evolutionary change in complex quantitative traits can be predicted using the multivariate breeders' equation, but such predictions are only accurate if the matrices involved are stable over evolutionary time. Recent study, however, suggests that these matrices are temporally plastic, spatially variable and themselves evolvable. The data available on phenotypic variance-covariance matrix (P) stability are sparse, and largely focused on morphological traits. Here, we compared P for the structure of the complex sexual advertisement call of six divergent allopatric populations of the Australian black field cricket, Teleogryllus commodus. We measured a subset of calls from wild-caught crickets from each of the populations and then a second subset after rearing crickets under common-garden conditions for three generations. In a second experiment, crickets from each population were reared in the laboratory on high- and low-nutrient diets and their calls recorded. In both experiments, we estimated P for call traits and used multiple methods to compare them statistically (Flury hierarchy, geometric subspace comparisons and random skewers). Despite considerable variation in means and variances of individual call traits, the structure of P was largely conserved among populations, across generations and between our rearing diets. Our finding that P remains largely stable, among populations and between environmental conditions, suggests that selection has preserved the structure of call traits in order that they can function as an integrated unit.

  1. New Insights on the Maternal Diet Induced-Hypertension: Potential Role of the Phenotypic Plasticity and Sympathetic-Respiratory Overactivity

    PubMed Central

    Costa-Silva, João H.; de Brito-Alves, José L.; Barros, Monique Assis de V.; Nogueira, Viviane Oliveira; Paulino-Silva, Kássya M.; de Oliveira-Lira, Allan; Nobre, Isabele G.; Fragoso, Jéssica; Leandro, Carol G.

    2015-01-01

    Systemic arterial hypertension (SAH) is an important risk factor for cardiovascular disease and affects worldwide population. Current environment including life style coupled with genetic programming have been attributed to the rising incidence of hypertension. Besides, environmental conditions during perinatal development such as maternal malnutrition can program changes in the integration among renal, neural, and endocrine system leading to hypertension. This phenomenon is termed phenotypic plasticity and refers to the adjustment of a phenotype in response to environmental stimuli without genetic change, following a novel or unusual input during development. Human and animal studies indicate that fetal exposure to an adverse maternal environment may alter the renal morphology and physiology that contribute to the development of hypertension. Recently, it has been shown that the maternal protein restriction alter the central control of SAH by a mechanism that include respiratory dysfunction and enhanced sympathetic-respiratory coupling at early life, which may contribute to adult hypertension. This review will address the new insights on the maternal diet induced-hypertension that include the potential role of the phenotypic plasticity, specifically the perinatal protein malnutrition, and sympathetic-respiratory overactivity. PMID:26635631

  2. [Phenotypic plasticity of neural crest-derived melanocytes and Schwann cells].

    PubMed

    Dupin, Elisabeth

    2011-01-01

    expression. This review considers the issue of whether neural crest-derived lineages are endowed with some phenotypic plasticity. Emphasis is put on the ability of pigment cells and Schwann cells to dedifferentiate and reprogram their fate in vitro. To address this question, we have studied the clonal progeny of differentiated Schwann cells and melanocytes after their isolation from the sciatic nerve and the back skin of quail embryos, respectively. When stimulated to proliferate in vitro in the presence of endothelin-3, both cell types were able to dedifferentiate and produce alternative neural crest-derived cell lineages. Individual Schwann cells isolated by FACS, using a glial-specific surface marker, gave rise in culture to pigment cells and myofibroblasts/smooth muscle cells. Treatment of the cultures with endothelin-3 was required for Schwann cell conversion into melanocytes, which involved acquisition of multipotency. Moreover, Schwann cell plasticity could also be induced in vivo: following transplantation into the branchial arch of a young chick host embryo, dedifferentiating Schwann cells were able to integrate the forming head structures of the host and, specifically, to contribute smooth muscle cells to the wall of cranial blood vessels. We also analyzed the in vitro behavior of individual pigment cells obtained by microdissection and enzymatic treatment of quail epidermis at embryonic and hatching stages. In single cell cultures treated with endothelin-3, pigment cells strongly proliferated while rapidly dedifferentiating into unpigmented cells, leading to the formation of large colonies that comprised glial cells and myofibroblasts in addition to melanocytes. By serially subcloning these primary colonies, we could efficiently propagate a bipotent glial-melanocytic precursor that is generated in the progeny of the melanocytic founder. These data therefore suggest that pigment cells have the ability to revert back to the state of self-renewing neural crest

  3. Field Phenotyping Strategies and Breeding for Adaptation of Rice to Drought†

    PubMed Central

    Fischer, Ken S.; Fukai, Shu; Kumar, Arvind; Leung, Hei; Jongdee, Boonrat

    2012-01-01

    This paper is a section of the book “Drought phenotyping in crops: from theory to practice” (Monneveux Philippe and Ribaut Jean-Marcel eds, published by CGIAR Generation Challenge Programme. Texcoco, Mexico). The section describes recent experience in drought phenotyping in rice which is one of the most drought-susceptible crops. The section contains genetic and genomic resources for drought adaptation and methods for selection of drought-resistant varieties in rice. In appendix, there is experience from Thailand on integration of direct selection for grain yield and physiological traits to confer drought resistance. PMID:22934036

  4. Mechanism of a plastic phenotypic response: predator-induced shell thickening in the intertidal gastropod Littorina obtusata.

    PubMed

    Brookes, J I; Rochette, Rémy

    2007-05-01

    Phenotypic plasticity has been the object of considerable interest over the past several decades, but in few cases are mechanisms underlying plastic responses well understood. For example, it is unclear whether predator-induced changes in gastropod shell morphology represent an active physiological response or a by-product of reduced feeding. We address this question by manipulating feeding and growth of intertidal snails, Littorina obtusata, using two approaches: (i) exposure to predation cues from green crabs Carcinus maenas and (ii) reduced food availability, and quantifying growth in shell length, shell mass, and body mass, as well as production of faecal material and shell micro-structural characteristics (mineralogy and organic fraction) after 96 days. We demonstrate that L. obtusata actively increases calcification rate in response to predation threat, and that this response entails energetic and developmental costs. That this induced response is not strictly tied to the animal's behaviour should enhance its evolutionary potential.

