ASSORTATIVE MATING CAN IMPEDE OR FACILITATE FIXATION OF UNDERDOMINANT ALLELES

PubMed Central

NEWBERRY, MITCHELL G; MCCANDLISH, DAVID M; PLOTKIN, JOSHUA B

2017-01-01

Underdominant mutations have fixed between divergent species, yet classical models suggest that rare underdominant alleles are purged quickly except in small or subdivided populations. We predict that underdominant alleles that also influence mate choice, such as those affecting coloration patterns visible to mates and predators alike, can fix more readily. We analyze a mechanistic model of positive assortative mating in which individuals have n chances to sample compatible mates. This one-parameter model naturally spans random mating (n =1) and complete assortment (n → ∞), yet it produces sexual selection whose strength depends non-monotonically on n. This sexual selection interacts with viability selection to either inhibit or facilitate fixation. As mating opportunities increase, underdominant alleles fix as frequently as neutral mutations, even though sexual selection and underdominance independently each suppress rare alleles. This mechanism allows underdominant alleles to fix in large populations and illustrates how life history can affect evolutionary change. PMID:27497738

Size-assortative mating and effect of maternal body size on the reproductive output of the nassariid Buccinanops globulosus

NASA Astrophysics Data System (ADS)

Avaca, María Soledad; Narvarte, Maite; Martín, Pablo

2012-04-01

Size- assortative mating is usually present in populations where there is a positive relationship between female size and reproductive output. In this study, we tested for the presence of sexual size dimorphism, size-assortative mating and the effects of female size on reproductive output in a wild population of Buccinanops globulosus, an endemic nassariid of the Southwestern Atlantic Ocean with direct development. The results showed that: 1) females were larger than males, indicating sexual size dimorphism; 2) mate sizes were significantly correlated, indicating a component of size-assortative mating; 3) males of medium and large size classes were paired with larger females than small-sized males; 4) larger females were paired with large males; 5) maternal body size was positively related to some proxies of reproductive success (number of nurse eggs per egg capsule, egg capsular area and total length at hatching). Our results suggest that larger females may be favored as mates over smaller ones owing to their higher investment per offspring and consequently a larger initial juvenile size as juvenile.

The genetic correlation between height and IQ: shared genes or assortative mating?

PubMed

Keller, Matthew C; Garver-Apgar, Christine E; Wright, Margaret J; Martin, Nicholas G; Corley, Robin P; Stallings, Michael C; Hewitt, John K; Zietsch, Brendan P

2013-04-01

Traits that are attractive to the opposite sex are often positively correlated when scaled such that scores increase with attractiveness, and this correlation typically has a genetic component. Such traits can be genetically correlated due to genes that affect both traits ("pleiotropy") and/or because assortative mating causes statistical correlations to develop between selected alleles across the traits ("gametic phase disequilibrium"). In this study, we modeled the covariation between monozygotic and dizygotic twins, their siblings, and their parents (total N = 7,905) to elucidate the nature of the correlation between two potentially sexually selected traits in humans: height and IQ. Unlike previous designs used to investigate the nature of the height-IQ correlation, the present design accounts for the effects of assortative mating and provides much less biased estimates of additive genetic, non-additive genetic, and shared environmental influences. Both traits were highly heritable, although there was greater evidence for non-additive genetic effects in males. After accounting for assortative mating, the correlation between height and IQ was found to be almost entirely genetic in nature. Model fits indicate that both pleiotropy and assortative mating contribute significantly and about equally to this genetic correlation.

Mate Choice in Mus musculus Is Relative and Dependent on the Estrous State

PubMed Central

Zinck, Léa; Lima, Susana Q.

2013-01-01

Mate choice is a critical behavioral decision process with profound impact on evolution. However, the mechanistic basis of mate choice is poorly understood. In this study we focused on assortative mate choice, which is known to contribute to the reproductive isolation of the two European subspecies of house mouse, Mus musculus musculus and Mus musculus domesticus. To understand the decision process, we developed both full mating and limited-contact paradigms and tested musculus females' preference for musculus versus domesticus males, mimicking the natural musculus/domesticus contact zone. As hypothesized, when allowed to mate we found that sexually receptive musculus females exhibited a robust preference to mate with musculus males. In contrast, when non-receptive, females did not exhibit a preference and rather alternated between males in response to male mount attempts. Moreover in a no-choice condition, females mated readily with males from both subspecies. Finally, when no physical contact was allowed, and therefore male's behavior could not influence female's behavior, female's preference for its own subspecies was maintained independently of the estrous state. Together, our results suggest that the assortative preference is relative and based on a comparison of the options available rather than on an absolute preference. The results of the limited-contact experiments highlight the interplay between female's internal state and the nature of the interaction with prospective mates in the full mating conditions. With these experiments we believe we established an assortative mate preference assay that is appropriate for the investigation of its underlying substrates. PMID:23762466

Temporal variation in size-assortative mating and male mate choice in a spider with amphisexual care

NASA Astrophysics Data System (ADS)

Moura, Rafael R.; Gonzaga, Marcelo O.

2017-04-01

Males should be more selective when they have a high investment in reproduction, especially in species with biparental or paternal care. In this context, male mate choice can promote size-assortative mating (SAM) when (1) large males win intrasexual disputes, (2) large females are more fecund, and (3) males prefer larger females to smaller ones. In the spider Manogea porracea, males exhibit high reproductive investment by building their webs above those of females and exhibiting extended care of offspring in the absence of females. Under these circumstances, we expect the occurrence of SAM and male preference for large females. Herein, we performed observations and experiments in the field to evaluate the hypotheses that (1) M. porracea mates assortatively by size and (2) SAM is influenced by male mate choice. Furthermore, we measured variables that could affect mating patterns, the sex ratios, and densities of both sexes. Pairing in M. porracea was positively size-assortative in 2012, but not in 2013. Large males won most disputes for mates and preferred larger females, which produced more eggs. The inconsistency in detection of SAM was due to population dynamics, namely variations in sex ratio and population density across the breeding season. Furthermore, we found that the significance of male mate choice on sexual selection of body size in M. porracea strongly depends on the competition intensity for mating opportunities. The traditional sexual selection hypothesis of SAM needs to be reviewed and must include measures of competition intensity.

Size-assortative mating and sexual size dimorphism are predictable from simple mechanics of mate-grasping behavior

PubMed Central

2010-01-01

Background A major challenge in evolutionary biology is to understand the typically complex interactions between diverse counter-balancing factors of Darwinian selection for size assortative mating and sexual size dimorphism. It appears that rarely a simple mechanism could provide a major explanation of these phenomena. Mechanics of behaviors can predict animal morphology, such like adaptations to locomotion in animals from various of taxa, but its potential to predict size-assortative mating and its evolutionary consequences has been less explored. Mate-grasping by males, using specialized adaptive morphologies of their forelegs, midlegs or even antennae wrapped around female body at specific locations, is a general mating strategy of many animals, but the contribution of the mechanics of this wide-spread behavior to the evolution of mating behavior and sexual size dimorphism has been largely ignored. Results Here, we explore the consequences of a simple, and previously ignored, fact that in a grasping posture the position of the male's grasping appendages relative to the female's body is often a function of body size difference between the sexes. Using an approach taken from robot mechanics we model coercive grasping of females by water strider Gerris gracilicornis males during mating initiation struggles. We determine that the male optimal size (relative to the female size), which gives the males the highest grasping force, properly predicts the experimentally measured highest mating success. Through field sampling and simulation modeling of a natural population we determine that the simple mechanical model, which ignores most of the other hypothetical counter-balancing selection pressures on body size, is sufficient to account for size-assortative mating pattern as well as species-specific sexual dimorphism in body size of G. gracilicornis. Conclusion The results indicate how a simple and previously overlooked physical mechanism common in many taxa is sufficient to account for, or importantly contribute to, size-assortative mating and its consequences for the evolution of sexual size dimorphism. PMID:21092131

Effects of Early U.S. Compulsory Schooling Laws on Educational Assortative Mating: The Importance of Context.

PubMed

Rauscher, Emily

2015-08-01

Modernization theory predicts that rising education should increase assortative mating by education and decrease sorting by race. Recent research suggests that effects of educational expansion depend on contextual factors, such as economic development. Using log-linear and log-multiplicative models of male household heads ages 36 to 75 in the 1940 U.S. census data--the first U.S. census with educational attainment information--I investigate how educational assortative mating changed with one instance of educational expansion: early U.S. compulsory school attendance laws. To improve on existing research and distinguish effects of expansion from changes due to particular years or cohorts, I capitalize on state variation in the timing of these compulsory laws (ranging from 1852 to 1918). Aggregate results suggest that compulsory laws had minimal impact on assortative mating. However, separate analyses by region (and supplemental analyses by race) reveal that assortative mating by education decreased with the laws in the South but increased in the North. Whether due to economic, legal, political, or other differences, results suggest that the implications of educational expansion for marital sorting depend on context. Contemporary implications are discussed in light of President Obama's 2012 suggested extension of compulsory schooling to age 18.

Testing for Non-Random Mating: Evidence for Ancestry-Related Assortative Mating in the Framingham Heart Study

PubMed Central

Sebro, Ronnie; Hoffman, Thomas J.; Lange, Christoph; Rogus, John J.; Risch, Neil J.

2013-01-01

Population stratification leads to a predictable phenomenon—a reduction in the number of heterozygotes compared to that calculated assuming Hardy-Weinberg Equilibrium (HWE). We show that population stratification results in another phenomenon—an excess in the proportion of spouse-pairs with the same genotypes at all ancestrally informative markers, resulting in ancestrally related positive assortative mating. We use principal components analysis to show that there is evidence of population stratification within the Framingham Heart Study, and show that the first principal component correlates with a North-South European cline. We then show that the first principal component is highly correlated between spouses (r=0.58, p=0.0013), demonstrating that there is ancestrally related positive assortative mating among the Framingham Caucasian population. We also show that the single nucleotide polymorphisms loading most heavily on the first principal component show an excess of homozygotes within the spouses, consistent with similar ancestry-related assortative mating in the previous generation. This nonrandom mating likely affects genetic structure seen more generally in the North American population of European descent today, and decreases the rate of decay of linkage disequilibrium for ancestrally informative markers. PMID:20842694

Intergenerational effects of shifts in women's educational distribution in South Korea: Transmission, differential fertility, and assortative mating

PubMed Central

Kye, Bongoh; Mare, Robert D.

2014-01-01

This study examines the intergenerational effects of changes in women's education in South Korea. We define intergenerational effects as changes in the distribution of educational attainment in an offspring generation associated with the changes in a parental generation. Departing from the previous approach in research on social mobility that has focused on intergenerational association, we examine the changes in the distribution of educational attainment across generations. Using a simulation method based on Mare and Maralani's recursive population renewal model, we examine how intergenerational transmission, assortative mating, and differential fertility influence intergenerational effects. The results point to the following conclusions. First, we find a positive intergenerational effect: improvement in women's education leads to improvement in daughter's education. Second, we find that the magnitude of intergenerational effects substantially depends on assortative marriage and differential fertility: assortative mating amplifies and differential fertility dampens the intergenerational effects. Third, intergenerational effects become bigger for the less educated and smaller for the better educated over time, which is a consequence of educational expansion. We compare our results with Mare and Maralani's original Indonesian study to illustrate how the model of intergenerational effects works in different socioeconomic circumstances. PMID:23017970

Assortative mating can impede or facilitate fixation of underdominant alleles.

PubMed

Newberry, Mitchell G; McCandlish, David M; Plotkin, Joshua B

2016-12-01

Underdominant mutations have fixed between divergent species, yet classical models suggest that rare underdominant alleles are purged quickly except in small or subdivided populations. We predict that underdominant alleles that also influence mate choice, such as those affecting coloration patterns visible to mates and predators alike, can fix more readily. We analyze a mechanistic model of positive assortative mating in which individuals have n chances to sample compatible mates. This one-parameter model naturally spans random mating (n=1) and complete assortment (n→∞), yet it produces sexual selection whose strength depends non-monotonically on n. This sexual selection interacts with viability selection to either inhibit or facilitate fixation. As mating opportunities increase, underdominant alleles fix as frequently as neutral mutations, even though sexual selection and underdominance independently each suppress rare alleles. This mechanism allows underdominant alleles to fix in large populations and illustrates how life history can affect evolutionary change. Copyright © 2016 Elsevier Inc. All rights reserved.

Strong assortative mating between allopatric sticklebacks as a by-product of adaptation to different environments

PubMed Central

Vines, Timothy H; Schluter, Dolph

2005-01-01

Speciation involves the evolution of reproductive isolation between populations. One potentially important mechanism is the evolution of pre- or postzygotic isolation between populations as a by-product of adaptation to different environments. In this paper, we tested for assortative mating between allopatric stickleback populations adapted to different ecological niches. Our experimental design controlled for interpopulation interactions and non-adaptive explanations for assortative mating. We found that prezygotic isolation was surprisingly strong: when given a choice, the majority of matings occurred between individuals from similar environments. Our results indicate that the by-product mechanism is a potent source of reproductive isolation, and likely contributed to the origin of sympatric species of sticklebacks. PMID:16627275

Arousal, Personality, and Assortative Mating in Marriage

ERIC Educational Resources Information Center

Farley, Frank H.; Davis, Sandy A.

1977-01-01

A compound major individual difference variable having a putative physiological basis--arousal and the stimulation-seeking motive, which has not heretofore been intestigated in studies of assortative mating--was the focus of the present study. In addition, three choticism--were included for study. (Author)

Heritability, assortative mating and gender differences in violent crime: results from a total population sample using twin, adoption, and sibling models.

PubMed

Frisell, Thomas; Pawitan, Yudi; Långström, Niklas; Lichtenstein, Paul

2012-01-01

Research addressing genetic and environmental determinants to antisocial behaviour suggests substantial variability across studies. Likewise, evidence for etiologic gender differences is mixed, and estimates might be biased due to assortative mating. We used longitudinal Swedish total population registers to estimate the heritability of objectively measured violent offending (convictions) in classic twin (N = 36,877 pairs), adoptee-parent (N = 5,068 pairs), adoptee-sibling (N = 10,610 pairs), and sibling designs (N = 1,521,066 pairs). Type and degree of assortative mating were calculated from comparisons between spouses of siblings and half-siblings, and across consecutive spouses. Heritability estimates for the liability of violent offending agreed with previously reported heritability for self-reported antisocial behaviour. While the sibling model yielded estimates similar to the twin model (A ≈ 55%, C ≈ 13%), adoptee-models appeared to underestimate familial effects (A ≈ 20-30%, C ≈ 0%). Assortative mating was moderate to strong (r (spouse) = 0.4), appeared to result from both phenotypic assortment and social homogamy, but had only minor effect on variance components. Finally, we found significant gender differences in the etiology of violent crime.

A Twin-Family Study of General IQ

ERIC Educational Resources Information Center

van Leeuwen, Marieke; van den Berg, Stephanie M.; Boomsma, Dorret I.

2008-01-01

In this paper we assess the presence of assortative mating, gene-environment interaction and the heritability of intelligence in childhood using a twin family design with twins, their siblings and parents from 112 families. We evaluate two competing hypotheses about the cause of assortative mating in intelligence: social homogamy and phenotypic…

Intergenerational effects of shifts in women's educational distribution in South Korea: Transmission, differential fertility, and assortative mating.

PubMed

Kye, Bongoh; Mare, Robert D

2012-11-01

This study examines the intergenerational effects of changes in women's education in South Korea. We define intergenerational effects as changes in the distribution of educational attainment in an offspring generation associated with the changes in a parental generation. Departing from the previous approach in research on social mobility that has focused on intergenerational association, we examine the changes in the distribution of educational attainment across generations. Using a simulation method based on Mare and Maralani's recursive population renewal model, we examine how intergenerational transmission, assortative mating, and differential fertility influence intergenerational effects. The results point to the following conclusions. First, we find a positive intergenerational effect: improvement in women's education leads to improvement in daughter's education. Second, we find that the magnitude of intergenerational effects substantially depends on assortative marriage and differential fertility: assortative mating amplifies and differential fertility dampens the intergenerational effects. Third, intergenerational effects become bigger for the less educated and smaller for the better educated over time, which is a consequence of educational expansion. We compare our results with Mare and Maralani's original Indonesian study to illustrate how the model of intergenerational effects works in different socioeconomic circumstances. Copyright © 2012 Elsevier Inc. All rights reserved.

Assortative mating and mutation diffusion in spatial evolutionary systems

NASA Astrophysics Data System (ADS)

Paley, C. J.; Taraskin, S. N.; Elliott, S. R.

2010-04-01

The influence of spatial structure on the equilibrium properties of a sexual population model defined on networks is studied numerically. Using a small-world-like topology of the networks as an investigative tool, the contributions to the fitness of assortative mating and of global mutant spread properties are considered. Simple measures of nearest-neighbor correlations and speed of spread of mutants through the system have been used to confirm that both of these dynamics are important contributory factors to the fitness. It is found that assortative mating increases the fitness of populations. Quick global spread of favorable mutations is shown to be a key factor increasing the equilibrium fitness of populations.

Marital Homophily on Illicit Drug Use among Young Adults: Assortative Mating or Marital Influence?

ERIC Educational Resources Information Center

Yamaguchi, Kazuo; Kandel, Denise

1993-01-01

Analysis of longitudinal and current survey data on 545 married/cohabiting couples found highest marital homophily for ethnicity, fertility expectations, religion, educational attainment, marital satisfaction, and illicit drug use. On drug use, data best supported a model of marital selection and assortative mating but was inconclusive concerning…

Intergenerational Mobility and Assortative Mating: Effects of an Educational Reform. CEE DP 91

ERIC Educational Resources Information Center

Holmlund, Helena

2008-01-01

The purpose of the study is to evaluate the effects of the Swedish compulsory school reform on intergenerational mobility, and to assess the extent to which the effect operates through assortative mating. A better understanding of the mechanisms underlying intergenerational mobility is important for the design of educational policies. In…

Role of DFNB1 mutations in hereditary hearing loss among assortative mating hearing impaired families from South India.

PubMed

Amritkumar, Pavithra; Jeffrey, Justin Margret; Chandru, Jayasankaran; Vanniya S, Paridhy; Kalaimathi, M; Ramakrishnan, Rajagopalan; Karthikeyen, N P; Srikumari Srisailapathy, C R

2018-06-19

DFNB1, the first locus to have been associated with deafness, has two major genes GJB2 & GJB6, whose mutations have played vital role in hearing impairment across many ethnicities in the world. In our present study we have focused on the role of these mutations in assortative mating hearing impaired families from south India. One hundred and six assortatively mating hearing impaired (HI) families of south Indian origin comprising of two subsets: 60 deaf marrying deaf (DXD) families and 46 deaf marrying normal hearing (DXN) families were recruited for this study. In the 60 DXD families, 335 members comprising of 118 HI mates, 63 other HI members and 154 normal hearing members and in the 46 DXN families, 281 members comprising of 46 HI and their 43 normal hearing partners, 50 other HI members and 142 normal hearing family members, participated in the molecular study. One hundred and sixty five (165) healthy normal hearing volunteers were recruited as controls for this study. All the participating members were screened for variants in GJB2 and GJB6 genes and the outcome of gene mutations were compared in the subsequent generation in begetting deaf offspring. The DFNB1 allele frequencies for DXD mates and their offspring were 36.98 and 38.67%, respectively and for the DXN mates and their offspring were 22.84 and 24.38%, respectively. There was a 4.6% increase in the subsequent generation in the DXD families, while a 6.75% increase in the DXN families, which demonstrates the role of assortative mating along with consanguinity in the increase of DFNB1 mutations in consecutive generations. Four novel variants, p.E42D (in GJB2 gene), p.Q57R, p.E101Q, p.R104H (in GJB6 gene) were also identified in this study. This is the first study from an Indian subcontinent reporting novel variants in the coding region of GJB6 gene. This is perhaps the first study in the world to test real-time, the hypothesis proposed by Nance et al. in 2000 (intense phenotypic assortative mating mechanism can double the frequency of the commonest forms of recessive deafness [DFNB1]) in assortative mating HI parental generation and their offspring.

Genetic Model Fitting in IQ, Assortative Mating & Components of IQ Variance.

ERIC Educational Resources Information Center

Capron, Christiane; Vetta, Adrian R.; Vetta, Atam

1998-01-01

The biometrical school of scientists who fit models to IQ data traces their intellectual ancestry to R. Fisher (1918), but their genetic models have no predictive value. Fisher himself was critical of the concept of heritability, because assortative mating, such as for IQ, introduces complexities into the study of a genetic trait. (SLD)

Income inequality and educational assortative mating: Evidence from the Luxembourg Income Study.

PubMed

Monaghan, David

2015-07-01

Though extensive research has explored the prevalence of educational assortative mating, what causes its variation across countries and over time is not well understood. Using data from the Luxembourg Income Study Database, I investigate the hypothesis that assortative mating by income is influenced by income inequality between educational strata. I find that in countries with greater returns to education, the odds of any sort of union that crosses educational boundaries is substantially reduced. However, I do not find substantial evidence of an effect of changes in returns to education on marital sorting within countries. Educational and labor market parity between males and females appear to be negatively related to marital sorting. Copyright © 2015 Elsevier Inc. All rights reserved.

The Changing Importance of White Women's Economic Prospects for Assortative Mating

ERIC Educational Resources Information Center

Sweeney, Megan M.; Cancian, Maria

2004-01-01

Given recent changes in the labor force participation and economic standing of women, we ask whether a woman's position in the labor market has become a more important determinant of her position in the marriage market. Unlike much prior research on trends over time in assortative mating, we take an individual-level approach to the analysis and…

Multifactorial inheritance with cultural transmission and assortative mating. II. a general model of combined polygenic and cultural inheritance.

PubMed Central

Cloninger, C R; Rice, J; Reich, T

1979-01-01

A general linear model of combined polygenic-cultural inheritance is described. The model allows for phenotypic assortative mating, common environment, maternal and paternal effects, and genic-cultural correlation. General formulae for phenotypic correlation between family members in extended pedigrees are given for both primary and secondary assortative mating. A FORTRAN program BETA, available upon request, is used to provide maximum likelihood estimates of the parameters from reported correlations. American data about IQ and Burks' culture index are analyzed. Both cultural and genetic components of phenotypic variance are observed to make significant and substantial contributions to familial resemblance in IQ. The correlation between the environments of DZ twins is found to equal that of singleton sibs, not that of MZ twins. Burks' culture index is found to be an imperfect measure of midparent IQ rather than an index of home environment as previously assumed. Conditions under which the parameters of the model may be uniquely and precisely estimated are discussed. Interpretation of variance components in the presence of assortative mating and genic-cultural covariance is reviewed. A conservative, but robust, approach to the use of environmental indices is described. PMID:453202

Phase Transition Behavior in a Neutral Evolution Model

NASA Astrophysics Data System (ADS)

King, Dawn; Scott, Adam; Maric, Nevena; Bahar, Sonya

2014-03-01

The complexity of interactions among individuals and between individuals and the environment make agent based modeling ideal for studying emergent speciation. This is a dynamically complex problem that can be characterized via the critical behavior of a continuous phase transition. Concomitant with the main tenets of natural selection, we allow organisms to reproduce, mutate, and die within a neutral phenotype space. Previous work has shown phase transition behavior in an assortative mating model with variable fitness landscapes as the maximum mutation size (μ) was varied (Dees and Bahar, 2010). Similarly, this behavior was recently presented in the work of Scott et al. (2013), even on a completely neutral landscape, for bacterial-like fission as well as for assortative mating. Here we present another neutral model to investigate the `critical' phase transition behavior of three mating types - assortative, bacterial, and random - in a phenotype space as a function of the percentage of random death. Results show two types of phase transitions occurring for the parameters of the population size and the number of clusters (an analogue of species), indicating different evolutionary dynamics for system survival and clustering. This research was supported by funding from: University of Missouri Research Board and James S. McDonnell Foundation.

Assortative Mating by Education and Hukou in Shanghai

PubMed Central

Qian, Yue; Qian, Zhenchao

2018-01-01

Previous research on Hukou-based stratification mostly focuses on Hukou-derived labor market outcomes, with growing attention paid to the role of Hukou locality (local vs. nonlocal) as an increasingly important agent of social stratification in urban China. Few studies have, however, examined how Hukou shapes the patterns of who marries whom in geographically-defined marriage markets, despite the far-reaching implications of assortative mating for migrant integration into the host society, economic inequality among families, and intergenerational transmissions of social traits. In this paper, using a most recent, representative sample of the post-’80s generation living in Shanghai, we evaluate how Hukou locality intersects with educational attainment to shape assortative marriage patterns. We find that highly-educated Hukou residents and non-Hukou migrants are both more likely than their less-educated counterparts to marry a Hukou resident, suggesting that Shanghai Hukou is a valuable attribute in Shanghai marriage market. In addition, Hukou intermarriage seldom occurs when Hukou residents marry a non-Hukou migrant with less education than themselves. The results indicate that Hukou locality is an important stratifier in contemporary China that shapes marriage market conditions and individual mating choices. PMID:29564190

A Preliminary Investigation into the Potential Role of Waist Hip Ratio (WHR) Preference within the Assortative Mating Hypothesis of Autistic Spectrum Disorders

ERIC Educational Resources Information Center

Brosnan, Mark; Walker, Ian

2009-01-01

Of particular interest to studying the etiology of Autistic Spectrum Disorders (ASDs) is the potential for multiple risk factors to combine through non-random mechanisms--assortative mating. Both genetic influences and a high-testosterone prenatal environment have been implicated in the etiology of ASDs, and given that waist-hip ratio (WHR) is…

Geography, assortative mating, and the effects of sexual selection on speciation with gene flow.

PubMed

Servedio, Maria R

2016-01-01

Theoretical and empirical research on the evolution of reproductive isolation have both indicated that the effects of sexual selection on speciation with gene flow are quite complex. As part of this special issue on the contributions of women to basic and applied evolutionary biology, I discuss my work on this question in the context of a broader assessment of the patterns of sexual selection that lead to, versus inhibit, the speciation process, as derived from theoretical research. In particular, I focus on how two factors, the geographic context of speciation and the mechanism leading to assortative mating, interact to alter the effect that sexual selection through mate choice has on speciation. I concentrate on two geographic contexts: sympatry and secondary contact between two geographically separated populations that are exchanging migrants and two mechanisms of assortative mating: phenotype matching and separate preferences and traits. I show that both of these factors must be considered for the effects of sexual selection on speciation to be inferred.

Parenting across Racial and Class Lines: Assortative Mating Patterns of New Parents Who Are Married, Cohabiting, Dating or No Longer Romantically Involved

ERIC Educational Resources Information Center

Goldstein, Joshua R.; Harknett, Kristen

2006-01-01

We examine the assortative mating patterns of new parents who are married, cohabiting, romantically involved and no longer romantically involved. Using data from the Fragile Families and Child Wellbeing study, we find that relationship status at the time of a birth depends mainly on father's race rather than on whether mother and father's…

Mate choice, sexual imprinting, and speciation: a test of a one-allele isolating mechanism in sympatric sticklebacks.

PubMed

Albert, Arianne Y K

2005-04-01

One-allele isolating mechanisms should make the evolution of reproductive isolation between potentially hybridizing taxa easier than two-allele mechanisms, but the generality of one-allele mechanisms in nature has yet to be established. A potentially important one-allele mechanism is sexual imprinting, where the mate preferences of individuals are based on the phenotype of their parents. Here I test the possibility that sexual imprinting promotes reproductive isolation using sympatric species of threespine sticklebacks (Gasterosteus aculeatus). Sympatric species of sticklebacks consist of large benthic species and small limnetic species that are reproductively isolated and adapted to feeding in different environments. I fostered families of F1 hybrids between the species to males of both species. Preferences of these fostered females for males of either type revealed little or no effect of sexual imprinting on assortative mating. However, F1 females showed preferences for males that were similar to themselves in length, suggesting that size-assortative mating may be more important than sexual imprinting for promoting reproductive isolation between species pairs of threespine sticklebacks.

Universality in a Neutral Evolution Model

NASA Astrophysics Data System (ADS)

King, Dawn; Scott, Adam; Maric, Nevena; Bahar, Sonya

2013-03-01

Agent-based models are ideal for investigating the complex problems of biodiversity and speciation because they allow for complex interactions between individuals and between individuals and the environment. Presented here is a ``null'' model that investigates three mating types - assortative, bacterial, and random - in phenotype space, as a function of the percentage of random death δ. Previous work has shown phase transition behavior in an assortative mating model with variable fitness landscapes as the maximum mutation size (μ) was varied (Dees and Bahar, 2010). Similarly, this behavior was recently presented in the work of Scott et al. (submitted), on a completely neutral landscape, for bacterial-like fission as well as for assortative mating. Here, in order to achieve an appropriate ``null'' hypothesis, the random death process was changed so each individual, in each generation, has the same probability of death. Results show a continuous nonequilibrium phase transition for the order parameters of the population size and the number of clusters (analogue of species) as δ is varied for three different mutation sizes of the system. The system shows increasing robustness as μ increases. Universality classes and percolation properties of this system are also explored. This research was supported by funding from: University of Missouri Research Board and James S. McDonnell Foundation

Assortative Mating: Encounter-Network Topology and the Evolution of Attractiveness

PubMed Central

Dipple, S.; Jia, T.; Caraco, T.; Korniss, G.; Szymanski, B. K.

2017-01-01

We model a social-encounter network where linked nodes match for reproduction in a manner depending probabilistically on each node’s attractiveness. The developed model reveals that increasing either the network’s mean degree or the “choosiness” exercised during pair formation increases the strength of positive assortative mating. That is, we note that attractiveness is correlated among mated nodes. Their total number also increases with mean degree and selectivity during pair formation. By iterating over the model’s mapping of parents onto offspring across generations, we study the evolution of attractiveness. Selection mediated by exclusion from reproduction increases mean attractiveness, but is rapidly balanced by skew in the offspring distribution of highly attractive mated pairs. PMID:28345625

Incipient speciation driven by hypertrophied lips in Midas cichlid fishes?

PubMed

Machado-Schiaffino, Gonzalo; Kautt, Andreas F; Torres-Dowdall, Julian; Baumgarten, Lukas; Henning, Frederico; Meyer, Axel

2017-04-01

Sympatric speciation has been debated in evolutionary biology for decades. Although it has gained in acceptance recently, still only a handful of empirical examples are seen as valid (e.g. crater lake cichlids). In this study, we disentangle the role of hypertrophied lips in the repeated adaptive radiations of Nicaraguan crater lake cichlid fish. We assessed the role of disruptive selection and assortative mating during the early stages of divergence and found a functional trade-off in feeding behaviour between thick- and thin-lipped ecotypes, suggesting that this trait is a target of disruptive selection. Thick-lipped fish perform better on nonevasive prey at the cost of a poorer performance on evasive prey. Using enclosures in the wild, we found that thick-lipped fish perform significantly better in rocky than in sandy habitats. We found almost no mixed pairs during two breeding seasons and hence significant assortative mating. Genetic differentiation between ecotypes seems to be related to the time since colonization, being subtle in L. Masaya (1600 generations ago) and absent in the younger L. Apoyeque (<600 generations ago). Genome-wide differentiation between ecotypes was higher in the old source lakes than in the young crater lakes. Our results suggest that hypertrophied lips might be promoting incipient sympatric speciation through divergent selection (ecological divergence in feeding performance) and nonrandom mating (assortative mating) in the young Nicaraguan crater lakes. Nonetheless, further manipulative experiments are needed in order to confirm the role of hypertrophied lips as the main cue for assortative mating. © 2017 John Wiley & Sons Ltd.

Sympatric speciation as a consequence of male pregnancy in seahorses

PubMed Central

Jones, Adam G.; Moore, Glenn I.; Kvarnemo, Charlotta; Walker, DeEtte; Avise, John C.

2003-01-01

The phenomenon of male pregnancy in the family Syngnathidae (seahorses, pipefishes, and sea dragons) undeniably has sculpted the course of behavioral evolution in these fishes. Here we explore another potentially important but previously unrecognized consequence of male pregnancy: a predisposition for sympatric speciation. We present microsatellite data on genetic parentage that show that seahorses mate size-assortatively in nature. We then develop a quantitative genetic model based on these empirical findings to demonstrate that sympatric speciation indeed can occur under this mating regime in response to weak disruptive selection on body size. We also evaluate phylogenetic evidence bearing on sympatric speciation by asking whether tiny seahorse species are sister taxa to large sympatric relatives. Overall, our results indicate that sympatric speciation is a plausible mechanism for the diversification of seahorses, and that assortative mating (in this case as a result of male parental care) may warrant broader attention in the speciation process for some other taxonomic groups as well. PMID:12732712

Is telomere length associated with mate choice in a songbird with a high rate of extra-pair paternity?

PubMed

Johnsen, Arild; Pauliny, Angela; Lifjeld, Jan T; Blomqvist, Donald

2017-01-01

Telomere length is related to aging in many eukaryotes and the rate of telomere attrition has been suggested to reflect individual genetic quality. Telomere length could thus have implications for mate choice. We investigated telomere length variation in bluethroat Luscinia svecica families with mixed paternity, including social parents, extra-pair fathers and nestlings, testing whether telomere length is associated with social and/or extra-pair mate choice through assortative mating or selection of mates with relatively long telomeres. In adults, relative telomere length (rTL) did not differ between the sexes, nor between two age categories. In chicks, however, rTL decreased with body mass at sampling (an index of nestling age). We found a positive correlation between the rTL of social mates, suggesting assortative mating with respect to telomere length or a correlative thereof. However, extra-pair males did not differ from social mates in rTL, and accordingly there was also no difference between within- and extra-pair young (i.e. half-siblings) when controlling for the effect of mass. We found no relationships between telomere length, age and fitness-related traits in adults, but an intriguing year-difference in telomere length in both sexes. In conclusion, we found no support for the idea that females choose extra-pair males based on their telomere length, but social mate choice seems to be influenced by rTL, possibly through its co-variation with aspects reflecting individual quality, like early arrival at the breeding grounds.

Measuring genomic pre-selection in theory and in practice

USDA-ARS?s Scientific Manuscript database

Potential biases from genomic pre-selection were estimated from actual selection and mating patterns of US Holsteins. Traditional models using only phenotypes and pedigrees do not adjust for average genomic merit of an animal’s parents, progeny, mates, or contemporaries. Positive assortative mating ...

Assortative Mating and the Reversal of Gender Inequality in Education in Europe: An Agent-Based Model

PubMed Central

Grow, André; Van Bavel, Jan

2015-01-01

While men have always received more education than women in the past, this gender imbalance in education has turned around in large parts of the world. In many countries, women now excel men in terms of participation and success in higher education. This implies that, for the first time in history, there are more highly educated women than men reaching the reproductive ages and looking for a partner. We develop an agent-based computational model that explicates the mechanisms that may have linked the reversal of gender inequality in education with observed changes in educational assortative mating. Our model builds on the notion that individuals search for spouses in a marriage market and evaluate potential candidates based on preferences. Based on insights from earlier research, we assume that men and women prefer partners with similar educational attainment and high earnings prospects, that women tend to prefer men who are somewhat older than themselves, and that men prefer women who are in their mid-twenties. We also incorporate the insight that the educational system structures meeting opportunities on the marriage market. We assess the explanatory power of our model with systematic computational experiments, in which we simulate marriage market dynamics in 12 European countries among individuals born between 1921 and 2012. In these experiments, we make use of realistic agent populations in terms of educational attainment and earnings prospects and validate model outcomes with data from the European Social Survey. We demonstrate that the observed changes in educational assortative mating can be explained without any change in male or female preferences. We argue that our model provides a useful computational laboratory to explore and quantify the implications of scenarios for the future. PMID:26039151

Assortative mating and the reversal of gender inequality in education in europe: an agent-based model.

PubMed

Grow, André; Van Bavel, Jan

2015-01-01

While men have always received more education than women in the past, this gender imbalance in education has turned around in large parts of the world. In many countries, women now excel men in terms of participation and success in higher education. This implies that, for the first time in history, there are more highly educated women than men reaching the reproductive ages and looking for a partner. We develop an agent-based computational model that explicates the mechanisms that may have linked the reversal of gender inequality in education with observed changes in educational assortative mating. Our model builds on the notion that individuals search for spouses in a marriage market and evaluate potential candidates based on preferences. Based on insights from earlier research, we assume that men and women prefer partners with similar educational attainment and high earnings prospects, that women tend to prefer men who are somewhat older than themselves, and that men prefer women who are in their mid-twenties. We also incorporate the insight that the educational system structures meeting opportunities on the marriage market. We assess the explanatory power of our model with systematic computational experiments, in which we simulate marriage market dynamics in 12 European countries among individuals born between 1921 and 2012. In these experiments, we make use of realistic agent populations in terms of educational attainment and earnings prospects and validate model outcomes with data from the European Social Survey. We demonstrate that the observed changes in educational assortative mating can be explained without any change in male or female preferences. We argue that our model provides a useful computational laboratory to explore and quantify the implications of scenarios for the future.

Gradient Evolution of Body Colouration in Surface- and Cave-Dwelling Poecilia mexicana and the Role of Phenotype-Assortative Female Mate Choice

PubMed Central

Penshorn, Marina; Hamfler, Sybille; Herbert, Denise B.; Appel, Jessica; Meyer, Philipp; Slattery, Patrick; Charaf, Sarah; Wolf, Raoul; Völker, Johannes; Berger, Elisabeth A. M.; Dröge, Janis; Riesch, Rüdiger; Arias-Rodriguez, Lenin; Indy, Jeanne R.; Plath, Martin

2013-01-01

Ecological speciation assumes reproductive isolation to be the product of ecologically based divergent selection. Beside natural selection, sexual selection via phenotype-assortative mating is thought to promote reproductive isolation. Using the neotropical fish Poecilia mexicana from a system that has been described to undergo incipient ecological speciation in adjacent, but ecologically divergent habitats characterized by the presence or absence of toxic H2S and darkness in cave habitats, we demonstrate a gradual change in male body colouration along the gradient of light/darkness, including a reduction of ornaments that are under both inter- and intrasexual selection in surface populations. In dichotomous choice tests using video-animated stimuli, we found surface females to prefer males from their own population over the cave phenotype. However, female cave fish, observed on site via infrared techniques, preferred to associate with surface males rather than size-matched cave males, likely reflecting the female preference for better-nourished (in this case: surface) males. Hence, divergent selection on body colouration indeed translates into phenotype-assortative mating in the surface ecotype, by selecting against potential migrant males. Female cave fish, by contrast, do not have a preference for the resident male phenotype, identifying natural selection against migrants imposed by the cave environment as the major driver of the observed reproductive isolation. PMID:24175282

Propagation of Obesity Across Generations: The Roles of Differential Realized Fertility and Assortative Mating by Body Mass Index

PubMed Central

Dawson, John A.; Dhurandhar, Emily J.; Vazquez, Ana I.; Peng, Bo; Allison, David B.

2013-01-01

Background/Aims To quantify the extent to which the increase in obesity observed across recent generations of the American population is associated with the individual or combined effects of assortative mating for body mass index (BMI; kg/m2) and differential realized fertility by BMI. Methods A Monte Carlo framework is formed and informed using data collected from the National Longitudinal Survey of Youth (NLSY). The model has two portions, one that generates childbirth events on an annual basis and another that produces a BMI for each child. Once the model is informed using the data, a reference distribution of offspring BMIs is simulated. We quantify the effects of our factors of interest by removing them from the model and comparing the resulting offspring BMI distributions with that of the baseline scenario. Results An association between maternal BMI and number of offspring is evidenced in the NLSY data, as well as the presence of assortative mating. These two factors combined are associated with increased mean BMI (+0.067, C.I. [0.056, 0.078]), increased BMI variance (+0.578, C.I. [0.418, 0.736]) and increased prevalence of obesity (RR 1.032, 95% C.I. [1.023, 1.041]) and BMIs over 40 (RR 1.083, 95% C.I. [1.053, 1.118]) among offspring. Conclusion Our investigation suggests that both differential realized fertility and assortative mating by BMI appear to play a role in the increasing prevalence of obesity in America. PMID:24081235

Match makers and deal breakers: analyses of assortative mating in newlywed couples.

PubMed

Watson, David; Klohnen, Eva C; Casillas, Alex; Simms, Ericka Nus; Haig, Jeffrey; Berry, Diane S

2004-10-01

We conducted a comprehensive analysis of assortative mating (i.e., the similarity between wives and husbands on a given characteristic) in a newlywed sample. These newlyweds showed (a) strong similarity in age, religiousness, and political orientation; (b) moderate similarity in education and verbal intelligence; (c) modest similarity in values; and (d) little similarity in matrix reasoning, self- and spouse-rated personality, emotional experience and expression, and attachment. Further analyses established that similarity was not simply due to background variables such as age and education and reflected initial assortment (i.e., similarity at the time of marriage) rather than convergence (i.e., increasing similarity with time). Finally, marital satisfaction primarily was a function of the rater's own traits and showed little relation to spousal similarity.

Assortative mating among animals of captive and wild origin following experimental conservation releases

PubMed Central

Slade, Brendan; Parrott, Marissa L.; Paproth, Aleisha; Magrath, Michael J. L.; Gillespie, Graeme R.; Jessop, Tim S.

2014-01-01

Captive breeding is a high profile management tool used for conserving threatened species. However, the inevitable consequence of generations in captivity is broad scale and often-rapid phenotypic divergence between captive and wild individuals, through environmental differences and genetic processes. Although poorly understood, mate choice preference is one of the changes that may occur in captivity that could have important implications for the reintroduction success of captive-bred animals. We bred wild-caught house mice for three generations to examine mating patterns and reproductive outcomes when these animals were simultaneously released into multiple outdoor enclosures with wild conspecifics. At release, there were significant differences in phenotypic (e.g. body mass) and genetic measures (e.g. Gst and F) between captive-bred and wild adult mice. Furthermore, 83% of offspring produced post-release were of same source parentage, inferring pronounced assortative mating. Our findings suggest that captive breeding may affect mating preferences, with potentially adverse implications for the success of threatened species reintroduction programmes. PMID:25411380

Higher male educational hypergamy: evidence from Portugal.

PubMed

Correia, Hamilton R

2003-04-01

Studies of human mate choice have been based almost exclusively on stated preferences and personal advertisements, and the external validity of such studies has therefore been questioned. In the present study, real-life matings based on a large representative sample of newly wed couples in 1998 (n=66,598) were analysed according to educational assortative mating. The results demonstrate a strong educational homogamy in this national Portuguese sample. However, men tend to marry women who are slightly more educated than themselves. The results are compared with those of a modern society (US, 1940-87) and a traditional society (Kipsigis, 1952-91). Since educational attainment is strongly associated with social status and intelligence, these results are discussed in an evolutionary perspective.

Learning to speciate: The biased learning of mate preferences promotes adaptive radiation

PubMed Central

Gilman, R. Tucker; Kozak, Genevieve M.

2015-01-01

Bursts of rapid repeated speciation called adaptive radiations have generated much of Earth's biodiversity and fascinated biologists since Darwin, but we still do not know why some lineages radiate and others do not. Understanding what causes assortative mating to evolve rapidly and repeatedly in the same lineage is key to understanding adaptive radiation. Many species that have undergone adaptive radiations exhibit mate preference learning, where individuals acquire mate preferences by observing the phenotypes of other members of their populations. Mate preference learning can be biased if individuals also learn phenotypes to avoid in mates, and shift their preferences away from these avoided phenotypes. We used individual‐based computational simulations to study whether biased and unbiased mate preference learning promotes ecological speciation and adaptive radiation. We found that ecological speciation can be rapid and repeated when mate preferences are biased, but is inhibited when mate preferences are learned without bias. Our results suggest that biased mate preference learning may play an important role in generating animal biodiversity through adaptive radiation. PMID:26459795

Male mate choice influences female promiscuity in Soay sheep

PubMed Central

Preston, B.T.; Stevenson, I.R.; Pemberton, J.M.; Coltman, D.W.; Wilson, K.

2005-01-01

In most animal species, males are predicted to compete for reproductive opportunities, while females are expected to choose between potential mates. However, when males’ rate of reproduction is constrained, or females vary widely in ‘quality’, male mate choice is also predicted to occur. Such conditions exist in the promiscuous mating system of feral Soay sheep on St Kilda, Scotland, where a highly synchronized mating season, intense sperm competition and limitations on sperm production constrain males’ potential reproductive rate, and females vary substantially in their ability to produce successful offspring. We show that, consistent with predictions, competitive rams focus their mating activity and siring success towards heavier females with higher inclusive fitness. To our knowledge, this is the first time that male mate choice has been identified and shown to lead to assortative patterns of parentage in a natural mammalian system, and occurs despite fierce male–male competition for mates. An additional consequence of assortative mating in this population is that lighter females experience a series of unstable consorts with less adept rams, and hence are mated by a greater number of males during their oestrus. We have thus also identified a novel male-driven mechanism that generates variation in female promiscuity, which suggests that the high levels of female promiscuity in this system are not part of an adaptive female tactic to intensify post-copulatory competition between males. PMID:15734690

Male mate choice influences female promiscuity in Soay sheep.

PubMed

Preston, B T; Stevenson, I R; Pemberton, J M; Coltman, D W; Wilson, K

2005-02-22

In most animal species, males are predicted to compete for reproductive opportunities, while females are expected to choose between potential mates. However, when males' rate of reproduction is constrained, or females vary widely in 'quality', male mate choice is also predicted to occur. Such conditions exist in the promiscuous mating system of feral Soay sheep on St Kilda, Scotland, where a highly synchronized mating season, intense sperm competition and limitations on sperm production constrain males' potential reproductive rate, and females vary substantially in their ability to produce successful offspring. We show that, consistent with predictions, competitive rams focus their mating activity and siring success towards heavier females with higher inclusive fitness. To our knowledge, this is the first time that male mate choice has been identified and shown to lead to assortative patterns of parentage in a natural mammalian system, and occurs despite fierce male-male competition for mates. An additional consequence of assortative mating in this population is that lighter females experience a series of unstable consorts with less adept rams, and hence are mated by a greater number of males during their oestrus. We have thus also identified a novel male-driven mechanism that generates variation in female promiscuity, which suggests that the high levels of female promiscuity in this system are not part of an adaptive female tactic to intensify post-copulatory competition between males.

Personality Trait Similarity Between Spouses in Four Cultures

PubMed Central

Martin, Thomas A.; H⊆ebí ková, Martina; Urbánek, Tomáš; Boomsma, Dorret I.; Willemsen, Gonneke; Costa, Paul T.

2008-01-01

We examined patterns of trait similarity (assortative mating) in married couples in four cultures, using both self-reports and spouse ratings on versions of the Revised NEO Personality Inventory. There was evidence of a subtle but pervasive perceived contrast bias in the spouse rating data. However, there was strong agreement across methods of assessment and moderate agreement across cultures in the pattern of results. Most assortment effects were small, but correlations exceeding .40 were seen for a subset of traits, chiefly from the Openness and Agreeableness domains. Except in Russia, where more positive assortment was seen for younger couples, comparisons of younger and older cohorts showed little systematic difference. This suggested that mate selection, rather than convergence over time, accounted for similarity. Future research on personality similarity in dyads can utilize different designs, but should assess personality at both domain and the facet levels. PMID:18665894

Integration of Spectral Reflectance across the Plumage: Implications for Mating Patterns

PubMed Central

Laczi, Miklós; Török, János; Rosivall, Balázs; Hegyi, Gergely

2011-01-01

Background In complex sexual signaling systems such as plumage color, developmental or genetic links may occur among seemingly distinct traits. However, the interrelations of such traits and the functional significance of their integration rarely have been examined. Methodology/Principal Findings We investigated the parallel variation of two reflectance descriptors (brightness and UV chroma) across depigmented and melanized plumage areas of collared flycatchers (Ficedula albicollis), and the possible role of integrated color signals in mate acquisition. We found moderate integration in brightness and UV chroma across the plumage, with similar correlation structures in the two sexes despite the strong sexual dichromatism. Patterns of parallel color change across the plumage were largely unrelated to ornamental white patch sizes, but they all showed strong assortative mating between the sexes. Comparing different types of assortative mating patterns for individual spectral variables suggested a distinct role for plumage-level color axes in mate acquisition. Conclusions/Significance Our results indicate that the plumage-level, parallel variation of coloration might play a role in mate acquisition. This study underlines the importance of considering potential developmental and functional integration among apparently different ornaments in studies of sexual selection. PMID:21853088

Climate change alters reproductive isolation and potential gene flow in an annual plant.

PubMed

Franks, Steven J; Weis, Arthur E

2009-11-01

Climate change will likely cause evolution due not only to selection but also to changes in reproductive isolation within and among populations. We examined the effects of a natural drought on the timing of flowering in two populations of Brassica rapa and the consequences for predicted reproductive isolation and potential gene flow. Seeds were collected before and after a 5-year drought in southern California from two populations varying in soil moisture. Lines derived from these seeds were raised in the greenhouse under wet and drought conditions. We found that the natural drought caused changes in reproductive timing and that the changes were greater for plants from the wet than from the dry site. This differential shift caused the populations to become more phenological similar, which should lead to less reproductive isolation and increased gene flow. We estimated a high level of assortative mating by flowering time, which potentially contributed to the rapid evolution of phenological traits following the drought. Estimates of assortative mating were higher for the wet site population, and assortative mating was reduced following the drought. This study shows that climate change can potentially alter gene flow and reproductive isolation within and among populations, strongly influencing evolution.

High temperatures disrupt Artemia franciscana mating patterns and impact sexual selection intensity

NASA Astrophysics Data System (ADS)

Santos, Maria R.; Vieira, Natividade; Monteiro, Nuno M.

2018-07-01

Temperature plays a critical role in survival and reproduction, especially in ectotherms. Therefore, it is important to understand the mechanisms influencing life history traits and reproductive behaviours in order to predict climate change impacts on species' occurrence and performance. Here, we used the crustacean Artemia franciscana to investigate the potential impacts of temperature on life history traits, mating patterns and intensity of sexual selection. We reared A. franciscana at three temperatures 20 °C, 25 °C, and 30 °C and measured life history traits such as growth, mortality or development of sexual traits. Our observations confirmed a clear link between life history traits and temperature, with advanced sexual maturity and increased mortality rates following temperature rises. Also, we found that mating is size assortative close to the ideal developmental temperature. Nevertheless, when temperatures deviate from the optimum, mating patterns were altered. Although selection intensity for females remained similar at all tested temperatures, as males preferentially mated with the larger females, size assortative mating disappeared at the highest temperature. Overall, our results highlight the potential for a temperature-dependent disruption of A. franciscana mating patterns. This disruption is especially pronounced under high temperatures as reproduction becomes progressively more random, thus entailing a relaxation of sexual selection intensity.

Effects of assortative mate choice on the genomic and morphological structure of a hybrid zone between two bird subspecies.

PubMed

Semenov, Georgy A; Scordato, Elizabeth S C; Khaydarov, David R; Smith, Chris C R; Kane, Nolan C; Safran, Rebecca J

2017-11-01

Phenotypic differentiation plays an important role in the formation and maintenance of reproductive barriers. In some cases, variation in a few key aspects of phenotype can promote and maintain divergence; hence, the identification of these traits and their associations with patterns of genomic divergence is crucial for understanding the patterns and processes of population differentiation. We studied hybridization between the alba and personata subspecies of the white wagtail (Motacilla alba), and quantified divergence and introgression of multiple morphological traits and 19,437 SNP loci on a 3,000 km transect. Our goal was to identify traits that may contribute to reproductive barriers and to assess how variation in these traits corresponds to patterns of genome-wide divergence. Variation in only one trait-head plumage patterning-was consistent with reproductive isolation. Transitions in head plumage were steep and occurred over otherwise morphologically and genetically homogeneous populations, whereas cline centres for other traits and genomic ancestry were displaced over 100 km from the head cline. Field observational data show that social pairs mated assortatively by head plumage, suggesting that these phenotypes are maintained by divergent mating preferences. In contrast, variation in all other traits and genetic markers could be explained by neutral diffusion, although weak ecological selection cannot be ruled out. Our results emphasize that assortative mating may maintain phenotypic differences independent of other processes shaping genome-wide variation, consistent with other recent findings that raise questions about the relative importance of mate choice, ecological selection and selectively neutral processes for divergent evolution. © 2017 John Wiley & Sons Ltd.

Mate Selection among Married and Cohabiting Couples.

ERIC Educational Resources Information Center

Blackwell, Debra L.; Lichter, Daniel T.

2000-01-01

Examines comparative patterns of educational and racial assortative mating or homogany among married and cohabiting couples, and evaluates whether women and men trade in socioeconomic status and racial caste prestige. Lists several findings, including married/cohabiting couples are highly homogenous with respect to race and education. Suggests…

Mate value asymmetry and relationship satisfaction in female opinion.

PubMed

Nowak, Natalia; Danel, Dariusz

2014-01-01

A considerable amount of studies highlight positive assortative mating in terms of various aspects of mate value. However, there is a lack of studies that directly show how both partners' mate value and mate value differences are related to the satisfaction in heterosexual relationship. In the present study, the authors focused on women and analyzed how their mate value self-assessment and perception of their partners' mate value are related to female relationship satisfaction. The authors also classified them under 3 categories of couples defined by partners' mate value discrepancy, that is, in which a woman has higher, lower, and equal mate value than does her male partner. Women's relationship satisfaction was positively related to the perception of their partners' mate value but negatively correlated to their mate value self-assessment. Moreover, relationship satisfaction was the lowest in the category where woman has higher self-assessed mate value. The level of women's relationship satisfaction did not differ in 2 other categories of relationships. Our results suggest that women's perception of mate value and mate value asymmetry may significantly affect women's satisfaction from their relationships. The authors provide several possible, evolutionary-based explanatory mechanisms.

Loss of red opsin genes relaxes sexual isolation between skin-colour variants of medaka.

PubMed

Kamijo, Makiko; Kawamura, Mayuko; Fukamachi, Shoji

2018-05-01

Colour vision is often essential for animals. Fine discrimination of colours enhances the ability of animals to find food, predators, or mating partners. Using two colour variants of medaka (Oryzias latipes), which mate assortatively depending on visual cues (pale grey versus dark orange), we recently established red colour-blind strains by knocking out the red opsin (long-wavelength-sensitive) genes and elucidated that the fish were indeed insensitive to red light. In the present study, we investigated the mate choice of these red-blind fish. The colour variants with normal colour vision strongly preferred to mate with their own strain. The red-blind ones also preferred their own strain; i.e. they still mated assortatively. However, their preference was significantly weaker than that of fish with normal colour vision. In other words, the red-blind fish showed increased sexual interest in the other colour variant. These results indicated that reduced sensitivity to red light also reduced their ability to discriminate colours. This empirical evidence directly demonstrates that a change in cone-opsin repertoire changes mating decision behaviours, which would affect gene flow and speciation processes between conspecific colour variants in nature, as suggested in other studies. Copyright © 2018 Elsevier B.V. All rights reserved.