  5. Light and Nutrient Dependent Responses in Secondary Metabolites of Plantago lanceolata Offspring Are Due to Phenotypic Plasticity in Experimental Grasslands

    PubMed Central

    Miehe-Steier, Annegret; Roscher, Christiane; Reichelt, Michael; Gershenzon, Jonathan; Unsicker, Sybille B.

    2015-01-01

    A few studies in the past have shown that plant diversity in terms of species richness and functional composition can modify plant defense chemistry. However, it is not yet clear to what extent genetic differentiation of plant chemotypes or phenotypic plasticity in response to diversity-induced variation in growth conditions or a combination of both is responsible for this pattern. We collected seed families of ribwort plantain (Plantago lanceolata) from six-year old experimental grasslands of varying plant diversity (Jena Experiment). The offspring of these seed families was grown under standardized conditions with two levels of light and nutrients. The iridoid glycosides, catalpol and aucubin, and verbascoside, a caffeoyl phenylethanoid glycoside, were measured in roots and shoots. Although offspring of different seed families differed in the tissue concentrations of defensive metabolites, plant diversity in the mothers' environment did not explain the variation in the measured defensive metabolites of P. lanceolata offspring. However secondary metabolite levels in roots and shoots were strongly affected by light and nutrient availability. Highest concentrations of iridoid glycosides and verbascoside were found under high light conditions, and nutrient availability had positive effects on iridoid glycoside concentrations in plants grown under high light conditions. However, verbascoside concentrations decreased under high levels of nutrients irrespective of light. The data from our greenhouse study show that phenotypic plasticity in response to environmental variation rather than genetic differentiation in response to plant community diversity is responsible for variation in secondary metabolite concentrations of P. lanceolata in the six-year old communities of the grassland biodiversity experiment. Due to its large phenotypic plasticity P. lanceolata has the potential for a fast and efficient adjustment to varying environmental conditions in plant communities of

  6. Resolving phenotypic plasticity and species designation in the morphologically challenging Caulerpa racemosa-peltata complex (Chlorophyta, Caulerpaceae).

    PubMed

    Belton, Gareth S; van Reine, Willem F Prud'homme; Huisman, John M; Draisma, Stefano G A; D Gurgel, Carlos Frederico

    2014-02-01

    Although recent molecular studies have indicated the presence of a number of distinct species within the Caulerpa racemosa-peltata complex, due to the difficulties presented by high levels of phenotypic plasticity and the large number of synonyms, infra-specific taxa, and names of uncertain affinity, taxonomic proposals are yet to be made. In this study, we aimed to resolve the taxonomy of the complex and provide an example of how historical nomenclature can best be integrated into molecular based taxonomies. We accomplished this by first determining the number of genetic species within our globally sampled data set through a combination of phylogenetic and species-delimitation approaches of partial elongation factor TU and RUBISCO large subunit gene sequences. Guided by these results, comparative morphological examinations were then undertaken to gauge the extent of phenotypic plasticity within each species, as well as any morphological overlap between them. Our results revealed the presence of 11 distinct species within the complex, five of which showed high levels of phenotypic plasticity and partial overlap with other species. On the basis of observations of a large number of specimens, including type specimens/descriptions, and geographic inferences, we were able to confidently designate names for the lineages. Caulerpa peltata, C. imbricata and C. racemosa vars. laetevirens, occidentalis and turbinata were found to represent environmentally induced forms of a single species, for which the earlier-described C. chemnitzia, previously regarded as a synonym of C. racemosa var. turbinata, is reinstated. C. cylindracea, C. lamourouxii, C. macrodisca, C. nummularia and C. oligophylla are also reinstated and two new species, C. macra stat. nov. and C. megadisca sp. nov., are proposed.

  7. Self-Adaptive Spike-Time-Dependent Plasticity of Metal-Oxide Memristors

    PubMed Central

    Prezioso, M.; Merrikh Bayat, F.; Hoskins, B.; Likharev, K.; Strukov, D.

    2016-01-01

    Metal-oxide memristors have emerged as promising candidates for hardware implementation of artificial synapses – the key components of high-performance, analog neuromorphic networks - due to their excellent scaling prospects. Since some advanced cognitive tasks require spiking neuromorphic networks, which explicitly model individual neural pulses (“spikes”) in biological neural systems, it is crucial for memristive synapses to support the spike-time-dependent plasticity (STDP). A major challenge for the STDP implementation is that, in contrast to some simplistic models of the plasticity, the elementary change of a synaptic weight in an artificial hardware synapse depends not only on the pre-synaptic and post-synaptic signals, but also on the initial weight (memristor’s conductance) value. Here we experimentally demonstrate, for the first time, an STDP behavior that ensures self-adaptation of the average memristor conductance, making the plasticity stable, i.e. insensitive to the initial state of the devices. The experiments have been carried out with 200-nm Al2O3/TiO2−x memristors integrated into 12 × 12 crossbars. The experimentally observed self-adaptive STDP behavior has been complemented with numerical modeling of weight dynamics in a simple system with a leaky-integrate-and-fire neuron with a random spike-train input, using a compact model of memristor plasticity, fitted for quantitatively correct description of our memristors. PMID:26893175

  8. [The cellular mechanisms of exercise adaptation from the perspective of skeletal muscle plasticity].

    PubMed

    Sun, Yi; Ding, Shu-Zhe

    2014-10-01

    As highly plastic tissue, skeletal muscle adapts to stressors such as exercise. Reasonable amount of exercise is known to play a role in the prevention of cardiovascular diseases, diabetes and cancer. However, in the field of Exercise Physiology, the debate has been on for a while as to which kind of exercise is more effective in health promotion. In this review, the authors contrast and compare the signaling pathways mediated by different types of exercise, and boldly speculate the intrinsic similarities and discrepancies among them, hoping to enrich the theoretical frames of exercise adaptation, as well as provide effective exercise regimen to the public.

  9. Adaptive variability in the duration of critical windows of plasticity: Implications for the programming of obesity.

    PubMed

    Wells, Jonathan C K

    2014-08-05

    Developmental plasticity underlies widespread associations between early-life exposures and many components of adult phenotype, including the risk of chronic diseases. Humans take almost two decades to reach reproductive maturity, and yet the 'critical windows' of physiological sensitivity that confer developmental plasticity tend to close during fetal life or infancy. While several explanations for lengthy human maturation have been offered, the brevity of physiological plasticity has received less attention. I argue that offspring plasticity is only viable within the niche of maternal care, and that as this protection is withdrawn, the offspring is obliged to canalize many developmental traits in order to minimize environmental disruptions. The schedule of maternal care may therefore shape the duration of critical windows, and since the duration of this care is subject to parent-offspring conflict, the resolution of this conflict may shape the duration of critical windows. This perspective may help understand (i) why windows close at different times for different traits, and (ii) why the duration of critical windows may vary across human populations. The issue is explored in relation to population differences in the association between infant weight gain and later body composition. The occupation of more stable environments by western populations may have favoured earlier closure of the critical window during which growth in lean mass is sensitive to nutritional intake. This may paradoxically have elevated the risk of obesity following rapid infant weight gain in such populations.

  10. MUTZ-3 derived Langerhans cells in human skin equivalents show differential migration and phenotypic plasticity after allergen or irritant exposure.

    PubMed

    Kosten, Ilona J; Spiekstra, Sander W; de Gruijl, Tanja D; Gibbs, Susan

    2015-08-15

    After allergen or irritant exposure, Langerhans cells (LC) undergo phenotypic changes and exit the epidermis. In this study we describe the unique ability of MUTZ-3 derived Langerhans cells (MUTZ-LC) to display similar phenotypic plasticity as their primary counterparts when incorporated into a physiologically relevant full-thickness skin equivalent model (SE-LC). We describe differences and similarities in the mechanisms regulating LC migration and plasticity upon allergen or irritant exposure. The skin equivalent consisted of a reconstructed epidermis containing primary differentiated keratinocytes and CD1a(+) MUTZ-LC on a primary fibroblast-populated dermis. Skin equivalents were exposed to a panel of allergens and irritants. Topical exposure to sub-toxic concentrations of allergens (nickel sulfate, resorcinol, cinnamaldehyde) and irritants (Triton X-100, SDS, Tween 80) resulted in LC migration out of the epidermis and into the dermis. Neutralizing antibody to CXCL12 blocked allergen-induced migration, whereas anti-CCL5 blocked irritant-induced migration. In contrast to allergen exposure, irritant exposure resulted in cells within the dermis becoming CD1a(-)/CD14(+)/CD68(+) which is characteristic of a phenotypic switch of MUTZ-LC to a macrophage-like cell in the dermis. This phenotypic switch was blocked with anti-IL-10. Mechanisms previously identified as being involved in LC activation and migration in native human skin could thus be reproduced in the in vitro constructed skin equivalent model containing functional LC. This model therefore provides a unique and relevant research tool to study human LC biology in situ under controlled in vitro conditions, and will provide a powerful tool for hazard identification, testing novel therapeutics and identifying new drug targets.

  11. Adaptive, convergent origins of the pygmy phenotype in African rainforest hunter-gatherers

    PubMed Central

    Perry, George H.; Foll, Matthieu; Grenier, Jean-Christophe; Patin, Etienne; Nédélec, Yohann; Pacis, Alain; Barakatt, Maxime; Gravel, Simon; Zhou, Xiang; Nsobya, Sam L.; Excoffier, Laurent; Quintana-Murci, Lluis; Dominy, Nathaniel J.; Barreiro, Luis B.

    2014-01-01

    The evolutionary history of the human pygmy phenotype (small body size), a characteristic of African and Southeast Asian rainforest hunter-gatherers, is largely unknown. Here we use a genome-wide admixture mapping analysis to identify 16 genomic regions that are significantly associated with the pygmy phenotype in the Batwa, a rainforest hunter-gatherer population from Uganda (east central Africa). The identified genomic regions have multiple attributes that provide supporting evidence of genuine association with the pygmy phenotype, including enrichments for SNPs previously associated with stature variation in Europeans and for genes with growth hormone receptor and regulation functions. To test adaptive evolutionary hypotheses, we computed the haplotype-based integrated haplotype score (iHS) statistic and the level of population differentiation (FST) between the Batwa and their agricultural neighbors, the Bakiga, for each genomic SNP. Both |iHS| and FST values were significantly higher for SNPs within the Batwa pygmy phenotype-associated regions than the remainder of the genome, a signature of polygenic adaptation. In contrast, when we expanded our analysis to include Baka rainforest hunter-gatherers from Cameroon and Gabon (west central Africa) and Nzebi and Nzime neighboring agriculturalists, we did not observe elevated |iHS| or FST values in these genomic regions. Together, these results suggest adaptive and at least partially convergent origins of the pygmy phenotype even within Africa, supporting the hypothesis that small body size confers a selective advantage for tropical rainforest hunter-gatherers but raising questions about the antiquity of this behavior. PMID:25136101

  12. Bayesian approach increases accuracy when selecting cowpea genotypes with high adaptability and phenotypic stability.