PERSONAL VULNERABILITIES AND ASSORTATIVE MATE SELECTION AMONG NEWLYWED SPOUSES.

PubMed

Trombello, Joseph M; Schoebi, Dominik; Bradbury, Thomas N

2015-06-01

Assortative-mating theories propose that individuals select romantic relationship partners who are similar to them on positive and negative qualities. Furthermore, stress-generation and intergenerational transmission of divorce models argue that one's depression history or family-of-origin relationship problems predict qualities of a marital partner that predispose them to relationship distress. We analyzed data from 172 newlywed couples to examine predictors and mediators of a marital partner's risk index. First, an index of one's own and one's partner risk was created through factor analysis and was comprised of measures that indicate insecurity about oneself. This index was significantly correlated with baseline marital satisfaction and, among men, steps toward divorce at follow-up. Then, structural equation modeling tested direct and indirect pathways predicting partner's risk index, analyzing prior depression history and family-of-origin relational impairment as predictors and one's own risk index as the mediator. Results demonstrated that own risk index reliably predicted partner's risk, while own risk index also mediated the relationship between own family-of-origin relational dysfunction/depression history and partner's risk index. These results support assortative mating theories and suggest that the association between adverse family-of-origin relationships or depression history and the risk profile in one's marital partner is explained by one's own risk profile.

Experimental hybridization and backcrossing reveal forces of reproductive isolation in Microbotryum

PubMed Central

2013-01-01

Background Hybridization and reproductive isolation are central to the origin and maintenance of species, and especially for sympatric species, gene flow is often inhibited through barriers that depend upon mating compatibility factors. The anther-smut fungi (genus Microbotryum) serve as models for speciation in the face of sympatry, and previous studies have tested for but not detected assortative mating. In addition, post-mating barriers are indicated by reduced fitness of hybrids, but sources of those barriers (i.e. ecological maladaptation or genetic incompatibilities) have not yet been detected. Here, backcrossing experiments, specifically controlling for the fungal species origins of the mating compatibility factors, were used to investigate reproductive isolation in the recently-derived species Microbotryum lychnidis-dioicae and Microbotryum silenes-dioicae. Results Assortative mating was detected during backcrossing and was manifested by the preferential conjugation of the hybrid-produced gametes with non-hybrid gametes containing mating compatibility factors from the same parental species. Patterns of post-mating performance supported either a level of extrinsic isolation mechanism, where backcross progeny with a higher proportion of the pathogen genome adapted to the particular host environment were favored, or an infection advantage attributed to greater genetic contribution to the hybrid from the M. lychnidis-dioicae genome. Conclusion The use of controlled backcrossing experiments reveals significant species-specific mating type effects on conjugations between recently-derived sister species, which are likely to play important roles in both maintaining species separation and the nature of hybrids lineages that emerge in sympatry between Microbotryum species. PMID:24112452

Is there an own-race preference in attractiveness?

PubMed

Burke, Darren; Nolan, Caroline; Hayward, William Gordon; Russell, Robert; Sulikowski, Danielle

2013-08-15

Even in multicultural nations interracial relationships and marriages are quite rare, one reflection of assortative mating. A relatively unexplored factor that could explain part of this effect is that people may find members of their own racial group more attractive than members of other groups. We tested whether there is an own-race preference in attractiveness judgments, and also examined the effect of familiarity by comparing the attractiveness ratings given by participants of different ancestral and geographic origins to faces of European, East Asian and African origin. We did not find a strong own-race bias in attractiveness judgments, but neither were the data consistent with familiarity, suggesting an important role for other factors determining the patterns of assortative mating observed.

Colour assortative pairing in a colour polymorphic lizard is independent of population morph diversity

NASA Astrophysics Data System (ADS)

Pérez i de Lanuza, Guillem; Font, Enrique; Carretero, Miguel Ángel

2016-10-01

Previous work with a colour polymorphic population of Podarcis muralis (Lacertidae) revealed that lizards pair by ventral colour, favouring the same colour (i.e. homomorphic) pairs. Such assortative pairing, which probably results in colour assortative mating, can have consequences for the genetic structure of the population and potentially promote speciation. The population previously studied, located in the Pyrenees, encompasses white, yellow and orange animals, as well as intermediate white-orange and yellow-orange morphs. However, other Pyrenean populations of P. muralis have less ventral colour morphs. Our aim in this study is to test the generality of the assortative colour pairing system, extending our previous analyses to populations with different morph compositions and frequencies. The results show that the assortative pattern of pairing is similar in all the populations analysed and, hence, independent of morph composition and not restricted to pentamorphic populations. This suggests that assortative pairing by colour is a general phenomenon for colour polymorphic populations of P. muralis.

Choosy Wolves? Heterozygote Advantage But No Evidence of MHC-Based Disassortative Mating.

PubMed

Galaverni, Marco; Caniglia, Romolo; Milanesi, Pietro; Lapalombella, Silvana; Fabbri, Elena; Randi, Ettore

2016-03-01

A variety of nonrandom mate choice strategies, including disassortative mating, are used by vertebrate species to avoid inbreeding, maintain heterozygosity and increase fitness. Disassortative mating may be mediated by the major histocompatibility complex (MHC), an important gene cluster controlling immune responses to pathogens. We investigated the patterns of mate choice in 26 wild-living breeding pairs of gray wolf (Canis lupus) that were identified through noninvasive genetic methods and genotyped at 3 MHC class II and 12 autosomal microsatellite (STR) loci. We tested for deviations from random mating and evaluated the covariance of genetic variables at functional and STR markers with fitness proxies deduced from pedigree reconstructions. Results did not show evidences of MHC-based disassortative mating. Rather we found a higher peptide similarity between mates at MHC loci as compared with random expectations. Fitness values were positively correlated with heterozygosity of the breeders at both MHC and STR loci, whereas they decreased with relatedness at STRs. These findings may indicate fitness advantages for breeders that, while avoiding highly related mates, are more similar at the MHC and have high levels of heterozygosity overall. Such a pattern of MHC-assortative mating may reflect local coadaptation of the breeders, while a reduction in genetic diversity may be balanced by heterozygote advantages. © The American Genetic Association 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Cytonuclear Theory for Haplodiploid Species and X-Linked Genes. I. Hardy-Weinberg Dynamics and Continent-Island, Hybrid Zone Models

PubMed Central

Goodisman, MAD.; Asmussen, M. A.

1997-01-01

We develop models that describe the cytonuclear structure for either a cytoplasmic and nuclear marker in a haplodiploid species or a cytoplasmic and X-linked marker in a diploid species. Sex-specific disequilibrium statistics that summarize nonrandom cytonuclear associations in such systems are defined, and their basic Hardy-Weinberg dynamics and admixture formulae are delimited. We focus on the context of hybrid zones and develop continent-island models whereby individuals from two genetically differentiated source populations migrate into and mate within a single zone of admixture. We examine the effects of differential migration of the sexes, assortative mating by pure type females, and census time (relative to mating and migration), as well as special cases of random mating and migration subsumed under the general models. We show that pure type individuals and nonzero cytonuclear disequilibria can be maintained within a hybrid zone if there is continued migration from both source populations, and that females generally have a greater influence over these cytonuclear variables than males. The resulting theoretical framework can be used to estimate the rates of assortative mating and sex-specific gene flow in hybrid zones and other zones of admixture involving haplodiploid or sex-linked cytonuclear data. PMID:9286692

Left or right? Sources of political orientation: the roles of genetic factors, cultural transmission, assortative mating, and personality.

PubMed

Kandler, Christian; Bleidorn, Wiebke; Riemann, Rainer

2012-03-01

In this study, we used an extended twin family design to investigate the influences of genetic and cultural transmission as well as different sources of nonrandom mating on 2 core aspects of political orientation: acceptance of inequality and rejecting system change. In addition, we studied the sources of phenotypic links between Big Five personality traits and political beliefs using self- and other reports. Data of 1,992 individuals (224 monozygotic and 166 dizygotic twin pairs, 92 unmatched twins, 530 spouses of twins, 268 fathers, and 322 mothers) were analyzed. Genetically informative analyses showed that political attitudes are genetically but not environmentally transmitted from parents to offspring and that a substantial proportion of this genetic variance can be accounted for by genetic variance in personality traits. Beyond genetic effects and genotypic assortative mating, generation-specific environmental sources act to increase twins' and spouses' resemblance in political beliefs. The results suggest multiple sources of political orientations in a modern democracy.

Looking for a similar partner: host plants shape mating preferences of herbivorous insects by altering their contact pheromones.

PubMed

Geiselhardt, Sven; Otte, Tobias; Hilker, Monika

2012-09-01

The role of phenotypical plasticity in ecological speciation and the evolution of sexual isolation remains largely unknown. We investigated whether or not divergent host plant use in an herbivorous insect causes assortative mating by phenotypically altering traits involved in mate recognition. We found that males of the mustard leaf beetle Phaedon cochleariae preferred to mate with females that were reared on the same plant species to females provided with a different plant species, based on divergent cuticular hydrocarbon profiles that serve as contact pheromones. The cuticular hydrocarbon phenotypes of the beetles were host plant specific and changed within 2 weeks after a shift to a novel host plant species. We suggest that plant-induced phenotypic divergence in mate recognition cues may act as an early barrier to gene flow between herbivorous insect populations on alternative host species, preceding genetic divergence and thus, promoting ecological speciation. © 2012 Blackwell Publishing Ltd/CNRS.

Mutual Mate Choice: When it Pays Both Sexes to Avoid Inbreeding

PubMed Central

Lihoreau, Mathieu; Zimmer, Cédric; Rivault, Colette

2008-01-01

Theoretical models of sexual selection predict that both males and females of many species should benefit by selecting their mating partners. However, empirical evidence testing and validating this prediction is scarce. In particular, whereas inbreeding avoidance is expected to induce sexual conflicts, in some cases both partners could benefit by acting in concert and exerting mutual mate choice for non-assortative pairings. We tested this prediction with the gregarious cockroach Blattella germanica (L.). We demonstrated that males and females base their mate choice on different criteria and that choice occurs at different steps during the mating sequence. Males assess their relatedness to females through antennal contacts before deciding to court preferentially non-siblings. Conversely, females biased their choice towards the most vigorously courting males that happened to be non-siblings. This study is the first to demonstrate mutual mate choice leading to close inbreeding avoidance. The fact that outbred pairs were more fertile than inbred pairs strongly supports the adaptive value of this mating system, which includes no “best phenotype” as the quality of two mating partners is primarily linked to their relatedness. We discuss the implications of our results in the light of inbreeding conflict models. PMID:18843373

Mutual mate choice: when it pays both sexes to avoid inbreeding.

PubMed

Lihoreau, Mathieu; Zimmer, Cédric; Rivault, Colette

2008-01-01

Theoretical models of sexual selection predict that both males and females of many species should benefit by selecting their mating partners. However, empirical evidence testing and validating this prediction is scarce. In particular, whereas inbreeding avoidance is expected to induce sexual conflicts, in some cases both partners could benefit by acting in concert and exerting mutual mate choice for non-assortative pairings. We tested this prediction with the gregarious cockroach Blattella germanica (L.). We demonstrated that males and females base their mate choice on different criteria and that choice occurs at different steps during the mating sequence. Males assess their relatedness to females through antennal contacts before deciding to court preferentially non-siblings. Conversely, females biased their choice towards the most vigorously courting males that happened to be non-siblings. This study is the first to demonstrate mutual mate choice leading to close inbreeding avoidance. The fact that outbred pairs were more fertile than inbred pairs strongly supports the adaptive value of this mating system, which includes no "best phenotype" as the quality of two mating partners is primarily linked to their relatedness. We discuss the implications of our results in the light of inbreeding conflict models.

Assortative mating and fragmentation within dog breeds.

PubMed

Björnerfeldt, Susanne; Hailer, Frank; Nord, Maria; Vilà, Carles

2008-01-28

There are around 400 internationally recognized dog breeds in the world today, with a remarkable diversity in size, shape, color and behavior. Breeds are considered to be uniform groups with similar physical characteristics, shaped by selection rooted in human preferences. This has led to a large genetic difference between breeds and a large extent of linkage disequilibrium within breeds. These characteristics are important for association mapping of candidate genes for diseases and therefore make dogs ideal models for gene mapping of human disorders. However, genetic uniformity within breeds may not always be the case. We studied patterns of genetic diversity within 164 poodles and compared it to 133 dogs from eight other breeds. Our analyses revealed strong population structure within poodles, with differences among some poodle groups as pronounced as those among other well-recognized breeds. Pedigree analysis going three generations back in time confirmed that subgroups within poodles result from assortative mating imposed by breed standards as well as breeder preferences. Matings have not taken place at random or within traditionally identified size classes in poodles. Instead, a novel set of five poodle groups was identified, defined by combinations of size and color, which is not officially recognized by the kennel clubs. Patterns of genetic diversity in other breeds suggest that assortative mating leading to fragmentation may be a common feature within many dog breeds. The genetic structure observed in poodles is the result of local mating patterns, implying that breed fragmentation may be different in different countries. Such pronounced structuring within dog breeds can increase the power of association mapping studies, but also represents a serious problem if ignored. In dog breeding, individuals are selected on the basis of morphology, behaviour, working or show purposes, as well as geographic population structure. The same processes which have historically created dog breeds are still ongoing, and create further subdivision within current dog breeds.

Assortative mating and fragmentation within dog breeds

PubMed Central

2008-01-01

Background There are around 400 internationally recognized dog breeds in the world today, with a remarkable diversity in size, shape, color and behavior. Breeds are considered to be uniform groups with similar physical characteristics, shaped by selection rooted in human preferences. This has led to a large genetic difference between breeds and a large extent of linkage disequilibrium within breeds. These characteristics are important for association mapping of candidate genes for diseases and therefore make dogs ideal models for gene mapping of human disorders. However, genetic uniformity within breeds may not always be the case. We studied patterns of genetic diversity within 164 poodles and compared it to 133 dogs from eight other breeds. Results Our analyses revealed strong population structure within poodles, with differences among some poodle groups as pronounced as those among other well-recognized breeds. Pedigree analysis going three generations back in time confirmed that subgroups within poodles result from assortative mating imposed by breed standards as well as breeder preferences. Matings have not taken place at random or within traditionally identified size classes in poodles. Instead, a novel set of five poodle groups was identified, defined by combinations of size and color, which is not officially recognized by the kennel clubs. Patterns of genetic diversity in other breeds suggest that assortative mating leading to fragmentation may be a common feature within many dog breeds. Conclusion The genetic structure observed in poodles is the result of local mating patterns, implying that breed fragmentation may be different in different countries. Such pronounced structuring within dog breeds can increase the power of association mapping studies, but also represents a serious problem if ignored. In dog breeding, individuals are selected on the basis of morphology, behaviour, working or show purposes, as well as geographic population structure. The same processes which have historically created dog breeds are still ongoing, and create further subdivision within current dog breeds. PMID:18226210

A preliminary investigation into the potential role of waist hip ratio (WHR) preference within the assortative mating hypothesis of autistic spectrum disorders.

PubMed

Brosnan, Mark; Walker, Ian

2009-01-01

Of particular interest to studying the etiology of Autistic Spectrum Disorders (ASDs) is the potential for multiple risk factors to combine through non-random mechanisms-assortative mating. Both genetic influences and a high-testosterone prenatal environment have been implicated in the etiology of ASDs, and given that waist-hip ratio (WHR) is indicative of a woman's circulating testosterone level, a man attracted to higher-than-average WHR women is likely to have a higher-than-average prenatal testosterone exposure for their offspring. We show that whereas fathers of children without ASD show a statistically reliable preference for WHRs at the low end of the normal range, indicative of women with low testosterone levels, fathers of children diagnosed with ASD do not consistently show this preference.

Some genetic problems in physical growth and development. A longitudinal study on children aged 0--7 years.

PubMed

Chrzastek-Spruch, H M

1977-01-01

Aiming at determining the influence of some genetic factors on growth and development, a longitudinal study of 180 children (90 M and 90 F) from the city of Lublin was carried out, with periodical medical examinations and anthropometric measurements from birth to 7 years of age. The parents of each child were also examined. The correlation coefficients between parents and children show that, as regards height, the greatest similarity occurs between mothers and daughters, and a lesser one between fathers and sons. As regards weight, sons are more similar to fathers than daughters to mothers. The relationship between the growth and development of children and the mating type of parents, parental age, and birth order, was also investigated. In negative assortative mating, the children are taller than the children of middle-height parents from positive assortative mating couples. Children (especially daughters) of tall mothers and short fathers grow taller than children of tall fathers and short mothers. Finally, the dependence of growth on parental age and birth order was analysed and the conclusions reached were quite interesting.

Patterns of MHC-dependent mate selection in humans and nonhuman primates: a meta-analysis.

PubMed

Winternitz, J; Abbate, J L; Huchard, E; Havlíček, J; Garamszegi, L Z

2017-01-01

Genes of the major histocompatibility complex (MHC) in vertebrates are integral for effective adaptive immune response and are associated with sexual selection. Evidence from a range of vertebrates supports MHC-based preference for diverse and dissimilar mating partners, but evidence from human mate choice studies has been disparate and controversial. Methodologies and sampling peculiarities specific to human studies make it difficult to know whether wide discrepancies in results among human populations are real or artefact. To better understand what processes may affect MHC-mediated mate choice across humans and nonhuman primates, we performed phylogenetically controlled meta-analyses using 58 effect sizes from 30 studies across seven primate species. Primates showed a general trend favouring more MHC-diverse mates, which was statistically significant for humans. In contrast, there was no tendency for MHC-dissimilar mate choice, and for humans, we observed effect sizes indicating selection of both MHC-dissimilar and MHC-similar mates. Focusing on MHC-similar effect sizes only, we found evidence that preference for MHC similarity was an artefact of population ethnic heterogeneity in observational studies but not among experimental studies with more control over sociocultural biases. This suggests that human assortative mating biases may be responsible for some patterns of MHC-based mate choice. Additionally, the overall effect sizes of primate MHC-based mating preferences are relatively weak (Fisher's Z correlation coefficient for dissimilarity Zr = 0.044, diversity Zr = 0.153), calling for careful sampling design in future studies. Overall, our results indicate that preference for more MHC-diverse mates is significant for humans and likely conserved across primates. © 2016 John Wiley & Sons Ltd.

Cross-Cultural Comparison of Genetic and Cultural Transmission of Smoking Initiation Using an Extended Twin Kinship Model.

PubMed

Maes, Hermine H; Morley, Kate; Neale, Michael C; Kendler, Kenneth S; Heath, Andrew C; Eaves, Lindon J; Martin, Nicholas G

2018-06-01

Considerable evidence from twin and adoption studies indicates that genetic and shared environmental factors play a role in the initiation of smoking behavior. Although twin and adoption designs are powerful to detect genetic and environmental influences, they do not provide information on the processes of assortative mating and parent-offspring transmission and their contribution to the variability explained by genetic and/or environmental factors. We examined the role of genetic and environmental factors in individual differences for smoking initiation (SI) using an extended kinship design. This design allows the simultaneous testing of additive and non-additive genetic, shared and individual-specific environmental factors, as well as sex differences in the expression of genes and environment in the presence of assortative mating and combined genetic and cultural transmission, while also estimating the regression of the prevalence of SI on age. A dichotomous lifetime 'ever' smoking measure was obtained from twins and relatives in the 'Virginia 30,000' sample and the 'Australian 25,000'. Results demonstrate that both genetic and environmental factors play a significant role in the liability to SI. Major influences on individual differences appeared to be additive genetic and unique environmental effects, with smaller contributions from assortative mating, shared sibling environment, twin environment, cultural transmission, and resulting genotype-environment covariance. Age regression of the prevalence of SI was significant. The finding of negative cultural transmission without dominance led us to investigate more closely two possible mechanisms for the lower parent-offspring correlations compared to the sibling and DZ twin correlations in subsets of the data: (1) age × gene interaction, and (2) social homogamy. Neither of the mechanism provided a significantly better explanation of the data. This study showed significant heritability, partly due to assortment, and significant effects of primarily non-parental shared environment on liability to SI.

Polymorphic butterfly reveals the missing link in ecological speciation.

PubMed

Chamberlain, Nicola L; Hill, Ryan I; Kapan, Durrell D; Gilbert, Lawrence E; Kronforst, Marcus R

2009-11-06

Ecological speciation occurs when ecologically based, divergent selection causes the evolution of reproductive isolation. There are many empirical examples of this process; however, there exists a poorly characterized stage during which the traits that distinguish species ecologically and reproductively segregate in a single population. By using a combination of genetic mapping, mate-choice experiments, field observations, and population genetics, we studied a butterfly population with a mimetic wing color polymorphism and found that the butterflies exhibited partial, color-based, assortative mate preference. These traits represent the divergent, ecologically based signal and preference components of sexual isolation that usually distinguish incipient and sibling species. The association between behavior and recognition trait in a single population may enhance the probability of speciation and provides an example of the missing link between an interbreeding population and isolated species.

Airborne-pollen pool and mating pattern in a hybrid zone between Pinus pumila and P. parviflora var. pentaphylla.

PubMed

Ito, Megumi; Suyama, Yoshihisa; Ohsawa, Takeshi A; Watano, Yasuyuki

2008-12-01

The reproductive isolation barriers and the mating patterns among Pinus pumila, P. parviflora var. pentaphylla and their hybrids were examined by flowering phenology and genetic assays of three life stages: airborne-pollen grains, adults and seeds, in a hybrid zone on Mount Apoi, Hokkaido, Japan. Chloroplast DNA composition of the airborne-pollen was determined by single-pollen polymerase chain reaction. Mating patterns were analysed by estimating the molecular hybrid index of the seed parent, their seed embryos and pollen parents. The observation of flowering phenology showed that the flowering of P. pumila precedes that of P. parviflora var. pentaphylla by about 6 to 10 days within the same altitudinal ranges. Although this prezygotic isolation barrier is effective, the genetic assay of airborne-pollen showed that the two pine species, particularly P. pumila, still have chances to form F(1) hybrid seeds. Both parental species showed a strong assortative mating pattern; F(1) seeds were found in only 1.4% of seeds from P. pumila mother trees and not at all in P. parviflora var. pentaphylla. The assortative mating was concluded as the combined result of flowering time differentiation and cross-incompatibility. In contrast to the parental species, hybrids were fertilized evenly by the two parental species and themselves. The breakdown of prezygotic barriers (intermediate flowering phenology) and cross-incompatibility may account for the unselective mating. It is suggested that introgression is ongoing on Mount Apoi through backcrossing between hybrids and parental species, despite strong isolation barriers between the parental species.

Direct fitness benefits explain mate preference, but not choice, for similarity in heterozygosity levels.

PubMed

Zandberg, Lies; Gort, Gerrit; van Oers, Kees; Hinde, Camilla A

2017-10-01

Under sexual selection, mate preferences can evolve for traits advertising fitness benefits. Observed mating patterns (mate choice) are often assumed to represent preference, even though they result from the interaction between preference, sampling strategy and environmental factors. Correlating fitness with mate choice instead of preference will therefore lead to confounded conclusions about the role of preference in sexual selection. Here we show that direct fitness benefits underlie mate preferences for genetic characteristics in a unique experiment on wild great tits. In repeated mate preference tests, both sexes preferred mates that had similar heterozygosity levels to themselves, and not those with which they would optimise offspring heterozygosity. In a subsequent field experiment where we cross fostered offspring, foster parents with more similar heterozygosity levels had higher reproductive success, despite the absence of assortative mating patterns. These results support the idea that selection for preference persists despite constraints on mate choice. © 2017 The Authors Ecology Letters published by CNRS and John Wiley & Sons Ltd.

Mate choice and human stature: homogamy as a unified framework for understanding mating preferences.

PubMed

Courtiol, Alexandre; Raymond, Michel; Godelle, Bernard; Ferdy, Jean-Baptiste

2010-08-01

Assortative mating for human height has long attracted interest in evolutionary biology, and the phenomenon has been demonstrated in numerous human populations. It is often argued that mating preferences generate this pattern, but other processes can also induce trait correlations between mates. Here, we present a methodology tailored to quantify continuous preferences based on choice experiments between pairs of stimuli. In particular, it is possible to explore determinants of interindividual variations in preferences, such as the height of the chooser. We collected data from a sample of 200 individuals from France. Measurements obtained show that the perception of attractiveness depends on both the height of the stimuli and the stature of the individual who judged them. Therefore, this study demonstrates that homogamy is present at the level of preferences for both sexes. We also show that measurements of the function describing this homogamy are concordant with several distinct mating rules proposed in the literature. In addition, the quantitative approach introduced here fulfills metrics that can be used to compare groups of individuals. In particular, our results reveal an important disagreement between sexes regarding height preferences in the context of mutual mate choice. Finally, both women and men prefer individuals who are significantly taller than average. All major findings are confirmed by a reanalysis of previously published data.

Personality differentially affects individual mate choice decisions in female and male Western mosquitofish (Gambusia affinis).

PubMed

Chen, Bo-Jian; Liu, Kai; Zhou, Lin-Jun; Gomes-Silva, Guilherme; Sommer-Trembo, Carolin; Plath, Martin

2018-01-01

Consistent individual differences in behavioral tendencies (animal personality) can affect individual mate choice decisions. We asked whether personality traits affect male and female mate choice decisions similarly and whether potential personality effects are consistent across different mate choice situations. Using western mosquitofish (Gambusia affinis) as our study organism, we characterized focal individuals (males and females) twice for boldness, activity, and sociability/shoaling and found high and significant behavioral repeatability. Additionally, each focal individual was tested in two different dichotomous mate choice tests in which it could choose between computer-animated stimulus fish of the opposite sex that differed in body size and activity levels, respectively. Personality had different effects on female and male mate choice: females that were larger than average showed stronger preferences for large-bodied males with increasing levels of boldness/activity (i.e., towards more proactive personality types). Males that were larger than average and had higher shoaling tendencies showed stronger preferences for actively swimming females. Size-dependent effects of personality on the strength of preferences for distinct phenotypes of potential mating partners may reflect effects of age/experience (especially in females) and social dominance (especially in males). Previous studies found evidence for assortative mate choice based on personality types or hypothesized the existence of behavioral syndromes of individuals' choosiness across mate choice criteria, possibly including other personality traits. Our present study exemplifies that far more complex patterns of personality-dependent mate choice can emerge in natural systems.

Assortment of encounters and evolution of cooperativeness.

PubMed

Eshel, I; Cavalli-Sforza, L L

1982-02-01

The method of evolutionary stable strategies (ESS), in its current form, is confronted with a difficulty when it tries to explain how some social behaviors initiate their evolution. We show that this difficulty may be removed by changing the assumption made tacitly in game theory (and in ESS) of randomness of meetings or encounters. In reality, such randomness seems to be rare in nature. Family, population and social structure, customs, and habits impose various types of deviation from randomness. Introducing nonrandomness of meeting in a way formally similar to assortative mating, we show that the bar to initial increase of inherited cooperative or altruistic behaviors can be removed, provided there is sufficient assortment of meetings. Family structure may cause contacts predominantly between certain types of relatives, and one can reconstruct some results of classical kin selection in terms of evolutionary stable strategy with assortative meetings. Neighbor effects and group selection might be similarly treated. Assortment need not be a passive consequence of population and social structure, but it can also be actively pursued. Behaviors favoring the choice of cooperative companions will have the effect of favoring the evolution of cooperativeness. It can be shown that discrimination in the choice of companions, especially if combined with assortment, can favor the development of cooperativeness, making initial increase of cooperative behavior possible even at levels of assortment passively imposed which would not be adequate, per se, to guarantee the increase of cooperativeness. It is possible that, in some cases, cooperativeness and behavior favoring some type of assortment are coselected.

PARTIAL REPRODUCTIVE ISOLATION OF A RECENTLY DERIVED RESIDENT-FRESHWATER POPULATION OF THREESPINE STICKLEBACK (GASTEROSTEUS ACULEATUS) FROM ITS PUTATIVE ANADROMOUS ANCESTOR

PubMed Central

Furin, Christoff G.; Von Hippel, Frank A.; Bell, Michael A.

2012-01-01

We used no-choice mating trials to test for assortative mating between a newly derived resident-freshwater population (8 – 22 generations since founding) of threespine stickleback (Gasterosteus aculeatus) in Loberg Lake, Alaska and its putative anadromous ancestor as well as a morphologically convergent but distantly related resident-freshwater population. Partial reproductive isolation has evolved between the Loberg Lake population and its ancestor within a remarkably short time period. However, Loberg stickleback readily mate with morphologically similar, but distantly related resident-freshwater stickleback. Partial pre-mating isolation is asymmetrical; anadromous females and smaller, resident-freshwater males from Loberg Lake readily mate, but the anadromous males and smaller Loberg females do not. Our results indicate that pre-mating isolation can begin to evolve in allopatry within a few generations after isolation as a correlated effect of evolution of reduced body size. PMID:23025615

Beyond magic traits: Multimodal mating cues in Heliconius butterflies.

PubMed

Mérot, Claire; Frérot, Brigitte; Leppik, Ene; Joron, Mathieu

2015-11-01

Species coexistence involves the evolution of reproductive barriers opposing gene flow. Heliconius butterflies display colorful patterns affecting mate choice and survival through warning signaling and mimicry. These patterns are called "magic traits" for speciation because divergent natural selection may promote mimicry shifts in pattern whose role as mating cue facilitates reproductive isolation. By contrast, between comimetic species, natural selection promotes pattern convergence. We addressed whether visual convergence interferes with reproductive isolation by testing for sexual isolation between two closely related species with similar patterns, H. timareta thelxinoe and H. melpomene amaryllis. Experiments with models confirmed visual attraction based on wing phenotype, leading to indiscriminate approach. Nevertheless, mate choice experiments showed assortative mating. Monitoring male behavior toward live females revealed asymmetry in male preference, H. melpomene males courting both species equally while H. timareta males strongly preferred conspecifics. Experiments with hybrid males suggested an important genetic component for such asymmetry. Behavioral observations support a key role for short-distance cues in determining male choice in H. timareta. Scents extracts from wings and genitalia revealed interspecific divergence in chemical signatures, and hybrid female scent composition was significantly associated with courtship intensity by H. timareta males, providing candidate chemical mating cues involved in sexual isolation. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

Synergy from reproductive division of labor and genetic complexity drive the evolution of sex.

PubMed

Jaffe, Klaus

2018-04-16

Computer experiments that mirror the evolutionary dynamics of sexual and asexual organisms as they occur in nature were used to test features proposed to explain the evolution of sexual recombination. Results show that this evolution is better described as a network of interactions between possible sexual forms, including diploidy, thelytoky, facultative sex, assortation, bisexuality, and division of labor between the sexes, rather than a simple transition from parthenogenesis to sexual recombination. Diploidy was shown to be fundamental for the evolution of sex; bisexual reproduction emerged only among anisogamic diploids with a synergistic division of reproductive labor; and facultative sex was more likely to evolve among haploids practicing assortative mating. Looking at the evolution of sex as a complex system through individual-based simulations explains better the diversity of sexual strategies known to exist in nature, compared to classical analytical models.

Heritability of Self-reported Phobic Fear

PubMed Central

Vink, Jacqueline M.; Willemsen, Gonneke; Middeldorp, Christel M.; Merckelbach, Harald L. G. J.; Boomsma, Dorret I.

2007-01-01

Twin studies on fear and phobia suggest moderate genetic effects. However, results are inconclusive regarding the presence of dominant genetic effects and sex differences. Using an extended twin design, including male and female twins (n = 5,465) and their siblings (n = 1,624), we examined the genetic and environmental influences on blood-injury, social, and agoraphobic fear and investigated their interaction with sex and age. Data of spouses (n = 708) of twins were used to evaluate assortative mating for the three fear dimensions. Results showed that there was no assortative mating for blood-injury, social and agoraphobic fear. Resemblance between biological relatives could be explained by additive and non-additive genetic effects for blood-injury and agoraphobic fear in all participants, and social fear in participants aged 14–25 years. For social fear in participants aged 26–65 only additive genetic effects were detected. Broad-sense heritability estimates ranged from 36 to 51% and were similar for men and women. PMID:18074221

Religion, Marriage Markets, and Assortative Mating in the United States

PubMed Central

McClendon, David

2016-01-01

As interfaith marriage has become more common, religion is thought to be less important for sorting partners. However, prior studies on religious assortative mating use samples of prevailing marriages, which miss how local marriage markets shape both partner selection and marriage timing. Drawing on search theory and data from 8,699 young adults (ages 18–31) in the National Longitudinal Study of Youth 1997, the author examined the association between the concentration of co-religionists in local marriage markets and marriage timing and partner selection using event history methods. Religious concentration is associated with higher odds of transitioning to marriage and religious homogamy (conditional on marriage) for women and men at older ages (24–31) but not at younger ages (18–23). The association was also stronger for non-Hispanic Whites compared to other race-ethnic groups. The findings indicate that religion remains relevant in sorting partners for many young adults in today’s marriage market. PMID:27818530

Mating Success, Longevity, and Fertility of Diabrotica virgifera virgifera LeConte (Chrysomelidae: Coleoptera) in Relation to Body Size and Cry3Bb1-Resistant and Cry3Bb1-Susceptible Genotypes

PubMed Central

French, Bryan Wade; Hammack, Leslie; Tallamy, Douglas W.

2015-01-01

Insect resistance to population control methodologies is a widespread problem. The development of effective resistance management programs is often dependent on detailed knowledge regarding the biology of individual species and changes in that biology associated with resistance evolution. This study examined the reproductive behavior and biology of western corn rootworm beetles of known body size from lines resistant and susceptible to the Cry3Bb1 protein toxin expressed in transgenic Bacillus thuringiensis maize. In crosses between, and within, the resistant and susceptible genotypes, no differences occurred in mating frequency, copulation duration, courtship duration, or fertility; however, females mated with resistant males showed reduced longevity. Body size did not vary with genotype. Larger males and females were not more likely to mate than smaller males and females, but larger females laid more eggs. Moderately strong, positive correlation occurred between the body sizes of successfully mated males and females; however, weak correlation also existed for pairs that did not mate. Our study provided only limited evidence for fitness costs associated with the Cry3Bb1-resistant genotype that might reduce the persistence in populations of the resistant genotype but provided additional evidence for size-based, assortative mating, which could favor the persistence of resistant genotypes affecting body size. PMID:26569315

Crozier's paradox revisited: maintenance of genetic recognition systems by disassortative mating.

PubMed

Holman, Luke; van Zweden, Jelle S; Linksvayer, Timothy A; d'Ettorre, Patrizia

2013-09-27

Organisms are predicted to behave more favourably towards relatives, and kin-biased cooperation has been found in all domains of life from bacteria to vertebrates. Cooperation based on genetic recognition cues is paradoxical because it disproportionately benefits individuals with common phenotypes, which should erode the required cue polymorphism. Theoretical models suggest that many recognition loci likely have some secondary function that is subject to diversifying selection, keeping them variable. Here, we use individual-based simulations to investigate the hypothesis that the dual use of recognition cues to facilitate social behaviour and disassortative mating (e.g. for inbreeding avoidance) can maintain cue diversity over evolutionary time. Our model shows that when organisms mate disassortatively with respect to their recognition cues, cooperation and recognition locus diversity can persist at high values, especially when outcrossed matings produce more surviving offspring. Mating system affects cue diversity via at least four distinct mechanisms, and its effects interact with other parameters such as population structure. Also, the attrition of cue diversity is less rapid when cooperation does not require an exact cue match. Using a literature review, we show that there is abundant empirical evidence that heritable recognition cues are simultaneously used in social and sexual behaviour. Our models show that mate choice is one possible resolution of the paradox of genetic kin recognition, and the literature review suggests that genetic recognition cues simultaneously inform assortative cooperation and disassortative mating in a large range of taxa. However, direct evidence is scant and there is substantial scope for future work.

Problem Behavior and Romantic Relationships: Assortative Mating, Behavior Contagion, and Desistance

ERIC Educational Resources Information Center

Rhule-Louie, Dana M.; McMahon, Robert J.

2007-01-01

Antisocial behavior and substance misuse are forms of problem behavior demonstrating considerable continuity over time. Accordingly, problem behavior influences interpersonal contexts across the life course, which may result in the replication of coercive interactions and a problem behavior lifestyle within romantic relationships. Furthermore,…

Mate choice and genetic monogamy in a biparental, colonial fish.

PubMed

Schaedelin, Franziska C; van Dongen, Wouter F D; Wagner, Richard H

2015-01-01

In socially monogamous species, in which both sexes provide essential parental care, males as well as females are expected to be choosy. Whereas hundreds of studies have examined monogamy in biparental birds, only several such studies exist in fish. We examined mate choice in the biparental, colonial cichlid fish Neolamprologus caudopunctatus in Lake Tanganyika, Zambia. We genotyped more than 350 individuals at 11 microsatellite loci to investigate their mating system. We found no extrapair paternity, identifying this biparental fish as genetically monogamous. Breeders paired randomly according to their genetic similarity, suggesting a lack of selection against inbreeding avoidance. We further found that breeders paired assortatively by body size, a criterion of quality in fish, suggesting mutual mate choice. In a subsequent mate preference test in an aquarium setup, females showed a strong preference for male size by laying eggs near the larger of 2 males in 13 of 14 trials.

Mate choice and genetic monogamy in a biparental, colonial fish

PubMed Central

van Dongen, Wouter F.D.; Wagner, Richard H.

2015-01-01

In socially monogamous species, in which both sexes provide essential parental care, males as well as females are expected to be choosy. Whereas hundreds of studies have examined monogamy in biparental birds, only several such studies exist in fish. We examined mate choice in the biparental, colonial cichlid fish Neolamprologus caudopunctatus in Lake Tanganyika, Zambia. We genotyped more than 350 individuals at 11 microsatellite loci to investigate their mating system. We found no extrapair paternity, identifying this biparental fish as genetically monogamous. Breeders paired randomly according to their genetic similarity, suggesting a lack of selection against inbreeding avoidance. We further found that breeders paired assortatively by body size, a criterion of quality in fish, suggesting mutual mate choice. In a subsequent mate preference test in an aquarium setup, females showed a strong preference for male size by laying eggs near the larger of 2 males in 13 of 14 trials. PMID:26023276

The role of physiological traits in assortment among and within fish shoals

PubMed Central

Marras, Stefano

2017-01-01

Individuals of gregarious species often group with conspecifics to which they are phenotypically similar. This among-group assortment has been studied for body size, sex and relatedness. However, the role of physiological traits has been largely overlooked. Here, we discuss mechanisms by which physiological traits—particularly those related to metabolism and locomotor performance—may result in phenotypic assortment not only among but also within animal groups. At the among-group level, varying combinations of passive assortment, active assortment, phenotypic plasticity and selective mortality may generate phenotypic differences among groups. Even within groups, however, individual variation in energy requirements, aerobic and anaerobic capacity, neurological lateralization and tolerance to environmental stressors are likely to produce differences in the spatial location of individuals or associations between group-mates with specific physiological phenotypes. Owing to the greater availability of empirical research, we focus on groups of fishes (i.e. shoals and schools). Increased knowledge of physiological mechanisms influencing among- and within-group assortment will enhance our understanding of fundamental concepts regarding optimal group size, predator avoidance, group cohesion, information transfer, life-history strategies and the evolutionary effects of group membership. In a broader perspective, predicting animal responses to environmental change will be impossible without a comprehensive understanding of the physiological basis of the formation and functioning of animal social groups. This article is part of the themed issue ‘Physiological determinants of social behaviour in animals’. PMID:28673911

Genetic and Environmental Contributions to Educational Attainment in Australia.

ERIC Educational Resources Information Center

Miller, Paul; Mulvey, Charles; Martin, Nick

2001-01-01

Data from a large sample of Australian twins indicate that 50 to 65 percent of variance in educational attainments can be attributed to genetic endowments. Only about 25 to 40 percent may be due to environmental factors, depending on adjustments for measurement error and assortative mating. (Contains 51 references.) (MLH)

Genetic Variance in the SES-IQ Correlation.

ERIC Educational Resources Information Center

Eckland, Bruce K.

1979-01-01

Discusses questions dealing with genetic aspects of the correlation between IQ and socioeconomic status (SES). Questions include: How does assortative mating affect the genetic variance of IQ? Is the relationship between an individual's IQ and adult SES a causal one? And how can IQ research improve schools and schooling? (Author/DB)

Homogeneity of Political Party Preferences between Spouses

ERIC Educational Resources Information Center

Weiner, Terry S.

1978-01-01

A study investigated how political socialization within marriages affects political party affiliation. Findings indicated that the high degree of homogeneity of party preferences between spouses is due both to assortive mating and to influences of each spouse upon the other. For journal availability, see SO 506 355. (Author/DB)

Artificial neural networks in models of specialization, guild evolution and sympatric speciation.

PubMed

Holmgren, Noél M A; Norrström, Niclas; Getz, Wayne M

2007-03-29

Sympatric speciation can arise as a result of disruptive selection with assortative mating as a pleiotropic by-product. Studies on host choice, employing artificial neural networks as models for the host recognition system in exploiters, illustrate how disruptive selection on host choice coupled with assortative mating can arise as a consequence of selection for specialization. Our studies demonstrate that a generalist exploiter population can evolve into a guild of specialists with an 'ideal free' frequency distribution across hosts. The ideal free distribution arises from variability in host suitability and density-dependent exploiter fitness on different host species. Specialists are less subject to inter-phenotypic competition than generalists and to harmful mutations that are common in generalists exploiting multiple hosts. When host signals used as cues by exploiters coevolve with exploiter recognition systems, our studies show that evolutionary changes may be continuous and cyclic. Selection changes back and forth between specialization and generalization in the exploiters, and weak and strong mimicry in the hosts, where non-defended hosts use the host investing in defence as a model. Thus, host signals and exploiter responses are engaged in a red-queen mimicry process that is ultimately cyclic rather then directional. In one phase, evolving signals of exploitable hosts mimic those of hosts less suitable for exploitation (i.e. the model). Signals in the model hosts also evolve through selection to escape the mimic and its exploiters. Response saturation constraints in the model hosts lead to the mimic hosts finally perfecting its mimicry, after which specialization in the exploiter guild is lost. This loss of exploiter specialization provides an opportunity for the model hosts to escape their mimics. Therefore, this cycle then repeats. We suggest that a species can readily evolve sympatrically when disruptive selection for specialization on hosts is the first step. In a sexual reproduction setting, partial reproductive isolation may first evolve by mate choice being confined to individuals on the same host. Secondly, this disruptive selection will favour assortative mate choice on genotype, thereby leading to increased reproductive isolation.

Genetic effects on mating success and partner choice in a social mammal

PubMed Central

Tung, Jenny; Charpentier, Marie JE; Mukherjee, Sayan; Altmann, Jeanne; Alberts, Susan C

2012-01-01

Mating behavior has profound consequences for two phenomena – individual reproductive success and the maintenance of species boundaries – that contribute to evolutionary processes. Studies of mating behavior in relation to individual reproductive success are common in many species, but studies of mating behavior in relation to genetic variation and species boundaries are less commonly conducted in socially complex species. Here, we leveraged extensive observations of a wild yellow baboon (Papio cynocephalus) population that has experienced recent gene flow from a close sister taxon, the anubis baboon (Papio anubis), to examine how admixture-related genetic background affects mating behavior. We identified novel effects of genetic background on mating patterns, including an advantage accruing to anubis-like males and assortative mating among both yellow-like and anubis-like pairs. These genetic effects acted alongside social dominance rank, inbreeding avoidance, and age to produce highly nonrandom mating patterns. Our results suggest that this population may be undergoing admixture-related evolutionary change, driven in part by nonrandom mating. However, the strength of the genetic effects is mediated by behavioral plasticity and social interactions, emphasizing the strong influence of social context on mating behavior in socially complex species. PMID:22673655

Beauty and Intelligence May--or May Not--Be Related

ERIC Educational Resources Information Center

Denny, Kevin

2008-01-01

In a recent paper, [Kanazawa S. & Kovar J.L. (2004). Why beautiful people are more intelligent, "Intelligence," 32, 227-243] assert that given certain empirical regularities about assortative mating and the heritability of intelligence and beauty, that it logically follows that more intelligent people are more beautiful. It is argued here that…

A combination of sexual and ecological divergence contributes to the spread of a chromosomal rearrangement during initial stages of speciation

USDA-ARS?s Scientific Manuscript database

Chromosomal rearrangements between sympatric species often contain multiple loci contributing to assortative mating, local adaptation, and hybrid sterility. When and how these associations arise during the process of speciation remains a subject of debate. Here, we address the relative roles of loca...

The role of height in the sex difference in intelligence.

PubMed

Kanazawa, Satoshi; Reyniers, Diane J

2009-01-01

Recent studies conclude that men on average have higher intelligence than women by 3-5 IQ points. However, the ultimate evolutionary question of why men should have evolved to have higher intelligence than women remains. We suggest that men may have slightly higher intelligence than women through 4 mechanisms: (1) assortative mating of intelligent men and beautiful women, (2) assortative mating of tall men and beautiful women, (3) an extrinsic correlation between height and intelligence produced by Mechanisms 1 and 2, and (4) a higher-than-expected offspring sex ratio (more sons) among tall (and hence intelligent) parents. Consistent with our suggestion, we show that men may have higher IQs than women because they are taller, and once we control for height women have slightly higher IQs than men.The correlation between height and IQ and the female advantage in intelligence persist even after we control for health as a measure of genetic quality, as well as physical attractiveness, age, race, education, and earnings. Height is also strongly associated with intelligence within each sex.

Alternative reproductive tactics and inverse size-assortment in a high-density fish spawning aggregation.

PubMed

Karkarey, Rucha; Zambre, Amod; Isvaran, Kavita; Arthur, Rohan

2017-02-28

At high densities, terrestrial and marine species often employ alternate reproductive tactics (ARTs) to maximize reproductive benefits. We describe ARTs in a high-density and unfished spawning aggregation of the squaretail grouper (Plectropomus areolatus) in Lakshadweep, India. As previously reported for this species, territorial males engage in pair-courtship, which is associated with a pair-spawning tactic. Here, we document a previously unreported school-courtship tactic; where territorial males court multiple females in mid-water schools, which appears to culminate in a unique 'school-spawning' tactic. Courtship tactics were conditional on body size, local mate density and habitat, likely associated with changing trade-offs between potential mating opportunities and intra-sexual competition. Counter-intuitively, the aggregation showed a habitat-specific inverse size-assortment: large males courted small females on the reef slope while small males courted equal-sized or larger females on the shelf. These patterns remained stable across two years of observation at high, unfished densities. These unique density-dependent behaviours may disappear from this aggregation as overall densities decline due to increasing commercial fishing pressure, with potentially large consequences for demographics and fitness.

Monogamy in the maternally mouthbrooding Lake Tanganyika cichlid fish Tropheus moorii

PubMed Central

Egger, Bernd; Obermüller, Beate; Phiri, Harris; Sturmbauer, Christian; Sefc, Kristina M

2006-01-01

Supported by evidence for assortative mating and polygynandry, sexual selection through mate choice was suggested as the main force driving the evolution of colour diversity of haplochromine cichlids in Lakes Malawi and Victoria. The phylogenetically closely related tribe Tropheini of Lake Tanganyika includes the genus Tropheus, which comprises over 100 colour variants currently classified into six morphologically similar, polyphyletic species. To assess the potential for sexual selection in this sexually monochromatic maternal mouthbrooder, we used microsatellite-based paternity inference to investigate the mating system of Tropheus moorii. In contrast to haplochromines in Lake Malawi, multiple paternity is rare or even absent in broods of T. moorii. Eighteen of the 19 analysed families were consistent with genetic monogamy, while either a mutation or more than one sire explained the genotype of one offspring in another brood. We discuss the differences in breeding behaviour between T. moorii and the Lake Malawi haplochromines, and evaluate additional factors or alternatives to sexual selection as promoters of colour diversification. A preliminary survey of other Tropheini species suggested that multiple paternity is infrequent in the entire tribe. PMID:16790413

Sexual isolation and mating propensity among allopatric Drosophila mettleri populations.

PubMed

Castrezana, Sergio J; Markow, Therese Ann

2008-07-01

Drosophila mettleri is found in deserts of North America breeding in soil soaked by the juices of necrotic cacti. Saguaro (Carnegiea gigantea) and cardón (Pachycereus pringlei) are the usual host cacti in Mexico and Arizona, while prickly pear (Opuntia spp.) is used by an isolated population on Santa Catalina Island off the southern California Coast. Populations of D. mettleri show significant local genetic differentiation, especially when geographical isolation is coupled with host shifts. We tested for evidence of sexual isolation among allopatric populations of D. mettleri using a variety of choice and no-choice tests. Populations exhibited significant differences in mating propensity, which translated into significant deviations from random mating. While in some cases these deviations were consistent with sexual isolation, in others, negative assortative mating was observed. No relationship between degree of genetic differentiation and the appearance of sexual isolation was detected.

Five Decades of Educational Assortative Mating in 10 East Asian Societies

ERIC Educational Resources Information Center

Smits, Jeroen; Park, Hyunjoon

2009-01-01

We study trends in educational homogamy at six boundaries in the educational structure of 10 East-Asian societies and explain its variation using explanatory variables at the country, cohort and boundary level. Educational homogamy was higher at the higher boundaries in the educational structure. Since the 1950s it decreased at all but the lowest…

Risky Relationships? Assortative Mating and Women's Experiences of Intimate Partner Violence

ERIC Educational Resources Information Center

Carbone-Lopez, Kristin; Kruttschnitt, Candace

2010-01-01

Research indicates that female offenders are far more likely to have experienced intimate partner violence than women in the general population. Despite extensive research on women's pathways into offending, very little is known about why these women are at increased risk for partner violence. The authors use data from a sample of incarcerated…

Individual differences in boldness influence patterns of social interactions and the transmission of cuticular bacteria among group-mates

PubMed Central

Keiser, Carl N.; Pinter-Wollman, Noa; Augustine, David A.; Ziemba, Michael J.; Hao, Lingran; Lawrence, Jeffrey G.; Pruitt, Jonathan N.

2016-01-01

Despite the importance of host attributes for the likelihood of associated microbial transmission, individual variation is seldom considered in studies of wildlife disease. Here, we test the influence of host phenotypes on social network structure and the likelihood of cuticular bacterial transmission from exposed individuals to susceptible group-mates using female social spiders (Stegodyphus dumicola). Based on the interactions of resting individuals of known behavioural types, we assessed whether individuals assorted according to their behavioural traits. We found that individuals preferentially interacted with individuals of unlike behavioural phenotypes. We next applied a green fluorescent protein-transformed cuticular bacterium, Pantoea sp., to individuals and allowed them to interact with an unexposed colony-mate for 24 h. We found evidence for transmission of bacteria in 55% of cases. The likelihood of transmission was influenced jointly by the behavioural phenotypes of both the exposed and susceptible individuals: transmission was more likely when exposed spiders exhibited higher ‘boldness’ relative to their colony-mate, and when unexposed individuals were in better body condition. Indirect transmission via shared silk took place in only 15% of cases. Thus, bodily contact appears key to transmission in this system. These data represent a fundamental step towards understanding how individual traits influence larger-scale social and epidemiological dynamics. PMID:27097926

Individual differences in boldness influence patterns of social interactions and the transmission of cuticular bacteria among group-mates.

PubMed

Keiser, Carl N; Pinter-Wollman, Noa; Augustine, David A; Ziemba, Michael J; Hao, Lingran; Lawrence, Jeffrey G; Pruitt, Jonathan N

2016-04-27

Despite the importance of host attributes for the likelihood of associated microbial transmission, individual variation is seldom considered in studies of wildlife disease. Here, we test the influence of host phenotypes on social network structure and the likelihood of cuticular bacterial transmission from exposed individuals to susceptible group-mates using female social spiders (Stegodyphus dumicola). Based on the interactions of resting individuals of known behavioural types, we assessed whether individuals assorted according to their behavioural traits. We found that individuals preferentially interacted with individuals of unlike behavioural phenotypes. We next applied a green fluorescent protein-transformed cuticular bacterium,Pantoeasp., to individuals and allowed them to interact with an unexposed colony-mate for 24 h. We found evidence for transmission of bacteria in 55% of cases. The likelihood of transmission was influenced jointly by the behavioural phenotypes of both the exposed and susceptible individuals: transmission was more likely when exposed spiders exhibited higher 'boldness' relative to their colony-mate, and when unexposed individuals were in better body condition. Indirect transmission via shared silk took place in only 15% of cases. Thus, bodily contact appears key to transmission in this system. These data represent a fundamental step towards understanding how individual traits influence larger-scale social and epidemiological dynamics. © 2016 The Author(s).

Genetic determination of height-mediated mate choice.

PubMed

Tenesa, Albert; Rawlik, Konrad; Navarro, Pau; Canela-Xandri, Oriol

2016-01-19

Numerous studies have reported positive correlations among couples for height. This suggests that humans find individuals of similar height attractive. However, the answer to whether the choice of a mate with a similar phenotype is genetically or environmentally determined has been elusive. Here we provide an estimate of the genetic contribution to height choice in mates in 13,068 genotyped couples. Using a mixed linear model we show that 4.1% of the variation in the mate height choice is determined by a person's own genotype, as expected in a model where one's height determines the choice of mate height. Furthermore, the genotype of an individual predicts their partners' height in an independent dataset of 15,437 individuals with 13% accuracy, which is 64% of the theoretical maximum achievable with a heritability of 0.041. Theoretical predictions suggest that approximately 5% of the heritability of height is due to the positive covariance between allelic effects at different loci, which is caused by assortative mating. Hence, the coupling of alleles with similar effects could substantially contribute to the missing heritability of height. These estimates provide new insight into the mechanisms that govern mate choice in humans and warrant the search for the genetic causes of choice of mate height. They have important methodological implications and contribute to the missing heritability debate.

Comparison of sexual compatibility in crosses between the southern and northern populations of the cabbage beetle Colaphellus bowringi.