    PubMed

    Barroso, L M A; Teodoro, P E; Nascimento, M; Torres, F E; Dos Santos, A; Corrêa, A M; Sagrilo, E; Corrêa, C C G; Silva, F A; Ceccon, G

    2016-03-11

    This study aimed to verify that a Bayesian approach could be used for the selection of upright cowpea genotypes with high adaptability and phenotypic stability, and the study also evaluated the efficiency of using informative and minimally informative a priori distributions. Six trials were conducted in randomized blocks, and the grain yield of 17 upright cowpea genotypes was assessed. To represent the minimally informative a priori distributions, a probability distribution with high variance was used, and a meta-analysis concept was adopted to represent the informative a priori distributions. Bayes factors were used to conduct comparisons between the a priori distributions. The Bayesian approach was effective for selection of upright cowpea genotypes with high adaptability and phenotypic stability using the Eberhart and Russell method. Bayes factors indicated that the use of informative a priori distributions provided more accurate results than minimally informative a priori distributions.

  13. Pushing the limit: masticatory stress and adaptive plasticity in mammalian craniomandibular joints.

    PubMed

    Ravosa, Matthew J; Kunwar, Ravinder; Stock, Stuart R; Stack, M Sharon

    2007-02-01

    Excessive, repetitive and altered loading have been implicated in the initiation of a series of soft- and hard-tissue responses or ;functional adaptations' of masticatory and locomotor elements. Such adaptive plasticity in tissue types appears designed to maintain a sufficient safety factor, and thus the integrity of given element or system, for a predominant loading environment(s). Employing a mammalian species for which considerable in vivo data on masticatory behaviors are available, genetically similar domestic white rabbits were raised on diets of different mechanical properties so as to develop an experimental model of joint function in a normal range of physiological loads. These integrative experiments are used to unravel the dynamic inter-relationships among mechanical loading, tissue adaptive plasticity, norms of reaction and performance in two cranial joint systems: the mandibular symphysis and temporomandibular joint (TMJ). Here, we argue that a critical component of current and future research on adaptive plasticity in the skull, and especially cranial joints, should employ a multifaceted characterization of a functional system, one that incorporates data on myriad tissues so as to evaluate the role of altered load versus differential tissue response on the anatomical, cellular and molecular processes that contribute to the strength of such composite structures. Our study also suggests that the short-term duration of earlier analyses of cranial joint tissues may offer a limited notion of the complex process of developmental plasticity, especially as it relates to the effects of long-term variation in mechanical loads, when a joint is increasingly characterized by adaptive and degradative changes in tissue structure and composition. Indeed, it is likely that a component of the adaptive increases in rabbit TMJ and symphyseal proportions and biomineralization represent a compensatory mechanism to cartilage degradation that serves to maintain the overall

  14. Variability in the adaptive acid tolerance response phenotype of Salmonella enterica strains.

    PubMed

    Lianou, Alexandra; Nychas, George-John E; Koutsoumanis, Konstantinos P

    2017-04-01

    The objective of this study was the assessment of the stationary-phase, low-pH-inducible acid tolerance response (ATR) of different Salmonella enterica strains. For this purpose, 30 strains of the pathogen were grown in tryptone soy broth in the absence (non-adapted cultures) and presence (1% w/v; acid-adapted cultures) of glucose, and then subjected to 4-h acid challenge trials at pH 3.0. Surviving populations of each strain were determined at 1-h intervals, and the Weibull model was fitted to the derived microbiological data. Extensive variability in the acid stress responses of the tested S. enterica strains was observed, with the total population reductions (log CFU/ml) attained in 4 h of acid challenge ranging from 0.9 to 5.5 and from 0.6 to 7.0 for the non-adapted and acid-adapted cultures, respectively. As demonstrated by the model scale parameter δ and shape parameter p, the effect of acid adaptation on the inactivation curves was strain-specific. Although acid adaptation resulted in enhanced acid survival for the majority of the tested strains, there were strains exhibiting similar or decreased acid resistance compared to their non-adapted counterparts. Moreover, acid adaptation appeared to decrease the strain variability of δ whereas increasing the strain variability of p: the coefficient of variation of δ among the tested strains was 97.2 and 54.9% for the non-adapted and acid-adapted cultures, respectively, while the corresponding values for p were 12.7 and 48.1%. The data of the present study, which is the first one to systematically evaluate the adaptive ATR of multiple S. enterica strains, clearly demonstrate that this phenotype (attempted to be induced by growing the pathogen in the presence of glucose) is strain-dependent.

  15. Strong mutator phenotype drives faster adaptation from growth on glucose to growth on acetate in Salmonella.

    PubMed

    Le Bars, Hervé; Bonnaure-Mallet, Martine; Barloy-Hubler, Frédérique; Jolivet-Gougeon, Anne; Bousarghin, Latifa

    2014-10-01

    The metabolic adaptation of strong mutator strains was studied to better understand the link between the strong mutator phenotype and virulence. Analysis of the growth curves of isogenic strains of Salmonella, which were previously grown in M63 glucose media, revealed that the exponential phase of growth was reached earlier in an M63 acetate medium with strong mutator strains (mutated in mutS or in mutL) than with normomutator strains (P<0.05). Complemented strains confirmed the direct role of the strong mutator phenotype in this faster metabolic adaptation to the assimilation of acetate. In a mixed cell population, proliferation of strong mutators over normomutators was observed when the carbon source was switched from glucose to acetate. These results add to the sparse body of knowledge about strong mutators and highlight the selective advantage conferred by the strong mutator phenotype to adapt to a switch of carbon source in the environment. This work may provide clinically useful information given that there is a high prevalence of strong mutators among pathogenic strains of Salmonella and that acetate is the principal short chain fatty acid of the human terminal ileum and colon where Salmonella infection is localized.