PubMed

Liu, Xing-Ping; Tu, Xiao-Yun; He, Hai-Min; Chen, Chao; Xue, Fang-Sen

2014-12-01

It is widely accepted that the genetic divergence and reproductive incompatibility between closely related species and/or populations is often viewed as an important step toward speciation. In this study, sexual compatibility in crosses between the southern XS population and the northern TA population of the polyandrous cabbage beetle Colaphellus bowringi was investigated by testing their mating preferences, mating latency, copulation duration, and reproductive performances of post-mating. In choice mating experiments, the percentages of matings were significantly higher in intra-population crosses than in inter-population crosses. Both isolation index (I) and index of pair sexual isolation (IPSI ) indicated partial mating incompatibility or assortative mating in crosses between the two different geographical populations. In single pair mating experiments, XS females in inter-population crosses mated significantly later and copulated significantly shorter than those in intra-population crosses. However, TA females in inter-population crosses mated significantly earlier and copulated longer than those in intra-population crosses, suggesting that larger XS males may enhance heterotypic mating. The lifetime fecundity was highest in XS homotypic matings, lowest in TA homotypic matings, and intermediate in heterotypic matings between their parents. The inter-population crosses resulted in significantly lower egg hatching rate and shorter female longevity than intra-population crosses. These results demonstrated that there exist some incompatibilities in premating, postmating-prezygotic, and postzygotic stages between the southern XS population and northern TA population of the cabbage beetle Colaphellus bowringi. © 2013 Institute of Zoology, Chinese Academy of Sciences.

Monte Carlo simulations of parapatric speciation

NASA Astrophysics Data System (ADS)

Schwämmle, V.; Sousa, A. O.; de Oliveira, S. M.

2006-06-01

Parapatric speciation is studied using an individual-based model with sexual reproduction. We combine the theory of mutation accumulation for biological ageing with an environmental selection pressure that varies according to the individuals geographical positions and phenotypic traits. Fluctuations and genetic diversity of large populations are crucial ingredients to model the features of evolutionary branching and are intrinsic properties of the model. Its implementation on a spatial lattice gives interesting insights into the population dynamics of speciation on a geographical landscape and the disruptive selection that leads to the divergence of phenotypes. Our results suggest that assortative mating is not an obligatory ingredient to obtain speciation in large populations at low gene flow.

Heritability and Fitness Correlates of Personality in the Ache, a Natural-Fertility Population in Paraguay

PubMed Central

Bailey, Drew H.; Walker, Robert S.; Blomquist, Gregory E.; Hill, Kim R.; Hurtado, A. Magdalena; Geary, David C.

2013-01-01

The current study assessed the heritability of personality in a traditional natural-fertility population, the Ache of eastern Paraguay. Self-reports (n = 110) and other-reports (n = 66) on the commonly used Big Five Personality Inventory (i.e., extraversion, agreeableness, conscientiousness, neuroticism, openness) were collected. Self-reports did not support the Five Factor Model developed with Western samples, and did not correlate with other-reports for three of the five measured personality factors. Heritability was assessed using factors that were consistent across self- and other-reports and factors assessed using other-reports that showed reliabilities similar to those found in Western samples. Analyses of these items in combination with a multi-generation pedigree (n = 2,132) revealed heritability estimates similar to those found in most Western samples, although we were not able to separately estimate the influence of the common environment on these traits. We also assessed relations between personality and reproductive success (RS), allowing for a test of several mechanisms that might be maintaining heritable variation in personality. Phenotypic analyses, based largely on other-reports, revealed that extraverted men had higher RS than other men, but no other dimensions of personality predicted RS in either sex. Mothers with more agreeable children had more children, and parents mated assortatively on personality. Of the evolutionary processes proposed to maintain variation in personality, assortative mating, selective neutrality, and temporal variation in selection pressures received the most support. However, the current study does not rule out other processes affecting the evolution and maintenance of individual differences in human personality. PMID:23527163

Female Drosophila melanogaster gene expression and mate choice: the X chromosome harbours candidate genes underlying sexual isolation.

PubMed

Bailey, Richard I; Innocenti, Paolo; Morrow, Edward H; Friberg, Urban; Qvarnström, Anna

2011-02-28

The evolution of female choice mechanisms favouring males of their own kind is considered a crucial step during the early stages of speciation. However, although the genomics of mate choice may influence both the likelihood and speed of speciation, the identity and location of genes underlying assortative mating remain largely unknown. We used mate choice experiments and gene expression analysis of female Drosophila melanogaster to examine three key components influencing speciation. We show that the 1,498 genes in Zimbabwean female D. melanogaster whose expression levels differ when mating with more (Zimbabwean) versus less (Cosmopolitan strain) preferred males include many with high expression in the central nervous system and ovaries, are disproportionately X-linked and form a number of clusters with low recombination distance. Significant involvement of the brain and ovaries is consistent with the action of a combination of pre- and postcopulatory female choice mechanisms, while sex linkage and clustering of genes lead to high potential evolutionary rate and sheltering against the homogenizing effects of gene exchange between populations. Taken together our results imply favourable genomic conditions for the evolution of reproductive isolation through mate choice in Zimbabwean D. melanogaster and suggest that mate choice may, in general, act as an even more important engine of speciation than previously realized.

Parallel evolution of sexual isolation in sticklebacks.

PubMed

Boughman, Janette Wenrick; Rundle, Howard D; Schluter, Dolph

2005-02-01

Mechanisms of speciation are not well understood, despite decades of study. Recent work has focused on how natural and sexual selection cause sexual isolation. Here, we investigate the roles of divergent natural and sexual selection in the evolution of sexual isolation between sympatric species of threespine sticklebacks. We test the importance of morphological and behavioral traits in conferring sexual isolation and examine to what extent these traits have diverged in parallel between multiple, independently evolved species pairs. We use the patterns of evolution in ecological and mating traits to infer the likely nature of selection on sexual isolation. Strong parallel evolution implicates ecologically based divergent natural and/or sexual selection, whereas arbitrary directionality implicates nonecological sexual selection or drift. In multiple pairs we find that sexual isolation arises in the same way: assortative mating on body size and asymmetric isolation due to male nuptial color. Body size and color have diverged in a strongly parallel manner, similar to ecological traits. The data implicate ecologically based divergent natural and sexual selection as engines of speciation in this group.

Models of Cultural Niche Construction with Selection and Assortative Mating

PubMed Central

Feldman, Marcus W.

2012-01-01

Niche construction is a process through which organisms modify their environment and, as a result, alter the selection pressures on themselves and other species. In cultural niche construction, one or more cultural traits can influence the evolution of other cultural or biological traits by affecting the social environment in which the latter traits may evolve. Cultural niche construction may include either gene-culture or culture-culture interactions. Here we develop a model of this process and suggest some applications of this model. We examine the interactions between cultural transmission, selection, and assorting, paying particular attention to the complexities that arise when selection and assorting are both present, in which case stable polymorphisms of all cultural phenotypes are possible. We compare our model to a recent model for the joint evolution of religion and fertility and discuss other potential applications of cultural niche construction theory, including the evolution and maintenance of large-scale human conflict and the relationship between sex ratio bias and marriage customs. The evolutionary framework we introduce begins to address complexities that arise in the quantitative analysis of multiple interacting cultural traits. PMID:22905167

Genetic compatibility, mate choice and patterns of parentage: invited review.

PubMed

Tregenza, T; Wedell, N

2000-08-01

There is growing interest in the possibility that genetic compatibility may drive mate choice, including gamete choice, particularly from the perspective of understanding why females frequently mate with more than one male. Mate choice for compatibility differs from other forms of choice for genetic benefits (such as 'good genes') because individuals are expected to differ in their mate preferences, changing the evolutionary dynamics of sexual selection. Recent experiments designed to investigate genetic benefits of polyandry suggest that mate choice on the basis of genetic compatibility may be widespread. However, in most systems the mechanisms responsible for variation in compatibility are unknown. We review potential sources of variation in genetic compatibility and whether there is any evidence for mate choice driven by these factors. Selfish genetic elements appear to have the potential to drive mate compatibility mate choice, though as yet there is only one convincing example. There is abundant evidence for assortative mating between populations in hybrid zones, but very few examples where this is clearly a result of selection against mating with genetically less compatible individuals. There are also numerous cases of inbreeding avoidance, but little evidence that mate choice or differential fertilization success driven by genetic compatibility occurs between unrelated individuals. The exceptions to this are a handful of situations where both the alleles causing incompatibility and the alleles involved in mate choice are located in a chromosome region where recombination is suppressed. As yet there are only a few potential sources of genetic compatibility which have clearly been shown to drive mate choice. This may reflect limitations in the potential for the evolution of mate choice for genetic compatibility within populations, although the most promising sources of such incompatibilities have received relatively little research.

Are Human Mating Preferences with Respect to Height Reflected in Actual Pairings?

PubMed Central

Stulp, Gert; Buunk, Abraham P.; Pollet, Thomas V.; Nettle, Daniel; Verhulst, Simon

2013-01-01

Pair formation, acquiring a mate to form a reproductive unit, is a complex process. Mating preferences are a step in this process. However, due to constraining factors such as availability of mates, rival competition, and mutual mate choice, preferred characteristics may not be realised in the actual partner. People value height in their partner and we investigated to what extent preferences for height are realised in actual couples. We used data from the Millennium Cohort Study (UK) and compared the distribution of height difference in actual couples to simulations of random mating to test how established mate preferences map on to actual mating patterns. In line with mate preferences, we found evidence for: (i) assortative mating (r = .18), (ii) the male-taller norm, and, for the first time, (iii) for the male-not-too-tall norm. Couples where the male partner was shorter, or over 25 cm taller than the female partner, occurred at lower frequency in actual couples than expected by chance, but the magnitude of these effects was modest. We also investigated another preference rule, namely that short women (and tall men) prefer large height differences with their partner, whereas tall women (and short men) prefer small height differences. These patterns were also observed in our population, although the strengths of these associations were weaker than previously reported strength of preferences. We conclude that while preferences for partner height generally translate into actual pairing, they do so only modestly. PMID:23342102

Are human mating preferences with respect to height reflected in actual pairings?

PubMed

Stulp, Gert; Buunk, Abraham P; Pollet, Thomas V; Nettle, Daniel; Verhulst, Simon

2013-01-01

Pair formation, acquiring a mate to form a reproductive unit, is a complex process. Mating preferences are a step in this process. However, due to constraining factors such as availability of mates, rival competition, and mutual mate choice, preferred characteristics may not be realised in the actual partner. People value height in their partner and we investigated to what extent preferences for height are realised in actual couples. We used data from the Millennium Cohort Study (UK) and compared the distribution of height difference in actual couples to simulations of random mating to test how established mate preferences map on to actual mating patterns. In line with mate preferences, we found evidence for: (i) assortative mating (r = .18), (ii) the male-taller norm, and, for the first time, (iii) for the male-not-too-tall norm. Couples where the male partner was shorter, or over 25 cm taller than the female partner, occurred at lower frequency in actual couples than expected by chance, but the magnitude of these effects was modest. We also investigated another preference rule, namely that short women (and tall men) prefer large height differences with their partner, whereas tall women (and short men) prefer small height differences. These patterns were also observed in our population, although the strengths of these associations were weaker than previously reported strength of preferences. We conclude that while preferences for partner height generally translate into actual pairing, they do so only modestly.

Non-random pairing in American kestrels: mate choice versus intra-sexual competition

USGS Publications Warehouse

Bortolotti, Gary R.; Iko, William M.

1992-01-01

Natural selection may influence the arrangement of individuals into mated pairs through either inter-sexual (mate choice) or intra-sexual selection (competition). A study of the American kestrel, Falco sparverius, in northern Saskatchewan distinguished between these two processes using size as a measure of the bird's competitive ability, and condition (mass scaled to body size) as an index of quality. Both sexes arrive on the study area after spring migration in equal numbers and males establish territories. Males and females that moved among territories at the time of pair formation were not different in size or condition from those that did not move, suggesting that birds were not being displaced by superior competitors, and that females moved to encounter potential mates. Within mated pairs, there was no relationship between a bird's size and the condition of its mate for either sex as would be predicted if intra-sexual competitition explained mating patterns. Instead, there was positive assortative mating by condition, suggesting that both sexes used quality as the criterion in choosing mates. There was no correlation between the sizes of males and females in mated paird. Because there were no differences in size or condition of breeding and non-breeding males, factors other than physical attributes, such as prior experience with the area, may determine a male's success in obtaining a territory. Because females that did not obtain mates were in poorer condition than those that did, males may have rejected poor quality females. The results suggest that intra-sexual competition was not important for pair formation, and that kestrels chose mates on the basis of quality.

Mate preference in wild and domesticated (game-farm) mallards: II. Pairing success

USGS Publications Warehouse

Cheng, K.M.; Shoffner, R.N.; Phillips, R.E.; Lee, F.B.

1979-01-01

Experiments were designed to determine whether assortative mating occurs in wild and game-farm mallard strains (Anas platyrhynchos). Mallard males of either strain raised with females of their own strain courted females of their own strain more than females of the opposite strain, and these males were only successful in pairing with females of their own strain. Males raised with females of the opposite strain courted wild and game-farm females with equal intensity. They were successful in pairing with females of either strain. While this study does not settle the question of possible gene flow between these two mallard populations, it does indicate that there is a potential barrier to panmixia.

Intense Sperm-Mediated Sexual Conflict Promotes Reproductive Isolation in Caenorhabditis Nematodes

PubMed Central

Leung, Gemma; Shin, Na-Ra; Cutter, Asher D.; Haag, Eric S.

2014-01-01

Conflict between the sexes over reproductive interests can drive rapid evolution of reproductive traits and promote speciation. Here we show that inter-species mating between Caenorhabditis nematodes sterilizes maternal individuals. The principal effectors of male-induced harm are sperm cells, which induce sterility and shorten lifespan by displacing conspecific sperm, invading the ovary, and sometimes breaching the gonad to infiltrate other tissues. This sperm-mediated harm is pervasive across species, but idiosyncrasies in its magnitude implicate both independent histories of sexually antagonistic coevolution within species and differences in reproductive mode (self-fertilizing hermaphrodites versus females) in determining its severity. Consistent with this conclusion, in androdioecious species the hermaphrodites are more vulnerable, the males more benign, or both. Patterns of assortative mating and a low incidence of invasive sperm occurring with conspecific mating are indicative of ongoing intra-specific sexual conflict that results in inter-species reproductive incompatibility. PMID:25072732

The Co-Occurrence of Autism Spectrum Disorder and Attention-Deficit/Hyperactivity Disorder Symptoms in Parents of Children with ASD or ASD with ADHD

ERIC Educational Resources Information Center

van Steijn, Daphne J.; Richards, Jennifer S.; Oerlemans, Anoek M.; de Ruiter, Saskia W.; van Aken, Marcel A. G.; Franke, Barbara; Buitelaar, Jan. K.; Rommelse, Nanda N. J.

2012-01-01

Background: Autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) share about 50-72% of their genetic factors, which is the most likely explanation for their frequent co-occurrence within the same patient or family. An additional or alternative explanation for the co-occurrence may be (cross-)assortative mating, e.g.,…

Recurrence of reported CDH23 mutations causing DFNB12 in a special cohort of South Indian hearing impaired assortative mating families - an evaluation.

PubMed

Vanniya S, Paridhy; Chandru, Jayasankaran; Pavithra, Amritkumar; Jeffrey, Justin Margret; Kalaimathi, Murugesan; Ramakrishnan, Rajagopalan; Karthikeyen, Natarajan P; C R Srikumari, Srisailapathy

2018-03-01

Mutations in CDH23 are known to cause autosomal-recessive nonsyndromic hearing loss (DFNB12). Until now, there was only one study describing its frequency in Indian population. We screened for CDH23 mutations to identify prevalent and recurring mutations among South Indian assortative mating hearing-impaired individuals who were identified as non-DFNB1 (GJB2 and GJB6). Whole-exome sequencing was performed in individuals found to be heterozygous for CDH23 to determine whether there was a second pathogenic allele. In our study, 19 variants including 6 pathogenic missense mutations were identified. The allelic frequency of pathogenic mutations accounts to 4.7% in our cohort, which is higher than that reported previously; three mutations (c.429+4G>A, c.2968G>A, and c.5660C>T) reported in the previous Indian study were found to recur. DFNB12 was found to be the etiology in 3.4% of our cohort, with missense mutation c.2968G>A (p.Asp990Asn) being the most prevalent (2.6%). These results suggest a need to investigate the possibility for higher proportion of CDH23 mutations in the South Indian hearing-impaired population. © 2017 John Wiley & Sons Ltd/University College London.

International migration and educational assortative mating in Mexico and the United States.

PubMed

Choi, Kate H; Mare, Robert D

2012-05-01

This paper examines the relationship between migration and marriage by describing how the distributions of marital statuses and assortative mating patterns vary by individual and community experiences of migration. In Mexico, migrants and those living in areas with high levels of out-migration are more likely to be in heterogamous unions. This is because migration increases the relative attractiveness of single return migrants while disproportionately reducing the number of marriageable men in local marriage markets. In the United States, the odds of homogamy are lower for migrants compared with nonmigrants; however, they do not vary depending on the volume of migration in communities. Migrants are more likely than nonmigrants to "marry up" educationally because the relatively small size of this group compels them to expand their pool of potential spouses to include nonmigrants, who tend to be better educated than they are. Among migrants, the odds of marrying outside of one's education group increase the most among the least educated. In Mexican communities with high rates of out-migration, the odds of marrying outside of one's education group are highest among those with the highest level of education. These findings suggest that migration disrupts preferences and opportunities for homogamy by changing social arrangements and normative climates.

International Migration and Educational Assortative Mating in Mexico and the United States

PubMed Central

Mare, Robert D.

2014-01-01

This paper examines the relationship between migration and marriage by describing how the distributions of marital statuses and assortative mating patterns vary by individual and community experiences of migration. In Mexico, migrants and those living in areas with high levels of out-migration are more likely to be in heterogamous unions. This is because migration increases the relative attractiveness of single return migrants while disproportionately reducing the number of marriageable men in local marriage markets. In the United States, the odds of homogamy are lower for migrants compared with nonmigrants; however, they do not vary depending on the volume of migration in communities. Migrants are more likely than nonmigrants to “marry up” educationally because the relatively small size of this group compels them to expand their pool of potential spouses to include nonmigrants, who tend to be better educated than they are. Among migrants, the odds of marrying outside of one’s education group increase the most among the least educated. In Mexican communities with high rates of out-migration, the odds of marrying outside of one’s education group are highest among those with the highest level of education. These findings suggest that migration disrupts preferences and opportunities for homogamy by changing social arrangements and normative climates. PMID:22419447

Reproductive isolation and local adaptation quantified for a chromosome inversion in a malaria mosquito.

PubMed

Ayala, Diego; Guerrero, Rafael F; Kirkpatrick, Mark

2013-04-01

Chromosome inversions have long been thought to be involved in speciation and local adaptation. We have little quantitative information, however, about the effects that inversion polymorphisms have on reproductive isolation and viability. Here we provide the first estimates from any organism for the total amount of reproductive isolation associated with an inversion segregating in natural populations. We sampled chromosomes from 751 mosquitoes of the malaria vector Anopheles funestus along a 1421 km transect in Cameroon that traverses savannah, highland, and rainforest ecological zones. We then developed a series of population genetic models that account for selection, migration, and assortative mating, and fit the models to the data using likelihood. Results from the best-fit models suggest there is strong local adaptation, with relative viabilities of homozygotes ranging from 25% to 130% compared to heterozygotes. Viabilities vary qualitatively between regions: the inversion is underdominant in the savannah, whereas in the highlands it is overdominant. The inversion is also implicated in strong assortative mating. In the savannah, the two homozygote forms show 92% reproductive isolation, suggesting that this one inversion can generate most of the genetic barriers needed for speciation. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

The hawk-dove game in a sexually reproducing species explains a colourful polymorphism of an endangered bird.

PubMed

Kokko, Hanna; Griffith, Simon C; Pryke, Sarah R

2014-10-22

The hawk-dove game famously introduced strategic game theory thinking into biology and forms the basis of arguments for limited aggression in animal populations. However, aggressive 'hawks' and peaceful 'doves', with strategies inherited in a discrete manner, have never been documented in a real animal population. Thus, the applicability of game-theoretic arguments to real populations might be contested. Here, we show that the head-colour polymorphism of red and black Gouldian finches (Erythrura gouldiae) provides a real-life example. The aggressive red morph is behaviourally dominant and successfully invades black populations, but when red 'hawks' become too common, their fitness is severely compromised (via decreased parental ability). We also investigate the effects of real-life deviations, particularly sexual reproduction, from the simple original game, which assumed asexual reproduction. A protected polymorphism requires mate choice to be sufficiently assortative. Assortative mating is adaptive for individuals because of genetic incompatibilities affecting hybrid offspring fitness, but by allowing red 'hawks' to persist, it also leads to significantly reduced population sizes. Because reductions in male contributions to parental care are generally known to lead to lower population productivity in birds, we expect zero-sum competition to often have wide ranging population consequences. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Size‐assortative choice and mate availability influences hybridization between red wolves (Canis rufus) and coyotes (Canis latrans)

USGS Publications Warehouse

Hinton, Joseph W.; Gittleman, John L.; van Manen, Frank T.; Chamberlain, Michael J.

2018-01-01

Anthropogenic hybridization of historically isolated taxa has become a primary conservation challenge for many imperiled species. Indeed, hybridization between red wolves (Canis rufus) and coyotes (Canis latrans) poses a significant challenge to red wolf recovery. We considered seven hypotheses to assess factors influencing hybridization between red wolves and coyotes via pair‐bonding between the two species. Because long‐term monogamy and defense of all‐purpose territories are core characteristics of both species, mate choice has long‐term consequences. Therefore, red wolves may choose similar‐sized mates to acquire partners that behave similarly to themselves in the use of space and diet. We observed multiple factors influencing breeding pair formation by red wolves and found that most wolves paired with similar‐sized conspecifics and wolves that formed congeneric pairs with nonwolves (coyotes and hybrids) were mostly female wolves, the smaller of the two sexes. Additionally, we observed that lower red wolf abundance relative to nonwolves and the absence of helpers increased the probability that wolves consorted with nonwolves. However, successful pairings between red wolves and nonwolves were associated with wolves that maintained small home ranges. Behaviors associated with territoriality are energetically demanding and behaviors (e.g., aggressive interactions, foraging, and space use) involved in maintaining territories are influenced by body size. Consequently, we propose the hypothesis that size disparities between consorting red wolves and coyotes influence positive assortative mating and may represent a reproductive barrier between the two species. We offer that it may be possible to maintain wild populations of red wolves in the presence of coyotes if management strategies increase red wolf abundance on the landscape by mitigating key threats, such as human‐caused mortality and hybridization with coyotes. Increasing red wolf abundance would likely restore selection pressures that increase mean body and home‐range sizes of red wolves and decrease hybridization rates via reduced occurrence of congeneric pairs.

Disruptive ecological selection on a mating cue.

PubMed

Merrill, Richard M; Wallbank, Richard W R; Bull, Vanessa; Salazar, Patricio C A; Mallet, James; Stevens, Martin; Jiggins, Chris D

2012-12-22

Adaptation to divergent ecological niches can result in speciation. Traits subject to disruptive selection that also contribute to non-random mating will facilitate speciation with gene flow. Such 'magic' or 'multiple-effect' traits may be widespread and important for generating biodiversity, but strong empirical evidence is still lacking. Although there is evidence that putative ecological traits are indeed involved in assortative mating, evidence that these same traits are under divergent selection is considerably weaker. Heliconius butterfly wing patterns are subject to positive frequency-dependent selection by predators, owing to aposematism and Müllerian mimicry, and divergent colour patterns are used by closely related species to recognize potential mates. The amenability of colour patterns to experimental manipulation, independent of other traits, presents an excellent opportunity to test their role during speciation. We conducted field experiments with artificial butterflies, designed to match natural butterflies with respect to avian vision. These were complemented with enclosure trials with live birds and real butterflies. Our experiments showed that hybrid colour-pattern phenotypes are attacked more frequently than parental forms. For the first time, we demonstrate disruptive ecological selection on a trait that also acts as a mating cue.

Incipient sympatric speciation in Midas cichlid fish from the youngest and one of the smallest crater lakes in Nicaragua due to differential use of the benthic and limnetic habitats?

PubMed

Kautt, Andreas F; Machado-Schiaffino, Gonzalo; Torres-Dowdall, Julian; Meyer, Axel

2016-08-01

Understanding how speciation can occur without geographic isolation remains a central objective in evolutionary biology. Generally, some form of disruptive selection and assortative mating are necessary for sympatric speciation to occur. Disruptive selection can arise from intraspecific competition for resources. If this competition leads to the differential use of habitats and variation in relevant traits is genetically determined, then assortative mating can be an automatic consequence (i.e., habitat isolation). In this study, we caught Midas cichlid fish from the limnetic (middle of the lake) and benthic (shore) habitats of Crater Lake Asososca Managua to test whether some of the necessary conditions for sympatric speciation due to intraspecific competition and habitat isolation are given. Lake As. Managua is very small (<900 m in diameter), extremely young (maximally 1245 years of age), and completely isolated. It is inhabited by, probably, only a single endemic species of Midas cichlids, Amphilophus tolteca. We found that fish from the limnetic habitat were more elongated than fish collected from the benthic habitat, as would be predicted from ecomorphological considerations. Stable isotope analyses confirmed that the former also exhibit a more limnetic lifestyle than the latter. Furthermore, split-brood design experiments in the laboratory suggest that phenotypic plasticity is unlikely to explain much of the observed differences in body elongation that we observed in the field. Yet, neutral markers (microsatellites) did not reveal any genetic clustering in the population. Interestingly, demographic inferences based on RAD-seq data suggest that the apparent lack of genetic differentiation at neutral markers could simply be due to a lack of time, as intraspecific competition may only have begun a few hundred generations ago.

Preferential Mating in Symmetric Multilocus Systems: Limits for Multiallelism and for Many Loci

PubMed Central

Raper, J.

1982-01-01

Models in which general forms of preferential mating have been superimposed on the framework of the symmetric heterozygosity selection regime have been examined previously with respect to the existence and local stability of a central polymorphic equilibrium. The results are now extended to produce the limiting form of the stability conditions in two cases: First, where the number of alleles per locus is assumed to be very large; second, where the number of loci affecting the character is very large. It is argued that some type of frequency dependence in the mating pattern must be included, and a particular case is examined in detail. It is shown that multiallelism is ambiguous in its effect on stability, while an increasing number of loci, at least under zero linkage, leads to a simple stability condition which is analogous to the one-locus heterosis principle. Assortative mating appears to be more likely to produce a stable central polymorphism under high levels of allelism than is sexual selection, but is relatively very much weaker than sexual or viability selection if the number of loci involved is large. PMID:17246061

Clustering and phase transitions on a neutral landscape

NASA Astrophysics Data System (ADS)

Scott, Adam D.; King, Dawn M.; Marić, Nevena; Bahar, Sonya

2013-06-01

Recent computational studies have shown that speciation can occur under neutral conditions, i.e., when the simulated organisms all have identical fitness. These works bear comparison with mathematical studies of clustering on neutral landscapes in the context of branching and coalescing random walks. Here, we show that sympatric clustering/speciation can occur on a neutral landscape whose dimensions specify only the simulated organisms’ phenotypes. We demonstrate that clustering occurs not only in the case of assortative mating, but also in the case of asexual fission; it is not observed in the control case of random mating. We find that the population size and the number of clusters undergo a second-order non-equilibrium phase transition as the maximum mutation size is varied.

Meeting your match: how attractiveness similarity affects approach behavior in mixed-sex dyads.

PubMed

van Straaten, Ischa; Engels, Rutger C M E; Finkenauer, Catrin; Holland, Rob W

2009-06-01

This experimental study investigated approach behavior toward opposite-sex others of similar versus dissimilar physical attractiveness. Furthermore, it tested the moderating effects of sex. Single participants interacted with confederates of high and low attractiveness. Observers rated their behavior in terms of relational investment (i.e., behavioral efforts related to the improvement of interaction fluency, communication of positive interpersonal affect, and positive self-presentation). As expected, men displayed more relational investment behavior if their own physical attractiveness was similar to that of the confederate. For women, no effects of attractiveness similarity on relational investment behavior were found. Results are discussed in the light of positive assortative mating, preferences for physically attractive mates, and sex differences in attraction-related interpersonal behaviors.

Mate choice in the eye and ear of the beholder? Female multimodal sensory configuration influences her preferences.

PubMed

Ronald, Kelly L; Fernández-Juricic, Esteban; Lucas, Jeffrey R

2018-05-16

A common assumption in sexual selection studies is that receivers decode signal information similarly. However, receivers may vary in how they rank signallers if signal perception varies with an individual's sensory configuration. Furthermore, receivers may vary in their weighting of different elements of multimodal signals based on their sensory configuration. This could lead to complex levels of selection on signalling traits. We tested whether multimodal sensory configuration could affect preferences for multimodal signals. We used brown-headed cowbird ( Molothrus ater ) females to examine how auditory sensitivity and auditory filters, which influence auditory spectral and temporal resolution, affect song preferences, and how visual spatial resolution and visual temporal resolution, which influence resolution of a moving visual signal, affect visual display preferences. Our results show that multimodal sensory configuration significantly affects preferences for male displays: females with better auditory temporal resolution preferred songs that were shorter, with lower Wiener entropy, and higher frequency; and females with better visual temporal resolution preferred males with less intense visual displays. Our findings provide new insights into mate-choice decisions and receiver signal processing. Furthermore, our results challenge a long-standing assumption in animal communication which can affect how we address honest signalling, assortative mating and sensory drive. © 2018 The Author(s).

Educational Attainment Influences Levels of Homozygosity through Migration and Assortative Mating

PubMed Central

Abdellaoui, Abdel; Hottenga, Jouke-Jan; Willemsen, Gonneke; Bartels, Meike; van Beijsterveldt, Toos; Ehli, Erik A.; Davies, Gareth E.; Brooks, Andrew; Sullivan, Patrick F.; Penninx, Brenda W. J. H.; de Geus, Eco J.; Boomsma, Dorret I.

2015-01-01

Individuals with a higher education are more likely to migrate, increasing the chance of meeting a spouse with a different ancestral background. In this context, the presence of strong educational assortment can result in greater ancestry differences within more educated spouse pairs, while less educated individuals are more likely to mate with someone with whom they share more ancestry. We examined the association between educational attainment and F roh (= the proportion of the genome consisting of runs of homozygosity [ROHs]) in ~2,000 subjects of Dutch ancestry. The subjects’ own educational attainment showed a nominally significant negative association with F roh (p = .045), while the contribution of parental education to offspring F roh was highly significant (father: p < 10-5; mother: p = 9×10-5), with more educated parents having offspring with fewer ROHs. This association was significantly and fully mediated by the physical distance between parental birthplaces (paternal education: p mediation = 2.4 × 10-4; maternal education: p mediation = 2.3 × 10-4), which itself was also significantly associated with F roh (p = 9 × 10-5). Ancestry-informative principal components from the offspring showed a significantly decreasing association with geography as parental education increased, consistent with the significantly higher migration rates among more educated parents. Parental education also showed a high spouse correlation (Spearman’s ρ = .66, p = 3 × 10-262). We show that less educated parents are less likely to mate with the more mobile parents with a higher education, creating systematic differences in homozygosity due to ancestry differences not directly captured by ancestry-informative principal components (PCs). Understanding how behaviors influence the genomic structure of a population is highly valuable for studies on the genetic etiology of behavioral, cognitive, and social traits. PMID:25734509

Educational attainment influences levels of homozygosity through migration and assortative mating.

PubMed

Abdellaoui, Abdel; Hottenga, Jouke-Jan; Willemsen, Gonneke; Bartels, Meike; van Beijsterveldt, Toos; Ehli, Erik A; Davies, Gareth E; Brooks, Andrew; Sullivan, Patrick F; Penninx, Brenda W J H; de Geus, Eco J; Boomsma, Dorret I

2015-01-01

Individuals with a higher education are more likely to migrate, increasing the chance of meeting a spouse with a different ancestral background. In this context, the presence of strong educational assortment can result in greater ancestry differences within more educated spouse pairs, while less educated individuals are more likely to mate with someone with whom they share more ancestry. We examined the association between educational attainment and F roh (= the proportion of the genome consisting of runs of homozygosity [ROHs]) in ~2,000 subjects of Dutch ancestry. The subjects' own educational attainment showed a nominally significant negative association with F roh (p = .045), while the contribution of parental education to offspring F roh was highly significant (father: p < 10(-5); mother: p = 9 × 10(-5)), with more educated parents having offspring with fewer ROHs. This association was significantly and fully mediated by the physical distance between parental birthplaces (paternal education: pmediation = 2.4 × 10(-4); maternal education: pmediation = 2.3 × 10(-4)), which itself was also significantly associated with F roh (p = 9 × 10(-5)). Ancestry-informative principal components from the offspring showed a significantly decreasing association with geography as parental education increased, consistent with the significantly higher migration rates among more educated parents. Parental education also showed a high spouse correlation (Spearman's ρ = .66, p = 3 × 10(-262)). We show that less educated parents are less likely to mate with the more mobile parents with a higher education, creating systematic differences in homozygosity due to ancestry differences not directly captured by ancestry-informative principal components (PCs). Understanding how behaviors influence the genomic structure of a population is highly valuable for studies on the genetic etiology of behavioral, cognitive, and social traits.

Synergistic selection between ecological niche and mate preference primes diversification.

PubMed

Boughman, Janette W; Svanbäck, Richard

2017-01-01

The ecological niche and mate preferences have independently been shown to be important for the process of speciation. Here, we articulate a novel mechanism by which ecological niche use and mate preference can be linked to promote speciation. The degree to which individual niches are narrow and clustered affects the strength of divergent natural selection and population splitting. Similarly, the degree to which individual mate preferences are narrow and clustered affects the strength of divergent sexual selection and assortative mating between diverging forms. This novel perspective is inspired by the literature on ecological niches; it also explores mate preferences and how they may contribute to speciation. Unlike much comparative work, we do not search for evolutionary patterns using proxies for adaptation and sexual selection, but rather we elucidate how ideas from niche theory relate to mate preference, and how this relationship can foster speciation. Recognizing that individual and population niches are conceptually and ecologically linked to individual and population mate preference functions will significantly increase our understanding of rapid evolutionary diversification in nature. It has potential to help solve the difficult challenge of testing the role of sexual selection in the speciation process. We also identify ecological factors that are likely to affect individual niche and individual mate preference in synergistic ways and as a consequence to promote speciation. The ecological niche an individual occupies can directly affect its mate preference. Clusters of individuals with narrow, differentiated niches are likely to have narrow, differentiated mate preference functions. Our approach integrates ecological and sexual selection research to further our understanding of diversification processes. Such integration may be necessary for progress because these processes seem inextricably linked in the natural world. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

Equilibrium population dynamics when mating is by mutual choice based on age.

PubMed

Alpern, Steve; Katrantzi, Ioanna; Ramsey, David

2014-06-01

We consider a steady state model of mutual mate choice in which an individual's mate preferences depend on his/her age, and the preferences are over the ages of prospective mates of the opposite sex. We present a discrete time (and age) model corresponding to successive mating seasons. Males are fertile for m periods (corresponding to 'age' i=1 to m) and females for n≤m periods (they have ages j=1 to n), which is all that distinguishes the sexes. Although we can deal with arbitrary preferences, we concentrate on a simple fertility model where the common utility to a male age i and female age j who mate is the number K=min(m-i+1,n-j+1) of future periods of joint fertility. The incoming sex ratio R of age 1 males to age 1 females is given exogenously. In each period individuals are randomly (non assortatively) matched and form a mated couple by mutual consent; otherwise they go into the next period unmated and older. We derive properties of equilibrium threshold acceptance strategies and establish the existence of time-invariant age distributions. Our methods determine the age distribution of couples at marriage (mating) and the population sex ratio (OSR) at equilibrium. Since this can be determined empirically in a population, our model can be used to rule out most systems of age preferences (those not consistent with the observed distribution). This extends earlier models of mutual choice with one dimensional types of Alpern and Reyniers [1999. Strategic mating with homotypic preferences. J. Theor. Biol. 198, 71-88; 2005. Strategic mating with common preferences. J. Theor. Biol. 237, 337-354] where individuals sought, respectively, individuals with similar or high types, but in those models an individual's type was fixed over time. Under the simple fertility model, at equilibrium the maximum age of an acceptable partner is increasing in the age of the searcher. Our results relate to discussions in the literature regarding optimal parental age differences, age-related mate preferences, and to mate choice in general. We believe our model will be used as a tool in future investigations in these areas. Copyright © 2013 Elsevier Inc. All rights reserved.

Refining the conditions for sympatric ecological speciation.

PubMed

Débarre, F

2012-12-01

Can speciation occur in a single population when different types of resources are available, in the absence of any geographical isolation, or any spatial or temporal variation in selection? The controversial topics of sympatric speciation and ecological speciation have already stimulated many theoretical studies, most of them agreeing on the fact that mechanisms generating disruptive selection, some level of assortment, and enough heterogeneity in the available resources, are critical for sympatric speciation to occur. Few studies, however, have combined the three factors and investigated their interactions. In this article, I analytically derive conditions for sympatric speciation in a general model where the distribution of resources can be uni- or bimodal, and where a parameter controls the range of resources that an individual can exploit. This approach bridges the gap between models of a unimodal continuum of resources and Levene-type models with discrete resources. I then test these conditions against simulation results from a recently published article (Thibert-Plante & Hendry, 2011, J. Evol. Biol. 24: 2186-2196) and confirm that sympatric ecological speciation is favoured when (i) selection is disruptive (i.e. individuals with an intermediate trait are at a local fitness minimum), (ii) resources are differentiated enough and (iii) mating is assortative. I also discuss the role of mating preference functions and the need (or lack thereof) for bimodality in resource distributions for diversification. © 2012 The Author. Journal of Evolutionary Biology © 2012 European Society For Evolutionary Biology.

Mechanisms of rapid sympatric speciation by sex reversal and sexual selection in cichlid fish.

PubMed

Lande, R; Seehausen, O; van Alphen, J J

2001-01-01

Mechanisms of speciation in cichlid fish were investigated by analyzing population genetic models of sexual selection on sex-determining genes associated with color polymorphisms. The models are based on a combination of laboratory experiments and field observations on the ecology, male and female mating behavior, and inheritance of sex-determination and color polymorphisms. The models explain why sex-reversal genes that change males into females tend to be X-linked and associated with novel colors, using the hypothesis of restricted recombination on the sex chromosomes, as suggested by previous theory on the evolution of recombination. The models reveal multiple pathways for rapid sympatric speciation through the origin of novel color morphs with strong assortative mating that incorporate both sex-reversal and suppressor genes. Despite the lack of geographic isolation or ecological differentiation, the new species coexists with the ancestral species either temporarily or indefinitely. These results may help to explain different patterns and rates of speciation among groups of cichlids, in particular the explosive diversification of rock-dwelling haplochromine cichlids.

The Evolution of Homophily

NASA Astrophysics Data System (ADS)

Fu, Feng; Nowak, Martin A.; Christakis, Nicholas A.; Fowler, James H.

2012-11-01

Biologists have devoted much attention to assortative mating or homogamy, the tendency for sexual species to mate with similar others. In contrast, there has been little theoretical work on the broader phenomenon of homophily, the tendency for individuals to interact with similar others. Yet this behaviour is also widely observed in nature. Here, we model how natural selection can give rise to homophily when individuals engage in social interaction in a population with multiple observable phenotypes. Payoffs to interactions depend on whether or not individuals have the same or different phenotypes, and each individual has a preference that determines how likely they are to interact with others of their own phenotype (homophily) or of opposite phenotypes (heterophily). The results show that homophily tends to evolve under a wide variety of conditions, helping to explain its ubiquity in nature.

Expected utility violations evolve under status-based selection mechanisms.

PubMed

Dickson, Eric S

2008-10-07

The expected utility theory of decision making under uncertainty, a cornerstone of modern economics, assumes that humans linearly weight "utilities" for different possible outcomes by the probabilities with which these outcomes occur. Despite the theory's intuitive appeal, both from normative and from evolutionary perspectives, many experiments demonstrate systematic, though poorly understood, patterns of deviation from EU predictions. This paper offers a novel theoretical account of such patterns of deviation by demonstrating that EU violations can emerge from evolutionary selection when individual "status" affects inclusive fitness. In humans, battles for resources and social standing involve high-stakes decision making, and assortative mating ensures that status matters for fitness outcomes. The paper therefore proposes grounding the study of decision making under uncertainty in an evolutionary game-theoretic framework.

Reproductive isolation and the expansion of an invasive hybrid swarm

USGS Publications Warehouse

Blum, Michael J.; Walters, David M.; Burkhead, Noel M.; Freeman, Byron J.; Porter, Brady A.

2010-01-01

Biological invasions involving hybridization proceed according to prezygotic and postzygotic reproductive isolating mechanisms. Yet few comparisons of reproductive isolation have been carried out to understand how different mechanisms prevent or promote invasions involving hybridization. Here we present a study of prezygotic and postzygotic isolation between non-native red shiner (Cyprinella lutrensis) and native blacktail shiner (C. venusta stigmatura) from the Coosa River basin (USA) to better understand the formation and expansion of invasive hybrid swarms. We conducted spawning trials to measure mating preferences and raised broods from crosses to assay hybrid viability through early juvenile development. Females of both species were more responsive to conspecific mates, although blacktail shiner females responded more often to heterospecific mates than did red shiner females. Fecundity of red shiner females was also higher than blacktail shiner females. Heterospecific crosses resulted in lower fertilization and egg hatching rates, but we found no other evidence of inviability. Rather, we found comparatively low larval mortality of F1 hybrids, which is suggestive of heterosis. These findings support prior inferences of assortative mating from genetic descriptions of hybridization, and that the invasion in the Coosa River is likely proceeding due to interspecific competition and intrinsic hybrid viability.

Promiscuity in sand lizards (Lacerta agilis) and adder snakes (Vipera berus): causes and consequences.

PubMed

Olsson, M; Madsen, T

2001-01-01

We review postcopulatory phenomena in the Swedish sand lizard (Lacerta agilis) and adder (Vipera berus), and in particular, links between female promiscuity, determinants of paternity, and offspring viability. In both species, females mate multiply and exhibit a positive relationship between the number of partners and offspring viability. We conclude that this relationship is most likely the result of variable genetic compatibility between mates arising from postcopulatory phenomena, predominantly assortative fertilization with respect to parental genotypes. However, males who were more successful at mate acquisition were also more successful in situations of sperm competition, suggesting a possible link between male (diploid and haploid) genetic quality per se and probability of fertilization. Neither the number of partners nor the number of matings influenced the risk of infertility in sand lizards, suggesting that selection for reduced risk of infertility is not a sufficient explanation for maintaining female promiscuity in this population. Finally, we conclude that the relatively low genetic variability exhibited by our study populations may have facilitated detection of genetic benefits compared to more outbred ones. However, recent work derived from outbred populations in other taxa suggest a greater generality of the principles we discuss than previously may have been appreciated.

The evolution of resistance to two-toxin pyramid transgenic crops.

PubMed

Ives, Anthony R; Glaum, Paul R; Ziebarth, Nicolas L; Andow, David A

2011-03-01

Pyramid transgenic crops that express two Bacillus thuringiensis (Bt) toxins hold great potential for reducing insect damage and slowing the evolution of resistance to the toxins. Here, we analyzed a suite of models for pyramid Bt crops to illustrate factors that should be considered when implementing the high dose-refuge strategy for resistance management; this strategy involves the high expression of toxins in Bt plants and use of non-Bt plants as refuges. Although resistance evolution to pyramid Bt varieties should in general be slower, resistance to pyramid Bt varieties is nonetheless driven by the same evolutionary processes as single Bt-toxin varieties. The main advantage of pyramid varieties is the low survival of insects heterozygous for resistance alleles. We show that there are two modes of resistance evolution. When populations of purely susceptible insects persist, leading to density dependence, the speed of resistance evolution changes slowly with the proportion of refuges. However, once the proportion of non-Bt plants crosses the threshold below which a susceptible population cannot persist, the speed of resistance evolution increases rapidly. This suggests that adaptive management be used to guarantee persistence of susceptible populations. We compared the use of seed mixtures in which Bt and non-Bt plants are sown in the same fields to the use of spatial refuges. As found for single Bt varieties, seed mixtures can speed resistance evolution if larvae move among plants. Devising optimal management plans for deploying spatial refuges is difficult because they depend on crop rotation patterns, whether males or females have limited dispersal, and other characteristics. Nonetheless, the effects of spatial refuges on resistance evolution can be understood by considering the three mechanisms determining the rate of resistance evolution: the force of selection (the proportion of insects killed by Bt), assortative mating (deviations of the proportion of heterozygotes from Hardy-Weinberg equilibrium at the total population level), and male mating success (when males carrying resistance alleles find fewer mates). Of these three, assortative mating is often the least important, even though this mechanism is the most frequently cited explanation for the efficacy of the high dose-refuge strategy.

Whole-Exome Sequencing to Decipher the Genetic Heterogeneity of Hearing Loss in a Chinese Family with Deaf by Deaf Mating

PubMed Central

Qing, Jie; Yan, Denise; Zhou, Yuan; Liu, Qiong; Wu, Weijing; Xiao, Zian; Liu, Yuyuan; Liu, Jia; Du, Lilin; Xie, Dinghua; Liu, Xue Zhong

2014-01-01

Inherited deafness has been shown to have high genetic heterogeneity. For many decades, linkage analysis and candidate gene approaches have been the main tools to elucidate the genetics of hearing loss. However, this associated study design is costly, time-consuming, and unsuitable for small families. This is mainly due to the inadequate numbers of available affected individuals, locus heterogeneity, and assortative mating. Exome sequencing has now become technically feasible and a cost-effective method for detection of disease variants underlying Mendelian disorders due to the recent advances in next-generation sequencing (NGS) technologies. In the present study, we have combined both the Deafness Gene Mutation Detection Array and exome sequencing to identify deafness causative variants in a large Chinese composite family with deaf by deaf mating. The simultaneous screening of the 9 common deafness mutations using the allele-specific PCR based universal array, resulted in the identification of the 1555A>G in the mitochondrial DNA (mtDNA) 12S rRNA in affected individuals in one branch of the family. We then subjected the mutation-negative cases to exome sequencing and identified novel causative variants in the MYH14 and WFS1 genes. This report confirms the effective use of a NGS technique to detect pathogenic mutations in affected individuals who were not candidates for classical genetic studies. PMID:25289672

Evaluating mating compatibility within fruit fly cryptic species complexes and the potential role of sex pheromones in pre-mating isolation

PubMed Central

Juárez, M. Laura; Devescovi, Francisco; Břízová, Radka; Bachmann, Guillermo; Segura, Diego F.; Kalinová, Blanka; Fernández, Patricia; Ruiz, M. Josefina; Yang, Jianquan; Teal, Peter E.A.; Cáceres, Carlos; Vreysen, Marc J.B.; Hendrichs, Jorge; Vera, M. Teresa

2015-01-01

Abstract The study of sexual behavior and the identification of the signals involved in mate recognition between con-specifics are key components that can shed some light, as part of an integrative taxonomic approach, in delimitating species within species complexes. In the Tephritidae family several species complexes have received particular attention as they include important agricultural pests such as the Ceratitis fasciventris (Bezzi), Ceratitis anonae (Graham) and Ceratitis rosa Karsch (FAR) complex, the Bactrocera dorsalis (Hendel) complex and the Anastrepha fraterculus (Wiedemann) complex. Here the value and usefulness of a methodology that uses walk-in field cages with host trees to assess, under semi-natural conditions, mating compatibility within these complexes is reviewed, and the same methodology to study the role of chemical communication in pre-mating isolation among Anastrepha fraterculus populations is used. Results showed that under the same experimental conditions it was possible to distinguish an entire range of different outcomes: from full mating compatibility among some populations to complete assortative mating among others. The effectiveness of the methodology in contributing to defining species limits was shown in two species complexes: Anastrepha fraterculus and Bactrocera dorsalis, and in the case of the latter the synonymization of several established species was published. We conclude that walk-in field cages constitute a powerful tool to measure mating compatibility, which is also useful to determine the role of chemical signals in species recognition. Overall, this experimental approach provides a good source of information about reproductive boundaries to delimit species. However, it needs to be applied as part of an integrative taxonomic approach that simultaneously assesses cytogenetic, molecular, physiological and morphological traits in order to reach more robust species delimitations. PMID:26798257

Educational homogamy lowers the odds of reproductive failure.

PubMed

Huber, Susanne; Fieder, Martin

2011-01-01

Assortative mating based on education is a common phenomenon. We investigated whether it affected parameters of reproductive performance such as childlessness, offspring number and age at first marriage. On the basis of the US census from 1980 (n = 670,631 married US couples), we find that the proportion of childless individuals is usually minimal in women married to a husband of the same educational level. This holds particularly true in the highest and the lowest educated women. Educational homogamy is also associated with a lower average age at first marriage. No obvious effect of educational homogamy on a woman's average offspring number is found, where mean offspring number generally increases both with decreasing woman's and decreasing husband's educational attainment. We conclude that educational homogamy reduces the likelihood of reproductive failure.

Educational Homogamy Lowers the Odds of Reproductive Failure

PubMed Central

Huber, Susanne; Fieder, Martin

2011-01-01

Assortative mating based on education is a common phenomenon. We investigated whether it affected parameters of reproductive performance such as childlessness, offspring number and age at first marriage. On the basis of the US census from 1980 (n = 670,631 married US couples), we find that the proportion of childless individuals is usually minimal in women married to a husband of the same educational level. This holds particularly true in the highest and the lowest educated women. Educational homogamy is also associated with a lower average age at first marriage. No obvious effect of educational homogamy on a woman's average offspring number is found, where mean offspring number generally increases both with decreasing woman's and decreasing husband's educational attainment. We conclude that educational homogamy reduces the likelihood of reproductive failure. PMID:21818310

Is Beauty in the Face of the Beholder?

PubMed Central

Laeng, Bruno; Vermeer, Oddrun; Sulutvedt, Unni

2013-01-01

Opposing forces influence assortative mating so that one seeks a similar mate while at the same time avoiding inbreeding with close relatives. Thus, mate choice may be a balancing of phenotypic similarity and dissimilarity between partners. In the present study, we assessed the role of resemblance to Self’s facial traits in judgments of physical attractiveness. Participants chose the most attractive face image of their romantic partner among several variants, where the faces were morphed so as to include only 22% of another face. Participants distinctly preferred a “Self-based morph” (i.e., their partner’s face with a small amount of Self’s face blended into it) to other morphed images. The Self-based morph was also preferred to the morph of their partner’s face blended with the partner’s same-sex “prototype”, although the latter face was (“objectively”) judged more attractive by other individuals. When ranking morphs differing in level of amalgamation (i.e., 11% vs. 22% vs. 33%) of another face, the 22% was chosen consistently as the preferred morph and, in particular, when Self was blended in the partner’s face. A forced-choice signal-detection paradigm showed that the effect of self-resemblance operated at an unconscious level, since the same participants were unable to detect the presence of their own faces in the above morphs. We concluded that individuals, if given the opportunity, seek to promote “positive assortment” for Self’s phenotype, especially when the level of similarity approaches an optimal point that is similar to Self without causing a conscious acknowledgment of the similarity. PMID:23874608

Parallel changes in mate-attracting calls and female preferences in autotriploid tree frogs

PubMed Central

Tucker, Mitch A.; Gerhardt, H. C.

2012-01-01

For polyploid species to persist, they must be reproductively isolated from their diploid parental species, which coexist at the same time and place at least initially. In a complex of biparentally reproducing tetraploid and diploid tree frogs in North America, selective phonotaxis—mediated by differences in the pulse-repetition (pulse rate) of their mate-attracting vocalizations—ensures assortative mating. We show that artificially produced autotriploid females of the diploid species (Hyla chrysoscelis) show a shift in pulse-rate preference in the direction of the pulse rate produced by males of the tetraploid species (Hyla versicolor). The estimated preference function is centred near the mean pulse rate of the calls of artificially produced male autotriploids. Such a parallel shift, which is caused by polyploidy per se and whose magnitude is expected to be greater in autotetraploids, may have facilitated sympatric speciation by promoting reproductive isolation of the initially formed polyploids from their diploid parental forms. This process also helps to explain why tetraploid lineages with different origins have similar advertisement calls and freely interbreed. PMID:22113033

Male Choice in the Stream-Anadromous Stickleback Complex

PubMed Central

McKinnon, Jeffrey S.; Hamele, Nick; Frey, Nicole; Chou, Jennifer; McAleavey, Leia; Greene, Jess; Paulson, Windi

2012-01-01

Studies of mating preferences and pre-mating reproductive isolation have often focused on females, but the potential importance of male preferences is increasingly appreciated. We investigated male behavior in the context of reproductive isolation between divergent anadromous and stream-resident populations of threespine stickleback, Gasterosteus aculeatus, using size-manipulated females of both ecotypes. Specifically, we asked if male courtship preferences are present, and if they are based on relative body size, non-size aspects of ecotype, or other traits. Because male behaviors were correlated with each other, we conducted a principal components analysis on the correlations and ran subsequent analyses on the principal components. The two male ecotypes differed in overall behavioral frequencies, with stream-resident males exhibiting consistently more vigorous and positive courtship than anadromous males, and an otherwise aggressive behavior playing a more positive role in anadromous than stream-resident courtship. We observed more vigorous courtship toward smaller females by (relatively small) stream-resident males and the reverse pattern for (relatively large) anadromous males. Thus size-assortative male courtship preferences may contribute to reproductive isolation in this system, although preferences are far from absolute. We found little indication of males responding preferentially to females of their own ecotype independent of body size. PMID:22701589

Sexual imprinting on ecologically divergent traits leads to sexual isolation in sticklebacks

PubMed Central

Kozak, Genevieve M.; Head, Megan L.; Boughman, Janette W.

2011-01-01

During sexual imprinting, offspring learn parental phenotypes and then select mates who are similar to their parents. Imprinting has been thought to contribute to the process of speciation in only a few rare cases; this is despite imprinting's potential to generate assortative mating and solve the problem of recombination in ecological speciation. If offspring imprint on parental traits under divergent selection, these traits will then be involved in both adaptation and mate preference. Such ‘magic traits’ easily generate sexual isolation and facilitate speciation. In this study, we show that imprinting occurs in two ecologically divergent stickleback species (benthics and limnetics: Gasterosteus spp.). Cross-fostered females preferred mates of their foster father's species. Furthermore, imprinting is essential for sexual isolation between species; isolation was reduced when females were raised without fathers. Daughters imprinted on father odour and colour during a critical period early in development. These traits have diverged between the species owing to differences in ecology. Therefore, we provide the first evidence that imprinting links ecological adaptation to sexual isolation between species. Our results suggest that imprinting may facilitate the evolution of sexual isolation during ecological speciation, may be especially important in cases of rapid diversification, and thus play an integral role in the generation of biodiversity. PMID:21270044

Sexual imprinting on ecologically divergent traits leads to sexual isolation in sticklebacks.

PubMed

Kozak, Genevieve M; Head, Megan L; Boughman, Janette W

2011-09-07

During sexual imprinting, offspring learn parental phenotypes and then select mates who are similar to their parents. Imprinting has been thought to contribute to the process of speciation in only a few rare cases; this is despite imprinting's potential to generate assortative mating and solve the problem of recombination in ecological speciation. If offspring imprint on parental traits under divergent selection, these traits will then be involved in both adaptation and mate preference. Such 'magic traits' easily generate sexual isolation and facilitate speciation. In this study, we show that imprinting occurs in two ecologically divergent stickleback species (benthics and limnetics: Gasterosteus spp.). Cross-fostered females preferred mates of their foster father's species. Furthermore, imprinting is essential for sexual isolation between species; isolation was reduced when females were raised without fathers. Daughters imprinted on father odour and colour during a critical period early in development. These traits have diverged between the species owing to differences in ecology. Therefore, we provide the first evidence that imprinting links ecological adaptation to sexual isolation between species. Our results suggest that imprinting may facilitate the evolution of sexual isolation during ecological speciation, may be especially important in cases of rapid diversification, and thus play an integral role in the generation of biodiversity.

Does Higher Education Expansion Promote Educational Homogamy? Evidence from Married Couples of the Post-80s Generation in Shanghai, China

PubMed Central

Hu, Anning; Qian, Zhenchao

2017-01-01

The expansion of higher education witnessed in many societies influences the pattern of educational assortative mating. Structural transition theory predicts growing educational homogamy due to increasing preference for highly-educated partners who become more widely available. In contrast, social closure theory suggests depressed educational homogamy because the inflation of the education elite circle fosters the openness of marriage market, reducing the preference for a highly-educated mate and increasing the penetrability across social-status boundaries. Capitalizing the survey data that are representative of the post-80s one-child generation collected in Shanghai, China, we test the hypotheses derived from the two theories. Empirical results suggest that, with increasing availability of highly educated individuals, the extent of educational homogamy by birth cohort reveals a U-shaped pattern. This U-shaped pattern demonstrates increasing levels of educational homogamy and lends support to structural transition theory. PMID:27712675

The post-pollination ethylene burst and the continuation of floral advertisement are harbingers of non-random mate selection in Nicotiana attenuata.

PubMed

Bhattacharya, Samik; Baldwin, Ian T

2012-08-01

The self-compatible plant Nicotiana attenuata grows in genetically diverse populations after fires, and produces flowers that remain open for 3 days and are visited by assorted pollinators. To determine whether and when post-pollination non-random mate selection occurs among self and non-self pollen, seed paternity and semi-in vivo pollen tube growth were determined in controlled single/mixed pollinations. Despite all pollen sources being equally proficient in siring seeds in single-genotype pollinations, self pollen was consistently selected in mixed pollinations, irrespective of maternal genotype. However, clear patterns of mate discrimination occurred amongst non-self pollen when mixed pollinations were performed soon after corollas open, including selection against hygromycin B resistance (transformation selectable marker) in wild-type styles and for it in transformed styles. However, mate choice among pollen genotypes was completely shut down in plants transformed to be unable to produce (irACO) or perceive (ETR1) ethylene. The post-pollination ethylene burst, which originates primarily from the stigma and upper style, was strongly correlated with mate selection in single and mixed hand-pollinations using eight pollen donors in two maternal ecotypes. The post-pollination ethylene burst was also negatively correlated with the continuation of emission of benzylacetone, the most abundant pollinator-attracting corolla-derived floral volatile. We conclude that ethylene signaling plays a pivotal role in mate choice, and the post-pollination ethylene burst and the termination of benzylacetone release are accurate predictors, both qualitatively and quantitatively, of pre-zygotic mate selection and seed paternity. © 2012 The Authors. The Plant Journal © 2012 Blackwell Publishing Ltd.

Female mate choice in convict cichlids is transitive and consistent with a self-referent directional preference

PubMed Central

2013-01-01

Introduction One of the most important decisions that an animal has to make in its life is choosing a mate. Although most studies in sexual selection assume that mate choice is rational, this assumption has not been tested seriously. A crucial component of rationality is that animals exhibit transitive choices: if an individual prefers option A over B, and B over C, then it also prefers A over C. Results We assessed transitivity in mate choice: 40 female convict cichlids had to make a series of binary choices between males of varying size. Ninety percent of females showed transitive choices. The mean preference index was significantly higher when a female chose between their most preferred and least preferred male (male 1 vs. male 3) compared to when they chose between males of adjacent ranks (1 vs. 2 or 2 vs. 3). The results are consistent with a simple underlying preference function leading to transitive choice: females preferred males about one third larger than themselves. This rule of thumb correctly predicted which male was preferred in 67% of the cases and the ordering in binary choices in 78% of cases. Conclusions This study provides the first evidence for strong stochastic transitivity in a context of mate choice. The females exhibited ordinal preferences and the direction and magnitude of these preferences could be predicted from a simple rule. The females do not necessarily compare two males to choose the best; it is sufficient to use a self-referent evaluation. Such a simple decision rule has important implications for the evolution of the mating strategies and it is consistent with patterns of assortative mating repeatedly observed at population level. PMID:24216003

Facialmetric similarities mediate mate choice: sexual imprinting on opposite-sex parents.

PubMed

Bereczkei, Tamas; Hegedus, Gabor; Hajnal, Gabor

2009-01-07

Former studies have suggested that imprinting-like processes influence the shaping of human mate preferences. In this study, we provide more direct evidence for assessing facial resemblance between subjects' partner and subjects' parents. Fourteen facial proportions were measured on 312 adults belonging to 52 families, and the correlations between family members were compared with those of pairs randomly selected from the population. Spouses proved to be assortatively mated in the majority of measured facial proportions. Significant correlations have been found between the young men and their partner's father (but not his mother), especially on facial proportions belonging to the central area of the face. Women also showed resemblance to their partner's mother (but not to their father) in the facial characteristics of their lower face. Replicating our previous studies, facial photographs of participants were also matched by independent judges who ascribed higher resemblance between partners, and subjects and their partners' opposite-sex parents, compared with controls. Our results support the sexual imprinting hypothesis which states that children shape a mental template of their opposite-sex parents and search for a partner who resembles that perceptual schema. The fact that only the facial metrics of opposite-sex parents showed resemblance to the partner's face tends to rule out the role of familiarity in shaping mating preferences. Our findings also reject several other rival hypotheses. The adaptive value of imprinting-related human mating is discussed, and a hypothesis is made of why different facial areas are involved in males' and females' search for resemblance.

The Roles of Sexual and Viability Selection in the Evolution of Incomplete Reproductive Isolation: From Allopatry to Sympatry.

PubMed

Cotto, Olivier; Servedio, Maria R

2017-11-01

In recent years, theoretical models have introduced the concept that ongoing hybridization between "good" species can occur because incomplete reproductive isolation can be a selected optimum. They furthermore show that positive frequency-dependent sexual selection, which is naturally generated by some of the underlying processes that lead to assortative mating, plays a key role in the evolution of incomplete reproductive isolation. This occurs, however, through different mechanisms in sympatric versus allopatric scenarios. We investigate the evolution of incomplete reproductive isolation by sexual selection in scenarios ranging from sympatry to allopatry, to examine how these mechanisms interact. We consider an ecological scenario in which there are two habitats used during foraging and individuals can breed either within a habitat or in a common mating pool. We find that when trait divergence is maintained, sexual selection drives the evolution of choosiness in opposite ways in the common mating pool versus within each habitat. Specifically, strong choosiness is favored in the common mating pool, whereas intermediate choosiness is favored within habitat; the interaction of these forces determines whether intermediate reproductive isolation ultimately evolves in the system. We further find cases where the evolution of stronger choosiness occurs but leads to the loss of divergence. Overall, our study shows that contrasting forces on the evolution of reproductive isolation can occur in different mating areas, and we propose a new avenue for understanding the diversity in levels of reproductive isolation within and across species.

Pollinator Competition as a Driver of Floral Divergence: An Experimental Test.

PubMed

Temeles, Ethan J; Newman, Julia T; Newman, Jennifer H; Cho, Se Yeon; Mazzotta, Alexandra R; Kress, W John

2016-01-01

Optimal foraging models of floral divergence predict that competition between two different types of pollinators will result in partitioning, increased assortative mating, and divergence of two floral phenotypes. We tested these predictions in a tropical plant-pollinator system using sexes of purple-throated carib hummingbirds (Anthracothorax jugularis) as the pollinators, red and yellow inflorescence morphs of Heliconia caribaea as the plants, and fluorescent dyes as pollen analogs in an enclosed outdoor garden. When foraging alone, males exhibited a significant preference for the yellow morph of H. caribaea, whereas females exhibited no preference. In competition, males maintained their preference for the yellow morph and through aggression caused females to over-visit the red morph, resulting in resource partitioning. Competition significantly increased within-morph dye transfer (assortative mating) relative to non-competitive environments. Competition and partitioning of color morphs by sexes of purple-throated caribs also resulted in selection for floral divergence as measured by dye deposition on stigmas. Red and yellow morphs did not differ significantly in dye deposition in the competition trials, but differences in dye deposition and preferences for morphs when sexes of purple-throated caribs foraged alone implied fixation of one or the other color morph in the absence of competition. Competition also resulted in selection for divergence in corolla length, with the red morph experiencing directional selection for longer corollas and the yellow morph experiencing stabilizing selection on corolla length. Our results thus support predictions of foraging models of floral divergence and indicate that pollinator competition is a viable mechanism for divergence in floral traits of plants.

Pollinator Competition as a Driver of Floral Divergence: An Experimental Test

PubMed Central

Temeles, Ethan J.; Newman, Julia T.; Newman, Jennifer H.; Cho, Se Yeon; Mazzotta, Alexandra R.; Kress, W. John

2016-01-01

Optimal foraging models of floral divergence predict that competition between two different types of pollinators will result in partitioning, increased assortative mating, and divergence of two floral phenotypes. We tested these predictions in a tropical plant-pollinator system using sexes of purple-throated carib hummingbirds (Anthracothorax jugularis) as the pollinators, red and yellow inflorescence morphs of Heliconia caribaea as the plants, and fluorescent dyes as pollen analogs in an enclosed outdoor garden. When foraging alone, males exhibited a significant preference for the yellow morph of H. caribaea, whereas females exhibited no preference. In competition, males maintained their preference for the yellow morph and through aggression caused females to over-visit the red morph, resulting in resource partitioning. Competition significantly increased within-morph dye transfer (assortative mating) relative to non-competitive environments. Competition and partitioning of color morphs by sexes of purple-throated caribs also resulted in selection for floral divergence as measured by dye deposition on stigmas. Red and yellow morphs did not differ significantly in dye deposition in the competition trials, but differences in dye deposition and preferences for morphs when sexes of purple-throated caribs foraged alone implied fixation of one or the other color morph in the absence of competition. Competition also resulted in selection for divergence in corolla length, with the red morph experiencing directional selection for longer corollas and the yellow morph experiencing stabilizing selection on corolla length. Our results thus support predictions of foraging models of floral divergence and indicate that pollinator competition is a viable mechanism for divergence in floral traits of plants. PMID:26814810

Male courtship preferences demonstrate discrimination against allopatric colour morphs in a cichlid fish

PubMed Central

Zoppoth, P; Koblmüller, S; Sefc, K M

2013-01-01

Whether premating isolation is achieved by male-specific, female-specific or sex-independent assortative preferences often depends on the underlying evolutionary processes. Here we test mate preferences of males presented with females of different allopatric colour variants of the cichlid fish Tropheus sp., a Lake Tanganyika endemic with rich geographical colour pattern variation, in which the strength of sexual isolation varies between populations. We conducted two-way mate choice experiments to compare behaviour of males of a red-bodied morph (population Moliro) towards females from their own population with behaviour towards females from four allopatric populations at different stages of phylogenetic and phenotypic divergence. Males courted same-population females significantly more intensely than females of other populations, and reduced their heteromorphic courtship efforts both with increasing genetic and increasing phenotypic distinctness of the females. In particular, females of a closely related red-bodied population received significantly more courtship than either genetically distinct, similarly coloured females (‘Kirschfleck’ morph) or genetically related, differently coloured females (‘yellow-blotch’ morph), both of which were courted similarly. Genetically and phenotypically distinct females (Tropheus polli) were not courted at all. Consistent with previous female-choice experiments, female courtship activity also decreased with increasing genetic distance from the males’ population. Given successful experimental and natural introgression between colour morphs and the pervasive allopatry of related variants, we consider it unlikely that assortative preferences of both sexes were driven by direct selection during periods of secondary contact or, in turn, drove colour pattern differentiation in allopatry. Rather, we suggest that sexual isolation evolved as by-product of allopatric divergence. PMID:23405907

Low reproductive isolation and highly variable levels of gene flow reveal limited progress towards speciation between European river and brook lampreys.

PubMed

Rougemont, Q; Gaigher, A; Lasne, E; Côte, J; Coke, M; Besnard, A-L; Launey, S; Evanno, G

2015-12-01

Ecologically based divergent selection is a factor that could drive reproductive isolation even in the presence of gene flow. Population pairs arrayed along a continuum of divergence provide a good opportunity to address this issue. Here, we used a combination of mating trials, experimental crosses and population genetic analyses to investigate the evolution of reproductive isolation between two closely related species of lampreys with distinct life histories. We used microsatellite markers to genotype over 1000 individuals of the migratory parasitic river lamprey (Lampetra fluviatilis) and freshwater-resident nonparasitic brook lamprey (Lampetra planeri) distributed in 10 sympatric and parapatric population pairs in France. Mating trials, parentage analyses and artificial fertilizations demonstrated a low level of reproductive isolation between species even though size-assortative mating may contribute to isolation. Most parapatric population pairs were strongly differentiated due to the joint effects of geographic distance and barriers to migration. In contrast, we found variable levels of gene flow between sympatric populations ranging from panmixia to moderate differentiation, which indicates a gradient of divergence with some population pairs that may correspond to alternative morphs or ecotypes of a single species and others that remain partially isolated. Ecologically based divergent selection may explain these variable levels of divergence among sympatric population pairs, but incomplete genome swamping following secondary contact could have also played a role. Overall, this study illustrates how highly differentiated phenotypes can be maintained despite high levels of gene flow that limit the progress towards speciation. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

Role of demographic stochasticity in a speciation model with sexual reproduction

NASA Astrophysics Data System (ADS)

Lafuerza, Luis F.; McKane, Alan J.

2016-03-01

Recent theoretical studies have shown that demographic stochasticity can greatly increase the tendency of asexually reproducing phenotypically diverse organisms to spontaneously evolve into localized clusters, suggesting a simple mechanism for sympatric speciation. Here we study the role of demographic stochasticity in a model of competing organisms subject to assortative mating. We find that in models with sexual reproduction, noise can also lead to the formation of phenotypic clusters in parameter ranges where deterministic models would lead to a homogeneous distribution. In some cases, noise can have a sizable effect, rendering the deterministic modeling insufficient to understand the phenotypic distribution.

Effect of Larvae Treated with Mixed Biopesticide Bacillus thuringiensis - Abamectin on Sex Pheromone Communication System in Cotton Bollworm, Helicoverpa armigera

PubMed Central

Shen, Li-Ze; Chen, Peng-Zhou; Xu, Zhi-Hong; Deng, Jian-Yu; Harris, Marvin-K; Wanna, Ruchuon; Wang, Fu-Min; Zhou, Guo-Xin; Yao, Zhang-Liang

2013-01-01

Third instar larvae of the cotton bollworm (Helicoverpa armigera) were reared with artificial diet containing a Bacillus thuringiensis - abamectin (BtA) biopesticide mixture that resulted in 20% mortality (LD20). The adult male survivors from larvae treated with BtA exhibited a higher percentage of “orientation” than control males but lower percentages of “approaching” and “landing” in wind tunnel bioassays. Adult female survivors from larvae treated with BtA produced higher sex pheromone titers and displayed a lower calling percentage than control females. The ratio of Z-11-hexadecenal (Z11–16:Ald) and Z-9-hexadecenal (Z9–16:Ald) in BtA-treated females changed and coefficients of variation (CV) of Z11–16:Ald and Z9–16:Ald were expanded compared to control females. The peak circadian calling time of BtA-treated females occurred later than that of control females. In mating choice experiment, both control males and BtA-treated males preferred to mate with control females and a portion of the Bt-A treated males did not mate whereas all control males did. Our Data support that treatment of larvae with BtA had an effect on the sex pheromone communication system in surviving H.armigera moths that may contribute to assortative mating. PMID:23874751

Temporal variation in the mating structure of Sanday, Orkney Islands.

PubMed

Brennan, E R; Relethford, J H

1983-01-01

Pedigree and vital statistics data from the population of Sanday, Orkney Islands, Scotland, were used to assess temporal changes in population structure. Secular trends in patterns of mate choice were analysed for three separate birth cohorts of spouses: 1855-1884, 1885-1924 and 1925-1964. The degree to which mating was random or assortative with respect to both genealogical and geographic distance was determined by comparing average characteristics of all potential mates of married males with those of actual wives. We integrated this procedure, originally developed by Dyke (1971), into a three-fold investigation of population structure: (1) comparison of random and non-random components of relatedness as measured from pedigree data; (2) an analysis of marital distance distributions for actual and potential mates of married males; and (3) the relationship between genealogical relatedness and geographic distance. As population size decreased from 1881 to the present, total kinship and spatial distances between spouses increased. Whereas the random component of relatedness increased over time, consanguinity avoidance was sufficient to decrease the total coefficient of kinship over time. Part of the increase in consanguinity avoidance was associated with isolate breakdown, as distances between island-born spouses, as well as the total amount of off-island migration, increased from the mid-nineteenth century to the present. Mate choice was influenced by geographic distance for all time periods, although this effect diminished over time. Since decreases in population size, concomitant with increases in consanguinity avoidance and community exogamy, have probably occurred quite frequently in small human populations, as well as in rural Western communities in the past century, observed secular trends illustrate the potential for change in population structure characteristic of isolate breakdown.

Maximum number of live births per donor in artificial insemination.

PubMed

Wang, Charlotte; Tsai, Miao-Yu; Lee, Mei-Hsien; Huang, Su-Yun; Kao, Chen-Hung; Ho, Hong-Nerng; Hsiao, Chuhsing Kate

2007-05-01

The maximal number of live births (k) per donor was usually determined by cultural and social perspective. It was rarely decided on the basis of scientific evidence or discussed from mathematical or probabilistic viewpoint. To recommend a value for k, we propose three criteria to evaluate its impact on consanguinity and disease incidence due to artificial insemination by donor (AID). The first approach considers the optimization of k under the criterion of fixed tolerable number of consanguineous mating due to AID. The second approach optimizes k under fixed allowable average coefficient of inbreeding. This approach is particularly helpful when assessing the impact on the public, is of interest. The third criterion considers specific inheritance diseases. This approach is useful when evaluating the individual's risk of genetic diseases. When different diseases are considered, this criterion can be easily adopted. All these derivations are based on the assumption of shortage of gamete donors due to great demand and insufficient supply. Our results indicate that strong degree of assortative mating, small population size and insufficient supply in gamete donors will lead to greater risk of consanguinity. Recommendations under other settings are also tabulated for reference. A web site for calculating the limit for live births per donor is available.

Isolation by environment in the highly mobile olive ridley turtle (Lepidochelys olivacea) in the eastern Pacific.

PubMed

Rodríguez-Zárate, Clara J; Sandoval-Castillo, Jonathan; van Sebille, Erik; Keane, Robert G; Rocha-Olivares, Axayácatl; Urteaga, Jose; Beheregaray, Luciano B

2018-05-16

Spatial and temporal scales at which processes modulate genetic diversity over the landscape are usually overlooked, impacting the design of conservation management practices for widely distributed species. We examine processes shaping population divergence in highly mobile species by re-assessing the case of panmixia in the iconic olive ridley turtle from the eastern Pacific. We implemented a biophysical model of connectivity and a seascape genetic analysis based on nuclear DNA variation of 634 samples collected from 27 nesting areas. Two genetically distinct populations largely isolated during reproductive migrations and mating were detected, each composed of multiple nesting sites linked by high connectivity. This pattern was strongly associated with a steep environmental gradient and also influenced by ocean currents. These findings relate to meso-scale features of a dynamic oceanographic interface in the eastern tropical Pacific (ETP) region, a scenario that possibly provides different cost-benefit solutions and selective pressures for sea turtles during both the mating and migration periods. We reject panmixia and propose a new paradigm for olive ridley turtles where reproductive isolation due to assortative mating is linked to its environment. Our study demonstrates the relevance of integrative approaches for assessing the role of environmental gradients and oceanographic currents as drivers of genetic differentiation in widely distributed marine species. This is relevant for the conservation management of species of highly mobile behaviour, and assists the planning and development of large-scale conservation strategies for the threatened olive ridley turtles in the ETP. © 2018 The Author(s).

Facialmetric similarities mediate mate choice: sexual imprinting on opposite-sex parents

PubMed Central

Bereczkei, Tamas; Hegedus, Gabor; Hajnal, Gabor

2008-01-01

A retraction has been published Former studies have suggested that imprinting-like processes influence the shaping of human mate preferences. In this study, we provide more direct evidence for assessing facial resemblance between subjects' partner and subjects' parents. Fourteen facial proportions were measured on 312 adults belonging to 52 families, and the correlations between family members were compared with those of pairs randomly selected from the population. Spouses proved to be assortatively mated in the majority of measured facial proportions. Significant correlations have been found between the young men and their partner's father (but not his mother), especially on facial proportions belonging to the central area of the face. Women also showed resemblance to their partner's mother (but not to their father) in the facial characteristics of their lower face. Replicating our previous studies, facial photographs of participants were also matched by independent judges who ascribed higher resemblance between partners, and subjects and their partners' opposite-sex parents, compared with controls. Our results support the sexual imprinting hypothesis which states that children shape a mental template of their opposite-sex parents and search for a partner who resembles that perceptual schema. The fact that only the facial metrics of opposite-sex parents showed resemblance to the partner's face tends to rule out the role of familiarity in shaping mating preferences. Our findings also reject several other rival hypotheses. The adaptive value of imprinting-related human mating is discussed, and a hypothesis is made of why different facial areas are involved in males' and females' search for resemblance. PMID:18765339

Examining the Nature of the Association Between Attention-Deficit/Hyperactivity Disorder and Nicotine Dependence: A Familial Risk Analysis

PubMed Central

Biederman, Joseph; Petty, Carter R.; Hammerness, Paul; Woodworth, K. Yvonne; Faraone, Stephen V.

2013-01-01

Objective The main aim of this study was to use familial risk analysis to examine the association between attention-deficit/hyperactivity disorder (ADHD) and nicotine dependence. Methods Subjects were children with (n = 257) and without (n = 229) ADHD of both sexes ascertained form pediatric and psychiatric referral sources and their first-degree relatives (N = 1627). Results Nicotine dependence in probands increased the risk for nicotine dependence in relatives irrespective of ADHD status. There was no evidence of cosegregation or assortative mating between these disorders. Patterns of familial risk analysis suggest that the association between ADHD and nicotine dependence is most consistent with the hypothesis of independent transmission of these disorders. Conclusions These findings may have important implications for the identification of a subgroup of children with ADHD at high risk for nicotine dependence based on parental history of nicotine dependence. PMID:23461889

Genetics and intelligence differences: five special findings.

PubMed

Plomin, R; Deary, I J

2015-02-01

Intelligence is a core construct in differential psychology and behavioural genetics, and should be so in cognitive neuroscience. It is one of the best predictors of important life outcomes such as education, occupation, mental and physical health and illness, and mortality. Intelligence is one of the most heritable behavioural traits. Here, we highlight five genetic findings that are special to intelligence differences and that have important implications for its genetic architecture and for gene-hunting expeditions. (i) The heritability of intelligence increases from about 20% in infancy to perhaps 80% in later adulthood. (ii) Intelligence captures genetic effects on diverse cognitive and learning abilities, which correlate phenotypically about 0.30 on average but correlate genetically about 0.60 or higher. (iii) Assortative mating is greater for intelligence (spouse correlations ~0.40) than for other behavioural traits such as personality and psychopathology (~0.10) or physical traits such as height and weight (~0.20). Assortative mating pumps additive genetic variance into the population every generation, contributing to the high narrow heritability (additive genetic variance) of intelligence. (iv) Unlike psychiatric disorders, intelligence is normally distributed with a positive end of exceptional performance that is a model for 'positive genetics'. (v) Intelligence is associated with education and social class and broadens the causal perspectives on how these three inter-correlated variables contribute to social mobility, and health, illness and mortality differences. These five findings arose primarily from twin studies. They are being confirmed by the first new quantitative genetic technique in a century-Genome-wide Complex Trait Analysis (GCTA)-which estimates genetic influence using genome-wide genotypes in large samples of unrelated individuals. Comparing GCTA results to the results of twin studies reveals important insights into the genetic architecture of intelligence that are relevant to attempts to narrow the 'missing heritability' gap.

Genetics and intelligence differences: five special findings

PubMed Central

Plomin, R; Deary, I J

2015-01-01

Intelligence is a core construct in differential psychology and behavioural genetics, and should be so in cognitive neuroscience. It is one of the best predictors of important life outcomes such as education, occupation, mental and physical health and illness, and mortality. Intelligence is one of the most heritable behavioural traits. Here, we highlight five genetic findings that are special to intelligence differences and that have important implications for its genetic architecture and for gene-hunting expeditions. (i) The heritability of intelligence increases from about 20% in infancy to perhaps 80% in later adulthood. (ii) Intelligence captures genetic effects on diverse cognitive and learning abilities, which correlate phenotypically about 0.30 on average but correlate genetically about 0.60 or higher. (iii) Assortative mating is greater for intelligence (spouse correlations ~0.40) than for other behavioural traits such as personality and psychopathology (~0.10) or physical traits such as height and weight (~0.20). Assortative mating pumps additive genetic variance into the population every generation, contributing to the high narrow heritability (additive genetic variance) of intelligence. (iv) Unlike psychiatric disorders, intelligence is normally distributed with a positive end of exceptional performance that is a model for ‘positive genetics'. (v) Intelligence is associated with education and social class and broadens the causal perspectives on how these three inter-correlated variables contribute to social mobility, and health, illness and mortality differences. These five findings arose primarily from twin studies. They are being confirmed by the first new quantitative genetic technique in a century—Genome-wide Complex Trait Analysis (GCTA)—which estimates genetic influence using genome-wide genotypes in large samples of unrelated individuals. Comparing GCTA results to the results of twin studies reveals important insights into the genetic architecture of intelligence that are relevant to attempts to narrow the ‘missing heritability' gap. PMID:25224258

Genetic and environmental transmission of body mass index fluctuation.

PubMed

Bergin, Jocilyn E; Neale, Michael C; Eaves, Lindon J; Martin, Nicholas G; Heath, Andrew C; Maes, Hermine H

2012-11-01

This study sought to determine the relationship between body mass index (BMI) fluctuation and cardiovascular disease phenotypes, diabetes, and depression and the role of genetic and environmental factors in individual differences in BMI fluctuation using the extended twin-family model (ETFM). This study included 14,763 twins and their relatives. Health and Lifestyle Questionnaires were obtained from 28,492 individuals from the Virginia 30,000 dataset including twins, parents, siblings, spouses, and children of twins. Self-report cardiovascular disease, diabetes, and depression data were available. From self-reported height and weight, BMI fluctuation was calculated as the difference between highest and lowest BMI after age 18, for individuals 18-80 years. Logistic regression analyses were used to determine the relationship between BMI fluctuation and disease status. The ETFM was used to estimate the significance and contribution of genetic and environmental factors, cultural transmission, and assortative mating components to BMI fluctuation, while controlling for age. We tested sex differences in additive and dominant genetic effects, parental, non-parental, twin, and unique environmental effects. BMI fluctuation was highly associated with disease status, independent of BMI. Genetic effects accounted for ~34 % of variance in BMI fluctuation in males and ~43 % of variance in females. The majority of the variance was accounted for by environmental factors, about a third of which were shared among twins. Assortative mating, and cultural transmission accounted for only a small proportion of variance in this phenotype. Since there are substantial health risks associated with BMI fluctuation and environmental components of BMI fluctuation account for over 60 % of variance in males and over 50 % of variance in females, environmental risk factors may be appropriate targets to reduce BMI fluctuation.

Does higher education expansion promote educational homogamy? Evidence from married couples of the post-80s generation in Shanghai, China.

PubMed

Hu, Anning; Qian, Zhenchao

2016-11-01

The expansion of higher education witnessed in many societies influences the pattern of educational assortative mating. Structural transition theory predicts growing educational homogamy due to increasing preference for highly-educated partners who become more widely available. In contrast, social closure theory suggests depressed educational homogamy because the inflation of the education elite circle fosters the openness of marriage market, reducing the preference for a highly-educated mate and increasing the penetrability across social-status boundaries. Capitalizing the survey data that are representative of the post-80s one-child generation collected in Shanghai, China, we test the hypotheses derived from the two theories. Empirical results suggest that, with increasing availability of highly educated individuals, the extent of educational homogamy by birth cohort reveals a U-shaped pattern. This U-shaped pattern demonstrates increasing levels of educational homogamy and lends support to structural transition theory. Copyright © 2016 Elsevier Inc. All rights reserved.

Strategic mating with common preferences.

PubMed

Alpern, Steve; Reyniers, Diane

2005-12-21

We present a two-sided search model in which individuals from two groups (males and females, employers and workers) would like to form a long-term relationship with a highly ranked individual of the other group, but are limited to individuals who they randomly encounter and to those who also accept them. This article extends the research program, begun in Alpern and Reyniers [1999. J. Theor. Biol. 198, 71-88], of providing a game theoretic analysis for the Kalick-Hamilton [1986. J. Personality Soc. Psychol. 51, 673-682] mating model in which a cohort of males and females of various 'fitness' or 'attractiveness' levels are randomly paired in successive periods and mate if they accept each other. Their model compared two acceptance rules chosen to represent homotypic (similarity) preferences and common (or 'type') preferences. Our earlier paper modeled the first kind by assuming that if a level x male mates with a level y female, both get utility -|x-y|, whereas this paper models the second kind by giving the male utility y and the female utility x. Our model can also be seen as a continuous generalization of the discrete fitness-level game of Johnstone [1997. Behav. Ecol. Sociobiol. 40, 51-59]. We establish the existence of equilibrium strategy pairs, give examples of multiple equilibria, and conditions guaranteeing uniqueness. In all equilibria individuals become less choosy over time, with high fitness individuals pairing off with each other first, leaving the rest to pair off later. This route to assortative mating was suggested by Parker [1983. Mate Choice, Cambridge University Press, Cambridge, pp. 141-164]. If the initial fitness distributions have atoms, then mixed strategy equilibria may also occur. If these distributions are unknown, there are equilibria in which only individuals in the same fitness band are mated, as in the steady-state model of MacNamara and Collins [1990. J. Appl. Prob. 28, 815-827] for the job search problem.

Evolution of eukaryotic microbial pathogens via covert sexual reproduction

PubMed Central

Heitman, Joseph

2010-01-01

Sexual reproduction enables eukaryotic organisms to re-assort genetic diversity and purge deleterious mutations, producing better-fit progeny. Sex arose early and pervades eukaryotes. Fungal and parasite pathogens once thought asexual have maintained cryptic sexual cycles, including unisexual or parasexual reproduction. As pathogens become niche and host-adapted, sex appears to specialize to promote inbreeding and clonality yet maintain out-crossing potential. During self-fertile sexual modes, sex itself may generate genetic diversity de novo. Mating-type loci govern fungal sexual identity; how parasites establish sexual identity is unknown. Comparing and contrasting fungal and parasite sex promises to reveal how microbial pathogens evolved and are evolving. PMID:20638645

An Evaluation of Practical Applicability of Multi-Assortment Production Break-Even Analysis based on Mining Companies

NASA Astrophysics Data System (ADS)

Fuksa, Dariusz; Trzaskuś-Żak, Beata; Gałaś, Zdzisław; Utrata, Arkadiusz

2017-03-01

In the practice of mining companies, the vast majority of them produce more than one product. The analysis of the break-even, which is referred to as CVP (Cost-Volume-Profit) analysis (Wilkinson, 2005; Czopek, 2003) in their case is significantly constricted, given the necessity to include multi-assortment structure in the analysis, which may have more than 20 types of assortments (depending on the grain size) in their offer, as in the case of open-pit mines. The article presents methods of evaluation of break-even (volume and value) for both a single-assortment production and a multi-assortment production. The complexity of problem of break-even evaluation for multi-assortment production has resulted in formation of many methods, and, simultaneously, various approaches to its analysis, especially differences in accounting fixed costs, which may be either totally accounted for among particular assortments, relating to the whole company or partially accounted for among particular assortments and partially relating to the company, as a whole. The evaluation of the chosen methods of break-even analysis, given the availability of data, was based on two examples of mining companies: an open-pit mine of rock materials and an underground hard coal mine. The selection of methods was set by the available data provided by the companies. The data for the analysis comes from internal documentation of the mines - financial statements, breakdowns and cost calculations.

Assortative mating and directional or stabilizing selection for a non-linear function of traits in Tribolium.

PubMed

Campo, J L; Gil, M G

1993-01-12

Assortative or random mating following selection in either direction on a non-linear index (experiment 1) or stabilizing selection for pupal length (experiment 2) were carried out for five generations in two lines of Tribolium castaneum (A and R, respectively), with three replicates each. The selected proportion was 25% in all lines. In experiment 1, the selection criterion was designed to increase the aggregate value of adult weight and the first- and second-order powers of pupal length. The A and R lines gave significant responses for the aggregate value (184 ± 6 and 161 ± 14, respectively), pupal length (0.74 ± 0.02 and 0.64 ± 0.05, respectively), and adult weight (0.79 ± 0.03 and 0.78 ± 0.12, respectively). Although the A line was not significantly better than the R line, there was a consistent advantage for assortative mating over random mating, the mean response for aggregate value and pupal length being approximately 1.15 times greater for the A line. In experiment 2 the selection criterion was the square of the deviation from the mean pupal length (stabilizing selection); both lines did not show any change for pupal length. The phenotypic variance showed a significant decrease in the A and R lines, due to a decrease in between-family variance. The assortatively and randomly mated lines were similar for these changes in phenotypic variation. RESUMEN: Aparemiento clasificado y selección direccional o estabilizante para una función no lineal en Tribolium. Dos líneas de Tribolium castaneum fueron seleccionadas direccionalmente para un índice no lineal (experimento 1) o estabilizantemente para longitud de pupa (experimento 2), apareando los animales seleccionados clasificadamente (A) o aleatoriamente (R). Había tres repeticiones por experimento y línea, siendo la proporción de selección el 25%. En el experimento 1, el objetivo de selección incluía el peso adulto así como la longitud de pupa y su cuadrado. Ambas líneas dieron respuesta significativa para el valor agregado y sus dos caracteres componentes. Había una ventaja consistente aunque no significativa para el apareamiento clasificado, siendo la respuesta media para valor agregado y longitud de pupa 1.15 veces mayor en la línea A. En el experimento 2, el criterio de selección era el cuadrado de la desviación con respecto a la media de longitud de pupa (selección estabilizante); ambas líneas no mostraron ningún cambio significativo en longitud de pupa. La varianza fenotípica tuvo una disminución significativa debida a una reducción de la varianza genética, siendo estos cambios similares en ambas líneas. ZUSAMMENFASSUNG: Assortative Paarung, gerichtete oder stabilisierende Selektion für nicht-lineare Funktion von Merkmalen in Triboleum Assortative oder Zufallspaarung nach gerichteter Selektion in beiden Richtungen für nicht-lineare Merkmale (Versuch 1) oder stabilisierende für Puppenlänge (Versuch 2) wurden über 5 Generationen bei Triboleum castaneum (A bzw. R), mit je 3 Wiederholungen und 25% Remonte, durchgeführt. In Versuch 1 sollten adultes Gewicht und 1. und 2. Potenz der Puppenlänge gesteigert werden. A und R Linien ergaben signifikante Selektionserfolge für Gesamtwert (184 ± 6 bezw. 161 ± 14), Puppenlänge (0,74 ± 02, 0.64 ± 05) und adultes Gewicht (0.74 ± 03 und 0.78 ± 0.12). Obwohl Linie A nicht statistisch signifikant überlegen war, zeigte sich durchgehend überlegenheit gegenüber R Linien, im Durchschnitt 1,15 mal. In Versuch 2 zeigte keine der beiden Linien Veränderungen der Puppenlänge, aber die Varianz nahm signifikant ab wegen Verminderung der Varianz zwischen Familien, deren Abnahme in der zufalls- und in der assortativ gepaarten Linie gleich groß war. RÉSUMÉ: Accouplement classé et sélection directionelle o stabilisant pour une fonction no lineal chez Tribolium Deux lingnées de Tribolium castaneum on été soumis a sélection directionelle par un index no lineal (Expérience 1) o stabilisant pour la longeur de la pupae (Expérience 2), avec accouplement des animaux sélectiones de façon classé (A) ou aléatoire (R). Le travail compris 3 répétitions pour chacune des expériences et lignée, avec une presion de sélection du 25%. Dans l'expérience 1 l'objetive de sélection était composé pour le poids adult, la longeur de la pupae et sa carrée. On a obtenû une réponse significative chez les deux lignées por l'agregé et aussi pour les deux caractéres. On a obtenû une superiorité no significative mais consistant de l'accouplement classé, étant la réponse moyenne pour l'agregé et la longeur de la pupae 1.15 fois plus grand chez la lignée A. Pour l'experience 2 le critére de selection etait le carrée de la deviation a la moyenne de la longeur de la pupae (sélection stabilisant); aucune des lignees montrait changes significatives pour la longeur de la pupae. La variation phénotypique montre une réduction significative ` cause de la réduction du variation génétique, avec changes similaires chez les deux lignees. 1993 Blackwell Verlag GmbH.

Consequences for conservation: population density and genetic effects on reproduction of an endangered lagomorph.

PubMed

Demay, Stephanie M; Becker, Penny A; Waits, Lisette P; Johnson, Timothy R; Rachlow, Janet L

2016-04-01

Understanding reproduction and mating systems is important for managers tasked with conserving vulnerable species. Genetic tools allow biologists to investigate reproduction and mating systems with high resolution and are particularly useful for species that are otherwise difficult to study in their natural environments. We conducted parentage analyses using 19 nuclear DNA microsatellite loci to assess the influence of population density, genetic diversity, and ancestry on reproduction, and to examine the mating system of pygmy rabbits (Brachylagus idahoensis) bred in large naturalized enclosures for the reintroduction and recovery of the endangered distinct population in central Washington, USA. Reproductive output for females and males decreased as population density and individual homozygosity increased. We identified an interaction indicating that male reproductive output decreased as genetic diversity declined at high population densities, but there was no effect at low densities. Males with high amounts (> 50%) of Washington ancestry had higher reproductive output than the other ancestry groups, while reproductive output was decreased for males with high northern Utah/Wyoming ancestry and females with high Oregon/Nevada ancestry. Females and males bred with an average of 3.8 and 3.6 mates per year, respectively, and we found no evidence of positive or negative assortative mating with regards to ancestry. Multiple paternity was confirmed in 81% of litters, and we report the first documented cases of juvenile breeding by pygmy rabbits. This study demonstrates how variation in population density, genetic diversity, and ancestry impact fitness for an endangered species being bred for conservation. Our results advance understanding of basic life history characteristics for a cryptic species that is difficult to study in the wild and provide lessons for managing populations of vulnerable species in captive and free-ranging populations.

Intra- and Trans-Generational Costs of Reduced Female Body Size Caused by Food Limitation Early in Life in Mites

PubMed Central

Walzer, Andreas; Schausberger, Peter

2013-01-01

Background Food limitation early in life may be compensated for by developmental plasticity resulting in accelerated development enhancing survival at the expense of small adult body size. However and especially for females in non-matching maternal and offspring environments, being smaller than the standard may incur considerable intra- and trans-generational costs. Methodology/Principal Findings Here, we evaluated the costs of small female body size induced by food limitation early in life in the sexually size-dimorphic predatory mite Phytoseiulus persimilis. Females are larger than males. These predators are adapted to exploit ephemeral spider mite prey patches. The intra- and trans-generational effects of small maternal body size manifested in lower maternal survival probabilities, decreased attractiveness for males, and a reduced number and size of eggs compared to standard-sized females. The trans-generational effects of small maternal body size were sex-specific with small mothers producing small daughters but standard-sized sons. Conclusions/Significance Small female body size apparently intensified the well-known costs of sexual activity because mortality of small but not standard-sized females mainly occurred shortly after mating. The disadvantages of small females in mating and egg production may be generally explained by size-associated morphological and physiological constraints. Additionally, size-assortative mate preferences of standard-sized mates may have rendered small females disproportionally unattractive mating partners. We argue that the sex-specific trans-generational effects were due to sexual size dimorphism – females are the larger sex and thus more strongly affected by maternal stress than the smaller males – and to sexually selected lower plasticity of male body size. PMID:24265745

[Temporal dynamics of ethnic assortativeness in the Tsivil'sk region of Chuvashia].

PubMed

El'chinova, G I; Znichenko, R A; Ginter, E K

2003-04-01

Based on marriage records for 1950-1959, 1970-1979, and 1990-1999, ethnic assortativeness of Chuvash and Russian inhabitants of Tsivil'sk raion of the Chuvash Republic was calculated. It was shown that in half a century ethnic assortativeness of Chuvashes did not change (1.18, 1.15, and 1.15), while in Russians a clear downward trend was observed (4.20, 2.18, and 1.28). The data on ethnic assortativeness obtained were compared with those for the same populations from other regions of the Chuvashia examined earlier.

CD-Based Indices for Link Prediction in Complex Network.

PubMed

Wang, Tao; Wang, Hongjue; Wang, Xiaoxia

2016-01-01

Lots of similarity-based algorithms have been designed to deal with the problem of link prediction in the past decade. In order to improve prediction accuracy, a novel cosine similarity index CD based on distance between nodes and cosine value between vectors is proposed in this paper. Firstly, node coordinate matrix can be obtained by node distances which are different from distance matrix and row vectors of the matrix are regarded as coordinates of nodes. Then, cosine value between node coordinates is used as their similarity index. A local community density index LD is also proposed. Then, a series of CD-based indices include CD-LD-k, CD*LD-k, CD-k and CDI are presented and applied in ten real networks. Experimental results demonstrate the effectiveness of CD-based indices. The effects of network clustering coefficient and assortative coefficient on prediction accuracy of indices are analyzed. CD-LD-k and CD*LD-k can improve prediction accuracy without considering the assortative coefficient of network is negative or positive. According to analysis of relative precision of each method on each network, CD-LD-k and CD*LD-k indices have excellent average performance and robustness. CD and CD-k indices perform better on positive assortative networks than on negative assortative networks. For negative assortative networks, we improve and refine CD index, referred as CDI index, combining the advantages of CD index and evolutionary mechanism of the network model BA. Experimental results reveal that CDI index can increase prediction accuracy of CD on negative assortative networks.

CD-Based Indices for Link Prediction in Complex Network

PubMed Central

Wang, Tao; Wang, Hongjue; Wang, Xiaoxia

2016-01-01

Lots of similarity-based algorithms have been designed to deal with the problem of link prediction in the past decade. In order to improve prediction accuracy, a novel cosine similarity index CD based on distance between nodes and cosine value between vectors is proposed in this paper. Firstly, node coordinate matrix can be obtained by node distances which are different from distance matrix and row vectors of the matrix are regarded as coordinates of nodes. Then, cosine value between node coordinates is used as their similarity index. A local community density index LD is also proposed. Then, a series of CD-based indices include CD-LD-k, CD*LD-k, CD-k and CDI are presented and applied in ten real networks. Experimental results demonstrate the effectiveness of CD-based indices. The effects of network clustering coefficient and assortative coefficient on prediction accuracy of indices are analyzed. CD-LD-k and CD*LD-k can improve prediction accuracy without considering the assortative coefficient of network is negative or positive. According to analysis of relative precision of each method on each network, CD-LD-k and CD*LD-k indices have excellent average performance and robustness. CD and CD-k indices perform better on positive assortative networks than on negative assortative networks. For negative assortative networks, we improve and refine CD index, referred as CDI index, combining the advantages of CD index and evolutionary mechanism of the network model BA. Experimental results reveal that CDI index can increase prediction accuracy of CD on negative assortative networks. PMID:26752405

Experimental evidence for asymmetric mate preference and aggression: behavioral interactions in a woodrat (Neotoma) hybrid zone

PubMed Central

2013-01-01

Background Female mate preferences may be under strong selection in zones of contact between closely related species because of greater variation in available mates and the potential costs of hybridization. We studied female mate preferences experimentally in a zone of secondary contact between Desert and Bryant’s Woodrat (Neotoma lepida and N. bryanti) in the southern foothills of the Sierra Nevada of California. We tested female preference for conspecific versus heterospecific males in paired choice trials in which females could interact freely with males, but males could not interact directly with each other. We compared preferences of females from both allopatric and sympatric sites. Results We did not find evidence of the process of reinforcement as assortative preferences were not stronger in sympatry than in allopatry. Mate preferences, however, were asymmetric, with N. lepida females mating preferentially with conspecifics and N. bryanti females showing no preference by species. Sympatric females were less likely to mate than allopatric females, due in part to an increase in aggressive interactions. However, even in the absence of aggression, courtship led to mating less often in sympatric females, suggesting they were choosier or had lower sexual motivation than allopatric females. Conclusions Patterns of mate choice in this woodrat system appear to be strongly impacted by body size and aggressive behavior. In particular, females of the smaller-bodied species rarely interact with the relatively large heterospecific males. In contrast females of the larger-bodied species accept the relatively small heterospecific males. For sympatric animals, rates of aggression were markedly higher than for allopatric animals and reduced affiliative and reproductive behavior in our trials. Sympatric animals are larger and more aggressive, traits that are likely under strong ecological selection across the sharp resource gradient that characterizes the contact zone. However, our results suggest that these traits that are likely favored in competitive interactions between the species also impact reproductive interactions. Combined with our previous findings of post-zygotic isolation in this system, this study suggests that multiple isolating mechanisms contribute to the rate of genetic exchange between these species when they come into contact, and that these mechanisms are the result of selection on traits that are important in a range of ecological and reproductive interactions. PMID:24093823

War and Marriage: Assortative Mating and the World War II GI Bill.

PubMed

Larsen, Matthew F; McCarthy, T J; Moulton, Jeremy G; Page, Marianne E; Patel, Ankur J

2015-10-01

World War II and its subsequent GI Bill have been widely credited with playing a transformative role in American society, but there have been few quantitative analyses of these historical events' broad social effects. We exploit between-cohort variation in the probability of military service to investigate how WWII and the GI Bill altered the structure of marriage, and find that it had important spillover effects beyond its direct effect on men's educational attainment. Our results suggest that the additional education received by returning veterans caused them to "sort" into wives with significantly higher levels of education. This suggests an important mechanism by which socioeconomic status may be passed on to the next generation.

The impact of recombination on short-term selection gain in plant breeding experiments.

PubMed

McClosky, Benjamin; Tanksley, Steven D

2013-09-01

Recombination is a requirement for response to selection, but researchers still debate whether increasing recombination beyond normal levels will result in significant gains in short-term selection. We tested this hypothesis, in the context of plant breeding, through a series of simulation experiments comparing short-term selection response (≤20 cycles) between populations with normal levels of recombination and similar populations with unconstrained recombination (i.e., free recombination). We considered additive and epistatic models and examined a wide range of values for key design variables: selection cycles, QTL number, heritability, linkage phase, selection intensity and population size. With few exceptions, going from normal to unconstrained levels of recombination produced only modest gains in response to selection (≈11 % on average). We then asked how breeders might capture some of this theoretical gain by increasing recombination through either (1) extra rounds of mating or (2) selection of highly recombinant individuals via use of molecular markers/maps. All methods tested captured less than half of the potential gain, but our analysis indicates that the most effective method is to select for increased recombination and the trait simultaneously. This recommendation is based on evidence of a favorable interaction between trait selection and the impact of recombination on selection gains. Finally, we examined the relative contributions of the two components of meiotic recombination, chromosome assortment and crossing over, to short-term selection gain. Depending primarily on the presence of trait selection pressure, chromosome assortment alone accounted for 40-75 % of gain in response to short-term selection.

Clustering and Phase Transitions on a Neutral Landscape

NASA Astrophysics Data System (ADS)

Scott, Adam; King, Dawn; Maric, Nevena; Bahar, Sonya

2012-02-01

The problem of speciation and species aggregation on a neutral landscape, subject to random mutational fluctuations rather than selective drive, has been a focus of research since the seminal work of Kimura on genetic drift. These ideas have received increased attention due to the more recent development of a neutral ecological theory by Hubbell. De Aguiar et al. recently demonstrated, in a computational model, that speciation can occur under neutral conditions; this study bears some comparison with more mathematical studies of clustering on neutral landscapes in the context of branching and annihilating random walks. Here, we show that clustering can occur on a neutral landscape where the dimensions specify the simulated organisms' phenotypes. Unlike the De Aguiar et al. model, we simulate sympatric speciation: the organisms cluster phenotypically, but are not spatially separated. Moreover, we find that clustering occurs not only in the case of assortative mating, but also in the case of asexual fission. Clustering is not observed in a control case where organisms can mate randomly. We find that the population size and the number of clusters undergo phase-transition-like behavior as the maximum mutation size is varied.

Population cage experiments with a vertebrate: The temporal demography and cytonuclear genetics of hybridization on Gambusia fishes

USGS Publications Warehouse

Scribner, Kim T.; Avise, John C.

1994-01-01

The dynamics of mitochondrial and multilocus nuclear genotypic frequencies were monitored for 2 yr in experimental populations established with equal numbers of two poeciliid fishes (Gambusia affinis and Gambusia holbrooki) that hybridize naturally in the southeastern United States. In replicated "small-pool" populations (experiment I), 1018 sampled individuals at six time periods revealed an initial flush of hybridization, followed by a rapid decline in frequencies of G. affinis nuclear and mitochondrial alleles over 64 wk. Decay of gametic and cytonuclear disequilibria differed from expectations under random mating as well as under a model of assortative mating involving empirically estimated mating propensities. In two replicate "large-pond" populations (experiment II), 841 sampled individuals across four reproductive cohorts revealed lower initial frequencies of F1 hybrids than in experiment I, but again G. holbrooki alleles achieved high frequencies over four generations (72 wk). Thus, evolution within experimental Gambusia hybrid populations can be extremely rapid, resulting in consistent loss of G. affinis nuclear and cytoplasmic alleles. Concordance in results between experiments and across genetic markers suggests strong directional selection favoring G. holbrooki genotypes. Results are interpreted in light of previous reports of genotype-specific differences in life-history traits, reproductive ecology, patterns of recruitment, and size-specific mortality, and in the context of patterns of introgression previously studied indirectly from spatial observations on cytonuclear genotypes in natural Gambusia populations.

Plumage brightness as an indicator of parental care in northern cardinals

PubMed

Linville; Breitwisch; Schilling

1998-01-01

Good parent and differential allocation models predict relationships between degree of sexual ornamentation and parental care, but relatively few studies have tested these models. The northern cardinal, Cardinalis cardinalis, is a sexually dichromatic species in which both sexes are ornamented. Males have red plumage, and females have tan plumage with limited areas of red feathering. Cardinals were used to address the two models and determine whether plumage brightness signals level of parental care by both sexes. Absolute effort in feeding nestlings by males was not correlated with male breast plumage colour, but effort by females was positively correlated with female underwing plumage colour. Absolute feeding effort by females was also inversely related to brightness of the mate's breast colour. As a consequence, the proportion of a pair's total feedings provided by the male was positively correlated with male breast colour. Proportion of total feedings provided by the female was positively correlated with female wing colour. Feeding efforts (both per nest and per nestling) were correlated between mates, but birds did not mate assortatively in relation to colour. These results support the good parent hypothesis, suggesting colour brightness is a signal of parental care. The results also indicate that ornamentation of both members of the pair may be important determinants of relative efforts in provisioning nestlings by parent birds. Copyright 1998 The Association for the Study of Animal Behaviour.

Experimental evolution: Assortative mating and sexual selection, independent of local adaptation, lead to reproductive isolation in the nematode Caenorhabditis remanei.

PubMed

Castillo, Dean M; Burger, Melissa K; Lively, Curtis M; Delph, Lynda F

2015-12-01

Using experimental evolution, we investigated the contributions of ecological divergence, sexual selection, and genetic drift to the evolution of reproductive isolation in Caenorhabditis remanei. The nematodes were reared on two different environments for 100 generations. They were assayed for fitness on both environments after 30, 64, and 100 generations, and hybrid fitness were analyzed after 64 and 100 generations. Mating propensity within and between populations was also analyzed. The design allowed us to determine whether local adaptation was synchronous with pre- and postzygotic reproductive isolation. Prezygotic isolation evolved quickly but was unconnected with adaptation to the divergent environments. Instead, prezygotic isolation was driven by mate preferences favoring individuals from the same replicate population. A bottleneck treatment, meant to enhance the opportunity for genetic drift, had no effect on prezygotic isolation. Postzygotic isolation occurred in crosses where at least one population had a large fitness advantage in its "home" environment. Taken together, our results suggest that prezygotic isolation did not depend on drift or adaptation to divergent environments, but instead resulted from differences in sexual interactions within individual replicates. Furthermore, our results suggest that postzygotic isolation can occur between populations even when only one population has greater fitness in its home environment. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

The End of Hypergamy: Global Trends and Implications.

PubMed

Esteve, Albert; Schwartz, Christine R; Van Bavel, Jan; Permanyer, Iñaki; Klesment, Martin; Garcia, Joan

2016-12-01

The gender gap in education that has long favored men has reversed for young adults in almost all high and middle-income countries. In 2010, the proportion of women aged 25-29 with a college education was higher than that of men in more than 139 countries which altogether represent 86% of the world's population. According to recent population forecasts, women will have more education than men in nearly every country in the world by 2050, with the exception of only a few African and West Asian countries (KC et al. 2010). The reversal of the gender gap in education has major implications for the composition of marriage markets, assortative mating, gender equality, and marital outcomes such as divorce and childbearing (Van Bavel 2012). In this work, we focus on its implications for trends in assortative mating and, in particular, for educational hypergamy: the pattern in which husbands have more education than their wives. This represents a substantial update to previous studies (Esteve et al. 2012) in terms of the number of countries and years included in the analysis. We present findings from an almost comprehensive world-level analysis using census and survey microdata from 420 samples and 120 countries spanning from 1960 to 2011, which allow us to assert that the reversal of the gender gap in education is strongly associated with the end of hypergamy and increases in hypogamy (wives have more education that their husbands). We not only provide near universal evidence of this trend but extend our analysis to consider the implications of the end of hypergamy for family dynamics, outcomes and gender equality. We draw on European microdata to examine whether women are more likely to be the breadwinners when they marry men with lower education than themselves and discuss recent research regarding divorce risks among hypogamous couples. We close our analysis with an examination of attitudes about women earning more money than their husbands and about the implications for children when a woman works for pay.