  16. Rice Root Architectural Plasticity Traits and Genetic Regions for Adaptability to Variable Cultivation and Stress Conditions1[OPEN

    PubMed Central

    Sandhu, Nitika; Raman, K. Anitha; Torres, Rolando O.; Audebert, Alain; Dardou, Audrey; Kumar, Arvind; Henry, Amelia

    2016-01-01

    Future rice (Oryza sativa) crops will likely experience a range of growth conditions, and root architectural plasticity will be an important characteristic to confer adaptability across variable environments. In this study, the relationship between root architectural plasticity and adaptability (i.e. yield stability) was evaluated in two traditional × improved rice populations (Aus 276 × MTU1010 and Kali Aus × MTU1010). Forty contrasting genotypes were grown in direct-seeded upland and transplanted lowland conditions with drought and drought + rewatered stress treatments in lysimeter and field studies and a low-phosphorus stress treatment in a Rhizoscope study. Relationships among root architectural plasticity for root dry weight, root length density, and percentage lateral roots with yield stability were identified. Selected genotypes that showed high yield stability also showed a high degree of root plasticity in response to both drought and low phosphorus. The two populations varied in the soil depth effect on root architectural plasticity traits, none of which resulted in reduced grain yield. Root architectural plasticity traits were related to 13 (Aus 276 population) and 21 (Kali Aus population) genetic loci, which were contributed by both the traditional donor parents and MTU1010. Three genomic loci were identified as hot spots with multiple root architectural plasticity traits in both populations, and one locus for both root architectural plasticity and grain yield was detected. These results suggest an important role of root architectural plasticity across future rice crop conditions and provide a starting point for marker-assisted selection for plasticity. PMID:27342311

  17. [Responses of Agriophyllum squarrosum phenotypic plasticity to the changes of soil nutrient and moisture contents and population density].

    PubMed

    Huang, Ying-xin; Zhao, Xue-yong; Zhang, Hong-xuan; Luo, Ya-yong; Mao, Wei

    2008-12-01

    This paper studied the phenotypic plasticity of Agriophyllum squarrosum under effects of soil nutrient and moisture contents and population density. The results showed that with the increase of soil nutrient content, the root/shoot ratio of A. squarrosum was decreased from 0.135 to 0.073. However, soil moisture content and population density had less effect on the root/shoot ratio. The plasticity of reproductive allocation of A. squarrosum as responding to the changes of soil nutrient and moisture contents was a "real plasticity", and the allocation was negatively correlated with soil nutrient content but positively correlated with soil moisture content. When soil nutrient content was high or moisture content was low, the reproductive allocation of A. squarrosum changed larger with plant size. Population density had no effects on the reproductive allocation, while plant size conditioned the allocation. Among the three test affecting factors, soil nutrient content had the greatest effects on the morphological characters and biomass of A. squarrosum.

  18. Phenotypic plasticity in a complex world: interactive effects of food and temperature on fitness components of a seed beetle.

    PubMed

    Stillwell, R Craig; Wallin, William G; Hitchcock, Lisa J; Fox, Charles W

    2007-08-01

    Most studies of phenotypic plasticity investigate the effects of an individual environmental factor on organism phenotypes. However, organisms exist in an ecologically complex world where multiple environmental factors can interact to affect growth, development and life histories. Here, using a multifactorial experimental design, we examine the separate and interactive effects of two environmental factors, rearing host species (Vigna radiata, Vigna angularis and Vigna unguiculata) and temperature (20, 25, 30 and 35 degrees C), on growth and life history traits in two populations [Burkina Faso (BF) and South India (SI)] of the seed beetle, Callosobruchus maculatus. The two study populations of beetles responded differently to both rearing host and temperature. We also found a significant interaction between rearing host and temperature for body size, growth rate and female lifetime fecundity but not larval development time or larval survivorship. The interaction was most apparent for growth rate; the variance in growth rate among hosts increased with increasing temperature. However, the details of host differences differed between our two study populations; the degree to which V. unguiculata was a better host than V. angularis or V. radiata increased at higher temperatures for BF beetles, whereas the degree to which V. unguiculata was the worst host increased at higher temperatures for SI beetles. We also found that the heritabilities of body mass, growth rate and fecundity were similar among rearing hosts and temperatures, and that the cross-temperature genetic correlation was not affected by rearing host, suggesting that genetic architecture is generally stable across rearing conditions. The most important finding of our study is that multiple environmental factors can interact to affect organism growth, but the degree of interaction, and thus the degree of complexity of phenotypic plasticity, varies among traits and between populations.

  19. Phenotypic, functional, and plasticity features of classical and alternatively activated human macrophages.

    PubMed

    Tarique, Abdullah A; Logan, Jayden; Thomas, Emma; Holt, Patrick G; Sly, Peter D; Fantino, Emmanuelle

    2015-11-01

    Macrophages are dynamic cells that mature under the influence of signals from the local microenvironment into either classically (M1) or alternatively (M2) activated macrophages with specific functional and phenotypic properties. Although the phenotypic identification of M1 and M2 macrophages is well established in mice, this is less clear for human macrophages. In addition, the persistence and reversibility of polarized human phenotypes is not well established. Human peripheral blood monocytes were differentiated into uncommitted macrophages (M0) and then polarized to M1 and M2 phenotypes using LPS/IFN-γ and IL-4/IL-13, respectively. M1 and M2 were identified as CD64(+)CD80(+) and CD11b(+)CD209(+), respectively, by flow cytometry. Polarized M1 cells secreted IP-10, IFN-γ, IL-8, TNF-α, IL-1β, and RANTES, whereas M2 cells secreted IL-13, CCL17, and CCL18. Functionally, M2 cells were highly endocytic. In cytokine-deficient medium, the polarized macrophages reverted back to the M0 state within 12 days. If previously polarized macrophages were given the alternative polarizing stimulus after 6 days of resting in cytokine-deficient medium, a switch in polarization was seen (i.e., M1 macrophages switched to M2 and expressed CD11b(+)CD209(+) and vice versa). In summary, we report phenotypic identification of human M1 and M2 macrophages, their functional characteristics, and their ability to be reprogrammed given the appropriate stimuli.

  20. Hemodynamic Influence on Smooth Muscle Cell Kinetics and Phenotype During Early Vein Graft Adaptation.

    PubMed

    Klein, Benjamin; Destephens, Anthony; Dumeny, Leanne; Hu, Qiongyao; He, Yong; O'Malley, Kerri; Jiang, Zhihua; Tran-Son-Tay, Roger; Berceli, Scott

    2017-03-01

    Pathologic vascular adaptation following local injury is the primary driver for accelerated intimal hyperplasia and an occlusive phenotype. Smooth muscle cell (SMC) proliferation within the wall, and migration into the developing intima, is a major component of this remodeling response. The primary objective in the current study was to investigate the effect of the local biomechanical forces on early vein graft adaptation, specifically focusing on the spatial and temporal response of SMC proliferation and conversion from a contractile to synthetic architecture. Taking advantage of the differential adaptation that occurs during exposure to divergent flow environments, vein grafts were implanted in rabbits to create two distinct flow environments and harvested at times ranging from 2 h to 28 days. Using an algorithm for the virtual reconstruction of unfixed, histologic specimens, immunohistochemical tracking of DNA synthesis, and high-throughput transcriptional analysis, the spatial and temporal changes in graft morphology, cell proliferation, and SMC phenotype were catalogued. Notable findings include a burst of cell proliferation at 7 days post-implantation, which was significantly augmented by exposure to a reduced flow environment. Compared to the adjacent media, proliferation rates were 3-fold greater in the intima, and a specific spatial distribution of these proliferating cells was identified, with a major peak in the sub-endothelial region and a second peak centering on the internal elastic lamina. Genomic markers of a contractile SMC phenotype were reduced as early as 2 h post-implantation and reached a nadir at 7 days. Network analysis of upstream regulatory pathways identified GATA6 and KLF5 as important transcription factors that regulate this shift in SMC phenotype.

  1. Fixed spaced stimulation restores adaptive plasticity within the spinal cord: Identifying the eliciting conditions.

    PubMed

    Baumbauer, Kyle M; Turtle, Joel D; Grau, James W

    2017-02-24

    Prior work has shown that neurons within the spinal cord are sensitive to temporal relations and that stimulus regularity impacts nociceptive processing and adaptive plasticity. Application of brief (80ms) shocks (180-900) in a variable manner induces a form of maladaptive plasticity that inhibits spinally-mediated learning and enhances nociceptive reactivity. In contrast, an extended exposure (720-900) to stimuli given at regular (fixed spaced) intervals has a restorative effect that counters nociceptive sensitization and enables learning. The present paper explores the stimulus parameters under which this therapeutic effect of fixed spaced stimulation emerges. Spinally transected rats received variably spaced stimulation (180 shocks) to the sciatic nerve at an intensity (40-V) that recruits pain (C) fibers, producing a form of maladaptive plasticity that impairs spinal learning. As previously shown, exposure to 720 fixed spaced shocks had a therapeutic effect that restored adaptive learning. This therapeutic effect was most robust at a lower shock intensity (20V) and was equally strong irrespective of pulse duration (20-80ms). A restorative effect was observed when stimuli were given at a frequency between 0.5 and 5Hz, but not at a higher (50Hz) or lower (0.05Hz) rate. The results are consistent with prior work implicating neural systems related to the central pattern generator that drives stepping behavior. Clinical implications are discussed.

  2. Neuromagnetic correlates of adaptive plasticity across the hand-face border in human primary somatosensory cortex.

    PubMed

    Muret, Dollyane; Daligault, Sébastien; Dinse, Hubert R; Delpuech, Claude; Mattout, Jérémie; Reilly, Karen T; Farnè, Alessandro

    2016-04-01

    It is well established that permanent or transient reduction of somatosensory inputs, following hand deafferentation or anesthesia, induces plastic changes across the hand-face border, supposedly responsible for some altered perceptual phenomena such as tactile sensations being referred from the face to the phantom hand. It is also known that transient increase of hand somatosensory inputs, via repetitive somatosensory stimulation (RSS) at a fingertip, induces local somatosensory discriminative improvement accompanied by cortical representational changes in the primary somatosensory cortex (SI). We recently demonstrated that RSS at the tip of the right index finger induces similar training-independent perceptual learning across the hand-face border, improving somatosensory perception at the lips (Muret D, Dinse HR, Macchione S, Urquizar C, Farnè A, Reilly KT.Curr Biol24: R736-R737, 2014). Whether neural plastic changes across the hand-face border accompany such remote and adaptive perceptual plasticity remains unknown. Here we used magnetoencephalography to investigate the electrophysiological correlates underlying RSS-induced behavioral changes across the hand-face border. The results highlight significant changes in dipole location after RSS both for the stimulated finger and for the lips. These findings reveal plastic changes that cross the hand-face border after an increase, instead of a decrease, in somatosensory inputs.

  3. Neuromagnetic correlates of adaptive plasticity across the hand-face border in human primary somatosensory cortex

    PubMed Central

    Daligault, Sébastien; Dinse, Hubert R.; Delpuech, Claude; Mattout, Jérémie; Reilly, Karen T.; Farnè, Alessandro

    2016-01-01

    It is well established that permanent or transient reduction of somatosensory inputs, following hand deafferentation or anesthesia, induces plastic changes across the hand-face border, supposedly responsible for some altered perceptual phenomena such as tactile sensations being referred from the face to the phantom hand. It is also known that transient increase of hand somatosensory inputs, via repetitive somatosensory stimulation (RSS) at a fingertip, induces local somatosensory discriminative improvement accompanied by cortical representational changes in the primary somatosensory cortex (SI). We recently demonstrated that RSS at the tip of the right index finger induces similar training-independent perceptual learning across the hand-face border, improving somatosensory perception at the lips (Muret D, Dinse HR, Macchione S, Urquizar C, Farnè A, Reilly KT. Curr Biol 24: R736–R737, 2014). Whether neural plastic changes across the hand-face border accompany such remote and adaptive perceptual plasticity remains unknown. Here we used magnetoencephalography to investigate the electrophysiological correlates underlying RSS-induced behavioral changes across the hand-face border. The results highlight significant changes in dipole location after RSS both for the stimulated finger and for the lips. These findings reveal plastic changes that cross the hand-face border after an increase, instead of a decrease, in somatosensory inputs. PMID:26888099