What’s in a Surname? Physique, Aptitude, and Sports Type Comparisons between Tailors and Smiths

PubMed Central

Voracek, Martin; Rieder, Stephan; Stieger, Stefan; Swami, Viren

2015-01-01

Combined heredity of surnames and physique, coupled with past marriage patterns and trade-specific physical aptitude and selection factors, may have led to differential assortment of bodily characteristics among present-day men with specific trade-reflecting surnames (Tailor vs. Smith). Two studies reported here were partially consistent with this genetic-social hypothesis, first proposed by Bäumler (1980). Study 1 (N = 224) indicated significantly higher self-rated physical aptitude for prototypically strength-related activities (professions, sports, hobbies) in a random sample of Smiths. The counterpart effect (higher aptitude for dexterity-related activities among Tailors) was directionally correct, but not significant, and Tailor-Smith differences in basic physique variables were nil. Study 2 examined two large total-population-of-interest datasets (Austria/Germany combined, and UK: N = 7001 and 20532) of men’s national high-score lists for track-and-field events requiring different physiques. In both datasets, proportions of Smiths significantly increased from light-stature over medium-stature to heavy-stature sports categories. The predicted counterpart effect (decreasing prevalences of Tailors along these categories) was not supported. Related prior findings, the viability of possible alternative interpretations of the evidence (differential positive selection for trades and occupations, differential endogamy and assortative mating patterns, implicit egotism effects), and directions for further inquiry are discussed in conclusion. PMID:26161803

What's in a Surname? Physique, Aptitude, and Sports Type Comparisons between Tailors and Smiths.

PubMed

Voracek, Martin; Rieder, Stephan; Stieger, Stefan; Swami, Viren

2015-01-01

Combined heredity of surnames and physique, coupled with past marriage patterns and trade-specific physical aptitude and selection factors, may have led to differential assortment of bodily characteristics among present-day men with specific trade-reflecting surnames (Tailor vs. Smith). Two studies reported here were partially consistent with this genetic-social hypothesis, first proposed by Bäumler (1980). Study 1 (N = 224) indicated significantly higher self-rated physical aptitude for prototypically strength-related activities (professions, sports, hobbies) in a random sample of Smiths. The counterpart effect (higher aptitude for dexterity-related activities among Tailors) was directionally correct, but not significant, and Tailor-Smith differences in basic physique variables were nil. Study 2 examined two large total-population-of-interest datasets (Austria/Germany combined, and UK: N = 7001 and 20,532) of men's national high-score lists for track-and-field events requiring different physiques. In both datasets, proportions of Smiths significantly increased from light-stature over medium-stature to heavy-stature sports categories. The predicted counterpart effect (decreasing prevalences of Tailors along these categories) was not supported. Related prior findings, the viability of possible alternative interpretations of the evidence (differential positive selection for trades and occupations, differential endogamy and assortative mating patterns, implicit egotism effects), and directions for further inquiry are discussed in conclusion.

Parental conflict and blue egg coloration in a seabird

NASA Astrophysics Data System (ADS)

Morales, Judith; Torres, Roxana; Velando, Alberto

2010-02-01

When both parents provide offspring care, equal sharing of costly parental duties may enhance reproductive success. This is crucial for longlived species, where increased parental effort in current reproduction profoundly affects future reproduction. Indication of reproductive value or willingness to invest in reproduction may promote matching responses by mates, thus reducing the conflict over care. In birds with biparental care, blue-green eggshell color may function as a signal of reproductive value that affects parental effort, as predicted by the signaling hypothesis of blue-green eggshell coloration. However, this hypothesis has not been explored during incubation, when the potential stimulus of egg color is present, and has been little studied in longlived birds. We experimentally studied if egg color affected incubation patterns in the blue-footed booby, a longlived species with biparental care and blue eggs. We exchanged fresh eggs between nests of the same laying date and recorded parental incubation effort on the following 4 days. Although egg color did not affect male effort, original eggshell color was correlated with pair matching in incubation. Exchanged eggshell color did not affect incubation patterns. This suggests that biliverdin-based egg coloration reflects female quality features that are associated with pair incubation effort or that blue-footed boobies mate assortatively high-quality pairs incubating more colorful clutches. An intriguing possibility is that egg coloration facilitates an equal sharing of incubation, the signal being functional only during a short period close to laying. Results also suggest that indication of reproductive value reduces the conflict over care.

Bad, burdened or ill? Characterizing the spouses of women with schizophrenia.

PubMed

Seeman, Mary V

2013-12-01

The husbands of women with schizophrenia have been variously characterized in the psychiatric literature as abusive, burdened and ill. The aim of this paper is to summarize what has been written about these three perspectives. The search terms 'schizophrenia', 'mental illness', 'marriage', 'spouse', 'partner', 'caregiver', 'caregiving', 'burden', 'assortative mating' and 'domestic abuse' were entered into PubMed and Google Scholar. Criteria for inclusion of articles were relevance to the three identified themes of abuse, burden and mental illness in husbands of women with schizophrenia. The results show considerable variation, some of it cultural, with partial evidence for all three characterizations. There is a need for support and psychoeducation programmes that are specifically designated for spouses and that address their special concerns.

Positive Network Assortativity of Influenza Vaccination at a High School: Implications for Outbreak Risk and Herd Immunity

PubMed Central

He, Jianping; Cao, Guohong; Rainey, Jeanette J.; Gao, Hongjiang; Uzicanin, Amra; Salathé, Marcel

2014-01-01

Schools are known to play a significant role in the spread of influenza. High vaccination coverage can reduce infectious disease spread within schools and the wider community through vaccine-induced immunity in vaccinated individuals and through the indirect effects afforded by herd immunity. In general, herd immunity is greatest when vaccination coverage is highest, but clusters of unvaccinated individuals can reduce herd immunity. Here, we empirically assess the extent of such clustering by measuring whether vaccinated individuals are randomly distributed or demonstrate positive assortativity across a United States high school contact network. Using computational models based on these empirical measurements, we further assess the impact of assortativity on influenza disease dynamics. We found that the contact network was positively assortative with respect to influenza vaccination: unvaccinated individuals tended to be in contact more often with other unvaccinated individuals than with vaccinated individuals, and these effects were most pronounced when we analyzed contact data collected over multiple days. Of note, unvaccinated males contributed substantially more than unvaccinated females towards the measured positive vaccination assortativity. Influenza simulation models using a positively assortative network resulted in larger average outbreak size, and outbreaks were more likely, compared to an otherwise identical network where vaccinated individuals were not clustered. These findings highlight the importance of understanding and addressing heterogeneities in seasonal influenza vaccine uptake for prevention of large, protracted school-based outbreaks of influenza, in addition to continued efforts to increase overall vaccine coverage. PMID:24505274

The evolution of conditional dispersal and reproductive isolation along environmental gradients

PubMed Central

Payne, Joshua L.; Mazzucco, Rupert; Dieckmann, Ulf

2011-01-01

Dispersal modulates gene flow throughout a population’s spatial range. Gene flow affects adaptation at local spatial scales, and consequently impacts the evolution of reproductive isolation. A recent theoretical investigation has demonstrated that local adaptation along an environmental gradient, facilitated by the evolution of limited dispersal, can lead to parapatric speciation even in the absence of assortative mating. This and other studies assumed unconditional dispersal, so individuals start dispersing without regard to local environmental conditions. However, many species disperse conditionally; their propensity to disperse is contingent upon environmental cues, such as the degree of local crowding or the availability of suitable mates. Here, we use an individual-based model in continuous space to investigate by numerical simulation the relationship between the evolution of threshold-based conditional dispersal and parapatric speciation driven by frequency-dependent competition along environmental gradients. We find that, as with unconditional dispersal, parapatric speciation occurs under a broad range of conditions when reproduction is asexual, and under a more restricted range of conditions when reproduction is sexual. In both the asexual and sexual cases, the evolution of conditional dispersal is strongly influenced by the slope of the environmental gradient: shallow environmental gradients result in low dispersal thresholds and high dispersal distances, while steep environmental gradients result in high dispersal thresholds and low dispersal distances. The latter, however, remain higher than under unconditional dispersal, thus undermining isolation by distance, and hindering speciation in sexual populations. Consequently, the speciation of sexual populations under conditional dispersal is triggered by a steeper gradient than under unconditional dispersal. Enhancing the disruptiveness of frequency-dependent selection, more box-shaped competition kernels dramatically lower the speciation-enabling slope of the environmental gradient. PMID:21194533

The evolution of conditional dispersal and reproductive isolation along environmental gradients.

PubMed

Payne, Joshua L; Mazzucco, Rupert; Dieckmann, Ulf

2011-03-21

Dispersal modulates gene flow throughout a population's spatial range. Gene flow affects adaptation at local spatial scales, and consequently impacts the evolution of reproductive isolation. A recent theoretical investigation has demonstrated that local adaptation along an environmental gradient, facilitated by the evolution of limited dispersal, can lead to parapatric speciation even in the absence of assortative mating. This and other studies assumed unconditional dispersal, so individuals start dispersing without regard to local environmental conditions. However, many species disperse conditionally; their propensity to disperse is contingent upon environmental cues, such as the degree of local crowding or the availability of suitable mates. Here, we use an individual-based model in continuous space to investigate by numerical simulation the relationship between the evolution of threshold-based conditional dispersal and parapatric speciation driven by frequency-dependent competition along environmental gradients. We find that, as with unconditional dispersal, parapatric speciation occurs under a broad range of conditions when reproduction is asexual, and under a more restricted range of conditions when reproduction is sexual. In both the asexual and sexual cases, the evolution of conditional dispersal is strongly influenced by the slope of the environmental gradient: shallow environmental gradients result in low dispersal thresholds and high dispersal distances, while steep environmental gradients result in high dispersal thresholds and low dispersal distances. The latter, however, remain higher than under unconditional dispersal, thus undermining isolation by distance, and hindering speciation in sexual populations. Consequently, the speciation of sexual populations under conditional dispersal is triggered by a steeper gradient than under unconditional dispersal. Enhancing the disruptiveness of frequency-dependent selection, more box-shaped competition kernels dramatically lower the speciation-enabling slope of the environmental gradient. Copyright © 2010 Elsevier Ltd. All rights reserved.

Lengthening of Insect Development on Bt Zone Results in Adult Emergence Asynchrony: Does It Influence the Effectiveness of the High Dose/Refuge Zone Strategy?

PubMed Central

Gryspeirt, Aiko; Grégoire, Jean-Claude

2012-01-01

The “High Dose/Refuge” strategy (HD/R) is the currently recommended Insect Resistance Management strategy (IRM) to limit resistance development to Bacillus thuringiensis (Bt) plants. This strategy requires planting a “refuge zone” composed of non-Bt plants suitable for the target insect and in close proximity to a “Bt zone” expressing a high toxin concentration. One of the main assumptions is that enough susceptible adults mate with resistant insects. However, previous studies have suggested that the high toxin concentration produced by Bt plants induces slower insect development, creating an asynchrony in emergence between the refuge and the Bt zone and leading to assortative mating between adults inside each zone. Here, we develop a deterministic model to estimate the impact of toxin concentration, emergence asynchrony and refuge zone size on the effectiveness of the HD/R strategy. We conclude that emergence asynchrony only affects resistance when toxin concentration is high and resistance is recessive. Resistance develops more rapidly and survival of susceptible insects is higher at lower toxin concentration, but in such situations, resistance is insensitive to emergence asynchrony. PMID:23202319

Structured mating: Patterns and implications

PubMed Central

Sebro, Ronnie; Peloso, Gina M.; Risch, Neil J.

2017-01-01

Genetic similarity of spouses can reflect factors influencing mate choice, such as physical/behavioral characteristics, and patterns of social endogamy. Spouse correlations for both genetic ancestry and measured traits may impact genotype distributions (Hardy Weinberg and linkage equilibrium), and therefore genetic association studies. Here we evaluate white spouse-pairs from the Framingham Heart Study (FHS) original and offspring cohorts (N = 124 and 755, respectively) to explore spousal genetic similarity and its consequences. Two principal components (PCs) of the genome-wide association (GWA) data were identified, with the first (PC1) delineating clines of Northern/Western to Southern European ancestry and the second (PC2) delineating clines of Ashkenazi Jewish ancestry. In the original (older) cohort, there was a striking positive correlation between the spouses in PC1 (r = 0.73, P = 3x10-22) and also for PC2 (r = 0.80, P = 7x10-29). In the offspring cohort, the spouse correlations were lower but still highly significant for PC1 (r = 0.38, P = 7x10-28) and for PC2 (r = 0.45, P = 2x10-39). We observed significant Hardy-Weinberg disequilibrium for single nucleotide polymorphisms (SNPs) loading heavily on PC1 and PC2 across 3 generations, and also significant linkage disequilibrium between unlinked SNPs; both decreased with time, consistent with reduced ancestral endogamy over generations and congruent with theoretical calculations. Ignoring ancestry, estimates of spouse kinship have a mean significantly greater than 0, and more so in the earlier generations. Adjusting kinship estimates for genetic ancestry through the use of PCs led to a mean spouse kinship not different from 0, demonstrating that spouse genetic similarity could be fully attributed to ancestral assortative mating. These findings also have significance for studies of heritability that are based on distantly related individuals (kinship less than 0.05), as we also demonstrate the poor correlation of kinship estimates in that range when ancestry is or is not taken into account. PMID:28384154

Mares Prefer the Voices of Highly Fertile Stallions

PubMed Central

Lemasson, Alban; Remeuf, Kévin; Trabalon, Marie; Cuir, Frédérique; Hausberger, Martine

2015-01-01

We investigated the possibility that stallion whinnies, known to encode caller size, also encoded information about caller arousal and fertility, and the reactions of mares in relation to type of voice. Voice acoustic features are correlated with arousal and reproduction success, the lower-pitched the stallion’s voice, the slower his heart beat and the higher his fertility. Females from three study groups preferred playbacks of low-pitched voices. Hence, females are attracted by frequencies encoding for large male size, calmness and high fertility. More work is needed to explore the relative importance of morpho-physiological features. Assortative mating may be involved as large females preferred voices of larger stallions. Our study contributes to basic and applied ongoing research on mammal reproduction, and questions the mechanisms used by females to detect males’ fertility. PMID:25714814

A Darker Shade of Love: Machiavellianism and Positive Assortative Mating Based on Romantic Ideals

PubMed Central

Ináncsi, Tamás; Láng, András; Bereczkei, Tamás

2016-01-01

Machiavellianism is a personality trait that is characterized by manipulative and exploitative attitude toward others, lack of empathy, and a cynical view of human nature. In itself or as part of the Dark Triad it has been the target of several studies investigating romantic relations. Nevertheless, the relationship between Machiavellianism and romantic ideals has not been revealed yet. An undergraduate sample of 143 (92 females) with an average age of 19.83 years (SD = 1.51 years) filled out self-report measures of Machiavellianism (Mach-IV Scale) and romantic ideals (Ideal Standards Scale and NEO-FFI-IDEAL). According to our results, Machiavellianism correlated negatively with the importance of partner’s warmth-trustworthiness, extraversion, openness, agreeableness, and with the importance of intimacy and loyalty in their ideal relationships. Machiavellianism correlated positively with the ideal partner’s possession over status and resources. Explorative factor analysis revealed three components of ideal partner’s characteristics. Machiavellianism loaded significantly on two out of three components. Results are discussed with regard to Ideal Standards Model and the Big Five model of personality. PMID:27247697

DNA profiling of Tilapia guinasana, a species endemic to a single sinkhole, to determine the genetic divergence between color forms.

PubMed

Nxomani, C; Ribbink, A J; Kirby, R

1999-06-01

Northwestern South Africa and Namibia contain a number of sinkholes in the dolomitic rock formations found in this area. These contain isolated populations of Tilapia. Most contain Tilapia sparmanii, but the one in Namibia, Guinas, is of particular interest as it contains the endemic species, Tilapia guinasana, which exhibits none sex-limited polychromatisms, which is unique for Tilapia. This sinkhole is under environmental threat, particularly as a result of being a recreational diving site. This study, using randomly amplified polymorphic DNA sequences (RAPDs), when analyzed using analysis of variance (ANOVA), shows that the colour forms of Tilapia guinasana are genetically distinct. This confirms previous evidence that assortative mating between color forms takes place. The various possible hypotheses for the occurrence and genetic stability of the color polymorphism are discussed. Further, a new hypothesis is put forward based on a need to maximize outbreeding in fully isolated population with no possibility of increase in size above the maximum and limited carrying capacity of the sinkhole.

Replication of a gene-environment interaction Via Multimodel inference: additive-genetic variance in adolescents' general cognitive ability increases with family-of-origin socioeconomic status.

PubMed

Kirkpatrick, Robert M; McGue, Matt; Iacono, William G

2015-03-01

The present study of general cognitive ability attempts to replicate and extend previous investigations of a biometric moderator, family-of-origin socioeconomic status (SES), in a sample of 2,494 pairs of adolescent twins, non-twin biological siblings, and adoptive siblings assessed with individually administered IQ tests. We hypothesized that SES would covary positively with additive-genetic variance and negatively with shared-environmental variance. Important potential confounds unaddressed in some past studies, such as twin-specific effects, assortative mating, and differential heritability by trait level, were found to be negligible. In our main analysis, we compared models by their sample-size corrected AIC, and base our statistical inference on model-averaged point estimates and standard errors. Additive-genetic variance increased with SES-an effect that was statistically significant and robust to model specification. We found no evidence that SES moderated shared-environmental influence. We attempt to explain the inconsistent replication record of these effects, and provide suggestions for future research.

Replication of a Gene-Environment Interaction via Multimodel Inference: Additive-Genetic Variance in Adolescents’ General Cognitive Ability Increases with Family-of-Origin Socioeconomic Status

PubMed Central

Kirkpatrick, Robert M.; McGue, Matt; Iacono, William G.

2015-01-01

The present study of general cognitive ability attempts to replicate and extend previous investigations of a biometric moderator, family-of-origin socioeconomic status (SES), in a sample of 2,494 pairs of adolescent twins, non-twin biological siblings, and adoptive siblings assessed with individually administered IQ tests. We hypothesized that SES would covary positively with additive-genetic variance and negatively with shared-environmental variance. Important potential confounds unaddressed in some past studies, such as twin-specific effects, assortative mating, and differential heritability by trait level, were found to be negligible. In our main analysis, we compared models by their sample-size corrected AIC, and base our statistical inference on model-averaged point estimates and standard errors. Additive-genetic variance increased with SES—an effect that was statistically significant and robust to model specification. We found no evidence that SES moderated shared-environmental influence. We attempt to explain the inconsistent replication record of these effects, and provide suggestions for future research. PMID:25539975

Assortative social learning and its implications for human (and animal?) societies.

PubMed

Katsnelson, Edith; Lotem, Arnon; Feldman, Marcus W

2014-07-01

Choosing from whom to learn is an important element of social learning. It affects learner success and the profile of behaviors in the population. Because individuals often differ in their traits and capabilities, their benefits from different behaviors may also vary. Homophily, or assortment, the tendency of individuals to interact with other individuals with similar traits, is known to affect the spread of behaviors in humans. We introduce models to study the evolution of assortative social learning (ASL), where assorting on a trait acts as an individual-specific mechanism for filtering relevant models from which to learn when that trait varies. We show that when the trait is polymorphic, ASL may maintain a stable behavioral polymorphism within a population (independently of coexistence with individual learning in a population). We explore the evolution of ASL when assortment is based on a nonheritable or partially heritable trait, and when ASL competes with different non-ASL strategies: oblique (learning from the parental generation) and vertical (learning from the parent). We suggest that the tendency to assort may be advantageous in the context of social learning, and that ASL might be an important concept for the evolutionary theory of social learning. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

Geographically selective assortment of cycles in pandemics: meta-analysis of data collected by Chizhevsky.

PubMed

Gumarova, L; Cornélissen, G; Hillman, D; Halberg, F

2013-10-01

In the incidence patterns of cholera, diphtheria and croup during the past when they were of epidemic proportions, we document a set of cycles (periods), one of which was reported and discussed by A. L. Chizhevsky in the same data with emphasis on the mirroring in human disease of the ~11-year sunspot cycle. The data in this study are based on Chizhevsky’s book The Terrestrial Echo of Solar Storms and on records from the World Health Organization. For meta-analysis, we used the extended linear and nonlinear cosinor. We found a geographically selective assortment of various cycles characterizing the epidemiology of infections, which is the documented novel topic of this paper, complementing the earlier finding in the 21st century or shortly before, of a geographically selective assortment of cycles characterizing human sudden cardiac death. Solar effects, if any, interact with geophysical processes in contributing to this assortment.

Ecological separation in a polymorphic terrestrial salamander.

PubMed

Anthony, Carl D; Venesky, Matthew D; Hickerson, Cari-Ann M

2008-07-01

1. When studying speciation, researchers commonly examine reproductive isolation in recently diverged populations. Polymorphic species provide an opportunity to examine the role of reproductive isolation in populations that may be in the process of divergence. 2. We examined a polymorphic population of Plethodon cinereus (red-backed salamanders) for evidence of sympatric ecological separation by colour morphology. Recent studies have correlated temperature and climate with colour morphology in this species, but no studies have looked at differences in diet or mate choice between colour morphs. We used artificial cover objects to assess salamander diet, mating preference and surface activity over a 2-year period at a field site in north-eastern Ohio. 3. We detected differences in diet between two colour morphs, striped and unstriped. The diets of striped individuals were significantly more diverse and were made up of more profitable prey than the diets of unstriped salamanders. 4. Opposite sex pairs were made up of individuals of the same colour morph and striped males were found more often with larger females than were unstriped males. 5. We corroborate findings of earlier studies suggesting that the unstriped form is adapted to warmer conditions. Unstriped individuals were the first to withdraw from the forest floor as temperatures fell in the late fall. We found no evidence that the colour morphs responded differently to abiotic factors such as soil moisture and relative humidity, and responses to surface temperatures were also equivocal. 6. We conclude that the two colour morphs exhibit some degree of ecological separation and tend to mate assortatively, but are unlikely to be undergoing divergence given the observed frequency of intermorph pairings.

Tracing the first step to speciation: ecological and genetic differentiation of a salamander population in a small forest.

PubMed

Steinfartz, Sebastian; Weitere, Markus; Tautz, Diethard

2007-11-01

Mechanisms and processes of ecologically driven adaptive speciation are best studied in natural situations where the splitting process is still occurring, i.e. before complete reproductive isolation is achieved. Here, we present a case of an early stage of adaptive differentiation under sympatric conditions in the fire salamander, Salamandra salamandra, that allows inferring the underlying processes for the split. Larvae of S. salamandra normally mature in small streams until metamorphosis, but in an old, continuous forest area near Bonn (the Kottenforst), we found salamander larvae not only in small streams but also in shallow ponds, which are ecologically very different from small streams. Common-environment experiments with larvae from both habitat types reveal specific adaptations to these different ecological conditions. Mitochondrial and microsatellite analyses show that the two ecologically differentiated groups also show signs of genetic differentiation. A parallel analysis of animals from a neighbouring much larger forest area (the Eifel), in which larvae mature only in streams, shows no signs of genetic differentiation, indicating that gene flow between ecologically similar types can occur over large distances. Hence, geographical factors cannot explain the differential larval habitat adaptations in the Kottenforst, in particular since adult life and mating of S. salamandra is strictly terrestrial and not associated with larval habitats. We propose therefore that the evolution of these adaptations was coupled with the evolution of cues for assortative mating which would be in line with models of sympatric speciation that suggest a co-evolution of habitat adaptations and associated mating signals.

Parental choice: exploring in-law preferences and their contingencies in the Greek-Cypriot culture.

PubMed

Apostolou, Menelaos

2014-01-30

Despite the fact that parents exercise considerable influence over their children's choice of a mate, little is known of their preferences for daughters- and sons-in-law, particularly in a post-industrial context. This research aims to close the gap in our knowledge by making a taxonomic contribution on the qualities desired in an in-law. In particular, parents have rated the desirability of 88 traits in a prospective daughter-in-law and a son-in-law; using principal components analysis, these traits have been classified into 11 broader in-law preferences. On the basis of this classification, four hypotheses were tested: First, parents ascribe different weights to different traits; second, parental preferences are contingent upon the sex of the in-law (i.e., certain traits are valued differently in a son- and in a daughter-in-law); third, parents have a preference for assortative mating (i.e., they want their prospective in-laws and their families to be similar to them); and fourth, in-law preferences are independent of the sex of the parent (i.e., mothers and fathers are in agreement with respect to what qualities they seek in a spouse for their children). The results from two independent studies provide support for the first three hypotheses, but little support for the fourth hypothesis.

Females discriminate against heterospecific sperm in a natural hybrid zone.

PubMed

Cramer, Emily R A; Ålund, Murielle; McFarlane, S Eryn; Johnsen, Arild; Qvarnström, Anna

2016-08-01

When hybridization is maladaptive, species-specific mate preferences are selectively favored, but low mate availability may constrain species-assortative pairing. Females paired to heterospecifics may then benefit by copulating with multiple males and subsequently favoring sperm of conspecifics. Whether such mechanisms for biasing paternity toward conspecifics act as important reproductive barriers in socially monogamous vertebrate species remains to be determined. We use a combination of long-term breeding records from a natural hybrid zone between collared and pied flycatchers (Ficedula albicollis and F. hypoleuca), and an in vitro experiment comparing conspecific and heterospecific sperm performance in female reproductive tract fluid, to evaluate the potential significance of female cryptic choice. We show that the females most at risk of hybridizing (pied flycatchers) frequently copulate with multiple males and are able to inhibit heterospecific sperm performance. The negative effect on heterospecific sperm performance was strongest in pied flycatcher females that were most likely to have been previously exposed to collared flycatcher sperm. We thus demonstrate that a reproductive barrier acts after copulation but before fertilization in a socially monogamous vertebrate. While the evolutionary history of this barrier is unknown, our results imply that there is opportunity for it to be accentuated via a reinforcement-like process. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

Genetic differentiation and selection against migrants in evolutionarily replicated extreme environments.

PubMed

Plath, Martin; Pfenninger, Markus; Lerp, Hannes; Riesch, Rüdiger; Eschenbrenner, Christoph; Slattery, Patrick A; Bierbach, David; Herrmann, Nina; Schulte, Matthias; Arias-Rodriguez, Lenin; Rimber Indy, Jeane; Passow, Courtney; Tobler, Michael

2013-09-01

We investigated mechanisms of reproductive isolation in livebearing fishes (genus Poecilia) inhabiting sulfidic and nonsulfidic habitats in three replicate river drainages. Although sulfide spring fish convergently evolved divergent phenotypes, it was unclear if mechanisms of reproductive isolation also evolved convergently. Using microsatellites, we found strongly reduced gene flow between adjacent populations from different habitat types, suggesting that local adaptation to sulfidic habitats repeatedly caused the emergence of reproductive isolation. Reciprocal translocation experiments indicate strong selection against immigrants into sulfidic waters, but also variation among drainages in the strength of selection against immigrants into nonsulfidic waters. Mate choice experiments revealed the evolution of assortative mating preferences in females from nonsulfidic but not from sulfidic habitats. The inferred strength of sexual selection against immigrants (RI(s)) was negatively correlated with the strength of natural selection (RI(m)), a pattern that could be attributed to reinforcement, whereby natural selection strengthens behavioral isolation due to reduced hybrid fitness. Overall, reproductive isolation and genetic differentiation appear to be replicated and direct consequences of local adaptation to sulfide spring environments, but the relative contributions of different mechanisms of reproductive isolation vary across these evolutionarily independent replicates, highlighting both convergent and nonconvergent evolutionary trajectories of populations in each drainage. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

Unwed fathers' ability to pay child support: new estimates accounting for multiple-partner fertility.

PubMed

Sinkewicz, Marilyn; Garfinkel, Irwin

2009-05-01

We present new estimates of unwed fathers' ability to pay child support. Prior research relied on surveys that drastically undercounted nonresident unwed fathers and provided no link to their children who lived in separate households. To overcome these limitations, previous research assumed assortative mating and that each mother partnered with one father who was actually eligible to pay support and had no other child support obligations. Because the Fragile Families and Child Wellbeing Study contains data on couples, multiple-partner fertility, and a rich array of other previously unmeasured characteristics of fathers, it is uniquely suited to address the limitations of previous research. We also use an improved method of dealing with missing data. Our findings suggest that previous research overestimated the aggregate ability of unwed nonresident fathers to pay child support by 33% to 60%.

Humming in Tune: Sex and Species Recognition by Mosquitoes on the Wing

PubMed Central

Gibson, Gabriella; Warren, Ben

2010-01-01

Mosquitoes are more sensitive to sound than any other insect due to the remarkable properties of their antennae and Johnston’s organ at the base of each antenna. Male mosquitoes detect and locate female mosquitoes by hearing the female’s flight tone, but until recently we had no idea that females also respond to male flight tones. Our investigation of a novel mechanism of sex recognition in Toxorhynchites brevipalpis revealed that male and female mosquitoes actively respond to the flight tones of other flying mosquitoes by altering their own wing-beat frequencies. Male–female pairs converge on a shared harmonic of their respective fundamental flight tones, whereas same sex pairs diverge. Most frequency matching occurs at frequencies beyond the detection range of the Johnston’s organ but within the range of mechanical responsiveness of the antennae. We have shown that this is possible because the Johnston’s organ is tuned to, and able to detect difference tones in, the harmonics of antennal vibrations which are generated by the combined input of flight tones from both mosquitoes. Acoustic distortion in hearing organs exists usually as an interesting epiphenomenon. Mosquitoes, however, appear to use it as a sensory cue that enables male–female pairs to communicate through a signal that depends on auditory interactions between them. Frequency matching may also provide a means of species recognition. Morphologically identical but reproductively isolated molecular forms of Anopheles gambiae fly in the same mating swarms, but rarely hybridize. Extended frequency matching occurs almost exclusively between males and females of the same molecular form, suggesting that this behavior is associated with observed assortative mating. PMID:20976515

Marine Corps Shelterized Expeditionary Food Service System. Marine Corps ISO (International Organization for Standardization) Galley and Sanitation Unit

DTIC Science & Technology

1982-07-01

Scrambled Eggs Hard Boiled Eggs Bacon Sausage Patties Lyonnaise Potatoes Apricot Quick Coffee Cake Assorted Dry Cereals Assorted Fresh Fruits Bread and...Butter Assorted Beverages Lunch Baked Spanish Beef Patties Lyonnaise Potatoes Stewed Tomatoes Hamburger Buns Apple Crisp Assorted Beverages Dinner...Yellow Cake with Chocolate Frosting Assorted Beverages 5. 16 SEPTEMBER 1981 Breakfast Scrambled Eggs Hard Boiled Eggs Ham Creamed Beef Lyonnaise Potatoes

Population and genomic lessons from genetic analysis of two Indian populations.

PubMed

Juyal, Garima; Mondal, Mayukh; Luisi, Pierre; Laayouni, Hafid; Sood, Ajit; Midha, Vandana; Heutink, Peter; Bertranpetit, Jaume; Thelma, B K; Casals, Ferran

2014-10-01

Indian demographic history includes special features such as founder effects, interpopulation segregation, complex social structure with a caste system and elevated frequency of consanguineous marriages. It also presents a higher frequency for some rare mendelian disorders and in the last two decades increased prevalence of some complex disorders. Despite the fact that India represents about one-sixth of the human population, deep genetic studies from this terrain have been scarce. In this study, we analyzed high-density genotyping and whole-exome sequencing data of a North and a South Indian population. Indian populations show higher differentiation levels than those reported between populations of other continents. In this work, we have analyzed its consequences, by specifically assessing the transferability of genetic markers from or to Indian populations. We show that there is limited genetic marker portability from available genetic resources such as HapMap or the 1,000 Genomes Project to Indian populations, which also present an excess of private rare variants. Conversely, tagSNPs show a high level of portability between the two Indian populations, in contrast to the common belief that North and South Indian populations are genetically very different. By estimating kinship from mates and consanguinity in our data from trios, we also describe different patterns of assortative mating and inbreeding in the two populations, in agreement with distinct mating preferences and social structures. In addition, this analysis has allowed us to describe genomic regions under recent adaptive selection, indicating differential adaptive histories for North and South Indian populations. Our findings highlight the importance of considering demography for design and analysis of genetic studies, as well as the need for extending human genetic variation catalogs to new populations and particularly to those with particular demographic histories.

Genetic and Environmental Influences on Individual Differences in Attitudes Toward Homosexuality: An Australian Twin Study

PubMed Central

Shekar, Sri N.; Zietsch, Brendan P.; Eaves, Lindon J.; Bailey, J. Michael; Boomsma, Dorret I.; Martin, Nicholas G.

2008-01-01

Previous research has shown that many heterosexuals hold negative attitudes toward homosexuals and homosexuality (homophobia). Although a great deal of research has focused on the profile of homophobic individuals, this research provides little theoretical insight into the aetiology of homophobia. To examine genetic and environmental influences on variation in attitudes toward homophobia, we analysed data from 4,688 twins who completed a questionnaire concerning sexual behaviour and attitudes, including attitudes toward homosexuality. Results show that, in accordance with literature, males have significantly more negative attitudes toward homosexuality than females and non-heterosexuals are less homophobic than heterosexuals. In contrast with some earlier findings, age had no significant effect on the homophobia scores in this study. Genetic modelling showed that variation in homophobia scores could be explained by additive genetic (36%), shared environmental (18%) and unique environmental factors (46%). However, corrections based on previous findings show that the shared environmental estimate may be almost entirely accounted for as extra additive genetic variance arising from assortative mating for homophobic attitudes. The results suggest that variation in attitudes toward homosexuality is substantially inherited, and that social environmental influences are relatively minor. PMID:18347968

“Bad Romance”: Links between Psychological and Physical Aggression and Relationship Functioning in Adolescent Couples

PubMed Central

Seiffge-Krenke, Inge; Burk, William J.

2015-01-01

Assortative mating is an important issue in explaining antisocial, aggressive behavior. It is yet unclear, whether the similarity paradigm fully explains frequent displays of aggression in adolescents’ romantic relationships. In a sample of 194 romantic partner dyads, differences between female and male partners’ reports of aggression (psychological and physical) and different measures of relationship functioning (e.g., jealousy, conflicts, and the affiliative and romantic quality of the relationship) were assessed. A hierarchical cluster analysis identified five distinct subgroups of dyads based on male and female reports of psychological and physical aggression: nonaggressive couples, couples with higher perceived aggressiveness (both physical and psychological) by females, couples with higher aggressiveness perceived by males and mutually aggressive couples. A substantial number of non-aggressive dyads emerged. Of note was the high number of females showing one-sided aggression, which was, however, not countered by their partner. The mutually aggressive couples showed the least adaptive relationship functioning, with a lack of supportive, trusting relationship qualities, high conflict rates and high jealousy. The discussion focuses on the different functions of aggression in these early romantic relations, and the aggravating impact of mutual aggression on relationship functioning and its potential antisocial outcomes. PMID:26067515

Riverscape genetics identifies replicated ecological divergence across an Amazonian ecotone.

PubMed

Cooke, Georgina M; Landguth, Erin L; Beheregaray, Luciano B

2014-07-01

Ecological speciation involves the evolution of reproductive isolation and niche divergence in the absence of a physical barrier to gene flow. The process is one of the most controversial topics of the speciation debate, particularly in tropical regions. Here, we investigate ecologically based divergence across an Amazonian ecotone in the electric fish, Steatogenys elegans. We combine phylogenetics, genome scans, and population genetics with a recently developed individual-based evolutionary landscape genetics approach that incorporates selection. This framework is used to assess the relative contributions of geography and divergent natural selection between environments as biodiversity drivers. We report on two closely related and sympatric lineages that exemplify how divergent selection across a major Amazonian aquatic ecotone (i.e., between rivers with markedly different hydrochemical properties) may result in replicated ecologically mediated speciation. The results link selection across an ecological gradient with reproductive isolation and we propose that assortative mating based on water color may be driving the divergence. Divergence resulting from ecologically driven selection highlights the importance of considering environmental heterogeneity in studies of speciation in tropical regions. Furthermore, we show that framing ecological speciation in a spatially explicit evolutionary landscape genetics framework provides an important first step in exploring a wide range of the potential effects of spatial dependence in natural selection. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

From sparse to dense and from assortative to disassortative in online social networks

PubMed Central

Li, Menghui; Guan, Shuguang; Wu, Chensheng; Gong, Xiaofeng; Li, Kun; Wu, Jinshan; Di, Zengru; Lai, Choy-Heng

2014-01-01

Inspired by the analysis of several empirical online social networks, we propose a simple reaction-diffusion-like coevolving model, in which individuals are activated to create links based on their states, influenced by local dynamics and their own intention. It is shown that the model can reproduce the remarkable properties observed in empirical online social networks; in particular, the assortative coefficients are neutral or negative, and the power law exponents γ are smaller than 2. Moreover, we demonstrate that, under appropriate conditions, the model network naturally makes transition(s) from assortative to disassortative, and from sparse to dense in their characteristics. The model is useful in understanding the formation and evolution of online social networks. PMID:24798703

From sparse to dense and from assortative to disassortative in online social networks.

PubMed

Li, Menghui; Guan, Shuguang; Wu, Chensheng; Gong, Xiaofeng; Li, Kun; Wu, Jinshan; Di, Zengru; Lai, Choy-Heng

2014-05-06

Inspired by the analysis of several empirical online social networks, we propose a simple reaction-diffusion-like coevolving model, in which individuals are activated to create links based on their states, influenced by local dynamics and their own intention. It is shown that the model can reproduce the remarkable properties observed in empirical online social networks; in particular, the assortative coefficients are neutral or negative, and the power law exponents γ are smaller than 2. Moreover, we demonstrate that, under appropriate conditions, the model network naturally makes transition(s) from assortative to disassortative, and from sparse to dense in their characteristics. The model is useful in understanding the formation and evolution of online social networks.

Speciation in the Derrida-Higgs model with finite genomes and spatial populations

NASA Astrophysics Data System (ADS)

de Aguiar, Marcus A. M.

2017-02-01

The speciation model proposed by Derrida and Higgs demonstrated that a sexually reproducing population can split into different species in the absence of natural selection or any type of geographic isolation, provided that mating is assortative and the number of genes involved in the process is infinite. Here we revisit this model and simulate it for finite genomes, focusing on the question of how many genes it actually takes to trigger neutral sympatric speciation. We find that, for typical parameters used in the original model, it takes the order of 105 genes. We compare the results with a similar spatially explicit model where about 100 genes suffice for speciation. We show that when the number of genes is small the species that emerge are strongly segregated in space. For a larger number of genes, on the other hand, the spatial structure of the population is less important and the species distribution overlap considerably.

Shifting barriers and phenotypic diversification by hybridisation.

PubMed

Sefc, Kristina M; Mattersdorfer, Karin; Ziegelbecker, Angelika; Neuhüttler, Nina; Steiner, Oliver; Goessler, Walter; Koblmüller, Stephan

2017-05-01

The establishment of hybrid taxa relies on reproductive isolation from the parental forms, typically achieved by ecological differentiation. Here, we present an alternative mechanism, in which shifts in the strength and location of dispersal barriers facilitate diversification by hybridisation. Our case study concerns the highly diverse, stenotopic rock-dwelling cichlids of the African Great Lakes, many of which display geographic colour pattern variation. The littoral habitat of these fish has repeatedly been restructured in the course of ancient lake level fluctuations. Genetic data and an experimental cross support the hybrid origin of a distinct yellow-coloured variant of Tropheus moorii from ancient admixture between two allopatric, red and bluish variants. Deficient assortative mating preferences imply that reproductive isolation continues to be contingent on geographic separation. Linking paleolimnological data with the establishment of the hybrid variant, we sketch a selectively neutral diversification process governed solely by rearrangements of dispersal barriers. © 2017 John Wiley & Sons Ltd/CNRS.

SOME USES OF MODELS OF QUANTITATIVE GENETIC SELECTION IN SOCIAL SCIENCE.

PubMed

Weight, Michael D; Harpending, Henry

2017-01-01

The theory of selection of quantitative traits is widely used in evolutionary biology, agriculture and other related fields. The fundamental model known as the breeder's equation is simple, robust over short time scales, and it is often possible to estimate plausible parameters. In this paper it is suggested that the results of this model provide useful yardsticks for the description of social traits and the evaluation of transmission models. The differences on a standard personality test between samples of Old Order Amish and Indiana rural young men from the same county and the decline of homicide in Medieval Europe are used as illustrative examples of the overall approach. It is shown that the decline of homicide is unremarkable under a threshold model while the differences between rural Amish and non-Amish young men are too large to be a plausible outcome of simple genetic selection in which assortative mating by affiliation is equivalent to truncation selection.

Divergent host-plant use promotes reproductive isolation among cynipid gall wasp populations

PubMed Central

Egan, Scott P.; Hood, Glen R.; Feder, Jeff L.; Ott, James R.

2012-01-01

Ecological speciation occurs when reproductive isolation evolves as a consequence of divergent natural selection among environments. A direct prediction of this process is that ecologically divergent pairs of populations will exhibit greater reproductive isolation than ecologically similar pairs of populations. By comparing allopatric populations of the cynipid gall wasp Belonocnema treatae infesting Quercus virginiana and Quercus geminata, we tested the role that divergent host use plays in generating ecological divergence and sexual isolation. We found differences in body size and gall structure associated with divergent host use, but no difference in neutral genetic divergence between populations on the same or different host plant. We observed significant assortative mating between populations from alternative host plants but not between allopatric populations on the same host plant. Thus, we provide evidence that divergent host use promotes speciation among gall wasp populations. PMID:22337505

Marital assortment for genetic similarity.

PubMed

Eckman, Ronael E; Williams, Robert; Nagoshi, Craig

2002-10-01

The present study involved analyses of a Caucasian American sample (n=949) and a Japanese American sample (n=400) for factors supporting Genetic Similarity Theory (GST). The analyses found no evidence for the presence of genetic similarity between spouses in either sample for the blood group analyses of nine loci. All results indicated random mating for blood group genes. The results did not provide consistent substantial support to show that spousal similarity is correlated with the degree of genetic component of a trait for a set of seventeen individual differences variables, with only the Caucasian sample yielding significant correlations for this analysis. A third analysis examining the correlation between presence of spousal genetic similarity and spousal similarity on observable traits was not performed because spousal genetic similarity was not observed in either sample. The overall implication of the study is that GST is not supported as an explanation for spousal similarity in humans.

Unwed Fathers’ Ability to Pay Child Support: New Estimates Accounting for Multiple-Partner Fertility

PubMed Central

SINKEWICZ, MARILYN; GARFINKEL, IRWIN

2009-01-01

We present new estimates of unwed fathers’ ability to pay child support. Prior research relied on surveys that drastically undercounted nonresident unwed fathers and provided no link to their children who lived in separate households. To overcome these limitations, previous research assumed assortative mating and that each mother partnered with one father who was actually eligible to pay support and had no other child support obligations. Because the Fragile Families and Child Wellbeing Study contains data on couples, multiple-partner fertility, and a rich array of other previously unmeasured characteristics of fathers, it is uniquely suited to address the limitations of previous research. We also use an improved method of dealing with missing data. Our findings suggest that previous research overestimated the aggregate ability of unwed nonresident fathers to pay child support by 33% to 60%. PMID:21305392

Patterns of racial and educational assortative mating in Brazil.

PubMed

Gullickson, Aaron; Torche, Florencia

2014-06-01

Exchange of racial for educational status has been documented for black/white marriages in the United States. Exchange may be an idiosyncratic feature of U.S. society, resulting from unusually strong racial boundaries historically developed there. We examine status exchange across racial lines in Brazil. In contrast to the United States, Brazil features greater fluidity of racial boundaries and a middle tier of "brown" individuals. If exchange is contingent on strong racial boundaries, it should be weak or non-existent in Brazilian society. Contrary to this expectation, we find strong evidence of status exchange. However, this pattern results from a generalized penalty for darkness, which induces a negative association between higher education and marrying darker spouses ("market exchange") rather than from a direct trading of resources by partners ("dyadic exchange"). The substantive and methodological distinction between market and dyadic exchange helps clarify and integrate prior findings in the status exchange literature.

Divergence of Drosophila melanogaster repeatomes in response to a sharp microclimate contrast in Evolution Canyon, Israel

PubMed Central

Kim, Young Bun; Oh, Jung Hun; McIver, Lauren J.; Rashkovetsky, Eugenia; Michalak, Katarzyna; Garner, Harold R.; Kang, Lin; Nevo, Eviatar; Korol, Abraham B.; Michalak, Pawel

2014-01-01

Repeat sequences, especially mobile elements, make up large portions of most eukaryotic genomes and provide enormous, albeit commonly underappreciated, evolutionary potential. We analyzed repeatomes of Drosophila melanogaster that have been diverging in response to a microclimate contrast in Evolution Canyon (Mount Carmel, Israel), a natural evolutionary laboratory with two abutting slopes at an average distance of only 200 m, which pose a constant ecological challenge to their local biotas. Flies inhabiting the colder and more humid north-facing slope carried about 6% more transposable elements than those from the hot and dry south-facing slope, in parallel to a suite of other genetic and phenotypic differences between the two populations. Nearly 50% of all mobile element insertions were slope unique, with many of them disrupting coding sequences of genes critical for cognition, olfaction, and thermotolerance, consistent with the observed patterns of thermotolerance differences and assortative mating. PMID:25006263

Divergence of Drosophila melanogaster repeatomes in response to a sharp microclimate contrast in Evolution Canyon, Israel.

PubMed

Kim, Young Bun; Oh, Jung Hun; McIver, Lauren J; Rashkovetsky, Eugenia; Michalak, Katarzyna; Garner, Harold R; Kang, Lin; Nevo, Eviatar; Korol, Abraham B; Michalak, Pawel

2014-07-22

Repeat sequences, especially mobile elements, make up large portions of most eukaryotic genomes and provide enormous, albeit commonly underappreciated, evolutionary potential. We analyzed repeatomes of Drosophila melanogaster that have been diverging in response to a microclimate contrast in Evolution Canyon (Mount Carmel, Israel), a natural evolutionary laboratory with two abutting slopes at an average distance of only 200 m, which pose a constant ecological challenge to their local biotas. Flies inhabiting the colder and more humid north-facing slope carried about 6% more transposable elements than those from the hot and dry south-facing slope, in parallel to a suite of other genetic and phenotypic differences between the two populations. Nearly 50% of all mobile element insertions were slope unique, with many of them disrupting coding sequences of genes critical for cognition, olfaction, and thermotolerance, consistent with the observed patterns of thermotolerance differences and assortative mating.

The aetiology of obesity beyond eating more and exercising less.

PubMed

Dhurandhar, Emily J; Keith, Scott W

2014-08-01

Although recent increases in availability of energy dense, processed foods and reductions in institutionally driven physical activity have created an environment that is permissible for obesity to occur, several other factors may contribute to the development of obesity in this context. We review evidence for eleven such factors: endocrine disruptors, intrauterine effects, epigenetics, maternal age, differential fecundity and assortative mating by body mass index, microorganisms, reduction in variability of ambient temperatures, smoking cessation, sleep debt, and pharmaceutical iatrogenesis. Evidence for the role of endocrine disruptors, microorganisms, ambient temperatures, sleep and reproductive factors is accumulating, but additional research is needed to confirm the causative role of these factors in human obesity. However, the role of certain pharmaceuticals and smoking cessation in development of human obesity is clear. Practice points for consideration and future research needed are highlighted for each factor. Copyright © 2014 Elsevier Ltd. All rights reserved.

Rearing Environmental Influences on Religiousness: An Investigation of Adolescent Adoptees.

PubMed

Koenig, Laura B; McGue, Matt; Iacono, William G

2009-10-01

Religiousness is widely considered to be a culturally transmitted trait. However, twin studies suggest that religiousness is genetically influenced in adulthood, although largely environmentally influenced in childhood/adolescence. We examined genetic and environmental influences on a self-report measure of religiousness in a sample consisting of 284 adoptive families (two adopted adolescent siblings and their rearing parents); 208 biological families (two full biological adolescent siblings and their parents); and 124 mixed families (one adopted and one biological adolescent sibling and their parents). A sibling-family model was fit to the data to estimate genetic, shared environmental, and nonshared environmental effects on religiousness, as well as cultural transmission and assortative mating effects. Religiousness showed little evidence of heritability and large environmental effects, which did not vary significantly by gender. This finding is consistent with the results of twin studies of religiousness in adolescent and preadolescent samples.

Rearing Environmental Influences on Religiousness: An Investigation of Adolescent Adoptees

PubMed Central

Koenig, Laura B.; McGue, Matt; Iacono, William G.

2009-01-01

Religiousness is widely considered to be a culturally transmitted trait. However, twin studies suggest that religiousness is genetically influenced in adulthood, although largely environmentally influenced in childhood/adolescence. We examined genetic and environmental influences on a self-report measure of religiousness in a sample consisting of 284 adoptive families (two adopted adolescent siblings and their rearing parents); 208 biological families (two full biological adolescent siblings and their parents); and 124 mixed families (one adopted and one biological adolescent sibling and their parents). A sibling-family model was fit to the data to estimate genetic, shared environmental, and nonshared environmental effects on religiousness, as well as cultural transmission and assortative mating effects. Religiousness showed little evidence of heritability and large environmental effects, which did not vary significantly by gender. This finding is consistent with the results of twin studies of religiousness in adolescent and preadolescent samples. PMID:20161346

Phenotypic Robustness and the Assortativity Signature of Human Transcription Factor Networks

PubMed Central

Pechenick, Dov A.; Payne, Joshua L.; Moore, Jason H.

2014-01-01

Many developmental, physiological, and behavioral processes depend on the precise expression of genes in space and time. Such spatiotemporal gene expression phenotypes arise from the binding of sequence-specific transcription factors (TFs) to DNA, and from the regulation of nearby genes that such binding causes. These nearby genes may themselves encode TFs, giving rise to a transcription factor network (TFN), wherein nodes represent TFs and directed edges denote regulatory interactions between TFs. Computational studies have linked several topological properties of TFNs — such as their degree distribution — with the robustness of a TFN's gene expression phenotype to genetic and environmental perturbation. Another important topological property is assortativity, which measures the tendency of nodes with similar numbers of edges to connect. In directed networks, assortativity comprises four distinct components that collectively form an assortativity signature. We know very little about how a TFN's assortativity signature affects the robustness of its gene expression phenotype to perturbation. While recent theoretical results suggest that increasing one specific component of a TFN's assortativity signature leads to increased phenotypic robustness, the biological context of this finding is currently limited because the assortativity signatures of real-world TFNs have not been characterized. It is therefore unclear whether these earlier theoretical findings are biologically relevant. Moreover, it is not known how the other three components of the assortativity signature contribute to the phenotypic robustness of TFNs. Here, we use publicly available DNaseI-seq data to measure the assortativity signatures of genome-wide TFNs in 41 distinct human cell and tissue types. We find that all TFNs share a common assortativity signature and that this signature confers phenotypic robustness to model TFNs. Lastly, we determine the extent to which each of the four components of the assortativity signature contributes to this robustness. PMID:25121490

Chromosome-wide linkage disequilibrium caused by an inversion polymorphism in the white-throated sparrow (Zonotrichia albicollis).

PubMed

Huynh, L Y; Maney, D L; Thomas, J W

2011-04-01

Chromosomal inversions have been of long-standing interest to geneticists because they are capable of suppressing recombination and facilitating the formation of adaptive gene complexes. An exceptional inversion polymorphism (ZAL2(m)) in the white-throated sparrow (Zonotrichia albicollis) is linked to variation in plumage, social behavior and mate choice, and is maintained in the population by negative assortative mating. The ZAL2(m) polymorphism is a complex inversion spanning > 100 Mb and has been proposed to be a strong suppressor of recombination, as well as a potential model for studying neo-sex chromosome evolution. To quantify and evaluate these features of the ZAL2(m) polymorphism, we generated sequence from 8 ZAL2(m) and 16 ZAL2 chromosomes at 58 loci inside and 4 loci outside the inversion. Inside the inversion we found that recombination was completely suppressed between ZAL2 and ZAL2(m), resulting in uniformly high levels of genetic differentiation (F(ST)=0.94), the formation of two distinct haplotype groups representing the alternate chromosome arrangements and extensive linkage disequilibrium spanning ~104 Mb within the inversion, whereas gene flow was not suppressed outside the inversion. Finally, although ZAL2(m) homozygotes are exceedingly rare in the population, occurring at a frequency of < 1%, we detected evidence of historical recombination between ZAL2(m) chromosomes inside the inversion, refuting its potential status as a non-recombining autosome.

Robustness of networks with assortative dependence groups

NASA Astrophysics Data System (ADS)

Wang, Hui; Li, Ming; Deng, Lin; Wang, Bing-Hong

2018-07-01

Assortativity is one of the important characteristics in real networks. To study the effects of this characteristic on the robustness of networks, we propose a percolation model on networks with assortative dependence group. The assortativity in this model means that the nodes with the same or similar degrees form dependence groups, for which one node fails, other nodes in the same group are very likely to fail. We find that the assortativity makes the nodes with large degrees easier to survive from the cascading failure. In this way, such networks are more robust than that with random dependence group, which also proves the assortative network is robust in another perspective. Furthermore, we also present exact solutions to the size of the giant component and the critical point, which are in agreement with the simulation results well.

A rapid generalized least squares model for a genome-wide quantitative trait association analysis in families.

PubMed

Li, Xiang; Basu, Saonli; Miller, Michael B; Iacono, William G; McGue, Matt

2011-01-01

Genome-wide association studies (GWAS) using family data involve association analyses between hundreds of thousands of markers and a trait for a large number of related individuals. The correlations among relatives bring statistical and computational challenges when performing these large-scale association analyses. Recently, several rapid methods accounting for both within- and between-family variation have been proposed. However, these techniques mostly model the phenotypic similarities in terms of genetic relatedness. The familial resemblances in many family-based studies such as twin studies are not only due to the genetic relatedness, but also derive from shared environmental effects and assortative mating. In this paper, we propose 2 generalized least squares (GLS) models for rapid association analysis of family-based GWAS, which accommodate both genetic and environmental contributions to familial resemblance. In our first model, we estimated the joint genetic and environmental variations. In our second model, we estimated the genetic and environmental components separately. Through simulation studies, we demonstrated that our proposed approaches are more powerful and computationally efficient than a number of existing methods are. We show that estimating the residual variance-covariance matrix in the GLS models without SNP effects does not lead to an appreciable bias in the p values as long as the SNP effect is small (i.e. accounting for no more than 1% of trait variance). Copyright © 2011 S. Karger AG, Basel.

Combinatorial study of degree assortativity in networks.

PubMed

Estrada, Ernesto

2011-10-01

Why are some networks degree-degree correlated (assortative), while most of the real-world ones are anticorrelated (disassortative)? Here, we prove, by combinatorial methods, that the assortativity of a network depends only on three structural factors: transitivity (clustering coefficient), intermodular connectivity, and branching. Then, a network is assortative if the contributions of the first two factors are larger than that of the third. Highly branched networks are likely to be disassortative.

Genetic mosaic in a marine species flock.

PubMed

McCartney, Michael A; Acevedo, Jenny; Heredia, Christine; Rico, Ciro; Quenoville, Brice; Bermingham, Eldredge; McMillan, W Owen

2003-11-01

We used molecular approaches to study the status of speciation in coral reef fishes known as hamlets (Serranidae: Hypoplectrus). Several hamlet morphospecies coexist on Caribbean reefs, and mate assortatively with respect to their strikingly distinct colour patterns. We provide evidence that, genetically, the hamlets display characteristics common in species flocks on land and in freshwaters. Substitutions within two mitochondrial DNA (mtDNA) protein-coding genes place hamlets within a monophyletic group relative to members of two related genera (Serranus and Diplectrum), and establish that the hamlet radiation must have been very recent. mtDNA distances separating hamlet morphospecies were slight (0.6 +/- 0.04%), yielding a coalescent estimate for the age of the hamlet flock of approximately 430 000 years. Morphospecies did not sort into distinct mtDNA haplotype phylogroups, and alleles at five hypervariable microsatellite loci were shared broadly across species boundaries. None the less, molecular variation was not distributed at random. Analyses of mtDNA haplotype frequencies and nested clades in haplotype networks revealed significant genetic differences between geographical regions and among colour morphospecies. We also observed significant microsatellite differentiation between geographical regions and in Puerto Rico, among colour morphospecies; the latter providing evidence for reproductive isolation between colour morphospecies at this locale. In our Panama collection, however, colour morphospecies were mostly genetically indistinguishable. This mosaic pattern of DNA differentiation implies a complex interaction between population history, mating behaviour and geography and suggests that porous boundaries separate species in this flock of brilliantly coloured coral reef fishes.

The role of conditioning on heterosexual and homosexual partner preferences in rats.

PubMed

Coria-Avila, Genaro A

2012-01-01

Partner preferences are expressed by many social species, including humans. They are commonly observed as selective contacts with an individual, more time spent together, and directed courtship behavior that leads to selective copulation. This review discusses the effect of conditioning on the development of heterosexual and homosexual partner preferences in rodents. Learned preferences may develop when a conditioned stimulus (CS) is associated in contingency with an unconditioned stimulus (UCS) that functions as a reinforcer. Consequently, an individual may display preference for a partner that bears a CS. Some UCS may be more or less reinforcing, depending on when they are experienced, and may be different for males and females. For example, it could be that, only during periods of early development, that stimuli associated with nurture and juvenile play become conditioned. In adulthood, other stimuli such as sexual reward, cohabitation, mild stress, or even pharmacological manipulations may function as reinforcers to condition partner preferences. Evolutionary biologists and psychologists must take into consideration the idea that an individual's experience with reward (i.e. sexual and pharmacological) can override presumably 'innate' mate choices (e.g. assortativeness and orientation) or mate strategies (e.g. monogamy or polygamy) by means of Pavlovian and operant contingencies. In fact, it is likely as innate to learn about the environment in ways that maximize reward and minimize aversive outcomes, making so-called 'proximate' causes (e.g. pleasure) ultimately more powerful predictors of social behavior and choice than so-called 'ultimate' causes (e.g. genetic or reproductive fitness).

The Cognitive Social Network in Dreams: Transitivity, Assortativity, and Giant Component Proportion Are Monotonic.

PubMed

Han, Hye Joo; Schweickert, Richard; Xi, Zhuangzhuang; Viau-Quesnel, Charles

2016-04-01

For five individuals, a social network was constructed from a series of his or her dreams. Three important network measures were calculated for each network: transitivity, assortativity, and giant component proportion. These were monotonically related; over the five networks as transitivity increased, assortativity increased and giant component proportion decreased. The relations indicate that characters appear in dreams systematically. Systematicity likely arises from the dreamer's memory of people and their relations, which is from the dreamer's cognitive social network. But the dream social network is not a copy of the cognitive social network. Waking life social networks tend to have positive assortativity; that is, people tend to be connected to others with similar connectivity. Instead, in our sample of dream social networks assortativity is more often negative or near 0, as in online social networks. We show that if characters appear via a random walk, negative assortativity can result, particularly if the random walk is biased as suggested by remote associations. Copyright © 2015 Cognitive Science Society, Inc.

Considering genetic characteristics in German Holstein breeding programs.

PubMed

Segelke, D; Täubert, H; Reinhardt, F; Thaller, G

2016-01-01

Recently, several research groups have demonstrated that several haplotypes may cause embryonic loss in the homozygous state. Up to now, carriers of genetic disorders were often excluded from mating, resulting in a decrease of genetic gain and a reduced number of sires available for the breeding program. Ongoing research is very likely to identify additional genetic defects causing embryonic loss and calf mortality by genotyping a large proportion of the female cattle population and sequencing key ancestors. Hence, a clear demand is present to develop a method combining selection against recessive defects (e.g., Holstein haplotypes HH1-HH5) with selection for economically beneficial traits (e.g., polled) for mating decisions. Our proposed method is a genetic index that accounts for the allele frequencies in the population and the economic value of the genetic characteristic without excluding carriers from breeding schemes. Fertility phenotypes from routine genetic evaluations were used to determine the economic value per embryo lost. Previous research has shown that embryo loss caused by HH1 and HH2 occurs later than the loss for HH3, HH4, and HH5. Therefore, an economic value of € 97 was used against HH1 and HH2 and € 70 against HH3, HH4, and HH5. For polled, € 7 per polled calf was considered. Minor allele frequencies of the defects ranged between 0.8 and 3.3%. The polled allele has a frequency of 4.1% in the German Holstein population. A genomic breeding program was simulated to study the effect of changing the selection criteria from assortative mating based on breeding values to selecting the females using the genetic index. Selection for a genetic index on the female path is a useful method to control the allele frequencies by reducing undesirable alleles and simultaneously increasing economical beneficial characteristics maintaining most of the genetic gain in production and functional traits. Additionally, we applied the genetic index to real data and found a decrease of the genetic trend for the birth years 1990 to 2006. Since 2010 the genetic index has increased due to a strong increase in the polled frequency. However, further investigation is needed to better understand the biology to determine the correct time of embryo loss and the economic value of fertility disorders. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Educational homogamy and gender-specific earnings: Sweden, 1990-2009.

PubMed

Dribe, Martin; Nystedt, Paul

2013-08-01

Several studies have shown strong educational homogamy in most Western societies, although the trends over time differ across countries. In this article, we study the connection between educational assortative mating and gender-specific earnings in a sample containing the entire Swedish population born 1960-1974; we follow this sample from 1990 to 2009. Our empirical strategy exploits a longitudinal design, using distributed fixed-effects models capturing the impact of partner education on postmarital earnings, relating it to the income development before union formation. We find that being partnered with someone with more education (hypergamy) is associated with higher earnings, while partnering someone with less education (hypogamy) is associated with lower earnings. However, most of these differences in earnings emerge prior to the time of marriage, implying that the effect is explained by marital selection processes rather than by partner education affecting earnings. The exception is hypogamy among the highly educated, for which there are strong indications that in comparison with homogamy and hypergamy, earnings grow slower after union formation.

Fine-scale population structure and the era of next-generation sequencing.

PubMed

Henn, Brenna M; Gravel, Simon; Moreno-Estrada, Andres; Acevedo-Acevedo, Suehelay; Bustamante, Carlos D

2010-10-15

Fine-scale population structure characterizes most continents and is especially pronounced in non-cosmopolitan populations. Roughly half of the world's population remains non-cosmopolitan and even populations within cities often assort along ethnic and linguistic categories. Barriers to random mating can be ecologically extreme, such as the Sahara Desert, or cultural, such as the Indian caste system. In either case, subpopulations accumulate genetic differences if the barrier is maintained over multiple generations. Genome-wide polymorphism data, initially with only a few hundred autosomal microsatellites, have clearly established differences in allele frequency not only among continental regions, but also within continents and within countries. We review recent evidence from the analysis of genome-wide polymorphism data for genetic boundaries delineating human population structure and the main demographic and genomic processes shaping variation, and discuss the implications of population structure for the distribution and discovery of disease-causing genetic variants, in the light of the imminent availability of sequencing data for a multitude of diverse human genomes.

The Relationship between Partners' Family-Size Preferences in Southern Malawi.

PubMed

Yeatman, Sara; Sennott, Christie

2014-09-01

Studies of the relative influence of partners' fertility preferences on behaviors tend to treat preferences as fixed, largely independent traits despite existing theoretical arguments and empirical evidence suggesting that they are moving targets that may be jointly developed within relationships. In this study, we use couple-level panel data from married and unmarried young adults in southern Malawi to examine the relationship between partners' family-size preferences. We find evidence of assortative mating: young Malawians are more likely to partner with individuals who have similar family-size goals. Additionally, although partners' family-size preferences do not perfectly converge, changes among men's and women's preferences are significantly more likely to be "toward" than "away from" those of their partner. Our findings point to a need for studies regarding the relative influence of partners on reproductive outcomes to consider the interdependence of partners' preferences and the varied ways in which partners can influence shared reproductive behaviors. © 2014 The Population Council, Inc.

The Relationship between Partners’ Family-Size Preferences in Southern Malawi

PubMed Central

Yeatman, Sara; Sennott, Christie

2015-01-01

Studies of the relative influence of partners’ fertility preferences on behaviors tend to treat preferences as fixed, largely independent traits despite existing theoretical arguments and empirical evidence suggesting that they are moving targets that may be jointly developed within relationships. In this study, we use couple-level panel data from married and unmarried young adults in southern Malawi to examine the relationship between partners’ family-size preferences. We find evidence of assortative mating: young Malawians are more likely to partner with individuals who have similar family-size goals. Additionally, although partners’ family-size preferences do not perfectly converge, changes among men’s and women’s preferences are significantly more likely to be “toward” than “away from” those of their partner. Our findings point to a need for studies regarding the relative influence of partners on reproductive outcomes to consider the interdependence of partners’ preferences and the varied ways in which partners can influence shared reproductive behaviors. PMID:25207497

The colour of fitness: plumage coloration and lifetime reproductive success in the tawny owl

PubMed Central

Brommer, Jon E; Ahola, Kari; Karstinen, Teuvo

2005-01-01

We studied variation in plumage colour and life history in a population of tawny owls (Strix aluco) in southern Finland, using 26 years of data on individually marked male and female owls. Colour was scored on a semi-continuous scale from pale grey to reddish brown. Colour scoring was repeatable and showed a bimodal distribution (grey and brown morph) in both sexes. During the study period, colour composition was stable in the study population in both sexes. The sexes did not mate assortatively with respect to their colour. Colour was a highly heritable trait and was under selection. Grey-coloured male and female owls had a higher lifetime production of fledglings, and grey-coloured male (but not female) owls produced more recruits during their lifetime than brown individuals. Selection on colour was mediated through viability selection and not through fecundity selection. Our results reveal remarkably strong selection on a genetically determined phenotypic trait. PMID:16024349

Characterizing Phase Transitions in a Model of Neutral Evolutionary Dynamics

NASA Astrophysics Data System (ADS)

Scott, Adam; King, Dawn; Bahar, Sonya

2013-03-01

An evolutionary model was recently introduced for sympatric, phenotypic evolution over a variable fitness landscape with assortative mating (Dees & Bahar 2010). Organisms in the model are described by coordinates in a two-dimensional phenotype space, born at random coordinates with limited variation from their parents as determined by a mutation parameter, mutability. The model has been extended to include both neutral evolution and asexual reproduction in Scott et al (submitted). It has been demonstrated that a second order, non-equilibrium phase transition occurs for the temporal dynamics as the mutability is varied, for both the original model and for neutral conditions. This transition likely belongs to the directed percolation universality class. In contrast, the spatial dynamics of the model shows characteristics of an ordinary percolation phase transition. Here, we characterize the phase transitions exhibited by this model by determining critical exponents for the relaxation times, characteristic lengths, and cluster (species) mass distributions. Missouri Research Board; J.S. McDonnell Foundation

Sequence-based evidence for major histocompatibility complex-disassortative mating in a colonial seabird.

PubMed

Juola, Frans A; Dearborn, Donald C

2012-01-07

The major histocompatibility complex (MHC) is a polymorphic gene family associated with immune defence, and it can play a role in mate choice. Under the genetic compatibility hypothesis, females choose mates that differ genetically from their own MHC genotypes, avoiding inbreeding and/or enhancing the immunocompetence of their offspring. We tested this hypothesis of disassortative mating based on MHC genotypes in a population of great frigatebirds (Fregata minor) by sequencing the second exon of MHC class II B. Extensive haploid cloning yielded two to four alleles per individual, suggesting the amplification of two genes. MHC similarity between mates was not significantly different between pairs that did (n = 4) or did not (n = 42) exhibit extra-pair paternity. Comparing all 46 mated pairs to a distribution based on randomized re-pairings, we observed the following (i): no evidence for mate choice based on maximal or intermediate levels of MHC allele sharing (ii), significantly disassortative mating based on similarity of MHC amino acid sequences, and (iii) no evidence for mate choice based on microsatellite alleles, as measured by either allele sharing or similarity in allele size. This suggests that females choose mates that differ genetically from themselves at MHC loci, but not as an inbreeding-avoidance mechanism.

Over-Education and Assortative Matching in Partnerships: A Theoretical Analysis

ERIC Educational Resources Information Center

Tampieri, Alessandro

2016-01-01

This paper argues that assortative matching may explain over-education. Education determines individuals' income and, due to the presence of assortative matching, the quality of partners in personal, social and working life. Thus, an individual acquires education to improve the expected partners' quality. However, since every individual of the…

Assortative mixing in functional brain networks during epileptic seizures

NASA Astrophysics Data System (ADS)

Bialonski, Stephan; Lehnertz, Klaus

2013-09-01

We investigate assortativity of functional brain networks before, during, and after one-hundred epileptic seizures with different anatomical onset locations. We construct binary functional networks from multi-channel electroencephalographic data recorded from 60 epilepsy patients; and from time-resolved estimates of the assortativity coefficient, we conclude that positive degree-degree correlations are inherent to seizure dynamics. While seizures evolve, an increasing assortativity indicates a segregation of the underlying functional network into groups of brain regions that are only sparsely interconnected, if at all. Interestingly, assortativity decreases already prior to seizure end. Together with previous observations of characteristic temporal evolutions of global statistical properties and synchronizability of epileptic brain networks, our findings may help to gain deeper insights into the complicated dynamics underlying generation, propagation, and termination of seizures.

Complex networks generated by the Penna bit-string model: Emergence of small-world and assortative mixing

NASA Astrophysics Data System (ADS)

Li, Chunguang; Maini, Philip K.

2005-10-01

The Penna bit-string model successfully encompasses many phenomena of population evolution, including inheritance, mutation, evolution, and aging. If we consider social interactions among individuals in the Penna model, the population will form a complex network. In this paper, we first modify the Verhulst factor to control only the birth rate, and introduce activity-based preferential reproduction of offspring in the Penna model. The social interactions among individuals are generated by both inheritance and activity-based preferential increase. Then we study the properties of the complex network generated by the modified Penna model. We find that the resulting complex network has a small-world effect and the assortative mixing property.

Using Social Network Methods to Test for Assortment of Prosociality among Korean High School Students.

PubMed

Kim, Jun-Hong; Holman, Darryl J; Goodreau, Steven M

2015-01-01

Assortative interaction among altruistic individuals is a necessary condition for the evolution of cooperation. The requirement for assortment holds regardless of whether a meta-population is subdivided into distinct and isolated subgroups or has ephemeral boundaries with a high migration rate. The assumption, however, is rarely tested directly. In this paper, we develop a method to test for assortment of prosociality in network-structured data. The method is applied to a friendship network collected from 238 Korean students attending the same high school. A mixing matrix was used to explore the presence of assortative friendship among more prosocial individuals. An exponential random graph model of network structure that accounts for additional observed relational propensities (higher-than-expected number of people nominating no friends) and sampling constraints (upper bound on friendship nominations) found that individual prosociality predicted friendship propensity, and that individuals with higher prosocial scores had a higher probability of befriending other more prosocial individuals. The results reveal that a considerable level of assortment of prosociality characterizes this population.

Using Social Network Methods to Test for Assortment of Prosociality among Korean High School Students

PubMed Central

Kim, Jun-Hong; Holman, Darryl J.; Goodreau, Steven M.

2015-01-01

Assortative interaction among altruistic individuals is a necessary condition for the evolution of cooperation. The requirement for assortment holds regardless of whether a meta-population is subdivided into distinct and isolated subgroups or has ephemeral boundaries with a high migration rate. The assumption, however, is rarely tested directly. In this paper, we develop a method to test for assortment of prosociality in network-structured data. The method is applied to a friendship network collected from 238 Korean students attending the same high school. A mixing matrix was used to explore the presence of assortative friendship among more prosocial individuals. An exponential random graph model of network structure that accounts for additional observed relational propensities (higher-than-expected number of people nominating no friends) and sampling constraints (upper bound on friendship nominations) found that individual prosociality predicted friendship propensity, and that individuals with higher prosocial scores had a higher probability of befriending other more prosocial individuals. The results reveal that a considerable level of assortment of prosociality characterizes this population. PMID:25915508

Mate choice for major histocompatibility complex complementarity in a strictly monogamous bird, the grey partridge (Perdix perdix).

PubMed

Rymešová, Dana; Králová, Tereza; Promerová, Marta; Bryja, Josef; Tomášek, Oldřich; Svobodová, Jana; Šmilauer, Petr; Šálek, Miroslav; Albrecht, Tomáš

2017-01-01

Sexual selection has been hypothesised as favouring mate choice resulting in production of viable offspring with genotypes providing high pathogen resistance. Specific pathogen recognition is mediated by genes of the major histocompatibility complex (MHC) encoding proteins fundamental for adaptive immune response in jawed vertebrates. MHC genes may also play a role in odour-based individual recognition and mate choice, aimed at avoiding inbreeding. MHC genes are known to be involved in mate choice in a number of species, with 'good genes' (absolute criteria) and 'complementary genes' (self-referential criteria) being used to explain MHC-based mating. Here, we focus on the effect of morphological traits and variation and genetic similarity between individuals in MHC class IIB (MHCIIB) exon 2 on mating in a free-living population of a monogamous bird, the grey partridge. We found no evidence for absolute mate choice criteria as regards grey partridge MHCIIB genotypes, i.e., number and occurrence of amino acid variants, though red chroma of the spot behind eyes was positively associated with male pairing success. On the other hand, mate choice at MHCIIB was based on relative criteria as females preferentially paired with more dissimilar males having a lower number of shared amino acid variants. This observation supports the 'inbreeding avoidance' and 'complementary genes' hypotheses. Our study provides one of the first pieces of evidence for MHC-based mate choice for genetic complementarity in a strictly monogamous bird. The statistical approach employed can be recommended for testing mating preferences in cases where availability of potential mates (recorded with an appropriate method such as radio-tracking) shows considerable temporal variation. Additional genetic analyses using neutral markers may detect whether MHC-based mate choice for complementarity emerges as a by-product of general inbreeding avoidance in grey partridges.

Assortativity Patterns in Multi-dimensional Inter-organizational Networks: A Case Study of the Humanitarian Relief Sector

NASA Astrophysics Data System (ADS)

Zhao, Kang; Ngamassi, Louis-Marie; Yen, John; Maitland, Carleen; Tapia, Andrea

We use computational tools to study assortativity patterns in multi-dimensional inter-organizational networks on the basis of different node attributes. In the case study of an inter-organizational network in the humanitarian relief sector, we consider not only macro-level topological patterns, but also assortativity on the basis of micro-level organizational attributes. Unlike assortative social networks, this inter-organizational network exhibits disassortative or random patterns on three node attributes. We believe organizations' seek of complementarity is one of the main reasons for the special patterns. Our analysis also provides insights on how to promote collaborations among the humanitarian relief organizations.

Phenotypic assortment in wild primate networks: implications for the dissemination of information.

PubMed

Carter, Alecia J; Lee, Alexander E G; Marshall, Harry H; Ticó, Miquel Torrents; Cowlishaw, Guy

2015-05-01

Individuals' access to social information can depend on their social network. Homophily-a preference to associate with similar phenotypes-may cause assortment within social networks that could preclude information transfer from individuals who generate information to those who would benefit from acquiring it. Thus, understanding phenotypic assortment may lead to a greater understanding of the factors that could limit the transfer of information between individuals. We tested whether there was assortment in wild baboon (Papio ursinus) networks, using data collected from two troops over 6 years for six phenotypic traits-boldness, age, dominance rank, sex and the propensity to generate/exploit information-using two methods for defining a connection between individuals-time spent in proximity and grooming. Our analysis indicated that assortment was more common in grooming than proximity networks. In general, there was homophily for boldness, age, rank and the propensity to both generate and exploit information, but heterophily for sex. However, there was considerable variability both between troops and years. The patterns of homophily we observed for these phenotypes may impede information transfer between them. However, the inconsistency in the strength of assortment between troops and years suggests that the limitations to information flow may be quite variable.

Healthy snacks at the checkout counter: a lab and field study on the impact of shelf arrangement and assortment structure on consumer choices.

PubMed

van Kleef, Ellen; Otten, Kai; van Trijp, Hans C M

2012-12-12

The essence of nudging is to adapt the environment in which consumers make decisions to help them make better choices, without forcing certain outcomes upon them. To determine how consumers can effectively be guided to select healthier snacks, we examine the effect of manipulating the assortment structure and shelf layout of an impulse display including both healthy and unhealthy snacks near the checkout counter of a canteen. Both a lab and field study applied a two-factor experimental design manipulating snack offerings both in an on-screen choice environment and a natural environment (hospital staff restaurant). Shelf arrangement (i.e. accessibility) was altered by putting healthy snacks at higher shelves versus lower shelves. Assortment structure (i.e. availability) was altered by offering an assortment that either included 25% or 75% healthy snacks. Participants in the lab study (n = 158) made a choice from a shelf display. A brief survey following snack selection asked participants to evaluate the assortment and their choice. The field experiment took place in a hospital canteen. Daily sales data were collected for a period of four weeks. On completion of the field study, employees (n = 92) filled out a questionnaire about all four displays and rated their attractiveness, healthiness and perceived freedom of choice. The lab study showed a higher probability of healthy snack choice when 75% of the assortment consisted of healthy snacks compared to conditions with 25% healthy snack assortments, even though choices were not rated less satisfying or more restrictive. Regarding shelf display location of healthy snacks, no significant differences were observed. There was also no significant shelf arrangement by assortment structure interactive effect. The field study replicated these findings, in that this assortment structure led to higher sales of healthy snacks. Sales of unhealthy and total snacks were not impacted by manipulations (no main or interaction effects). Employees preferred shelf displays including a larger healthy snack assortment located at top shelves. Employees also felt more freedom in choice when healthy snacks were displayed at top shelves compared to lower shelves. Overall, results suggest that increasing the prominence of healthy snacks by enlarging their availability, while permitting access to unhealthy snacks, is a promising strategy to promote sales. These results point to the importance of nudging strategies to encourage healthier snack patterns.

Polarization in the social sciences: Assortative mixing in social science collaboration networks is resilient to interventions

NASA Astrophysics Data System (ADS)

Leifeld, Philip

2018-10-01

Academic collaboration in the social sciences is characterized by a polarization between hermeneutic and nomological researchers. This polarization is expressed in different publication strategies. The present article analyzes the complete co-authorship networks in a social science discipline in two separate countries over five years using an exponential random graph model. It examines whether and how assortative mixing in publication strategies is present and leads to a polarization in scientific collaboration. In the empirical analysis, assortative mixing is found to play a role in shaping the topology of the network and significantly explains collaboration. Co-authorship edges are more prevalent within each of the groups, but this mixing pattern does not fully account for the extent of polarization. Instead, a thought experiment reveals that other components of the complex system dampen or amplify polarization in the data-generating process and that microscopic interventions targeting behavior change with regard to assortativity would be hindered by the resilience of the system. The resilience to interventions is quantified in a series of simulations on the effect of microscopic behavior on macroscopic polarization. The empirical study controls for geographic proximity, supervision, and topical similarity (using a vector space model), and the interplay of these factors is likely responsible for this resilience. The paper also predicts the co-authorship network in one country based on the model of collaborations in the other country.

Investigating a novel pathway by which pheromone-based mating disruption may protect crops

USDA-ARS?s Scientific Manuscript database

Pheromone-based mating disruption has been a successful, relatively new technology that growers use to reduce key insect populations. Mating disruption systems function by sending out false plumes of the insect sex pheromones – this interferes with the insect’s ability to find a mate, preempting egg...

How many species of cichlid fishes are there in African lakes?

PubMed

Turner, G F; Seehausen, O; Knight, M E; Allender, C J; Robinson, R L

2001-03-01

The endemic cichlid fishes of Lakes Malawi, Tanganyika and Victoria are textbook examples of explosive speciation and adaptive radiation, and their study promises to yield important insights into these processes. Accurate estimates of species richness of lineages in these lakes, and elsewhere, will be a necessary prerequisite for a thorough comparative analysis of the intrinsic and extrinsic factors influencing rates of diversification. This review presents recent findings on the discoveries of new species and species flocks and critically appraises the relevant evidence on species richness from recent studies of polymorphism and assortative mating, generally using behavioural and molecular methods. Within the haplochromines, the most species-rich lineage, there are few reported cases of postzygotic isolation, and these are generally among allopatric taxa that are likely to have diverged a relatively long time in the past. However, many taxa, including many which occur sympatrically and do not interbreed in nature, produce viable, fertile hybrids. Prezygotic barriers are more important, and persist in laboratory conditions in which environmental factors have been controlled, indicating the primary importance of direct mate preferences. Studies to date indicate that estimates of alpha (within-site) diversity appear to be robust. Although within-species colour polymorphisms are common, these have been taken into account in previous estimates of species richness. However, overall estimates of species richness in Lakes Malawi and Victoria are heavily dependent on the assignation of species status to allopatric populations differing in male colour. Appropriate methods for testing the specific status of allopatric cichlid taxa are reviewed and preliminary results presented.

The role of conditioning on heterosexual and homosexual partner preferences in rats

PubMed Central

Coria-Avila, Genaro A.

2012-01-01

Partner preferences are expressed by many social species, including humans. They are commonly observed as selective contacts with an individual, more time spent together, and directed courtship behavior that leads to selective copulation. This review discusses the effect of conditioning on the development of heterosexual and homosexual partner preferences in rodents. Learned preferences may develop when a conditioned stimulus (CS) is associated in contingency with an unconditioned stimulus (UCS) that functions as a reinforcer. Consequently, an individual may display preference for a partner that bears a CS. Some UCS may be more or less reinforcing, depending on when they are experienced, and may be different for males and females. For example, it could be that, only during periods of early development, that stimuli associated with nurture and juvenile play become conditioned. In adulthood, other stimuli such as sexual reward, cohabitation, mild stress, or even pharmacological manipulations may function as reinforcers to condition partner preferences. Evolutionary biologists and psychologists must take into consideration the idea that an individual’s experience with reward (i.e. sexual and pharmacological) can override presumably ‘innate’ mate choices (e.g. assortativeness and orientation) or mate strategies (e.g. monogamy or polygamy) by means of Pavlovian and operant contingencies. In fact, it is likely as innate to learn about the environment in ways that maximize reward and minimize aversive outcomes, making so-called ‘proximate’ causes (e.g. pleasure) ultimately more powerful predictors of social behavior and choice than so-called ‘ultimate’ causes (e.g. genetic or reproductive fitness). PMID:24693350

Extensive population genetic structure in the giraffe

PubMed Central

Brown, David M; Brenneman, Rick A; Koepfli, Klaus-Peter; Pollinger, John P; Milá, Borja; Georgiadis, Nicholas J; Louis, Edward E; Grether, Gregory F; Jacobs, David K; Wayne, Robert K

2007-01-01

Background A central question in the evolutionary diversification of large, widespread, mobile mammals is how substantial differentiation can arise, particularly in the absence of topographic or habitat barriers to dispersal. All extant giraffes (Giraffa camelopardalis) are currently considered to represent a single species classified into multiple subspecies. However, geographic variation in traits such as pelage pattern is clearly evident across the range in sub-Saharan Africa and abrupt transition zones between different pelage types are typically not associated with extrinsic barriers to gene flow, suggesting reproductive isolation. Results By analyzing mitochondrial DNA sequences and nuclear microsatellite loci, we show that there are at least six genealogically distinct lineages of giraffe in Africa, with little evidence of interbreeding between them. Some of these lineages appear to be maintained in the absence of contemporary barriers to gene flow, possibly by differences in reproductive timing or pelage-based assortative mating, suggesting that populations usually recognized as subspecies have a long history of reproductive isolation. Further, five of the six putative lineages also contain genetically discrete populations, yielding at least 11 genetically distinct populations. Conclusion Such extreme genetic subdivision within a large vertebrate with high dispersal capabilities is unprecedented and exceeds that of any other large African mammal. Our results have significant implications for giraffe conservation, and imply separate in situ and ex situ management, not only of pelage morphs, but also of local populations. PMID:18154651

Extensive population genetic structure in the giraffe.

PubMed

Brown, David M; Brenneman, Rick A; Koepfli, Klaus-Peter; Pollinger, John P; Milá, Borja; Georgiadis, Nicholas J; Louis, Edward E; Grether, Gregory F; Jacobs, David K; Wayne, Robert K

2007-12-21

A central question in the evolutionary diversification of large, widespread, mobile mammals is how substantial differentiation can arise, particularly in the absence of topographic or habitat barriers to dispersal. All extant giraffes (Giraffa camelopardalis) are currently considered to represent a single species classified into multiple subspecies. However, geographic variation in traits such as pelage pattern is clearly evident across the range in sub-Saharan Africa and abrupt transition zones between different pelage types are typically not associated with extrinsic barriers to gene flow, suggesting reproductive isolation. By analyzing mitochondrial DNA sequences and nuclear microsatellite loci, we show that there are at least six genealogically distinct lineages of giraffe in Africa, with little evidence of interbreeding between them. Some of these lineages appear to be maintained in the absence of contemporary barriers to gene flow, possibly by differences in reproductive timing or pelage-based assortative mating, suggesting that populations usually recognized as subspecies have a long history of reproductive isolation. Further, five of the six putative lineages also contain genetically discrete populations, yielding at least 11 genetically distinct populations. Such extreme genetic subdivision within a large vertebrate with high dispersal capabilities is unprecedented and exceeds that of any other large African mammal. Our results have significant implications for giraffe conservation, and imply separate in situ and ex situ management, not only of pelage morphs, but also of local populations.

Consanguinity and spousal concordance in Kuwait.

PubMed

al-Kandari, Y; Crews, D E; Poirier, F E

2002-12-01

Consanguineous marriage is favored in Kuwait. This research focuses on the relationship of physical and cultural traits to marriage types in Kuwait and examines concordance as a function of consanguinity and marriage duration. In a nonrandom opportunistic sample of 242 couples anthropometric and blood pressure data have been collected as well as data on acculturation, religiosity, Farsi proficiency, level of education, occupation, and attitudes regarding fertility. Significant concordances occur in cultural characteristics among couples in all three types of marriages with respect to the degree of religiosity, acculturation, language similarity, education, and occupation. Non-consanguineous spouses have the highest concordance in educational level, occupation, and degree of acculturation, but the lowest for religiosity and Farsi proficiency. Nonkin marriages seem to be based on personal preferences. In the wider potential nonkin marriage pool spouses show more concordance in stature and education indicating the positive assortative mating for those traits. Non-consanguineous spouses show a significant association for triceps and subscapular skinfold thicknesses hip and waist circumferences, and body fat distribution. Unrelated spouses exhibit more concordance for physical traits than do related spouses. There is a significant correlation between spouses in first and double cousin marriages as well as in spouses in second and less than second cousin unions for systolic and diastolic blood pressure, while non-consanguineous spouses show a significant association in diastolic blood pressure only.

Coordinate control of initiative mating device for autonomous underwater vehicle based on TDES

NASA Astrophysics Data System (ADS)

Yan, Zhe-Ping; Hou, Shu-Ping

2005-06-01

A novel initiative mating device, which has four 2-degree manipulators around the mating skirt, is proposed to mate between a skirt of AUV (autonomons underwater vehicle) and a disabled submarine. The primary function of the device is to keep exact mating between skirt and disabled submarine in a badly sub sea environment. According to the characteristic of rescue, an automaton model is brought foward to describe the mating proceed between AUV and manipulators. The coordinated control is implemented by the TDES (time discrete event system). After taking into account the time problem, it is a useful method to control mating by simulation testing. The result shows that it reduces about 70 seconds after using intelligent co-ordinate control based on TDES through the whole mating procedure.

Coevolutionary, coexisting learning and teaching agents model for prisoner’s dilemma games enhancing cooperation with assortative heterogeneous networks

NASA Astrophysics Data System (ADS)

Tanimoto, Jun

2013-07-01

Unlike other natural network systems, assortativity can be observed in most human social networks, although it has been reported that a social dilemma situation represented by the prisoner’s dilemma favors dissortativity to enhance cooperation. We established a new coevolutionary model for both agents’ strategy and network topology, where teaching and learning agents coexist. Remarkably, this model enables agents’ enhancing cooperation more than a learners-only model on a time-frozen scale-free network and produces an underlying assortative network with a fair degree of power-law distribution. The model may imply how and why assortative networks are adaptive in human society.

Assortative sexual mixing patterns in male-female and male-male partnerships in Melbourne, Australia: implications for HIV and sexually transmissible infection transmission.

PubMed

Chow, Eric P F; Read, Tim R H; Law, Matthew G; Chen, Marcus Y; Bradshaw, Catriona S; Fairley, Christopher K

2016-10-01

Assortative mixing patterns have become a new and important focus in HIV/sexually transmissible infection (STI) research in recent years. There are very limited data on sexual mixing patterns, particularly in an Australian population. Male-female and male-male partnerships attending the Melbourne Sexual Health Centre (MSHC) between 2011 and 2014 were included. Correlation of age between two individuals within a partnership was examined by using Spearman's rank correlation. The Newman's assortativity coefficient was used as an aggregate quantitative measurement of sexual mixing for number of partners and condom use. 1165 male-female and 610 male-male partnerships were included in the analysis. There was a strong positive correlation of age in both male-female (rho=0.709; P<0.001) and male-male partnerships (rho=0.553; P<0.001). The assortative mixing pattern for number of partners was similar in male-female (r=0.255; 95% CI: 0.221-0.289) and male-male partnerships (r=0.264; 95% CI: 0.218-0.309). There was a stronger assortative mixing pattern for condom use in male-male (r=0.517, 95% CI: 0.465-0.569) compared with male-female (r=0.382; 95% CI: 0.353-0.412) partnerships. Male-female and male-male partnerships have a high assortativity mixing pattern for age, number of partners and condom use. The sexual mixing pattern is not purely assortative, and hence it may lead to increased HIV and STI transmission in certain risk groups.

Male resource defense mating system in primates? An experimental test in wild capuchin monkeys.

PubMed

Tiddi, Barbara; Heistermann, Michael; Fahy, Martin K; Wheeler, Brandon C

2018-01-01

Ecological models of mating systems provide a theoretical framework to predict the effect of the defendability of both breeding resources and mating partners on mating patterns. In resource-based mating systems, male control over breeding resources is tightly linked to female mating preference. To date, few field studies have experimentally investigated the relationship between male resource control and female mating preference in mammals due to difficulties in manipulating ecological factors (e.g., food contestability). We tested the within-group male resource defense hypothesis experimentally in a wild population of black capuchin monkeys (Sapajus nigritus) in Iguazú National Park, Argentina. Sapajus spp. represent an ideal study model as, in contrast to most primates, they have been previously argued to be characterized by female mate choice and a resource-based mating system in which within-group resource monopolization by high-ranking males drives female mating preference for those males. Here, we examined whether females (N = 12) showed a weaker preference for alpha males during mating seasons in which food distribution was experimentally manipulated to be less defendable relative to those in which it was highly defendable. Results did not support the within-group male resource defense hypothesis, as female sexual preferences for alpha males did not vary based on food defendability. We discuss possible reasons for our results, including the possibility of other direct and indirect benefits females receive in exercising mate choice, the potential lack of tolerance over food directed towards females by alpha males, and phylogenetic constraints.

The Role of Graphlets in Viral Processes on Networks

NASA Astrophysics Data System (ADS)

Khorshidi, Samira; Al Hasan, Mohammad; Mohler, George; Short, Martin B.

2018-05-01

Predicting the evolution of viral processes on networks is an important problem with applications arising in biology, the social sciences, and the study of the Internet. In existing works, mean-field analysis based upon degree distribution is used for the prediction of viral spreading across networks of different types. However, it has been shown that degree distribution alone fails to predict the behavior of viruses on some real-world networks and recent attempts have been made to use assortativity to address this shortcoming. In this paper, we show that adding assortativity does not fully explain the variance in the spread of viruses for a number of real-world networks. We propose using the graphlet frequency distribution in combination with assortativity to explain variations in the evolution of viral processes across networks with identical degree distribution. Using a data-driven approach by coupling predictive modeling with viral process simulation on real-world networks, we show that simple regression models based on graphlet frequency distribution can explain over 95% of the variance in virality on networks with the same degree distribution but different network topologies. Our results not only highlight the importance of graphlets but also identify a small collection of graphlets which may have the highest influence over the viral processes on a network.

Healthy snacks at the checkout counter: A lab and field study on the impact of shelf arrangement and assortment structure on consumer choices

PubMed Central

2012-01-01

Background The essence of nudging is to adapt the environment in which consumers make decisions to help them make better choices, without forcing certain outcomes upon them. To determine how consumers can effectively be guided to select healthier snacks, we examine the effect of manipulating the assortment structure and shelf layout of an impulse display including both healthy and unhealthy snacks near the checkout counter of a canteen. Methods Both a lab and field study applied a two-factor experimental design manipulating snack offerings both in an on-screen choice environment and a natural environment (hospital staff restaurant). Shelf arrangement (i.e. accessibility) was altered by putting healthy snacks at higher shelves versus lower shelves. Assortment structure (i.e. availability) was altered by offering an assortment that either included 25% or 75% healthy snacks. Participants in the lab study (n = 158) made a choice from a shelf display. A brief survey following snack selection asked participants to evaluate the assortment and their choice. The field experiment took place in a hospital canteen. Daily sales data were collected for a period of four weeks. On completion of the field study, employees (n = 92) filled out a questionnaire about all four displays and rated their attractiveness, healthiness and perceived freedom of choice. Results The lab study showed a higher probability of healthy snack choice when 75% of the assortment consisted of healthy snacks compared to conditions with 25% healthy snack assortments, even though choices were not rated less satisfying or more restrictive. Regarding shelf display location of healthy snacks, no significant differences were observed. There was also no significant shelf arrangement by assortment structure interactive effect. The field study replicated these findings, in that this assortment structure led to higher sales of healthy snacks. Sales of unhealthy and total snacks were not impacted by manipulations (no main or interaction effects). Employees preferred shelf displays including a larger healthy snack assortment located at top shelves. Employees also felt more freedom in choice when healthy snacks were displayed at top shelves compared to lower shelves. Conclusions Overall, results suggest that increasing the prominence of healthy snacks by enlarging their availability, while permitting access to unhealthy snacks, is a promising strategy to promote sales. These results point to the importance of nudging strategies to encourage healthier snack patterns. PMID:23231863

Ten Putative Contributors to the Obesity Epidemic

PubMed Central

McAllister, Emily J.; Dhurandhar, Nikhil V.; Keith, Scott W.; Aronne, Louis J.; Barger, Jamie; Baskin, Monica; Benca, Ruth M.; Biggio, Joseph; Boggiano, Mary M.; Eisenmann, Joe C.; Elobeid, Mai; Fontaine, Kevin R.; Gluckman, Peter; Hanlon, Erin C.; Katzmarzyk, Peter; Pietrobelli, Angelo; Redden, David T.; Ruden, Douglas M.; Wang, Chenxi; Waterland, Robert A.; Wright, Suzanne M.; Allison, David B.

2010-01-01

The obesity epidemic is a global issue and shows no signs of abating, while the cause of this epidemic remains unclear. Marketing practices of energy-dense foods and institutionally-driven declines in physical activity are the alleged perpetrators for the epidemic, despite a lack of solid evidence to demonstrate their causal role. While both may contribute to obesity, we call attention to their unquestioned dominance in program funding and public efforts to reduce obesity, and propose several alternative putative contributors that would benefit from equal consideration and attention. Evidence for microorganisms, epigenetics, increasing maternal age, greater fecundity among people with higher adiposity, assortative mating, sleep debt, endocrine disruptors, pharmaceutical iatrogenesis, reduction in variability of ambient temperatures, and intrauterine and intergenerational effects, as contributing factors to the obesity epidemic are reviewed herein. While the evidence is strong for some contributors such as pharmaceutical-induced weight gain, it is still emerging for other reviewed factors. Considering the role of such putative etiological factors of obesity may lead to comprehensive, cause specific, and effective strategies for prevention and treatment of this global epidemic. PMID:19960394

Female Preference for Sympatric vs. Allopatric Male Throat Color Morphs in the Mesquite Lizard (Sceloporus grammicus) Species Complex

PubMed Central

Bastiaans, Elizabeth; Bastiaans, Mary Jane; Morinaga, Gen; Castañeda Gaytán, José Gamaliel; Marshall, Jonathon C.; Bane, Brendan; de la Cruz, Fausto Méndez; Sinervo, Barry

2014-01-01

Color polymorphic sexual signals are often associated with alternative reproductive behaviors within populations, and the number, frequency, or type of morphs present often vary among populations. When these differences lead to assortative mating by population, the study of such polymorphic taxa may shed light on speciation mechanisms. We studied two populations of a lizard with polymorphic throat color, an important sexual signal. Males in one population exhibit orange, yellow, or blue throats; whereas males in the other exhibit orange, yellow, or white throats. We assessed female behavior when choosing between allopatric and sympatric males. We asked whether females discriminated more when the allopatric male was of an unfamiliar morph than when the allopatric male was similar in coloration to the sympatric male. We found that female rejection of allopatric males relative to sympatric males was more pronounced when males in a pair were more different in throat color. Our findings may help illuminate how behavioral responses to color morph differences between populations with polymorphic sexual signals contribute to reproductive isolation. PMID:24718297

From wild animals to domestic pets, an evolutionary view of domestication.

PubMed

Driscoll, Carlos A; Macdonald, David W; O'Brien, Stephen J

2009-06-16

Artificial selection is the selection of advantageous natural variation for human ends and is the mechanism by which most domestic species evolved. Most domesticates have their origin in one of a few historic centers of domestication as farm animals. Two notable exceptions are cats and dogs. Wolf domestication was initiated late in the Mesolithic when humans were nomadic hunter-gatherers. Those wolves less afraid of humans scavenged nomadic hunting camps and over time developed utility, initially as guards warning of approaching animals or other nomadic bands and soon thereafter as hunters, an attribute tuned by artificial selection. The first domestic cats had limited utility and initiated their domestication among the earliest agricultural Neolithic settlements in the Near East. Wildcat domestication occurred through a self-selective process in which behavioral reproductive isolation evolved as a correlated character of assortative mating coupled to habitat choice for urban environments. Eurasian wildcats initiated domestication and their evolution to companion animals was initially a process of natural, rather than artificial, selection over time driven during their sympatry with forbear wildcats.

Low-impact mating system

NASA Technical Reports Server (NTRS)

Lewis, James L. (Inventor); Carroll, Monty B. (Inventor); Le, Thang D. (Inventor); Morales, Ray H. (Inventor); Robertson, Brandan R. (Inventor)

2009-01-01

An androgynous mating system for mating two exoatmospheric space modules comprising a first mating assembly capable of mating with a second mating assembly; a second mating assembly structurally identical to said first mating assembly, said first mating assembly comprising; a load ring; a plurality of load cell subassemblies; a plurality of actuators; a base ring; a tunnel; a closed loop control system; one or more electromagnets; and one or more striker plates, wherein said one or more electomagnets on said second mating assembly are capable of mating with said one or more striker plates on said first mating assembly, and wherein said one or more striker plates is comprised of a plate of predetermined shape and a 5-DOF mechanism capable of maintaining predetermined contact requirements during said mating of said one or more electromagnets and said one or more striker plates.

Assortativity and Mixing by Sexual Behaviors and Sociodemographic Characteristics in Young Adult Heterosexual Dating Partnerships.

PubMed

Malagón, Talía; Burchell, Ann; El-Zein, Mariam; Tellier, Pierre-Paul; Coutlée, François; Franco, Eduardo L

2017-06-01

Assortative sexual mixing, the tendency for individuals to choose partners with similar characteristics to themselves, may be an important contributor to the unequal distribution of sexually transmitted infections in populations. We analyzed the tendency for assortative mixing on demographic and sexual behaviors characteristics in newly formed young adults dating partnerships. Women aged 18 to 24 years and their male sexual partners of no more than 6 months were recruited during 2005 to 2010 at universities in Montreal, Canada. New dating partners were also prospectively recruited during the 2-year follow-up. We used Spearman and Newman coefficients to examine correlations between partners' demographic characteristics and sexual behaviors, and multivariable logistic modeling to determine which characteristics were assortative. Participants in 502 recruited partnerships were assortative on age (Spearman P = 0.60), smoking behavior (P = 0.43), ethnicity (Newman coefficient=0.39), lifetime number of sexual partners (P = 0.36), sex partner acquisition rates (P = 0.22), gap length between partnerships (P = 0.20), and on whether they had concurrent partners (P = 0.33). Partners were assortative on number of lifetime partners, sexual partner acquisition rates, concurrency, and gap length between partnerships even after adjustment for demographic characteristics. Reported condom use was correlated between initial and subsequently recruited partners (P = 0.35). There was little correlation between the frequencies of vaginal/oral/digital/anal sex between subsequent partnerships. Dating partnerships were substantially assortative on various sexual behaviors as well as demographic characteristics. Though not a representative population sample, our recruitment of relatively new partnerships reduces survivor bias inherent to cross-sectional surveys where stable long-term partnerships are more likely to be sampled.

Mate preferences do predict attraction and choices in the early stages of mate selection.

PubMed

Li, Norman P; Yong, Jose C; Tov, William; Sng, Oliver; Fletcher, Garth J O; Valentine, Katherine A; Jiang, Yun F; Balliet, Daniel

2013-11-01

Although mate preference research has firmly established that men value physical attractiveness more than women do and women value social status more than men do, recent speed-dating studies have indicated mixed evidence (at best) for whether people's sex-differentiated mate preferences predict actual mate choices. According to an evolutionary, mate preference priority model (Li, Bailey, Kenrick, & Linsenmeier, 2002; Li & Kenrick, 2006; Li, Valentine, & Patel, 2011), the sexes are largely similar in what they ideally like, but for long-term mates, they should differ on what they most want to avoid in early selection contexts. Following this model, we conducted experiments using online messaging and modified speed-dating platforms. Results indicate that when a mating pool includes people at the low end of social status and physical attractiveness, mate choice criteria are sex-differentiated: Men, more than women, chose mates based on physical attractiveness, whereas women, more than men, chose mates based on social status. In addition, individuals who more greatly valued social status or physical attractiveness on paper valued these traits more in their actual choices. In particular, mate choices were sex-differentiated when considering long-term relationships but not short-term ones, where both sexes shunned partners with low physical attractiveness. The findings validate a large body of mate preferences research and an evolutionary perspective on mating, and they have implications for research using speed-dating and other interactive contexts. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Estimating Kinship in Admixed Populations

PubMed Central

Thornton, Timothy; Tang, Hua; Hoffmann, Thomas J.; Ochs-Balcom, Heather M.; Caan, Bette J.; Risch, Neil

2012-01-01

Genome-wide association studies (GWASs) are commonly used for the mapping of genetic loci that influence complex traits. A problem that is often encountered in both population-based and family-based GWASs is that of identifying cryptic relatedness and population stratification because it is well known that failure to appropriately account for both pedigree and population structure can lead to spurious association. A number of methods have been proposed for identifying relatives in samples from homogeneous populations. A strong assumption of population homogeneity, however, is often untenable, and many GWASs include samples from structured populations. Here, we consider the problem of estimating relatedness in structured populations with admixed ancestry. We propose a method, REAP (relatedness estimation in admixed populations), for robust estimation of identity by descent (IBD)-sharing probabilities and kinship coefficients in admixed populations. REAP appropriately accounts for population structure and ancestry-related assortative mating by using individual-specific allele frequencies at SNPs that are calculated on the basis of ancestry derived from whole-genome analysis. In simulation studies with related individuals and admixture from highly divergent populations, we demonstrate that REAP gives accurate IBD-sharing probabilities and kinship coefficients. We apply REAP to the Mexican Americans in Los Angeles, California (MXL) population sample of release 3 of phase III of the International Haplotype Map Project; in this sample, we identify third- and fourth-degree relatives who have not previously been reported. We also apply REAP to the African American and Hispanic samples from the Women's Health Initiative SNP Health Association Resource (WHI-SHARe) study, in which hundreds of pairs of cryptically related individuals have been identified. PMID:22748210

Brief report on the effect of providing single versus assorted brand name condoms to hospital patients: a descriptive study

PubMed Central

Williams, James L; Christensen, Carol J; Cagle, Henry H; Homan, Chriss E

2001-01-01

Objectives This study examined condom acquisition by persons in a hospital setting when single versus assorted brand name condoms were provided. Methods Condom receptacles were placed in exam rooms of two clinics. During Phase 1, a single brand name was provided; for Phase 2, assorted brand names were added. Number of condoms taken was recorded for each phase. Results For one clinic there was nearly a two-fold increase in number of condoms taken (Phase 1 to Phase 2); for the second clinic there was negligible difference in number of condoms taken. Conclusions The provision of assorted brand name condoms, over a single brand name, can serve to increase condom acquisition. Locations of condoms and target population characteristics are related factors. PMID:11446904

Abandoning sex: multiple origins of asexuality in the ciliate Tetrahymena

PubMed Central

2014-01-01

Background By segregating somatic and germinal functions into large, compound macronuclei and small diploid micronuclei, respectively, ciliates can explore sexuality in ways other eukaryotes cannot. Sex, for instance, is not for reproduction but for nuclear replacement in the two cells temporarily joined in conjugation. With equal contributions from both conjugants, there is no cost of sex which theory predicts should favor asexuality. Yet ciliate asexuality is rare. The exceptional Tetrahymena has abandoned sex through loss of the micronucleus; its amicronucleates are abundant in nature where they reproduce by binary fission but never form conjugating pairs. A possible reason for their abundance is that the Tetrahymena macronucleus does not accumulate mutations as proposed by Muller’s ratchet. As such, Tetrahymena amicronucleates have the potential to be very old. This study used cytochrome oxidase-1 barcodes to determine the phylogenetic origin and relative age of amicronucleates isolated from nature. Results Amicronucleates constituted 25% of Tetrahymena-like wild isolates. Of the 244 amicronucleates examined for cox1 barcodes, 237 belonged to Tetrahymena, seven to other genera. Sixty percent originated from 12 named species or barcoded strains, including the model Tetrahymena thermophila, while the remaining 40% represent 19 putative new species, eight of which have micronucleate counterparts and 11 of which are known only as amicronucleates. In some instances, cox1 haplotypes were shared among micronucleate and amicronucleates collected from the same source. Phylogenetic analysis showed that most amicronucleates belong to the “borealis” clade in which mating type is determined by gene rearrangement. Some amicronucleate species were clustered on the SSU phylogenetic tree and had longer branch lengths, indicating more ancient origin. Conclusions Naturally occurring Tetrahymena amicronucleates have multiple origins, arising from numerous species. Likely many more new species remain to be discovered. Shared haplotypes indicate that some are of contemporary origin, while phylogeny indicates that others may be millions of years old. The apparent success of amicronucleate Tetrahymena may be because macronuclear assortment and recombination allow them to avoid Muller’s ratchet, incorporate beneficial mutations, and evolve independently of sex. The inability of amicronucleates to mate may be the result of error(s) in mating type gene rearrangement. PMID:24885485

Using probability modelling and genetic parentage assignment to test the role of local mate availability in mating system variation.

PubMed

Blyton, Michaela D J; Banks, Sam C; Peakall, Rod; Lindenmayer, David B

2012-02-01

The formal testing of mating system theories with empirical data is important for evaluating the relative importance of different processes in shaping mating systems in wild populations. Here, we present a generally applicable probability modelling framework to test the role of local mate availability in determining a population's level of genetic monogamy. We provide a significance test for detecting departures in observed mating patterns from model expectations based on mate availability alone, allowing the presence and direction of behavioural effects to be inferred. The assessment of mate availability can be flexible and in this study it was based on population density, sex ratio and spatial arrangement. This approach provides a useful tool for (1) isolating the effect of mate availability in variable mating systems and (2) in combination with genetic parentage analyses, gaining insights into the nature of mating behaviours in elusive species. To illustrate this modelling approach, we have applied it to investigate the variable mating system of the mountain brushtail possum (Trichosurus cunninghami) and compared the model expectations with the outcomes of genetic parentage analysis over an 18-year study. The observed level of monogamy was higher than predicted under the model. Thus, behavioural traits, such as mate guarding or selective mate choice, may increase the population level of monogamy. We show that combining genetic parentage data with probability modelling can facilitate an improved understanding of the complex interactions between behavioural adaptations and demographic dynamics in driving mating system variation. © 2011 Blackwell Publishing Ltd.

Mate-Selection Systems and Criteria: Variation according to Family Structure.

ERIC Educational Resources Information Center

Lee, Gary R.; Stone, Lorene Hemphill

1980-01-01

Autonomous mate selection based on romantic attraction is more likely to be institutionalized in societies with nuclear family systems. Neolocal residence customs increase the probability that mate selection is autonomous but decrease the probability that it is based on romantic attraction. (Author)

No evidence of an MHC-based female mating preference in great reed warblers.