  4. Electro-bending characterization of adaptive 3D fiber reinforced plastics based on shape memory alloys

    NASA Astrophysics Data System (ADS)

    Ashir, Moniruddoza; Hahn, Lars; Kluge, Axel; Nocke, Andreas; Cherif, Chokri

    2016-03-01

    The industrial importance of fiber reinforced plastics (FRPs) is growing steadily in recent years, which are mostly used in different niche products, has been growing steadily in recent years. The integration of sensors and actuators in FRP is potentially valuable for creating innovative applications and therefore the market acceptance of adaptive FRP is increasing. In particular, in the field of highly stressed FRP, structural integrated systems for continuous component parts monitoring play an important role. This presented work focuses on the electro-mechanical characterization of adaptive three-dimensional (3D)FRP with integrated textile-based actuators. Here, the friction spun hybrid yarn, consisting of shape memory alloy (SMA) in wire form as core, serves as an actuator. Because of the shape memory effect, the SMA-hybrid yarn returns to its original shape upon heating that also causes the deformation of adaptive 3D FRP. In order to investigate the influences of the deformation behavior of the adaptive 3D FRP, investigations in this research are varied according to the structural parameters such as radius of curvature of the adaptive 3D FRP, fabric types and number of layers of the fabric in the composite. Results show that reproducible deformations can be realized with adaptive 3D FRP and that structural parameters have a significant impact on the deformation capability.

  5. A assessment of the plastic Thermafil obturation technique. Part 1. Radiographic evaluation of adaptation and placement.

    PubMed

    Gutmann, J L; Saunders, W P; Saunders, E M; Nguyen, L

    1993-05-01

    Adaptation and placement of alpha-phase gutta-percha delivered with a plastic core-carrier, Thermafil, was compared to the lateral condensation of gutta-percha in a specific tooth model. Fifty-one mandibular molar roots with separate canals, patent canal orifices and curvatures greater than 15 degrees were cleaned and shaped with K-files and 2.5% sodium hypochlorite to a size 30 at the apex, and flared with Hedstrom files to create a continuously tapering funnel preparation. Canals were randomly obturated with Sealapex root canal sealer and either alpha-phase gutta-percha on a plastic Thermafil carrier, or standard beta-phase gutta-percha with lateral condensation. Roots were radiographed from the proximal and evaluated by three examiners, based on established criteria for overall material adaptation, apical adaptation, and filling material extrusion. Thermafil provided a statistically significant better overall canal obturation (P < 0.001), while, in the apical third, both techniques were not significantly different (P > 0.05). When the apical orifice was patent there was a significant propensity for the extrusion of filling materials beyond the apex (P < 0.001) with the Thermafil technique.

  6. An Adaptive Fisher’s Combination Method for Joint Analysis of Multiple Phenotypes in Association Studies

    PubMed Central

    Liang, Xiaoyu; Wang, Zhenchuan; Sha, Qiuying; Zhang, Shuanglin

    2016-01-01

    Currently, the analyses of most genome-wide association studies (GWAS) have been performed on a single phenotype. There is increasing evidence showing that pleiotropy is a widespread phenomenon in complex diseases. Therefore, using only one single phenotype may lose statistical power to identify the underlying genetic mechanism. There is an increasing need to develop and apply powerful statistical tests to detect association between multiple phenotypes and a genetic variant. In this paper, we develop an Adaptive Fisher’s Combination (AFC) method for joint analysis of multiple phenotypes in association studies. The AFC method combines p-values obtained in standard univariate GWAS by using the optimal number of p-values which is determined by the data. We perform extensive simulations to evaluate the performance of the AFC method and compare the power of our method with the powers of TATES, Tippett’s method, Fisher’s combination test, MANOVA, MultiPhen, and SUMSCORE. Our simulation studies show that the proposed method has correct type I error rates and is either the most powerful test or comparable with the most powerful test. Finally, we illustrate our proposed methodology by analyzing whole-genome genotyping data from a lung function study. PMID:27694844

  7. Adaptive mechanisms and genomic plasticity for drought tolerance identified in European black poplar (Populus nigra L.)

    PubMed Central

    Viger, Maud; Smith, Hazel K.; Cohen, David; Dewoody, Jennifer; Trewin, Harriet; Steenackers, Marijke; Bastien, Catherine; Taylor, Gail

    2016-01-01

    Summer droughts are likely to increase in frequency and intensity across Europe, yet long-lived trees may have a limited ability to tolerate drought. It is therefore critical that we improve our understanding of phenotypic plasticity to drought in natural populations for ecologically and economically important trees such as Populus nigra L. A common garden experiment was conducted using ∼500 wild P. nigra trees, collected from 11 river populations across Europe. Phenotypic variation was found across the collection, with southern genotypes from Spain and France characterized by small leaves and limited biomass production. To examine the relationship between phenotypic variation and drought tolerance, six genotypes with contrasting leaf morphologies were subjected to a water deficit experiment. ‘North eastern’ genotypes were collected at wet sites and responded to water deficit with reduced biomass growth, slow stomatal closure and reduced water use efficiency (WUE) assessed by Δ13C. In contrast, ‘southern’ genotypes originating from arid sites showed rapid stomatal closure, improved WUE and limited leaf loss. Transcriptome analyses of a genotype from Spain (Sp2, originating from an arid site) and another from northern Italy (Ita, originating from a wet site) revealed dramatic differences in gene expression response to water deficit. Transcripts controlling leaf development and stomatal patterning, including SPCH, ANT, ER, AS1, AS2, PHB, CLV1, ERL1–3 and TMM, were down-regulated in Ita but not in Sp2 in response to drought. PMID:27174702

  8. Genetic analyses, phenotypic adaptability and stability in sugarcane genotypes for commercial cultivation in Pernambuco.