PubMed

Westerdahl, Helena

2004-08-01

Female mate-choice based on genetic compatibility is an area of growing interest. The major histocompatibility complex (MHC) genes are likely candidates for such mate-choice since these highly polymorphic genes may both increase offspring viability and also provide direct cues for mate-choice. In great reed warblers, females actively choose a breeding partner out of a handful of males that they visit and evaluate; thus, female preference for compatible or heterozygous MHC genes could have evolved. Here, I investigate whether great reed warbler females preferentially mate with males with dissimilar MHC class I alleles or with males that are heterozygous at MHC class I. Despite favourable conditions, a thorough screening method and a large sample size, there was no evidence of an MHC-based female mating preference based on either genetic compatibility or heterozygosity in this population. Power analyses of the data sets revealed that relatively small differences (15% and 8%, respectively) between true and random pairs should have been detected. Copyright 2004 Blackwell Publishing Ltd

Gasket Assembly for Sealing Mating Surfaces

NASA Technical Reports Server (NTRS)

Bryant, Melvin A., III (Inventor)

2003-01-01

A pair of substantially opposed mating surfaces are joined to each other and sealed in place by means of an electrically-conductive member which is placed in proximity to the mating surfaces. The electrically-conductive member has at least one element secured thereto which is positioned to contact the mating surfaces, and which softens when the electrically-conductive member is heated by passing an electric current therethrough. The softened element conforms to the mating surfaces, and upon cooling of the softened element the mating surfaces are joined together in an effective seal. Of particular significance is an embodiment of the electrically-conductive member which is a gasket having an electrically-conductive gasket base and a pair of the elements secured to opposite sides of the gasket base. This embodiment is positioned between the opposed mating surfaces to be joined to each other. Also significant is an embodiment of the electrically-conductive member which is an electrically-conductive sleeve having an element secured to its inner surface. This embodiment surrounds cylindrical members the bases of which are the substantially opposed mating surfaces to be joined, and the element on the inner surface of the sleeve contacts the outer surfaces of the cylindrical members.

Sexual Experience Enhances Drosophila melanogaster Male Mating Behavior and Success

PubMed Central

Saleem, Sehresh; Ruggles, Patrick H.; Abbott, Wiley K.; Carney, Ginger E.

2014-01-01

Competition for mates is a wide-spread phenomenon affecting individual reproductive success. The ability of animals to adjust their behaviors in response to changing social environment is important and well documented. Drosophila melanogaster males compete with one another for matings with females and modify their reproductive behaviors based on prior social interactions. However, it remains to be determined how male social experience that culminates in mating with a female impacts subsequent male reproductive behaviors and mating success. Here we show that sexual experience enhances future mating success. Previously mated D. melanogaster males adjust their courtship behaviors and out-compete sexually inexperienced males for copulations. Interestingly, courtship experience alone is not sufficient in providing this competitive advantage, indicating that copulation plays a role in reinforcing this social learning. We also show that females use their sense of hearing to preferentially mate with experienced males when given a choice. Our results demonstrate the ability of previously mated males to learn from their positive sexual experiences and adjust their behaviors to gain a mating advantage. These experienced-based changes in behavior reveal strategies that animals likely use to increase their fecundity in natural competitive environments. PMID:24805129

Fungal Sex: The Basidiomycota.

PubMed

Coelho, Marco A; Bakkeren, Guus; Sun, Sheng; Hood, Michael E; Giraud, Tatiana

2017-06-01

Fungi of the Basidiomycota, representing major pathogen lineages and mushroom-forming species, exhibit diverse means to achieve sexual reproduction, with particularly varied mechanisms to determine compatibilities of haploid mating partners. For species that require mating between distinct genotypes, discrimination is usually based on both the reciprocal exchange of diffusible mating pheromones, rather than sexes, and the interactions of homeodomain protein signals after cell fusion. Both compatibility factors must be heterozygous in the product of mating, and genetic linkage relationships of the mating pheromone/receptor and homeodomain genes largely determine the complex patterns of mating-type variation. Independent segregation of the two compatibility factors can create four haploid mating genotypes from meiosis, referred to as tetrapolarity. This condition is thought to be ancestral to the basidiomycetes. Alternatively, cosegregation by linkage of the two mating factors, or in some cases the absence of the pheromone-based discrimination, yields only two mating types from meiosis, referred to as bipolarity. Several species are now known to have large and highly rearranged chromosomal regions linked to mating-type genes. At the population level, polymorphism of the mating-type genes is an exceptional aspect of some basidiomycete fungi, where selection under outcrossing for rare, intercompatible allelic variants is thought to be responsible for numbers of mating types that may reach several thousand. Advances in genome sequencing and assembly are yielding new insights by comparative approaches among and within basidiomycete species, with the promise to resolve the evolutionary origins and dynamics of mating compatibility genetics in this major eukaryotic lineage.

Crossing to safety: dispersal, colonization and mate choice in evolutionarily distinct populations of Steller sea lions, Eumetopias jubatus.

PubMed

O'Corry-Crowe, Greg; Gelatt, Tom; Rea, Lorrie; Bonin, Carolina; Rehberg, Michael

2014-11-01

Population growth typically involves range expansion and establishment of new breeding sites, while the opposite occurs during declines. Although density dependence is widely invoked in theoretical studies of emigration and colonization in expanding populations, few empirical studies have documented the mechanisms. Still fewer have documented the direction and mechanisms of individual transfer in declining populations. Here, we screen large numbers of pups sampled on their natal rookeries for variation in mtDNA (n = 1106) and 16 microsatellite loci (n = 588) and show that new Steller sea lion breeding sites did not follow the typical paradigm and were instead colonized by sea lions from both a declining (Endangered) population and an increasing population. Dispersing individuals colonized rookeries in the distributional hiatus between two evolutionarily distinct (Φ¯(st) = 0.222, R¯(st) = 0.053, K = 2) metapopulations recently described as separate subspecies. Hardy-Weinberg, mixed-stock and relatedness analysis revealed levels of interbreeding on the new rookeries that exclude (i) assortative mating among eastern and western forms, and (ii) inbreeding avoidance as primary motivations for dispersal. Positive and negative density dependence is implicated in both cases of individual transfer. Migration distance limits, and conspecific attraction and performance likely influenced the sequence of rookery colonizations. This study demonstrates that resource limitation may trigger an exodus of breeding animals from declining populations, with substantial impacts on distribution and patterns of genetic variation. It also revealed that this event is rare because colonists dispersed across an evolutionary boundary, suggesting that the causative factors behind recent declines are unusual or of larger magnitude than normally occur. © 2014 John Wiley & Sons Ltd.

Problem-Based Learning in Accounting

ERIC Educational Resources Information Center

Dockter, DuWayne L.

2012-01-01

Seasoned educators use an assortment of student-centered methods and tools to enhance their student's learning environment. In respects to methodologies used in accounting, educators have utilized and created new forms of problem-based learning exercises, including case studies, simulations, and other projects, to help students become more active…

Multi-species pheromone-based mating disruption: Moth birth control in cranberries

USDA-ARS?s Scientific Manuscript database

Pheromone-based mating disruption is a proven method of pest control, but in cranberries, tailoring this technology to modern production practices has been difficult. Using the wax carrier, SPLAT, we have overcome many of these difficulties and now have three years of data suggesting that mating dis...

Endeavour and its modified 747 carrier aircraft are illuminated by the morning sun after mating was completed in the Mate-DeMate gantry at NASA DFRC

NASA Image and Video Library

2008-12-09

The Space Shuttle Endeavour and its modified Boeing 747 carrier aircraft are illuminated by the morning sun Tuesday after mating of the pair was completed overnight in the Mate-DeMate gantry at NASA Dryden Flight Research Center. The pair are scheduled to depart Edwards Air Force Base on their ferry flight back to the Kennedy Space Center early Wednesday morning, Dec. 10.

Reproductive Incompatibility Involving Senegalese Aedes aegypti (L) Is Associated with Chromosome Rearrangements

PubMed Central

Dickson, Laura B.; Sharakhova, Maria V.; Timoshevskiy, Vladimir A.; Fleming, Karen L.; Caspary, Alex; Sylla, Massamba; Black, William C.

2016-01-01

Aedes aegypti, the primary vector of dengue, yellow fever and Zika flaviviruses, consists of at least two subspecies. Aedes aegypti (Aaa) is light in color, has pale scales on the first abdominal tergite, oviposits in artificial containers, and preferentially feeds on humans. Aedes aegypti formosus (Aaf), has a dark cuticle, is restricted to sub-Saharan Africa, has no pale scales on the first abdominal tergite and frequently oviposits in natural containers. Scale patterns correlate with cuticle color in East Africa but not in Senegal, West Africa where black cuticle mosquitoes display a continuum of scaling patterns and breed domestically indoors. An earlier laboratory study did not indicate any pre- or postzygotic barriers to gene flow between Aaa and Aaf in East Africa. However, similar attempts to construct F1 intercross families between Aaa laboratory strains and Senegal Ae. aegypti (SenAae) failed due to poor F1 oviposition and low F2 egg-to-adult survival. Insemination and assortative mating experiments failed to identify prezygotic mating barriers. Backcrosses were performed to test for postzygotic isolation patterns consistent with Haldane’s rule modified for species, like Aedes, that have an autosomal sex determining locus (SDL). Egg-pupal survival was predicted to be low in females mated to hybrid F1 males but average when a male mates with a hybrid F1 female. Survival was in fact significantly reduced when females mated to hybrid males but egg-pupal survival was significantly increased when males were mated to hybrid F1 females. These observations are therefore inconclusive with regards to Haldane’s rule. Basic cytogenetic analyses and Fluorescent In Situ Hybridization (FISH) experiments were performed to compare SenAae strains with the IB12 strain of Aaa that was used for genome sequencing and physical mapping. Some SenAae strains had longer chromosomes than IB12 and significantly different centromeric indices on chromosomes 1 and 3. DAPI staining was used to identify AT-rich regions, chromomycin A3 following pretreatment with barium hydroxide stained for GC-rich regions and stained the ribosomal RNA locus and YOYO-1 was used to test for differential staining. Chromosome patterns in SenAae strains revealed by these three stains differed from those in IB12. For FISH, 40 BAC clones previously physically mapped on Aaa chromosomes were used to test for chromosome rearrangements in SenAae relative to IB12. Differences in the order of markers identified two chromosomal rearrangements between IB12 and SenAae strains. The first rearrangement involves two overlapping pericentric (containing the centromere) inversions in chromosome 3 or an insertion of a large fragment into the 3q arm. The second rearrangement is close to the centromere on the p arm of chromosome 2. Linkage analysis of the SDL and the white-eye locus identified a likely chromosomal rearrangement on chromosome 1. The reproductive incompatibility observed within SenAae and between SenAae and Aaa may be generally associated with chromosome rearrangements on all three chromosomes and specifically caused by pericentric inversions on chromosomes 2 and 3. PMID:27105225

Assortativeness and information in scale-free networks

NASA Astrophysics Data System (ADS)

Piraveenan, M.; Prokopenko, M.; Zomaya, A. Y.

2009-02-01

We analyze Shannon information of scale-free networks in terms of their assortativeness, and identify classes of networks according to the dependency of the joint remaining degree distribution on the assortativeness. We conjecture that these classes comprise minimalistic and maximalistic networks in terms of Shannon information. For the studied classes, the information is shown to depend non-linearly on the absolute value of the assortativeness, with the dominant term of the relationship being a power-law. We exemplify this dependency using a range of real-world networks. Optimization of scale-free networks according to information they contain depends on the landscape of parameters’ search-space, and we identify two regions of interest: a slope region and a stability region. In the slope region, there is more freedom to generate and evaluate candidate networks since the information content can be changed easily by modifying only the assortativeness, while even a small change in the power-law’s scaling exponent brings a reward in a higher rate of information change. This feature may explain why the exponents of real-world scale-free networks are within a certain range, defined by the slope and stability regions.

Geometric Assortative Growth Model for Small-World Networks

PubMed Central

2014-01-01

It has been shown that both humanly constructed and natural networks are often characterized by small-world phenomenon and assortative mixing. In this paper, we propose a geometrically growing model for small-world networks. The model displays both tunable small-world phenomenon and tunable assortativity. We obtain analytical solutions of relevant topological properties such as order, size, degree distribution, degree correlation, clustering, transitivity, and diameter. It is also worth noting that the model can be viewed as a generalization for an iterative construction of Farey graphs. PMID:24578661

Heritability of tic disorders: a twin-family study.

PubMed

Zilhão, N R; Olthof, M C; Smit, D J A; Cath, D C; Ligthart, L; Mathews, C A; Delucchi, K; Boomsma, D I; Dolan, C V

2017-04-01

Genetic-epidemiological studies that estimate the contributions of genetic factors to variation in tic symptoms are scarce. We estimated the extent to which genetic and environmental influences contribute to tics, employing various phenotypic definitions ranging between mild and severe symptomatology, in a large population-based adult twin-family sample. In an extended twin-family design, we analysed lifetime tic data reported by adult mono- and dizygotic twins (n = 8323) and their family members (n = 7164; parents and siblings) from 7311 families in the Netherlands Twin Register. We measured tics by the abbreviated version of the Schedule for Tourette and Other Behavioral Syndromes. Heritability was estimated by genetic structural equation modeling for four tic disorder definitions: three dichotomous and one trichotomous phenotype, characterized by increasingly strictly defined criteria. Prevalence rates of the different tic disorders in our sample varied between 0.3 and 4.5% depending on tic disorder definition. Tic frequencies decreased with increasing age. Heritability estimates varied between 0.25 and 0.37, depending on phenotypic definitions. None of the phenotypes showed evidence of assortative mating, effects of shared environment or non-additive genetic effects. Heritabilities of mild and severe tic phenotypes were estimated to be moderate. Overlapping confidence intervals of the heritability estimates suggest overlapping genetic liabilities between the various tic phenotypes. The most lenient phenotype (defined only by tic characteristics, excluding criteria B, C and D of DSM-IV) rendered sufficiently reliable heritability estimates. These findings have implications in phenotypic definitions for future genetic studies.

Population characteristics of DNA fingerprints in humpback whales (Megaptera novaeangliae).

PubMed

Baker, C S; Gilbert, D A; Weinrich, M T; Lambertsen, R; Calambokidis, J; McArdle, B; Chambers, G K; O'Brien, S J

1993-01-01

Humpback whales exhibit a remarkable social organization that is characterized by seasonal long-distance migration (> 10,000 km/year) between summer feeding grounds in high latitudes and winter calving and breeding grounds in tropical or near-tropical waters. All populations are currently considered endangered as a result of intensive commercial exploitation during the last 200 years. Using three hypervariable minisatellite DNA probes (33.15, 3'HVR, and M13) originally developed for studies of human genetic variation, we examined genetic variation within and among three regional subpopulations of humpback whales from the North Pacific and one from the North Atlantic oceans. Analysis of DNA extracted from skin tissues collected by biopsy darting from free-ranging whales revealed considerable variation in each subpopulation. The extent of this variation argues against a recent history of inbreeding among humpback whales as a result of nineteenth- and twentieth-century hunting. A canonical variate analysis suggested a relationship between scaled genetic distance, based on similarities of DNA fingerprints, and geographic distance (i.e., longitude of regional subpopulation). Significant categorical differences were found between the two oceanic populations using a multivariate analysis of variance (MANOVA) with a modification of the Mantel nonparametric permutation test. The relationship between DNA fingerprint similarities and geographic distance suggests that nuclear gene flow between regional subpopulations within the North Pacific is restricted by relatively low rates of migratory interchange between breeding grounds or assortative mating on common wintering grounds.

Heritability and Genome-Wide Association Studies for Hair Color in a Dutch Twin Family Based Sample

PubMed Central

Lin, Bochao Danae; Mbarek, Hamdi; Willemsen, Gonneke; Dolan, Conor V.; Fedko, Iryna O.; Abdellaoui, Abdel; de Geus, Eco J.; Boomsma, Dorret I.; Hottenga, Jouke-Jan

2015-01-01

Hair color is one of the most visible and heritable traits in humans. Here, we estimated heritability by structural equation modeling (N = 20,142), and performed a genome wide association (GWA) analysis (N = 7091) and a GCTA study (N = 3340) on hair color within a large cohort of twins, their parents and siblings from the Netherlands Twin Register (NTR). Self-reported hair color was analyzed as five binary phenotypes, namely “blond versus non-blond”, “red versus non-red”, “brown versus non-brown”, “black versus non-black”, and “light versus dark”. The broad-sense heritability of hair color was estimated between 73% and 99% and the genetic component included non-additive genetic variance. Assortative mating for hair color was significant, except for red and black hair color. From GCTA analyses, at most 24.6% of the additive genetic variance in hair color was explained by 1000G well-imputed SNPs. Genome-wide association analysis for each hair color showed that SNPs in the MC1R region were significantly associated with red, brown and black hair, and also with light versus dark hair color. Five other known genes (HERC2, TPCN2, SLC24A4, IRF4, and KITLG) gave genome-wide significant hits for blond, brown and light versus dark hair color. We did not find and replicate any new loci for hair color. PMID:26184321

How Are Mate Preferences Linked with Actual Mate Selection? Tests of Mate Preference Integration Algorithms Using Computer Simulations and Actual Mating Couples

PubMed Central

Conroy-Beam, Daniel; Buss, David M.

2016-01-01

Prior mate preference research has focused on the content of mate preferences. Yet in real life, people must select mates among potentials who vary along myriad dimensions. How do people incorporate information on many different mate preferences in order to choose which partner to pursue? Here, in Study 1, we compare seven candidate algorithms for integrating multiple mate preferences in a competitive agent-based model of human mate choice evolution. This model shows that a Euclidean algorithm is the most evolvable solution to the problem of selecting fitness-beneficial mates. Next, across three studies of actual couples (Study 2: n = 214; Study 3: n = 259; Study 4: n = 294) we apply the Euclidean algorithm toward predicting mate preference fulfillment overall and preference fulfillment as a function of mate value. Consistent with the hypothesis that mate preferences are integrated according to a Euclidean algorithm, we find that actual mates lie close in multidimensional preference space to the preferences of their partners. Moreover, this Euclidean preference fulfillment is greater for people who are higher in mate value, highlighting theoretically-predictable individual differences in who gets what they want. These new Euclidean tools have important implications for understanding real-world dynamics of mate selection. PMID:27276030

How Are Mate Preferences Linked with Actual Mate Selection? Tests of Mate Preference Integration Algorithms Using Computer Simulations and Actual Mating Couples.

PubMed

Conroy-Beam, Daniel; Buss, David M

2016-01-01

Prior mate preference research has focused on the content of mate preferences. Yet in real life, people must select mates among potentials who vary along myriad dimensions. How do people incorporate information on many different mate preferences in order to choose which partner to pursue? Here, in Study 1, we compare seven candidate algorithms for integrating multiple mate preferences in a competitive agent-based model of human mate choice evolution. This model shows that a Euclidean algorithm is the most evolvable solution to the problem of selecting fitness-beneficial mates. Next, across three studies of actual couples (Study 2: n = 214; Study 3: n = 259; Study 4: n = 294) we apply the Euclidean algorithm toward predicting mate preference fulfillment overall and preference fulfillment as a function of mate value. Consistent with the hypothesis that mate preferences are integrated according to a Euclidean algorithm, we find that actual mates lie close in multidimensional preference space to the preferences of their partners. Moreover, this Euclidean preference fulfillment is greater for people who are higher in mate value, highlighting theoretically-predictable individual differences in who gets what they want. These new Euclidean tools have important implications for understanding real-world dynamics of mate selection.

Scale-free networks which are highly assortative but not small world

NASA Astrophysics Data System (ADS)

Small, Michael; Xu, Xiaoke; Zhou, Jin; Zhang, Jie; Sun, Junfeng; Lu, Jun-An

2008-06-01

Uncorrelated scale-free networks are necessarily small world (and, in fact, smaller than small world). Nonetheless, for scale-free networks with correlated degree distribution this may not be the case. We describe a mechanism to generate highly assortative scale-free networks which are not small world. We show that it is possible to generate scale-free networks, with arbitrary degree exponent γ>1 , such that the average distance between nodes in the network is large. To achieve this, nodes are not added to the network with preferential attachment. Instead, we greedily optimize the assortativity of the network. The network generation scheme is physically motivated, and we show that the recently observed global network of Avian Influenza outbreaks arises through a mechanism similar to what we present here. Simulations show that this network exhibits very similar physical characteristics (very high assortativity, clustering, and path length).

Habitat assortment of sexes and water balance in a dioecious grass.

PubMed

Fox, J F; Harrison, A Tyrone

1981-05-01

For a dioecious plant species in which males are associated with more xeric habitats and females with more mesic ones, (a) the xeric-mesic habitat difference was confirmed by measuring plant water potential, (b) and males and females had similar water balances and seemed to have no different adaptations to drought. There are slight differences in water potential between the sexes of dioecious plant species, but water balance can be more favorable in either the male or the female. On this account, we reject the "disruptive selection" hypothesis of Freeman et al. (1975) as an explanation for habitat assortment of sexes in dioecious plants. Alternative explanations, based upon parental determination of offspring sex ratios, or environmentally determined sex change, seem more likely.

Under soggy skies on a Sunday morning, the Space Shuttle Endeavour is encased in the Mate-DeMate gantry during turnaround processing at NASA DFRC

NASA Image and Video Library

2008-12-07

Under soggy skies on a Sunday morning, the Space Shuttle Endeavour is encased in the Mate-DeMate gantry during turnaround processing at NASA's Dryden Flight Research Center following its STS-126 landing at Edwards Air Force Base a week earlier.

Assortativity and leadership emerge from anti-preferential attachment in heterogeneous networks.

PubMed

Sendiña-Nadal, I; Danziger, M M; Wang, Z; Havlin, S; Boccaletti, S

2016-02-18

Real-world networks have distinct topologies, with marked deviations from purely random networks. Many of them exhibit degree-assortativity, with nodes of similar degree more likely to link to one another. Though microscopic mechanisms have been suggested for the emergence of other topological features, assortativity has proven elusive. Assortativity can be artificially implanted in a network via degree-preserving link permutations, however this destroys the graph's hierarchical clustering and does not correspond to any microscopic mechanism. Here, we propose the first generative model which creates heterogeneous networks with scale-free-like properties in degree and clustering distributions and tunable realistic assortativity. Two distinct populations of nodes are incrementally added to an initial network by selecting a subgraph to connect to at random. One population (the followers) follows preferential attachment, while the other population (the potential leaders) connects via anti-preferential attachment: they link to lower degree nodes when added to the network. By selecting the lower degree nodes, the potential leader nodes maintain high visibility during the growth process, eventually growing into hubs. The evolution of links in Facebook empirically validates the connection between the initial anti-preferential attachment and long term high degree. In this way, our work sheds new light on the structure and evolution of social networks.

Assortativity and leadership emerge from anti-preferential attachment in heterogeneous networks

NASA Astrophysics Data System (ADS)

Sendiña-Nadal, I.; Danziger, M. M.; Wang, Z.; Havlin, S.; Boccaletti, S.

2016-02-01

Real-world networks have distinct topologies, with marked deviations from purely random networks. Many of them exhibit degree-assortativity, with nodes of similar degree more likely to link to one another. Though microscopic mechanisms have been suggested for the emergence of other topological features, assortativity has proven elusive. Assortativity can be artificially implanted in a network via degree-preserving link permutations, however this destroys the graph’s hierarchical clustering and does not correspond to any microscopic mechanism. Here, we propose the first generative model which creates heterogeneous networks with scale-free-like properties in degree and clustering distributions and tunable realistic assortativity. Two distinct populations of nodes are incrementally added to an initial network by selecting a subgraph to connect to at random. One population (the followers) follows preferential attachment, while the other population (the potential leaders) connects via anti-preferential attachment: they link to lower degree nodes when added to the network. By selecting the lower degree nodes, the potential leader nodes maintain high visibility during the growth process, eventually growing into hubs. The evolution of links in Facebook empirically validates the connection between the initial anti-preferential attachment and long term high degree. In this way, our work sheds new light on the structure and evolution of social networks.

Mate-choice copying in single and coupled women: the influence of mate acceptance and mate rejection decisions of other women.

PubMed

Deng, Yan; Zheng, Yong

2015-01-26

Studies of humans and non-human animals indicate that females tend to change the likelihood of choosing a potential mate based on the decisions of other females; this is known as mate-choice copying. In a sample of both single and coupled women, we examined the influence of other women's (model) mate-choice decisions, including mate acceptance and mate rejection, on participants' attractiveness ratings of men (target) and willingness of mate selection. We also examined whether different types of relationships between the target men and the model women affected mate-choice copying. We found that both the single and coupled women showed mate-choice copying, but their response patterns differed. The significant effects for single women were dependent on a decrease in attractiveness ratings when they perceived the models' mate rejection. However, the significant findings for coupled women relied on an increase in attractiveness ratings when they observed the models' mate acceptance. Furthermore, the relationship status between the target men and the model women affected the magnitude of mate-choice copying effects for the single women. Specifically, they showed less mate-choice copying when the targets and models were in a committed romantic relationship than when in a temporary relationship.

Including nonadditive genetic effects in mating programs to maximize dairy farm profitability.

PubMed

Aliloo, H; Pryce, J E; González-Recio, O; Cocks, B G; Goddard, M E; Hayes, B J

2017-02-01

We compared the outcome of mating programs based on different evaluation models that included nonadditive genetic effects (dominance and heterozygosity) in addition to additive effects. The additive and dominance marker effects and the values of regression on average heterozygosity were estimated using 632,003 single nucleotide polymorphisms from 7,902 and 7,510 Holstein cows with calving interval and production (milk, fat, and protein yields) records, respectively. Expected progeny values were computed based on the estimated genetic effects and genotype probabilities of hypothetical progeny from matings between the available genotyped cows and the top 50 young genomic bulls. An index combining the traits based on their economic values was developed and used to evaluate the performance of different mating scenarios in terms of dollar profit. We observed that mating programs with nonadditive genetic effects performed better than a model with only additive effects. Mating programs with dominance and heterozygosity effects increased milk, fat, and protein yields by up to 38, 1.57, and 1.21 kg, respectively. The inclusion of dominance and heterozygosity effects decreased calving interval by up to 0.70 d compared with random mating. The average reduction in progeny inbreeding by the inclusion of nonadditive genetic effects in matings compared with random mating was between 0.25 to 1.57 and 0.64 to 1.57 percentage points for calving interval and production traits, respectively. The reduction in inbreeding was accompanied by an average of A$8.42 (Australian dollars) more profit per mating for a model with additive, dominance, and heterozygosity effects compared with random mating. Mate allocations that benefit from nonadditive genetic effects can improve progeny performance only in the generation where it is being implemented, and the gain from specific combining abilities cannot be accumulated over generations. Continuous updating of genomic predictions and mate allocation programs are required to benefit from nonadditive genetic effects in the long term. The Authors. Published by the Federation of Animal Science Societies and Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

Identification and expression analysis of MATE genes involved in flavonoid transport in blueberry plants.

PubMed

Chen, Li; Liu, Yushan; Liu, Hongdi; Kang, Limin; Geng, Jinman; Gai, Yuzhuo; Ding, Yunlong; Sun, Haiyue; Li, Yadong

2015-01-01

Multidrug and toxic compound extrusion (MATE) proteins are the most recently identified family of multidrug transporters. In plants, this family is remarkably large compared to the human and bacteria counterpart, highlighting the importance of MATE proteins in this kingdom. Here 33 Unigenes annotated as MATE transporters were found in the blueberry fruit transcriptome, of which eight full-length cDNA sequences were identified and cloned. These proteins are composed of 477-517 residues, with molecular masses ~54 kDa, and theoretical isoelectric points from 5.35 to 8.41. Bioinformatics analysis predicted 10-12 putative transmembrane segments for VcMATEs, and localization to the plasma membrane without an N-terminal signal peptide. All blueberry MATE proteins shared 32.1-84.4% identity, among which VcMATE2, VcMATE3, VcMATE5, VcMATE7, VcMATE8, and VcMATE9 were more similar to the MATE-type flavonoid transporters. Phylogenetic analysis showed VcMATE2, VcMATE3, VcMATE5, VcMATE7, VcMATE8 and VcMATE9 clustered with MATE-type flavonoid transporters, indicating that they might be involved in flavonoid transport. VcMATE1 and VcMATE4 may be involved in the transport of secondary metabolites, the detoxification of xenobiotics, or the export of toxic cations. Real-time quantitative PCR demonstrated that the expression profile of the eight VcMATE genes varied spatially and temporally. Analysis of expression and anthocyanin accumulation indicated that there were some correlation between the expression profile and the accumulation of anthocyanins. These results showed VcMATEs might be involved in diverse physiological functions, and anthocyanins across the membranes might be mutually maintained by MATE-type flavonoid transporters and other mechanisms. This study will enrich the MATE-based transport mechanisms of secondary metabolite, and provide a new biotechonology strategy to develop better nutritional blueberry cultivars.

Identification and Expression Analysis of MATE Genes Involved in Flavonoid Transport in Blueberry Plants

PubMed Central

Chen, Li; Liu, Yushan; Liu, Hongdi; Kang, Limin; Geng, Jinman; Gai, Yuzhuo; Ding, Yunlong; Sun, Haiyue; Li, Yadong

2015-01-01

Multidrug and toxic compound extrusion (MATE) proteins are the most recently identified family of multidrug transporters. In plants, this family is remarkably large compared to the human and bacteria counterpart, highlighting the importance of MATE proteins in this kingdom. Here 33 Unigenes annotated as MATE transporters were found in the blueberry fruit transcriptome, of which eight full-length cDNA sequences were identified and cloned. These proteins are composed of 477–517 residues, with molecular masses ~54 kDa, and theoretical isoelectric points from 5.35 to 8.41. Bioinformatics analysis predicted 10–12 putative transmembrane segments for VcMATEs, and localization to the plasma membrane without an N-terminal signal peptide. All blueberry MATE proteins shared 32.1–84.4% identity, among which VcMATE2, VcMATE3, VcMATE5, VcMATE7, VcMATE8, and VcMATE9 were more similar to the MATE-type flavonoid transporters. Phylogenetic analysis showed VcMATE2, VcMATE3, VcMATE5, VcMATE7, VcMATE8 and VcMATE9 clustered with MATE-type flavonoid transporters, indicating that they might be involved in flavonoid transport. VcMATE1 and VcMATE4 may be involved in the transport of secondary metabolites, the detoxification of xenobiotics, or the export of toxic cations. Real-time quantitative PCR demonstrated that the expression profile of the eight VcMATE genes varied spatially and temporally. Analysis of expression and anthocyanin accumulation indicated that there were some correlation between the expression profile and the accumulation of anthocyanins. These results showed VcMATEs might be involved in diverse physiological functions, and anthocyanins across the membranes might be mutually maintained by MATE-type flavonoid transporters and other mechanisms. This study will enrich the MATE-based transport mechanisms of secondary metabolite, and provide a new biotechonology strategy to develop better nutritional blueberry cultivars. PMID:25781331

Vacuum holding fixture and method for fabricating piezoelectric polymer acoustic sensors

NASA Technical Reports Server (NTRS)

Hall, E. Thomas, Jr. (Inventor); Bryant, Timothy D. (Inventor)

1994-01-01

An apparatus and method for bonding a first film to a second film to form a sensor. The first and second films are piezoelectric films. A base section has a mating surface for holding the first film. A top section has a mating surface for holding the second film, the top section and base section being mateable together to form a cavity between the top section mating surface and the base section mating surface with the first film and the second film pressed together inside the cavity to bond the first film to the second film. An internal connection port forming mechanism forms an internal connection port between the first film and the second film when the base section and top section are mated together with the first film and the second film pressed together inside the cavity. Alternately, an internal connection tab forming mechanism can be used to form a sensor having an internal connection tab between the first and second film, instead of having an internal connection port.

PCR-based karyotyping of Anopheles gambiae inversion 2Rj identifies the BAMAKO chromosomal form.

PubMed

Coulibaly, Mamadou B; Pombi, Marco; Caputo, Beniamino; Nwakanma, Davis; Jawara, Musa; Konate, Lassana; Dia, Ibrahima; Fofana, Abdrahamane; Kern, Marcia; Simard, Frédéric; Conway, David J; Petrarca, Vincenzo; della Torre, Alessandra; Traoré, Sékou; Besansky, Nora J

2007-10-01

The malaria vector Anopheles gambiae is polymorphic for chromosomal inversions on the right arm of chromosome 2 that segregate nonrandomly between assortatively mating populations in West Africa. One such inversion, 2Rj, is associated with the BAMAKO chromosomal form endemic to southern Mali and northern Guinea Conakry near the Niger River. Although it exploits a unique ecology and both molecular and chromosomal data suggest reduced gene flow between BAMAKO and other A. gambiae populations, no molecular markers exist to identify this form. To facilitate study of the BAMAKO form, a PCR assay for molecular karyotyping of 2Rj was developed based on sequences at the breakpoint junctions. The assay was extensively validated using more than 700 field specimens whose karyotypes were determined in parallel by cytogenetic and molecular methods. As inversion 2Rj also occurs in SAVANNA populations outside the geographic range of BAMAKO, samples were tested from Senegal, Cameroon and western Guinea Conakry as well as from Mali. In southern Mali, where 2Rj polymorphism in SAVANNA populations was very low and most of the 2Rj homozygotes were found in BAMAKO karyotypes, the molecular and cytogenetic methods were almost perfectly congruent. Elsewhere agreement between the methods was much poorer, as the molecular assay frequently misclassified 2Rj heterozygotes as 2R+j standard homozygotes. Molecular karyotyping of 2Rj is robust and accurate on 2R+j standard and 2Rj inverted homozygotes. Therefore, the proposed approach overcomes the lack of a rapid tool for identifying the BAMAKO form across developmental stages and sexes, and opens new perspectives for the study of BAMAKO ecology and behaviour. On the other hand, the method should not be applied for molecular karyotyping of j-carriers within the SAVANNA chromosomal form.

Genomic BLUP including additive and dominant variation in purebreds and F1 crossbreds, with an application in pigs.

PubMed

Vitezica, Zulma G; Varona, Luis; Elsen, Jean-Michel; Misztal, Ignacy; Herring, William; Legarra, Andrès

2016-01-29

Most developments in quantitative genetics theory focus on the study of intra-breed/line concepts. With the availability of massive genomic information, it becomes necessary to revisit the theory for crossbred populations. We propose methods to construct genomic covariances with additive and non-additive (dominance) inheritance in the case of pure lines and crossbred populations. We describe substitution effects and dominant deviations across two pure parental populations and the crossbred population. Gene effects are assumed to be independent of the origin of alleles and allelic frequencies can differ between parental populations. Based on these assumptions, the theoretical variance components (additive and dominant) are obtained as a function of marker effects and allelic frequencies. The additive genetic variance in the crossbred population includes the biological additive and dominant effects of a gene and a covariance term. Dominance variance in the crossbred population is proportional to the product of the heterozygosity coefficients of both parental populations. A genomic BLUP (best linear unbiased prediction) equivalent model is presented. We illustrate this approach by using pig data (two pure lines and their cross, including 8265 phenotyped and genotyped sows). For the total number of piglets born, the dominance variance in the crossbred population represented about 13 % of the total genetic variance. Dominance variation is only marginally important for litter size in the crossbred population. We present a coherent marker-based model that includes purebred and crossbred data and additive and dominant actions. Using this model, it is possible to estimate breeding values, dominant deviations and variance components in a dataset that comprises data on purebred and crossbred individuals. These methods can be exploited to plan assortative mating in pig, maize or other species, in order to generate superior crossbred individuals in terms of performance.

Contribution of MATE1 to Renal Secretion of the NMDA Receptor Antagonist Memantine.

PubMed

Müller, Fabian; Weitz, Dietmar; Derdau, Volker; Sandvoss, Martin; Mertsch, Katharina; König, Jörg; Fromm, Martin F

2017-09-05

The weak base memantine is actively secreted into urine, however the underlying mechanisms are insufficiently understood. Potential candidates involved in memantine renal secretion are organic cation transporter 2 (OCT2) and multidrug and toxin extrusion proteins (MATE1, MATE2-K). The aim of this in vitro study was the examination of the interaction of memantine with OCT2 and MATEs. Memantine transporter inhibition and transport were examined in HEK cells expressing human OCT2, MATE1, or MATE2-K. Monolayers of single- (MDCK-OCT2, MDCK-MATE1) and double-transfected MDCK cells (MDCK-OCT2-MATE1) were used for studies on vectorial, basal to apical memantine transport. Memantine inhibited OCT2-, MATE1-, and MATE2-K-mediated metformin transport with IC 50 values of 3.2, 40.9, and 315.3 μM, respectively. In HEK cells, no relevant memantine uptake by OCT2, MATE1, or MATE2-K was detected. Vectorial transport experiments, however, indicated a role of MATE1 for memantine export: After memantine administration to the basal side of the monolayers, memantine cellular accumulation was considerably lower (MDCK-MATE1 vs MDCK control cells, P < 0.01) and memantine transcellular, basal to apical transport was higher in MATE1 expressing cells (MDCK-MATE1 vs MDCK control cells, P < 0.001 at 60 and 180 min). Both effects were abolished upon addition of the MATE inhibitor cimetidine. These experiments suggest a relevant role of MATE1 for renal secretion of memantine. In the clinical setting, renal elimination of memantine could be impaired by coadministration of MATE inhibitors.

Self-esteem links in families with 12-year-old children and in separated spouses.

PubMed

Elfhag, Kristina; Tynelius, Per; Rasmussen, Finn

2010-01-01

The aim of the present study is to map associations of self-esteem in families with 12-year-old children and in separated spouses. The authors assessed self-esteem using the Harter Self-Perception Profile for Adults (B. Messer & S. Harter, 1986) and the Harter Self-Perception Profile for Children (S. Harter, 1988; L. Wichstrom, 1995) in (a) 1,236 pairs of spouses and their 12-year-old children and (b) 159 pairs of ex-spouses. The authors found links for all aspects of self-esteem for married and cohabiting spouses in contrast with ex-spouses who lacked such associations. Ex-spouses had a lower global self-worth than did married and cohabiting spouses. The authors also found parent-child associations for self-esteem. Girls resembled their mothers' global self-worth more than their fathers' and more than the boys. Family members manifest similar levels of self-esteem. The spouses' similarity can be due to assortative mating, a convergence over time, or both. For children, environmental influence in the family context can contribute to the formation of self-esteem. The stronger mother-girl link suggests that maternal identification of self-esteem is an environmental factor for girls in particular.

Why do very unattractive workers earn so much?

PubMed

Kanazawa, Satoshi; Hu, Shihao; Larere, Adrien

2018-05-01

Kanazawa and Still (2018) showed that very unattractive workers earned more than unattractive workers, sometimes more than average-looking or attractive workers, because they had higher levels of intelligence and education, but they did not explain why very unattractive workers had higher intelligence and education. There are both theoretical and empirical reasons to expect that some intelligent men may prefer to marry very unattractive women. The analysis of the National Longitudinal Study of Adolescent Health (Add Health) shows that very unattractive women were significantly more likely to be married at Age 29 than unattractive or average-looking women, and their spouses or partners earned significantly more than those of unattractive or average-looking women. If intelligent men have historically preferred to marry very unattractive women generation after generation, then, because both general intelligence and physical attractiveness are highly heritable, this can explain why very unattractive workers are more intelligent and achieve higher education, thereby earning more. It can also explain why the positive correlation between intelligence and physical attractiveness is not larger despite assortative mating of intelligent men of higher status and physically attractive women over many generations. Copyright © 2018 Elsevier B.V. All rights reserved.

Autism As a Disorder of High Intelligence

PubMed Central

Crespi, Bernard J.

2016-01-01

A suite of recent studies has reported positive genetic correlations between autism risk and measures of mental ability. These findings indicate that alleles for autism overlap broadly with alleles for high intelligence, which appears paradoxical given that autism is characterized, overall, by below-average IQ. This paradox can be resolved under the hypothesis that autism etiology commonly involves enhanced, but imbalanced, components of intelligence. This hypothesis is supported by convergent evidence showing that autism and high IQ share a diverse set of convergent correlates, including large brain size, fast brain growth, increased sensory and visual-spatial abilities, enhanced synaptic functions, increased attentional focus, high socioeconomic status, more deliberative decision-making, profession and occupational interests in engineering and physical sciences, and high levels of positive assortative mating. These findings help to provide an evolutionary basis to understanding autism risk as underlain in part by dysregulation of intelligence, a core human-specific adaptation. In turn, integration of studies on intelligence with studies of autism should provide novel insights into the neurological and genetic causes of high mental abilities, with important implications for cognitive enhancement, artificial intelligence, the relationship of autism with schizophrenia, and the treatment of both autism and intellectual disability. PMID:27445671

The Proximate Determinants of Educational Homogamy: The Effects of First Marriage, Marital Dissolution, Remarriage, and Educational Upgrading

PubMed Central

Schwartz, Christine R.; Mare, Robert D.

2014-01-01

This paper adapts the population balancing equation to develop a framework for studying the proximate determinants of educational homogamy. Using data from the National Longitudinal Survey of Youth on a cohort of women born between 1957 and 1964, we decompose the odds of homogamy in prevailing marriages into four proximate determinants: (1) first marriages, (2) first and later marital dissolutions, (3) remarriages, and (4) educational attainment after marriage. The odds of homogamy among new first marriages are lower than among prevailing marriages, but not because of selective marital dissolution, remarriage, and educational attainment after marriage, as has been speculated. Prevailing marriages are more likely to be educationally homogamous than new first marriages because of the accumulation of homogamous first marriages in the stock of marriages. First marriages overwhelmingly account for the odds of homogamy in prevailing marriages in this cohort. Marital dissolutions, remarriages, and educational upgrades after marriage have relatively small and offsetting effects. Our results suggest that, despite the high prevalence of divorce, remarriage, and continued schooling after marriage in the United States, the key to understanding trends in educational homogamy lies primarily in variation in assortative mating into first marriage. PMID:22450676

Hybridization and the phylogenetic relationship between polecats and domestic ferrets in Britain

USGS Publications Warehouse

Davison, A.; Birks, J. D. S.; Griffiths, H. I.; Kitchener, A. C.; Biggins, D.; Butlin, R. K.

1999-01-01

Ferrets (Mustela furo) were domesticated from polecats (M. putorius, M. eversmannii) over 2000 years ago. Following their introduction to Britain, they escaped and hybridized with native European polecats (M. putorius). Native polecats declined to the point of near extinction prior to World War I, but have recently begun to expand from a Welsh refugium. Concern has arisen as to the extent of polecat/ferret introgression, and in particular, whether the expanding population is of mainly hybrid origin. Therefore, mitochondrial DNA sequencing was used to investigate polecat genetic diversity in Britain. Two geographically distinct lineages were found, where one may be ancestral to the British polecat, and the other to the domestic ferret. The ancestral distribution of each lineage, or assortative mating is sufficient to explain the observed pattern. A further comparison between the distribution of the polecat phenotype and mitochondrial haplotype implies that the current population expansion may be mediated by dispersing male polecats hybridizing with female feral ferrets. However, the wild source of the ferret remains obscure. Relatively recent speciation from European mink (M. lutreola) and black-footed ferrets (M. nigripes), and/or the effects of hybridization result in an unresolved molecular phylogeny.

Mediterranean blue tits as a case study of local adaptation.

PubMed

Charmantier, Anne; Doutrelant, Claire; Dubuc-Messier, Gabrielle; Fargevieille, Amélie; Szulkin, Marta

2016-01-01

While the study of the origins of biological diversity across species has provided numerous examples of adaptive divergence, the realization that it can occur at microgeographic scales despite gene flow is recent, and scarcely illustrated. We review here evidence suggesting that the striking phenotypic differentiation in ecologically relevant traits exhibited by blue tits Cyanistes caeruleus in their southern range-edge putatively reflects adaptation to the heterogeneity of the Mediterranean habitats. We first summarize the phenotypic divergence for a series of life history, morphological, behavioural, acoustic and colour ornament traits in blue tit populations of evergreen and deciduous forests. For each divergent trait, we review the evidence obtained from common garden experiments regarding a possible genetic origin of the observed phenotypic differentiation as well as evidence for heterogeneous selection. Second, we argue that most phenotypically differentiated traits display heritable variation, a fundamental requirement for evolution to occur. Third, we discuss nonrandom dispersal, selective barriers and assortative mating as processes that could reinforce local adaptation. Finally, we show how population genomics supports isolation - by - environment across landscapes. Overall, the combination of approaches converges to the conclusion that the strong phenotypic differentiation observed in Mediterranean blue tits is a fascinating case of local adaptation.

When can stress facilitate divergence by altering time to flowering?

PubMed

Jordan, Crispin Y; Ally, Dilara; Hodgins, Kathryn A

2015-12-01

Stressors and heterogeneity are ubiquitous features of natural environments, and theory suggests that when environmental qualities alter flowering schedules through phenotypic plasticity, assortative mating can result that promotes evolutionary divergence. Therefore, it is important to determine whether common ecological stressors induce similar changes in flowering time. We review previous studies to determine whether two important stressors, water restriction and herbivory, induce consistent flowering time responses among species; for example, how often do water restriction and herbivory both delay flowering? We focus on the direction of change in flowering time, which affects the potential for divergence in heterogeneous environments. We also tested whether these stressors influenced time to flowering and nonphenology traits using Mimulus guttatus. The literature review suggests that water restriction has variable effects on flowering time, whereas herbivory delays flowering with exceptional consistency. In the Mimulus experiment, low water and herbivory advanced and delayed flowering, respectively. Overall, our results temper theoretical predictions for evolutionary divergence due to habitat-induced changes in flowering time; in particular, we discuss how accounting for variation in the direction of change in flowering time can either increase or decrease the potential for divergence. In addition, we caution against adaptive interpretations of stress-induced phenology shifts.

Autism As a Disorder of High Intelligence.

PubMed

Crespi, Bernard J

2016-01-01

A suite of recent studies has reported positive genetic correlations between autism risk and measures of mental ability. These findings indicate that alleles for autism overlap broadly with alleles for high intelligence, which appears paradoxical given that autism is characterized, overall, by below-average IQ. This paradox can be resolved under the hypothesis that autism etiology commonly involves enhanced, but imbalanced, components of intelligence. This hypothesis is supported by convergent evidence showing that autism and high IQ share a diverse set of convergent correlates, including large brain size, fast brain growth, increased sensory and visual-spatial abilities, enhanced synaptic functions, increased attentional focus, high socioeconomic status, more deliberative decision-making, profession and occupational interests in engineering and physical sciences, and high levels of positive assortative mating. These findings help to provide an evolutionary basis to understanding autism risk as underlain in part by dysregulation of intelligence, a core human-specific adaptation. In turn, integration of studies on intelligence with studies of autism should provide novel insights into the neurological and genetic causes of high mental abilities, with important implications for cognitive enhancement, artificial intelligence, the relationship of autism with schizophrenia, and the treatment of both autism and intellectual disability.

Genetic Dissection of Clonally Inherited Genomes of Poeciliopsis. I. Linkage Analysis and Preliminary Assessment of Deleterious Gene Loads

PubMed Central

Leslie, James F.; Vrijenhoek, Robert C.

1978-01-01

Theoretical considerations suggest that a high load of deleterious mutations should accumulate in asexual genomes. An ideal system for testing this hypothesis occurs in the hybrid all-female fish Poeciliopsis monacha-lucida. The hybrid genotype is retained between generations by an oogenetic process that transmits only a nonrecombinant haploid monacha genome to their ova. The hybrid genotype is re-established in nature by fertilization of these monacha eggs with sperm from a sexual species, P. lucida. The unique reproductive mechanism of these hybrids allows the genetic dissection of the clonal monacha genome by forced matings with males of P. monacha. The resultant F1 hybrids and their backcross progeny were examined to determine the amount and kinds of genetic changes that might have occurred in two clonal monacha genomes.—Using six allozyme markers, four similar linkage groups were identified in each clonal genome. Segregation and assortment at these loci revealed no apparent differences between monacha genomes from sexually and clonally reproducing species. Mortality of F1 and backcross progeny revealed differences between the two clonal genomes, suggesting that deleterious genes may accumulate in genomes sheltered from recombination. PMID:17248875

Convenience stores and the marketing of foods and beverages through product assortment.

PubMed

Sharkey, Joseph R; Dean, Wesley R; Nalty, Courtney

2012-09-01

Product assortment (presence and variety) is a key in-store marketing strategy to influence consumer choice. Quantifying the product assortment of healthier and less-healthy foods and beverages in convenience stores can inform changes in the food environment. To document product assortment (i.e., presence and variety of specific foods and beverages) in convenience stores. Observational survey data were collected onsite in 2011 by trained promotora-researchers in 192 convenience stores. Frequencies of presence and distributions of variety were calculated in 2012. Paired differences were examined using the Wilcoxon matched-pairs signed-rank test. Convenience stores displayed a large product assortment of sugar-sweetened beverages (median 86.5 unique varieties); candy (76 varieties); salty snacks (77 varieties); fried chips (44 varieties); cookies and pastries (19 varieties); and frozen sweets (21 varieties). This compared with 17 varieties of non-sugar sweetened beverages and three varieties of baked chips. The Wilcoxon signed-rank test confirmed a (p<0.001) greater variety of sugar-sweetened than non-sugar-sweetened beverages, and of fried chips compared with baked chips. Basic food items provided by convenience stores included milk (84% of stores); fresh fruit (33%); fresh vegetables (35%); canned vegetables (78%); white bread (71%); and deli-style packaged meat (57%). Healthier versions of milk, canned fruit, canned tuna, bread, and deli-style packaged meat were displayed in 17%-71% of convenience stores. Convenience stores in this area provide a greater assortment of less-healthy compared with healthier foods and beverages. There are opportunities to influence consumer food choice through programs that alter the balance between healthier and less-healthy foods and beverages in existing convenience stores that serve rural and underserved neighborhoods and communities. Copyright © 2012 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

The Influence of Assortativity on the Robustness of Signal-Integration Logic in Gene Regulatory Networks

PubMed Central

Pechenick, Dov A.; Payne, Joshua L.; Moore, Jason H.

2011-01-01

Gene regulatory networks (GRNs) drive the cellular processes that sustain life. To do so reliably, GRNs must be robust to perturbations, such as gene deletion and the addition or removal of regulatory interactions. GRNs must also be robust to genetic changes in regulatory regions that define the logic of signal-integration, as these changes can affect how specific combinations of regulatory signals are mapped to particular gene expression states. Previous theoretical analyses have demonstrated that the robustness of a GRN is influenced by its underlying topological properties, such as degree distribution and modularity. Another important topological property is assortativity, which measures the propensity with which nodes of similar connectivity are connected to one another. How assortativity influences the robustness of the signal-integration logic of GRNs remains an open question. Here, we use computational models of GRNs to investigate this relationship. We separately consider each of the three dynamical regimes of this model for a variety of degree distributions. We find that in the chaotic regime, robustness exhibits a pronounced increase as assortativity becomes more positive, while in the critical and ordered regimes, robustness is generally less sensitive to changes in assortativity. We attribute the increased robustness to a decrease in the duration of the gene expression pattern, which is caused by a reduction in the average size of a GRN’s in-components. This study provides the first direct evidence that assortativity influences the robustness of the signal-integration logic of computational models of GRNs, illuminates a mechanistic explanation for this influence, and furthers our understanding of the relationship between topology and robustness in complex biological systems. PMID:22155134

Efficient Breeding by Genomic Mating.

PubMed

Akdemir, Deniz; Sánchez, Julio I

2016-01-01

Selection in breeding programs can be done by using phenotypes (phenotypic selection), pedigree relationship (breeding value selection) or molecular markers (marker assisted selection or genomic selection). All these methods are based on truncation selection, focusing on the best performance of parents before mating. In this article we proposed an approach to breeding, named genomic mating, which focuses on mating instead of truncation selection. Genomic mating uses information in a similar fashion to genomic selection but includes information on complementation of parents to be mated. Following the efficiency frontier surface, genomic mating uses concepts of estimated breeding values, risk (usefulness) and coefficient of ancestry to optimize mating between parents. We used a genetic algorithm to find solutions to this optimization problem and the results from our simulations comparing genomic selection, phenotypic selection and the mating approach indicate that current approach for breeding complex traits is more favorable than phenotypic and genomic selection. Genomic mating is similar to genomic selection in terms of estimating marker effects, but in genomic mating the genetic information and the estimated marker effects are used to decide which genotypes should be crossed to obtain the next breeding population.

Robustness of Oscillatory Behavior in Correlated Networks

PubMed Central

Sasai, Takeyuki; Morino, Kai; Tanaka, Gouhei; Almendral, Juan A.; Aihara, Kazuyuki

2015-01-01

Understanding network robustness against failures of network units is useful for preventing large-scale breakdowns and damages in real-world networked systems. The tolerance of networked systems whose functions are maintained by collective dynamical behavior of the network units has recently been analyzed in the framework called dynamical robustness of complex networks. The effect of network structure on the dynamical robustness has been examined with various types of network topology, but the role of network assortativity, or degree–degree correlations, is still unclear. Here we study the dynamical robustness of correlated (assortative and disassortative) networks consisting of diffusively coupled oscillators. Numerical analyses for the correlated networks with Poisson and power-law degree distributions show that network assortativity enhances the dynamical robustness of the oscillator networks but the impact of network disassortativity depends on the detailed network connectivity. Furthermore, we theoretically analyze the dynamical robustness of correlated bimodal networks with two-peak degree distributions and show the positive impact of the network assortativity. PMID:25894574

Mate choice for neutral and MHC genetic characteristics in Alpine marmots: different targets in different contexts?

PubMed

Ferrandiz-Rovira, Mariona; Allainé, Dominique; Callait-Cardinal, Marie-Pierre; Cohas, Aurélie

2016-07-01

Sexual selection through female mate choice for genetic characteristics has been suggested to be an important evolutionary force maintaining genetic variation in animal populations. However, the genetic targets of female mate choice are not clearly identified and whether female mate choice is based on neutral genetic characteristics or on particular functional loci remains an open question. Here, we investigated the genetic targets of female mate choice in Alpine marmots (Marmota marmota), a socially monogamous mammal where extra-pair paternity (EPP) occurs. We used 16 microsatellites to describe neutral genetic characteristics and two MHC loci belonging to MHC class I and II as functional genetic characteristics. Our results reveal that (1) neutral and MHC genetic characteristics convey different information in this species, (2) social pairs show a higher MHC class II dissimilarity than expected under random mate choice, and (3) the occurrence of EPP increases when social pairs present a high neutral genetic similarity or dissimilarity but also when they present low MHC class II dissimilarity. Thus, female mate choice is based on both neutral and MHC genetic characteristics, and the genetic characteristics targeted seem to be context dependent (i.e., the genes involved in social mate choice and genetic mate choice differ). We emphasize the need for empirical studies of mate choice in the wild using both neutral and MHC genetic characteristics because whether neutral and functional genetic characteristics convey similar information is not universal.