    PubMed

    Dutra Filho, J A; Junior, T C; Simões Neto, D E

    2015-10-05

    In the present study, we assessed the agro-industrial performance of 22 sugarcane genotypes adaptable to edaphoclimatic conditions in production microregions in the State of Pernambuco, Brazil, and we recommended the commercial cultivation of select genotypes. The variables analyzed were as follows: sucrose percentage in cane juice, tonnage of saccharose per hectare (TPH), sugarcane tonnage per hectare (TCH), fiber, solid soluble contents, total recoverable sugar tonnage (ATR), and total recoverable sugar tonnage per hectare (ATR t/ha). A randomized block design with 4 repeats was used. Combined variance of the experiments, genetic parameter estimates, and environment stratification were analyzed. Phenotypic adaptability and stability were analyzed using the Annicchiarico and Wricke methods and analysis of variance. Genetic gain was estimated using the classic index and sum of ranks. Genotype selection was efficient for TPH, TCH, and ATR t/ha. Genotypes presented a great potential for improvement and a similar response pattern in Litoral Norte and Mata Sul microregions for TPH and TCH and Litoral Norte and Litoral Sul microregions for ATR t/ha. Genotypes SP78-4764, RB813804, and SP79-101 showed better productivity and phenotypic adaptability and stability, according to the Wricke and Annicchiarico methods. These genotypes can be recommended for cultivation in the sugarcane belt in the State of Pernambuco.

  9. Does the Structure–Function Model GREENLAB Deal with Crop Phenotypic Plasticity Induced by Plant Spacing? A Case Study on Tomato

    PubMed Central

    Dong, Qiaoxue; Louarn, Gaëtan; Wang, Yiming; Barczi, Jean-Francois; de Reffye, Philippe

    2008-01-01

    Background and Aims Plant growth models able to simulate phenotypic plasticity are increasingly required because (1) they should enable better predictions of the observed variations in crop production, yield and quality, and (2) their parameters are expected to have a more robust genetic basis, with possible implications for selection of quantitative traits such as growth- and allocation-related processes. The structure–function plant model, GREENLAB, simulates resource-dependent plasticity of plant architecture. Evidence for its generality has been previously reported, but always for plants grown in a limited range of environments. This paper aims to test the model concept to its limits by using plant spacing as a means to generate a gradient of competition for light, and by using a new crop species, tomato, known to exhibit a strong photomorphogenetic response. Methods A greenhouse experiment was carried out with three homogeneous planting densities (plant spacing = 0·3, 0·6 and 1 m). Detailed records of plant development, plant architecture and organ growth were made throughout the growing period. Model calibration was performed for each situation using a statistical optimization procedure (multi-fitting). Key Results and Conclusions Obvious limitations of the present version of the model appeared to account fully for the plant plasticity induced by inter-plant competition for light. A lack of stability was identified for some model parameters at very high planting density. In particular, those parameters characterizing organ sink strengths and governing light interception proved to be environment-dependent. Remarkably, however, responses of the parameter values concerned were consistent with actual growth measurements and with previously reported results. Furthermore, modifications of total biomass production and of allocation patterns induced by the planting-density treatments were accurately simulated using the sets of optimized parameters. These results

  10. Recovery of phenotypes obtained by adaptive evolution through inverse metabolic engineering.

    PubMed

    Hong, Kuk-Ki; Nielsen, Jens

    2012-11-01

    In a previous study, system level analysis of adaptively evolved yeast mutants showing improved galactose utilization revealed relevant mutations. The governing mutations were suggested to be in the Ras/PKA signaling pathway and ergosterol metabolism. Here, site-directed mutants having one of the mutations RAS2(Lys77), RAS2(Tyr112), and ERG5(Pro370) were constructed and evaluated. The mutants were also combined with overexpression of PGM2, earlier proved as a beneficial target for galactose utilization. The constructed strains were analyzed for their gross phenotype, transcriptome and targeted metabolites, and the results were compared to those obtained from reference strains and the evolved strains. The RAS2(Lys77) mutation resulted in the highest specific galactose uptake rate among all of the strains with an increased maximum specific growth rate on galactose. The RAS2(Tyr112) mutation also improved the specific galactose uptake rate and also resulted in many transcriptional changes, including ergosterol metabolism. The ERG5(Pro370) mutation only showed a small improvement, but when it was combined with PGM2 overexpression, the phenotype was almost the same as that of the evolved mutants. Combination of the RAS2 mutations with PGM2 overexpression also led to a complete recovery of the adaptive phenotype in galactose utilization. Recovery of the gross phenotype by the reconstructed mutants was achieved with much fewer changes in the genome and transcriptome than for the evolved mutants. Our study demonstrates how the identification of specific mutations by systems biology can direct new metabolic engineering strategies for improving galactose utilization by yeast.

  11. Gene Expression Reaction Norms Unravel the Molecular and Cellular Processes Underpinning the Plastic Phenotypes of Alternanthera Philoxeroides in Contrasting Hydrological Conditions

    PubMed Central

    Gao, Lexuan; Geng, Yupeng; Yang, Hongxing; Hu, Yonghong; Yang, Ji

    2015-01-01

    Alternanthera philoxeroides is an amphibious invasive weed that can colonize both aquatic and terrestrial habitats. Individuals growing in different habitats exhibit extensive phenotypic variation but little genetic differentiation. Little is known about the molecular basis underlying environment-induced phenotypic changes. Variation in transcript abundance in A. philoxeroides was characterized throughout the time-courses of pond and upland treatments using RNA-