46 CFR 11.450 - Tonnage limitations and qualifying requirements for endorsements as master or mate of Great Lakes...

Code of Federal Regulations, 2014 CFR

2014-10-01

... endorsements as master or mate of Great Lakes and inland vessels of less than 200 GRT. 11.450 Section 11.450... limitations and qualifying requirements for endorsements as master or mate of Great Lakes and inland vessels... for master or mate of vessels of less than 200 GRT are issued in 50 GRT increments based on the...

46 CFR 11.450 - Tonnage limitations and qualifying requirements for endorsements as master or mate of Great Lakes...

Code of Federal Regulations, 2010 CFR

2010-10-01

... endorsements as master or mate of Great Lakes and inland vessels of not more than 200 gross tons. 11.450... and qualifying requirements for endorsements as master or mate of Great Lakes and inland vessels of... master or mate of vessels of not more than 200 gross tons are issued in 50 ton increments based on the...

46 CFR 11.450 - Tonnage limitations and qualifying requirements for endorsements as master or mate of Great Lakes...

Code of Federal Regulations, 2012 CFR

2012-10-01

... endorsements as master or mate of Great Lakes and inland vessels of not more than 200 gross tons. 11.450... and qualifying requirements for endorsements as master or mate of Great Lakes and inland vessels of... master or mate of vessels of not more than 200 gross tons are issued in 50 ton increments based on the...

46 CFR 11.450 - Tonnage limitations and qualifying requirements for endorsements as master or mate of Great Lakes...

Code of Federal Regulations, 2011 CFR

2011-10-01

... endorsements as master or mate of Great Lakes and inland vessels of not more than 200 gross tons. 11.450... and qualifying requirements for endorsements as master or mate of Great Lakes and inland vessels of... master or mate of vessels of not more than 200 gross tons are issued in 50 ton increments based on the...

46 CFR 11.450 - Tonnage limitations and qualifying requirements for endorsements as master or mate of Great Lakes...

Code of Federal Regulations, 2013 CFR

2013-10-01

... endorsements as master or mate of Great Lakes and inland vessels of not more than 200 gross tons. 11.450... and qualifying requirements for endorsements as master or mate of Great Lakes and inland vessels of... master or mate of vessels of not more than 200 gross tons are issued in 50 ton increments based on the...

Tested Demonstrations: Thermodynamic Changes, Kinetics, Equilibrium, and LeChatelier's Principle.

ERIC Educational Resources Information Center

Gilbert, George L., Ed.

1984-01-01

Procedures for demonstrating thermodynamic changes, kinetics and reaction mechanisms, equilibrium, and LeChatelier's principle are presented. The only materials needed for these demonstrations are beakers, water, assorted wooden blocks of varying thickness, assorted rubber tubing, and a sponge. The concepts illustrated in each demonstration are…

Accuracy in estimation of timber assortments and stem distribution - A comparison of airborne and terrestrial laser scanning techniques

NASA Astrophysics Data System (ADS)

Kankare, Ville; Vauhkonen, Jari; Tanhuanpää, Topi; Holopainen, Markus; Vastaranta, Mikko; Joensuu, Marianna; Krooks, Anssi; Hyyppä, Juha; Hyyppä, Hannu; Alho, Petteri; Viitala, Risto

2014-11-01

Detailed information about timber assortments and diameter distributions is required in forest management. Forest owners can make better decisions concerning the timing of timber sales and forest companies can utilize more detailed information to optimize their wood supply chain from forest to factory. The objective here was to compare the accuracies of high-density laser scanning techniques for the estimation of tree-level diameter distribution and timber assortments. We also introduce a method that utilizes a combination of airborne and terrestrial laser scanning in timber assortment estimation. The study was conducted in Evo, Finland. Harvester measurements were used as a reference for 144 trees within a single clear-cut stand. The results showed that accurate tree-level timber assortments and diameter distributions can be obtained, using terrestrial laser scanning (TLS) or a combination of TLS and airborne laser scanning (ALS). Saw log volumes were estimated with higher accuracy than pulpwood volumes. The saw log volumes were estimated with relative root-mean-squared errors of 17.5% and 16.8% with TLS and a combination of TLS and ALS, respectively. The respective accuracies for pulpwood were 60.1% and 59.3%. The differences in the bucking method used also caused some large errors. In addition, tree quality factors highly affected the bucking accuracy, especially with pulpwood volume.

Importance of small-degree nodes in assortative networks with degree-weight correlations

NASA Astrophysics Data System (ADS)

Ma, Sijuan; Feng, Ling; Monterola, Christopher Pineda; Lai, Choy Heng

2017-10-01

It has been known that assortative network structure plays an important role in spreading dynamics for unweighted networks. Yet its influence on weighted networks is not clear, in particular when weight is strongly correlated with the degrees of the nodes as we empirically observed in Twitter. Here we use the self-consistent probability method and revised nonperturbative heterogenous mean-field theory method to investigate this influence on both susceptible-infective-recovered (SIR) and susceptible-infective-susceptible (SIS) spreading dynamics. Both our simulation and theoretical results show that while the critical threshold is not significantly influenced by the assortativity, the prevalence in the supercritical regime shows a crossover under different degree-weight correlations. In particular, unlike the case of random mixing networks, in assortative networks, the negative degree-weight correlation leads to higher prevalence in their spreading beyond the critical transmissivity than that of the positively correlated. In addition, the previously observed inhibition effect on spreading velocity by assortative structure is not apparent in negatively degree-weight correlated networks, while it is enhanced for that of the positively correlated. Detailed investigation into the degree distribution of the infected nodes reveals that small-degree nodes play essential roles in the supercritical phase of both SIR and SIS spreadings. Our results have direct implications in understanding viral information spreading over online social networks and epidemic spreading over contact networks.

The Evolutionary Consequences of Disrupted Male Mating Signals: An Agent-Based Modelling Exploration of Endocrine Disrupting Chemicals in the Guppy

PubMed Central

Senior, Alistair McNair; Nakagawa, Shinichi; Grimm, Volker

2014-01-01

Females may select a mate based on signalling traits that are believed to accurately correlate with heritable aspects of male quality. Anthropogenic actions, in particular chemicals released into the environment, are now disrupting the accuracy of mating signals to convey information about male quality. The long-term prediction for disrupted mating signals is most commonly loss of female preference. Yet, this prediction has rarely been tested using quantitative models. We use agent-based models to explore the effects of rapid disruption of mating signals. In our model, a gene determines survival. Males signal their level of genetic quality via a signal trait, which females use to select a mate. We allowed this system of sexual selection to become established, before introducing a disruption between the male signal trait and quality, which was similar in nature to that induced by exogenous chemicals. Finally, we assessed the capacity of the system to recover from this disruption. We found that within a relatively short time frame, disruption of mating signals led to a lasting loss of female preference. Decreases in mean viability at the population-level were also observed, because sexual-selection acting against newly arising deleterious mutations was relaxed. The ability of the population to recover from disrupted mating signals was strongly influenced by the mechanisms that promoted or maintained genetic diversity in traits under sexual selection. Our simple model demonstrates that environmental perturbations to the accuracy of male mating signals can result in a long-term loss of female preference for those signals within a few generations. What is more, the loss of this preference can have knock-on consequences for mean population fitness. PMID:25047080

Nest-mate recognition in Manuelia postica (Apidae: Xylocopinae): an eusocial trait is present in a solitary bee.

PubMed

Flores-Prado, Luis; Aguilera-Olivares, Daniel; Niemeyer, Hermann M

2008-02-07

In eusocial Hymenoptera, females are more tolerant towards nest-mate than towards non-nest-mate females. In solitary Hymenoptera, females are generally aggressive towards any conspecific female. Field observations of the nest biology of Manuelia postica suggested nest-mate recognition. Experiments were performed involving two live interacting females or one live female interacting with a dead female. Live females from different nests were more intolerant to each other than females from the same nest. Females were more intolerant towards non-nest-mate than towards nest-mate dead females. When dead females were washed with pentane, no differences in tolerant and intolerant behaviours were detected between non-nest-mate and nest-mate females. Females were more intolerant towards nest-mate female carcasses coated with the cuticular extract from a non-nest-mate than towards non-nest-mate female carcasses coated with the cuticular extract from a nest-mate. The compositions of the cuticular extracts was more similar between females from the same nest than between females from different nests. The results demonstrate for the first time nest-mate recognition mediated by cuticular chemicals in a largely solitary species of Apidae. The position of Manuelia at the base of the Apidae phylogeny suggests that nest-mate recognition in eusocial species apical to Manuelia represents the retention of a primitive capacity in Apidae.

46 CFR 11.422 - Tonnage limitations and qualifying requirements for endorsements as master or mate of vessels of...

Code of Federal Regulations, 2014 CFR

2014-10-01

... endorsements as master or mate of vessels of less than 200 GRT. 11.422 Section 11.422 Shipping COAST GUARD... requirements for endorsements as master or mate of vessels of less than 200 GRT. (a) Each national endorsement as master or mate of vessels of less than 200 GRT is issued with a tonnage limitation based on the...

Extrapair mating between relatives in the barn swallow: a role for kin selection?

PubMed

Kleven, Oddmund; Jacobsen, Frode; Robertson, Raleigh J; Lifjeld, Jan T

2005-12-22

Why do females of many species mate with more than one male? One of the main hypotheses suggests that female promiscuity is an insurance mechanism against the potential detrimental effects of inbreeding. Accordingly, females should preferably mate with less related males in multiple or extrapair mating. Here we analyse paternity, relatedness among mating partners, and relatedness between parents and offspring, in the socially monogamous North American barn swallow (Hirundo rustica erythrogaster). In contrast to the inbreeding avoidance hypothesis, we found that extrapair mating partners were more related than expected by random choice, and tended to be more related than social partners. Furthermore, extrapair mating resulted in genetic parents being more related to their extrapair young than to their withinpair young. We propose a new hypothesis for extrapair mating based on kin selection theory as a possible explanation to these findings.

TrackMate: An open and extensible platform for single-particle tracking.

PubMed

Tinevez, Jean-Yves; Perry, Nick; Schindelin, Johannes; Hoopes, Genevieve M; Reynolds, Gregory D; Laplantine, Emmanuel; Bednarek, Sebastian Y; Shorte, Spencer L; Eliceiri, Kevin W

2017-02-15

We present TrackMate, an open source Fiji plugin for the automated, semi-automated, and manual tracking of single-particles. It offers a versatile and modular solution that works out of the box for end users, through a simple and intuitive user interface. It is also easily scriptable and adaptable, operating equally well on 1D over time, 2D over time, 3D over time, or other single and multi-channel image variants. TrackMate provides several visualization and analysis tools that aid in assessing the relevance of results. The utility of TrackMate is further enhanced through its ability to be readily customized to meet specific tracking problems. TrackMate is an extensible platform where developers can easily write their own detection, particle linking, visualization or analysis algorithms within the TrackMate environment. This evolving framework provides researchers with the opportunity to quickly develop and optimize new algorithms based on existing TrackMate modules without the need of having to write de novo user interfaces, including visualization, analysis and exporting tools. The current capabilities of TrackMate are presented in the context of three different biological problems. First, we perform Caenorhabditis-elegans lineage analysis to assess how light-induced damage during imaging impairs its early development. Our TrackMate-based lineage analysis indicates the lack of a cell-specific light-sensitive mechanism. Second, we investigate the recruitment of NEMO (NF-κB essential modulator) clusters in fibroblasts after stimulation by the cytokine IL-1 and show that photodamage can generate artifacts in the shape of TrackMate characterized movements that confuse motility analysis. Finally, we validate the use of TrackMate for quantitative lifetime analysis of clathrin-mediated endocytosis in plant cells. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

Reproductive investment when mate quality varies: differential allocation versus reproductive compensation.

PubMed

Harris, W Edwin; Uller, Tobias

2009-04-27

Reproductive investment decisions form an integral part of life-history biology. Selection frequently favours plasticity in investment that can generate maternal effects on offspring development. For example, if females differentially allocate resources based on mate attractiveness or quality, this can create a non-genetic link between mate attractiveness and offspring fitness with potential consequences for ecological and evolutionary dynamics. It is therefore important to understand under what conditions differential investment into offspring in relation to male quality is expected to occur and the direction of the effect. Two opposite predictions, increased investment into offspring produced with high-quality mates (differential allocation (DA)) and increased investment with low-quality males (reproductive compensation (RC)) have been suggested but no formal theoretical treatment justifying the assumptions underlying these two hypotheses has been conducted to date. Here, we used a state-based approach to investigate the circumstances under which the variation in mate quality results in differential female investment into offspring and how this interacts with female energetic resource levels. We found that a pattern of increased investment when mating with high-quality mates (i.e. DA) was the most common optimal investment strategy for females in our model. By contrast, increased investment when mating with low-quality mates (i.e. RC) was predicted only when the relative impact of parental investment on offspring quality was low. Finally, we found that the specific pattern of investment in relation to male quality depends on female energetic state, the likelihood for future mating opportunities and the expected future distribution of mate quality. Thus, the female's age and body condition should be important factors mediating DA and RC, which may help to explain the equivocal results of empirical studies.

Characterization of essential proteins based on network topology in proteins interaction networks

NASA Astrophysics Data System (ADS)

Bakar, Sakhinah Abu; Taheri, Javid; Zomaya, Albert Y.

2014-06-01

The identification of essential proteins is theoretically and practically important as (1) it is essential to understand the minimal surviving requirements for cellular lives, and (2) it provides fundamental for development of drug. As conducting experimental studies to identify essential proteins are both time and resource consuming, here we present a computational approach in predicting them based on network topology properties from protein-protein interaction networks of Saccharomyces cerevisiae. The proposed method, namely EP3NN (Essential Proteins Prediction using Probabilistic Neural Network) employed a machine learning algorithm called Probabilistic Neural Network as a classifier to identify essential proteins of the organism of interest; it uses degree centrality, closeness centrality, local assortativity and local clustering coefficient of each protein in the network for such predictions. Results show that EP3NN managed to successfully predict essential proteins with an accuracy of 95% for our studied organism. Results also show that most of the essential proteins are close to other proteins, have assortativity behavior and form clusters/sub-graph in the network.

Inversion of the chromosomal region between two mating type loci switches the mating type in Hansenula polymorpha.

PubMed

Maekawa, Hiromi; Kaneko, Yoshinobu

2014-11-01

Yeast mating type is determined by the genotype at the mating type locus (MAT). In homothallic (self-fertile) Saccharomycotina such as Saccharomyces cerevisiae and Kluveromyces lactis, high-efficiency switching between a and α mating types enables mating. Two silent mating type cassettes, in addition to an active MAT locus, are essential components of the mating type switching mechanism. In this study, we investigated the structure and functions of mating type genes in H. polymorpha (also designated as Ogataea polymorpha). The H. polymorpha genome was found to harbor two MAT loci, MAT1 and MAT2, that are ∼18 kb apart on the same chromosome. MAT1-encoded α1 specifies α cell identity, whereas none of the mating type genes were required for a identity and mating. MAT1-encoded α2 and MAT2-encoded a1 were, however, essential for meiosis. When present in the location next to SLA2 and SUI1 genes, MAT1 or MAT2 was transcriptionally active, while the other was repressed. An inversion of the MAT intervening region was induced by nutrient limitation, resulting in the swapping of the chromosomal locations of two MAT loci, and hence switching of mating type identity. Inversion-deficient mutants exhibited severe defects only in mating with each other, suggesting that this inversion is the mechanism of mating type switching and homothallism. This chromosomal inversion-based mechanism represents a novel form of mating type switching that requires only two MAT loci.

Trading height for education in the marriage market.

PubMed

Ponzo, Michela; Scoppa, Vincenzo

2015-01-01

Several empirical studies point out the relevance of individuals' physical attributes-such as height, weight, beauty-in the labor market. In the same way, physical characteristics may affect lifetime prospects through their impact on the selection of a partner in the marriage market. We analyzed to what extent an individual's height and weight (arguably affecting physical attractiveness, as documented in many studies) are related to lifetime economic outcomes through the marriage market, investigating whether individual height and weight affect the probability of marrying with a "high-quality partner," measuring quality as the partner's educational attainment or as the partner's prospective labor income. Using a large Italian dataset of married (and cohabiting) couples-the 2005 Italian Health Conditions Survey which provides information on health conditions, individual characteristics, and socioeconomic variables-we estimated separate OLS and Ordered Probit regressions for females and males. Since weight might be endogenously determined, to avoid any estimation bias we also estimated a reduced form equation in which predetermined height affects directly and indirectly (through BMI) physical attractiveness and, as a consequence, the choice of a partner with a given educational attainment. Our findings suggest that height is a desirable trait in mating selection affecting the partner's socioeconomic characteristics: we found that taller individuals tended to mate with more educated partners, controlling for their own educational level-to take into account the tendency for assortative mating for education-and for other personal traits such as age, geographical residence, city size, and the presence of health problems. On the other hand, we showed that individuals with higher BMI were married to partners with lower levels of education. The results also provide evidence of non-linearity in the relationship between height and educational attainment of the partner. These findings are confirmed for both males and females, but being taller seems to be more relevant for males, while being thinner is more important for females. We have also found that taller and thinner females and males tend to be married with partners earning higher labor incomes. These findings were robust to a number of checks. Our findings confirm that the physical characteristics that an individual brings to the marriage market influences the outcome in this market: physical attractiveness is exchanged in the marriage market for a higher educational attainment and the ability to earn a higher labor income. © 2014 Wiley Periodicals, Inc.

Heritable variation of sex pheromone composition and the potential for evolution of resistance to pheromone-based control of the Indian meal moth, Plodia interpunctella.

PubMed

Svensson, Glenn P; Ryne, Camilla; Löfstedt, Christer

2002-07-01

The short-term evolutionary effect of pheromone-based mating disruption on the mating ability of the Indian meal moth, Plodia interpunctella, was investigated. Three independent selection lines were established, and the mating ability of moths in plastic tents treated with high doses of pheromone and in control tents was compared for two consecutive generations. In addition, the heritability of the sex pheromone blend, measured as the ratio of two major pheromone components (Z,E)-9,12-tetradecadienyl acetate and (Z,E)-9,12-tetradecadienol, was estimated. Based on a mother-daughter regression analysis including 21 families, the heritability of the pheromone blend was 0.65 +/- 0.14, indicating a potential for evolutionary change of the character. However, no increase in mating ability of females in pheromone-treated tents or alteration of the pheromone blend was observed in any selection line when compared with control lines, indicating no or weak selection on the pheromone blend as well as other traits influencing mating ability of this species under the created mating disruption conditions. Factors contributing to the lack of selection effects are discussed.

'Good genes as heterozygosity': the major histocompatibility complex and mate choice in Atlantic salmon (Salmo salar).

PubMed

Landry, C; Garant, D; Duchesne, P; Bernatchez, L

2001-06-22

According to the theory of mate choice based on heterozygosity, mates should choose each other in order to increase the heterozygosity of their offspring. In this study, we tested the 'good genes as heterozygosity' hypothesis of mate choice by documenting the mating patterns of wild Atlantic salmon (Salmo salar) using both major histocompatibility complex (MHC) and microsatellite loci. Specifically, we tested the null hypotheses that mate choice in Atlantic salmon is not dependent on the relatedness between potential partners or on the MHC similarity between mates. Three parameters were assessed: (i) the number of shared alleles between partners (x and y) at the MHC (M(xy)), (ii) the MHC amino-acid genotypic distance between mates' genotypes (AA(xy)), and (iii) genetic relatedness between mates (r(xy)). We found that Atlantic salmon choose their mates in order to increase the heterozygosity of their offspring at the MHC and, more specifically, at the peptide-binding region, presumably in order to provide them with better defence against parasites and pathogens. This was supported by a significant difference between the observed and expected AA(xy) (p = 0.0486). Furthermore, mate choice was not a mechanism of overall inbreeding avoidance as genetic relatedness supported a random mating scheme (p = 0.445). This study provides the first evidence that MHC genes influence mate choice in fish.

Pheromone-based mating disruption in Wisconsin cranberries

USDA-ARS?s Scientific Manuscript database

Pheromone-based mating disruption is a promising method of pest control in cranberries. Three moth species, cranberry fruitworm, Acrobasis vaccinii Riley (Lepidoptera: Pyralidae), Sparganothis fruitworm, Sparganothis sulfureana Clemens (Lepidoptera: Tortricidae), and black-headed fireworm, Rhopobota...

Analysis of co-occurrence toponyms in web pages based on complex networks

NASA Astrophysics Data System (ADS)

Zhong, Xiang; Liu, Jiajun; Gao, Yong; Wu, Lun

2017-01-01

A large number of geographical toponyms exist in web pages and other documents, providing abundant geographical resources for GIS. It is very common for toponyms to co-occur in the same documents. To investigate these relations associated with geographic entities, a novel complex network model for co-occurrence toponyms is proposed. Then, 12 toponym co-occurrence networks are constructed from the toponym sets extracted from the People's Daily Paper documents of 2010. It is found that two toponyms have a high co-occurrence probability if they are at the same administrative level or if they possess a part-whole relationship. By applying complex network analysis methods to toponym co-occurrence networks, we find the following characteristics. (1) The navigation vertices of the co-occurrence networks can be found by degree centrality analysis. (2) The networks express strong cluster characteristics, and it takes only several steps to reach one vertex from another one, implying that the networks are small-world graphs. (3) The degree distribution satisfies the power law with an exponent of 1.7, so the networks are free-scale. (4) The networks are disassortative and have similar assortative modes, with assortative exponents of approximately 0.18 and assortative indexes less than 0. (5) The frequency of toponym co-occurrence is weakly negatively correlated with geographic distance, but more strongly negatively correlated with administrative hierarchical distance. Considering the toponym frequencies and co-occurrence relationships, a novel method based on link analysis is presented to extract the core toponyms from web pages. This method is suitable and effective for geographical information retrieval.

Genome-wide SNP data suggest complex ancestry of sympatric North Pacific killer whale ecotypes.

PubMed

Foote, A D; Morin, P A

2016-11-01

Three ecotypes of killer whale occur in partial sympatry in the North Pacific. Individuals assortatively mate within the same ecotype, resulting in correlated ecological and genetic differentiation. A key question is whether this pattern of evolutionary divergence is an example of incipient sympatric speciation from a single panmictic ancestral population, or whether sympatry could have resulted from multiple colonisations of the North Pacific and secondary contact between ecotypes. Here, we infer multilocus coalescent trees from >1000 nuclear single-nucleotide polymorphisms (SNPs) and find evidence of incomplete lineage sorting so that the genealogies of SNPs do not all conform to a single topology. To disentangle whether uncertainty in the phylogenetic inference of the relationships among ecotypes could also result from ancestral admixture events we reconstructed the relationship among the ecotypes as an admixture graph and estimated f 4 -statistics using TreeMix. The results were consistent with episodes of admixture between two of the North Pacific ecotypes and the two outgroups (populations from the Southern Ocean and the North Atlantic). Gene flow may have occurred via unsampled 'ghost' populations rather than directly between the populations sampled here. Our results indicate that because of ancestral admixture events and incomplete lineage sorting, a single bifurcating tree does not fully describe the relationship among these populations. The data are therefore most consistent with the genomic variation among North Pacific killer whale ecotypes resulting from multiple colonisation events, and secondary contact may have facilitated evolutionary divergence. Thus, the present-day populations of North Pacific killer whale ecotypes have a complex ancestry, confounding the tree-based inference of ancestral geography.

Heritability of Tic Disorders: a Twin-Family Study

PubMed Central

Zilhao, Nuno R.; Olthof, Maria C.; Smit, Dirk J.A.; Cath, Danielle C.; Ligthart, Lannie; Mathews, Carol A.; Delucchi, Kevin; Boomsma, Dorret I.; Dolan, Conor V.

2017-01-01

Background Genetic-epidemiological studies that estimate the contributions of genetic factors to variation in tic symptoms are scarce. We estimated the extent to which genetic and environmental influences contribute to tics, employing various phenotypic definitions ranging between mild and severe symptomatology, in a large population-based adult twin-family sample. Methods In an extended twin-family design, we analyzed lifetime tic data reported by adult mono- and dizygotic twins (n= 8,323) and their family members (n=7,164; parents and siblings) from 7,311 families in the Netherlands Twin Register (NTR). We measured tics by the abbreviated version of the Schedule for Tourette and Other Behavioral Syndromes (STOBS) (TSAICG, 2007). Heritability was estimated by genetic Structural Equation Modeling (SEM) for four tic disorder definitions: three dichotomous and one trichotomous phenotype, characterized by increasingly strictly defined criteria. Results Prevalence rates of the different tic disorders in our sample varied between 0.3 and 4.5% depending on tic disorder definition. Tic frequencies decreased with increasing age. Heritability estimates varied between .25 and .37, depending on phenotypic definitions. None of the phenotypes showed evidence of assortative mating, effects of shared environment, or non-additive genetic effects. Conclusions Heritabilities of mild and severe tic phenotypes were estimated to be moderate. Overlapping confidence intervals of the heritability estimates suggest overlapping genetic liabilities between the various tic phenotypes. The most lenient phenotype (defined only by tic characteristics, excluding criteria B, C and D of DSMIV) rendered sufficiently reliable heritability estimates. These findings have implications in phenotypic definitions for future genetic studies. PMID:27974054

Investigating spousal concordance of diabetes through statistical analysis and data mining.

PubMed

Wang, Jong-Yi; Liu, Chiu-Shong; Lung, Chi-Hsuan; Yang, Ya-Tun; Lin, Ming-Hung

2017-01-01

Spousal clustering of diabetes merits attention. Whether old-age vulnerability or a shared family environment determines the concordance of diabetes is also uncertain. This study investigated the spousal concordance of diabetes and compared the risk of diabetes concordance between couples and noncouples by using nationally representative data. A total of 22,572 individuals identified from the 2002-2013 National Health Insurance Research Database of Taiwan constituted 5,643 couples and 5,643 noncouples through 1:1 dual propensity score matching (PSM). Factors associated with concordance in both spouses with diabetes were analyzed at the individual level. The risk of diabetes concordance between couples and noncouples was compared at the couple level. Logistic regression was the main statistical method. Statistical data were analyzed using SAS 9.4. C&RT and Apriori of data mining conducted in IBM SPSS Modeler 13 served as a supplement to statistics. High odds of the spousal concordance of diabetes were associated with old age, middle levels of urbanization, and high comorbidities (all P < 0.05). The dual PSM analysis revealed that the risk of diabetes concordance was significantly higher in couples (5.19%) than in noncouples (0.09%; OR = 61.743, P < 0.0001). A high concordance rate of diabetes in couples may indicate the influences of assortative mating and shared environment. Diabetes in a spouse implicates its risk in the partner. Family-based diabetes care that emphasizes the screening of couples at risk of diabetes by using the identified risk factors is suggested in prospective clinical practice interventions.

Investigating spousal concordance of diabetes through statistical analysis and data mining

PubMed Central

Liu, Chiu-Shong; Lung, Chi-Hsuan; Yang, Ya-Tun; Lin, Ming-Hung

2017-01-01

Objective Spousal clustering of diabetes merits attention. Whether old-age vulnerability or a shared family environment determines the concordance of diabetes is also uncertain. This study investigated the spousal concordance of diabetes and compared the risk of diabetes concordance between couples and noncouples by using nationally representative data. Methods A total of 22,572 individuals identified from the 2002–2013 National Health Insurance Research Database of Taiwan constituted 5,643 couples and 5,643 noncouples through 1:1 dual propensity score matching (PSM). Factors associated with concordance in both spouses with diabetes were analyzed at the individual level. The risk of diabetes concordance between couples and noncouples was compared at the couple level. Logistic regression was the main statistical method. Statistical data were analyzed using SAS 9.4. C&RT and Apriori of data mining conducted in IBM SPSS Modeler 13 served as a supplement to statistics. Results High odds of the spousal concordance of diabetes were associated with old age, middle levels of urbanization, and high comorbidities (all P < 0.05). The dual PSM analysis revealed that the risk of diabetes concordance was significantly higher in couples (5.19%) than in noncouples (0.09%; OR = 61.743, P < 0.0001). Conclusions A high concordance rate of diabetes in couples may indicate the influences of assortative mating and shared environment. Diabetes in a spouse implicates its risk in the partner. Family-based diabetes care that emphasizes the screening of couples at risk of diabetes by using the identified risk factors is suggested in prospective clinical practice interventions. PMID:28817654

Origin and dynamics of admixture in Brazilians and its effect on the pattern of deleterious mutations.

PubMed

Kehdy, Fernanda S G; Gouveia, Mateus H; Machado, Moara; Magalhães, Wagner C S; Horimoto, Andrea R; Horta, Bernardo L; Moreira, Rennan G; Leal, Thiago P; Scliar, Marilia O; Soares-Souza, Giordano B; Rodrigues-Soares, Fernanda; Araújo, Gilderlanio S; Zamudio, Roxana; Sant Anna, Hanaisa P; Santos, Hadassa C; Duarte, Nubia E; Fiaccone, Rosemeire L; Figueiredo, Camila A; Silva, Thiago M; Costa, Gustavo N O; Beleza, Sandra; Berg, Douglas E; Cabrera, Lilia; Debortoli, Guilherme; Duarte, Denise; Ghirotto, Silvia; Gilman, Robert H; Gonçalves, Vanessa F; Marrero, Andrea R; Muniz, Yara C; Weissensteiner, Hansi; Yeager, Meredith; Rodrigues, Laura C; Barreto, Mauricio L; Lima-Costa, M Fernanda; Pereira, Alexandre C; Rodrigues, Maíra R; Tarazona-Santos, Eduardo

2015-07-14

While South Americans are underrepresented in human genomic diversity studies, Brazil has been a classical model for population genetics studies on admixture. We present the results of the EPIGEN Brazil Initiative, the most comprehensive up-to-date genomic analysis of any Latin-American population. A population-based genome-wide analysis of 6,487 individuals was performed in the context of worldwide genomic diversity to elucidate how ancestry, kinship, and inbreeding interact in three populations with different histories from the Northeast (African ancestry: 50%), Southeast, and South (both with European ancestry >70%) of Brazil. We showed that ancestry-positive assortative mating permeated Brazilian history. We traced European ancestry in the Southeast/South to a wider European/Middle Eastern region with respect to the Northeast, where ancestry seems restricted to Iberia. By developing an approximate Bayesian computation framework, we infer more recent European immigration to the Southeast/South than to the Northeast. Also, the observed low Native-American ancestry (6-8%) was mostly introduced in different regions of Brazil soon after the European Conquest. We broadened our understanding of the African diaspora, the major destination of which was Brazil, by revealing that Brazilians display two within-Africa ancestry components: one associated with non-Bantu/western Africans (more evident in the Northeast and African Americans) and one associated with Bantu/eastern Africans (more present in the Southeast/South). Furthermore, the whole-genome analysis of 30 individuals (42-fold deep coverage) shows that continental admixture rather than local post-Columbian history is the main and complex determinant of the individual amount of deleterious genotypes.

Origin and dynamics of admixture in Brazilians and its effect on the pattern of deleterious mutations

PubMed Central

Kehdy, Fernanda S. G.; Gouveia, Mateus H.; Machado, Moara; Magalhães, Wagner C. S.; Horimoto, Andrea R.; Horta, Bernardo L.; Moreira, Rennan G.; Leal, Thiago P.; Scliar, Marilia O.; Soares-Souza, Giordano B.; Rodrigues-Soares, Fernanda; Araújo, Gilderlanio S.; Zamudio, Roxana; Sant Anna, Hanaisa P.; Santos, Hadassa C.; Duarte, Nubia E.; Fiaccone, Rosemeire L.; Figueiredo, Camila A.; Silva, Thiago M.; Costa, Gustavo N. O.; Beleza, Sandra; Berg, Douglas E.; Cabrera, Lilia; Debortoli, Guilherme; Duarte, Denise; Ghirotto, Silvia; Gilman, Robert H.; Gonçalves, Vanessa F.; Marrero, Andrea R.; Muniz, Yara C.; Weissensteiner, Hansi; Yeager, Meredith; Rodrigues, Laura C.; Barreto, Mauricio L.; Lima-Costa, M. Fernanda; Pereira, Alexandre C.; Rodrigues, Maíra R.; Tarazona-Santos, Eduardo

2015-01-01

While South Americans are underrepresented in human genomic diversity studies, Brazil has been a classical model for population genetics studies on admixture. We present the results of the EPIGEN Brazil Initiative, the most comprehensive up-to-date genomic analysis of any Latin-American population. A population-based genome-wide analysis of 6,487 individuals was performed in the context of worldwide genomic diversity to elucidate how ancestry, kinship, and inbreeding interact in three populations with different histories from the Northeast (African ancestry: 50%), Southeast, and South (both with European ancestry >70%) of Brazil. We showed that ancestry-positive assortative mating permeated Brazilian history. We traced European ancestry in the Southeast/South to a wider European/Middle Eastern region with respect to the Northeast, where ancestry seems restricted to Iberia. By developing an approximate Bayesian computation framework, we infer more recent European immigration to the Southeast/South than to the Northeast. Also, the observed low Native-American ancestry (6–8%) was mostly introduced in different regions of Brazil soon after the European Conquest. We broadened our understanding of the African diaspora, the major destination of which was Brazil, by revealing that Brazilians display two within-Africa ancestry components: one associated with non-Bantu/western Africans (more evident in the Northeast and African Americans) and one associated with Bantu/eastern Africans (more present in the Southeast/South). Furthermore, the whole-genome analysis of 30 individuals (42-fold deep coverage) shows that continental admixture rather than local post-Columbian history is the main and complex determinant of the individual amount of deleterious genotypes. PMID:26124090

Analysis of Copy Number Variation in the Abp Gene Regions of Two House Mouse Subspecies Suggests Divergence during the Gene Family Expansions

PubMed Central

Pezer, Željka; Chung, Amanda G.; Karn, Robert C.

2017-01-01

Abstract The Androgen-binding protein (Abp) gene region of the mouse genome contains 64 genes, some encoding pheromones that influence assortative mating between mice from different subspecies. Using CNVnator and quantitative PCR, we explored copy number variation in this gene family in natural populations of Mus musculus domesticus (Mmd) and Mus musculus musculus (Mmm), two subspecies of house mice that form a narrow hybrid zone in Central Europe. We found that copy number variation in the center of the Abp gene region is very common in wild Mmd, primarily representing the presence/absence of the final duplications described for the mouse genome. Clustering of Mmd individuals based on this variation did not reflect their geographical origin, suggesting no population divergence in the Abp gene cluster. However, copy number variation patterns differ substantially between Mmd and other mouse taxa. Large blocks of Abp genes are absent in Mmm, Mus musculus castaneus and an outgroup, Mus spretus, although with differences in variation and breakpoint locations. Our analysis calls into question the reliance on a reference genome for interpreting the detailed organization of genes in taxa more distant from the Mmd reference genome. The polymorphic nature of the gene family expansion in all four taxa suggests that the number of Abp genes, especially in the central gene region, is not critical to the survival and reproduction of the mouse. However, Abp haplotypes of variable length may serve as a source of raw genetic material for new signals influencing reproductive communication and thus speciation of mice. PMID:28575204

Multi-species mating disruption in cranberries (Ericales: Ericaceae): Early evidence using a flowable emulsion

USDA-ARS?s Scientific Manuscript database

Pheromone-based mating disruption has proven to be a powerful pest management tool in many cropping systems, helping to reduce reliance on insecticide applications. However, a sustainable mating disruption program has not yet been developed for cranberries. In the cranberry system, two of the major ...

Testing a pollen-parent fecundity distribution model on seed-parent fecundity distributions in bee-pollinated forage legume polycrosses

USDA-ARS?s Scientific Manuscript database

Random mating (i.e., panmixis) is a fundamental assumption in quantitative genetics. In outcrossing bee-pollinated perennial forage legume polycrosses, mating is assumed by default to follow theoretical random mating. This assumption informs breeders of expected inbreeding estimates based on polycro...

Design of a candidate vibrational signal for mating disruption against the glassy-winged sharpshooter, Homalodisca Vitripennis

USDA-ARS?s Scientific Manuscript database

The glassy-winged sharpshooter (GWSS), Homalodisca vitripennis, is an important pest of grapevines due to its ability to transmit Xylella fastidiosa, the causal agent of Pierce’s disease. GWSS mating communication is based on vibrational signals; therefore, vibrational mating disruption could be an ...

Pheromone-based mating disruption to control the historical top three insect pests of Wisconsin cranberries

USDA-ARS?s Scientific Manuscript database

In 2012, the first 3-species pheromone mating disruption program was tested in Wisconsin cranberries. Preliminary data suggest that there was substantial disruption of blackheaded fireworm and Sparganothis fruitworm mating. The pheromone of cranberry fruitworm only contained a single component, and ...

Network Reliability: The effect of local network structure on diffusive processes

PubMed Central

Youssef, Mina; Khorramzadeh, Yasamin; Eubank, Stephen

2014-01-01

This paper re-introduces the network reliability polynomial – introduced by Moore and Shannon in 1956 – for studying the effect of network structure on the spread of diseases. We exhibit a representation of the polynomial that is well-suited for estimation by distributed simulation. We describe a collection of graphs derived from Erdős-Rényi and scale-free-like random graphs in which we have manipulated assortativity-by-degree and the number of triangles. We evaluate the network reliability for all these graphs under a reliability rule that is related to the expected size of a connected component. Through these extensive simulations, we show that for positively or neutrally assortative graphs, swapping edges to increase the number of triangles does not increase the network reliability. Also, positively assortative graphs are more reliable than neutral or disassortative graphs with the same number of edges. Moreover, we show the combined effect of both assortativity-by-degree and the presence of triangles on the critical point and the size of the smallest subgraph that is reliable. PMID:24329321

Examining assortativity in the mental lexicon: Evidence from word associations.

PubMed

Van Rensbergen, Bram; Storms, Gert; De Deyne, Simon

2015-12-01

Words are characterized by a variety of lexical and psychological properties, such as their part of speech, word-frequency, concreteness, or affectivity. In this study, we examine how these properties relate to a word's connectivity in the mental lexicon, the structure containing a person's knowledge of words. In particular, we examine the extent to which these properties display assortative mixing, that is, the extent to which words in the lexicon are more likely to be connected to words that share these properties. We investigated three types of word properties: 1) subjective word covariates: valence, dominance, arousal, and concreteness; 2) lexical information: part of speech; and 3) distributional word properties: age-of-acquisition, word frequency, and contextual diversity. We assessed which of these factors exhibit assortativity using a word association task, where the probability of producing a certain response to a cue is a measure of the associative strength between the cue and response in the mental lexicon. Our results show that the extent to which these aspects exhibit assortativity varies considerably, with a high cue-response correspondence on valence, dominance, arousal, concreteness, and part of speech, indicating that these factors correspond to the words people deem as related. In contrast, we find that cues and responses show only little correspondence on word frequency, contextual diversity, and age-of-acquisition, indicating that, compared to subjective and lexical word covariates, distributional properties exhibit only little assortativity in the mental lexicon. Possible theoretical accounts and implications of these findings are discussed.

A framework for analyzing contagion in assortative banking networks

PubMed Central

Hurd, Thomas R.; Gleeson, James P.; Melnik, Sergey

2017-01-01

We introduce a probabilistic framework that represents stylized banking networks with the aim of predicting the size of contagion events. Most previous work on random financial networks assumes independent connections between banks, whereas our framework explicitly allows for (dis)assortative edge probabilities (i.e., a tendency for small banks to link to large banks). We analyze default cascades triggered by shocking the network and find that the cascade can be understood as an explicit iterated mapping on a set of edge probabilities that converges to a fixed point. We derive a cascade condition, analogous to the basic reproduction number R0 in epidemic modelling, that characterizes whether or not a single initially defaulted bank can trigger a cascade that extends to a finite fraction of the infinite network. This cascade condition is an easily computed measure of the systemic risk inherent in a given banking network topology. We use percolation theory for random networks to derive a formula for the frequency of global cascades. These analytical results are shown to provide limited quantitative agreement with Monte Carlo simulation studies of finite-sized networks. We show that edge-assortativity, the propensity of nodes to connect to similar nodes, can have a strong effect on the level of systemic risk as measured by the cascade condition. However, the effect of assortativity on systemic risk is subtle, and we propose a simple graph theoretic quantity, which we call the graph-assortativity coefficient, that can be used to assess systemic risk. PMID:28231324

A framework for analyzing contagion in assortative banking networks.

PubMed

Hurd, Thomas R; Gleeson, James P; Melnik, Sergey

2017-01-01

We introduce a probabilistic framework that represents stylized banking networks with the aim of predicting the size of contagion events. Most previous work on random financial networks assumes independent connections between banks, whereas our framework explicitly allows for (dis)assortative edge probabilities (i.e., a tendency for small banks to link to large banks). We analyze default cascades triggered by shocking the network and find that the cascade can be understood as an explicit iterated mapping on a set of edge probabilities that converges to a fixed point. We derive a cascade condition, analogous to the basic reproduction number R0 in epidemic modelling, that characterizes whether or not a single initially defaulted bank can trigger a cascade that extends to a finite fraction of the infinite network. This cascade condition is an easily computed measure of the systemic risk inherent in a given banking network topology. We use percolation theory for random networks to derive a formula for the frequency of global cascades. These analytical results are shown to provide limited quantitative agreement with Monte Carlo simulation studies of finite-sized networks. We show that edge-assortativity, the propensity of nodes to connect to similar nodes, can have a strong effect on the level of systemic risk as measured by the cascade condition. However, the effect of assortativity on systemic risk is subtle, and we propose a simple graph theoretic quantity, which we call the graph-assortativity coefficient, that can be used to assess systemic risk.

Worthless and Nutritive Nuptial Gifts: Mating Duration, Sperm Stored and Potential Female Decisions in Spiders

PubMed Central

Albo, Maria J.; Peretti, Alfredo V.

2015-01-01

In nuptial gift-giving species females sometimes select their potential mates based on the presence and size of the gift. But in some species, such as the Neotropical polyandrous spider Paratrechalea ornate male gifts vary in quality, from nutritive to worthless, and this male strategy can be in conflict with female nutritional benefits. In this species, males without gifts experience a reduction in mating success and duration, while males that offer worthless or genuine nutritive gifts mate with similar frequencies and durations. The female apparently controls the duration of copulation. Thus, there is scope for females to favour males offering gifts and further if these are nutritious, via post-copulatory processes. We first tested whether females differentially store sperm from males that offer the highest nutritional benefits by experimentally presenting females with males that offer either nutritive or worthless gifts (uninterrupted matings). Second, we carried out another set of experiments to examine whether females can select sperm based only on gift presence. This time we interrupted matings after the first pedipalp insertion, thus matching number of insertions and mating duration for males that: offered and did not offer gift. Our results showed that the amount of sperm stored is positive related to mating duration in all groups, except in matings with worthless gifts. Gift presence itself did not affect the sperm stored by females, while they store similar number of sperm in matings with males offering either nutritive or worthless gifts. We discuss whether females prefer males with gifts regardless, if content, because it represents an attractive and/or reliable signal. Or alternatively, they prefer nutritive nuptial gifts, as they are an important source of food supply and/or signal of male donor ability. PMID:26107397

Fitness of Mass-Reared Males of Anastrepha obliqua (Diptera: Tephritidae) Resulting From Mating Competition Tests in Field Cages.

PubMed

Hernández, Emilio; Liedo, Pablo; Toledo, Jorge; Montoya, Pablo; Perales, Hugo; Ruiz-Montoya, Lorena

2017-12-05

The sterile insect technique uses males that have been mass-reared in a controlled environment. The insects, once released in the field, must compete to mate. However, the mass-rearing condition supposes a loss of fitness that will be noticeable by wild females. To compare the fitness of wild males and mass-reared males, three competition settings were established. In setting 1, wild males, mass-reared males and wild females were released in field cages. In setting 2, wild females and wild males were released without competition, and in setting 3, mass-reared males and mass-reared females were also released without competition. Male fitness was based on their mating success, fecundity, weight and longevity. The fitness of the females was measured based on weight and several demographic parameters. The highest percentage of mating was between wild males and wild females between 0800 and 0900 h in the competition condition, while the mass-reared males started one hour later. The successful wild males weighed more and showed longer mating times, greater longevity and a higher number of matings than the mass-reared males. Although the mass-reared males showed the lowest percentage of matings, their fecundity when mating with wild females indicated a high fitness. Since the survival and fecundity of wild females that mated with mass-reared males decreased to become similar to those of mass-reared females that mated with mass-reared males, females seem to be influenced by the type of male (wild or mass-reared). © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Associations between body morphology, mating success and mate preferences among Slovak males and females.

PubMed

Prokop, Pavol; Fedor, Peter

2013-01-01

Human body morphology is thought to be correlated with sexual behaviour and sociosexuality (defined as an increased willingness to engage in sex without commitment) influences the perception of certain cues of physical attractiveness. Based on a sample of Slovak university students, we investigated relationships between 1) male and female mating success and reported body morphology (body mass index, BMI and waist-to-hip ratio, WHR) and 2) mate preference characteristics and mating success. Both males and females reported a similar number of long-term sexual partners and frequency of engaging in extra-pair copulation (EPC). The mating success of both sexes was positively mediated by self-perceived attractiveness. However, female BMI was inversely associated with mating success whereas increasing BMI was positively associated with male mating success (the total number of lifetime sexual partners) as well as with the likelihood of engaging in EPC. Unrestricted sociosexuality positively correlated with direct and indirect benefits from mating and negatively with the religious/political background of a potential mate and with the desire for a home/ children. These results confirm the hypothesis that human body morphology is associated with sexual behaviour and that cues of direct/indirect benefits in a potential mate positively correlate with sociosexuality.

Reinforce Networking Theory with OPNET Simulation

ERIC Educational Resources Information Center

Guo, Jinhua; Xiang, Weidong; Wang, Shengquan

2007-01-01

As networking systems have become more complex and expensive, hands-on experiments based on networking simulation have become essential for teaching the key computer networking topics to students. The simulation approach is the most cost effective and highly useful because it provides a virtual environment for an assortment of desirable features…

Personal Finances Instructional Aids. Teacher Reference Guide.

ERIC Educational Resources Information Center

Internal Training Services, Media, PA.

This manual consists of reproducible forms that were collected or developed to represent the vast assortment of forms that may be encountered in the transaction of one's personal finances and related affairs. The items represent typical forms encountered by a resident of Pennsylvania, based on a review of forms collected throughout the…

Major histocompatibility complex class II compatibility, but not class I, predicts mate choice in a bird with highly developed olfaction.

PubMed

Strandh, Maria; Westerdahl, Helena; Pontarp, Mikael; Canbäck, Björn; Dubois, Marie-Pierre; Miquel, Christian; Taberlet, Pierre; Bonadonna, Francesco

2012-11-07

Mate choice for major histocompatibility complex (MHC) compatibility has been found in several taxa, although rarely in birds. MHC is a crucial component in adaptive immunity and by choosing an MHC-dissimilar partner, heterozygosity and potentially broad pathogen resistance is maximized in the offspring. The MHC genotype influences odour cues and preferences in mammals and fish and hence olfactory-based mate choice can occur. We tested whether blue petrels, Halobaena caerulea, choose partners based on MHC compatibility. This bird is long-lived, monogamous and can discriminate between individual odours using olfaction, which makes it exceptionally well suited for this analysis. We screened MHC class I and II B alleles in blue petrels using 454-pyrosequencing and quantified the phylogenetic, functional and allele-sharing similarity between individuals. Partners were functionally more dissimilar at the MHC class II B loci than expected from random mating (p = 0.033), whereas there was no such difference at the MHC class I loci. Phylogenetic and non-sequence-based MHC allele-sharing measures detected no MHC dissimilarity between partners for either MHC class I or II B. Our study provides evidence of mate choice for MHC compatibility in a bird with a high dependency on odour cues, suggesting that MHC odour-mediated mate choice occurs in birds.

Female choice for male cuticular hydrocarbon profile in decorated crickets is not based on similarity to their own profile.

PubMed

Steiger, S; Capodeanu-Nägler, A; Gershman, S N; Weddle, C B; Rapkin, J; Sakaluk, S K; Hunt, J

2015-12-01

Indirect genetic benefits derived from female mate choice comprise additive (good genes) and nonadditive genetic benefits (genetic compatibility). Although good genes can be revealed by condition-dependent display traits, the mechanism by which compatibility alleles are detected is unclear because evaluation of the genetic similarity of a prospective mate requires the female to assess the genotype of the male and compare it to her own. Cuticular hydrocarbons (CHCs), lipids coating the exoskeleton of most insects, influence female mate choice in a number of species and offer a way for females to assess genetic similarity of prospective mates. Here, we determine whether female mate choice in decorated crickets is based on male CHCs and whether it is influenced by females' own CHC profiles. We used multivariate selection analysis to estimate the strength and form of selection acting on male CHCs through female mate choice, and employed different measures of multivariate dissimilarity to determine whether a female's preference for male CHCs is based on similarity to her own CHC profile. Female mating preferences were significantly influenced by CHC profiles of males. Male CHC attractiveness was not, however, contingent on the CHC profile of the choosing female, as certain male CHC phenotypes were equally attractive to most females, evidenced by significant linear and stabilizing selection gradients. These results suggest that additive genetic benefits, rather than nonadditive genetic benefits, accrue to female mate choice, in support of earlier work showing that CHC expression of males, but not females, is condition dependent. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

How a microbial drug transporter became essential for crop cultivation on acid soils: aluminium tolerance conferred by the multidrug and toxic compound extrusion (MATE) family

PubMed Central

Magalhaes, Jurandir V.

2010-01-01

Background Aluminium (Al) toxicity is a major agricultural constraint for crop cultivation on acid soils, which comprise a large portion of the world's arable land. One of the most widely accepted mechanisms of Al tolerance in plants is based on Al-activated organic acid release into the rhizosphere, with organic acids forming stable, non-toxic complexes with Al. This mechanism has recently been validated by the isolation of bona-fide Al-tolerance genes in crop species, which encode membrane transporters that mediate Al-activated organic acid release leading to Al exclusion from root apices. In crop species such as sorghum and barley, members in the multidrug and toxic compound extrusion (MATE) family underlie Al tolerance by a mechanism based on Al-activated citrate release. Scope and Conclusions The study of Al tolerance in plants as conferred by MATE family members is in its infancy. Therefore, much is yet to be discovered about the functional diversity and evolutionary dynamics that led MATE proteins to acquire transport properties conducive to Al tolerance in plants. In this paper we review the major characteristics of transporters in the MATE family and will relate this knowledge to Al tolerance in plants. The MATE family is clearly extremely flexible with respect to substrate specificity, which raises the possibility that Al tolerance as encoded by MATE proteins may not be restricted to Al-activated citrate release in plant species. There are also indications that regulatory loci may be of pivotal importance to fully explore the potential for Al-tolerance improvement based on MATE genes. PMID:20511585

Mate choice screening in captive solitary carnivores: The role of male behavior and cues on mate preference and paternity in females of a model species, American mink (Neovison vison).

PubMed

Noer, Christina Lehmkuhl; Balsby, Thorsten Johannes Skovbjerg; Anistoroaei, Razvan; Stelvig, Mikkel; Dabelsteen, Torben

2017-12-01

Mate choice studies suggest that choosy females benefit from increased fecundity, litter size, and offspring survival. Thus, providing females with the opportunity to choose among potential mates, deemed genetically suitable based on studbook data, might improve breeding management in production and zoo animals and thereby the sustainability of captive populations. Investigating mate preference via odor from potential mates before animal transfer is a proposed strategy for incorporating mate choice into breeding management. In this study, we test whether olfactory cues and signals from males can be used to assess and measure female mate preference in American mink. Eighteen females were subjected to a 4-day stimulus test in which females showed a preference for one of two males' urine and feces. Subsequently, each female was subjected to a 10-day mate preference test involving the same two males of the first test. Paternity tests revealed that 13 females had offspring, which could be assigned to only one male, suggesting that these females performed a mate choice. In nine of these females preference during the stimulus test was directed toward the male that fathered their offspring. Our results suggest that even though there was a preference difference in scent stimulus trials from potential mates this preference was not predictive of eventual mate preference or paternity. Other factors such as aspects of male behavior seem to play a role, when the mates are introduced. Our study supports that mate preference and mate choice are complex matters influenced by multiple cues and signals. © 2017 Wiley Periodicals, Inc.

Hybridization and cytonuclear associations among native westslope cutthroat trout, introduced rainbow trout, and their hybrids within the Stehekin River drainage, North Cascades National Park

USGS Publications Warehouse

Ostberg, C.O.; Rodriguez, R.J.

2006-01-01

Historic introductions of nonnative rainbow trout Oncorhynchus mykiss into the native habitats of cutthroat trout O. clarkii have impacted cutthroat trout populations through introgressive hybridization, creating challenges and concerns for cutthroat trout conservation. We examined the effects of rainbow trout introductions on the native westslope cutthroat trout O. c. lewisii within the Stehekin River drainage, North Cascades National Park, Washington, by analyzing 1,763 salmonid DNA samples from 18 locations with nine diagnostic nuclear DNA markers and one diagnostic mitochondrial DNA (mtDNA) marker. Pure westslope cutthroat trout populations only occurred above upstream migration barriers in the Stehekin River and Park Creek. Two categories of rainbow trout admixture were observed: (1) less than 10% within the Stehekin River drainage above the Bridge Creek confluence and the middle and upper Bridge Creek drainage and (2) greater than 30% within the Stehekin River below the Bridge Creek confluence and in lower Bridge Creek. Hybrid indices and multilocus genotypes revealed an absence of rainbow trout and reduced hybrid diversity within the Stehekin River above the Bridge Creek confluence relative to hybrid diversity in the Stehekin River below the confluence and within lower Bridge Creek. Cytonuclear disequilibrium statistics revealed assortative mating between westslope cutthroat and rainbow trout but not among hybrids within the same locations. This suggests that a randomly mating hybrid swarm does not currently exist. However, continual migration of parental genotypes into the study location could also create significant cytonuclear disequilibria. The Stehekin River represents a novel and unique example of a dynamic hybridization zone where the invasion of rainbow trout alleles into the Stehekin River westslope cutthroat trout population above the Bridge Creek confluence appears to be impeded, suggesting that divergent ecological or evolutionary mechanisms promote the population structure within the Stehekin River drainage, depending upon location.

Evaluation of the MoleMate training program for assessment of suspicious pigmented lesions in primary care.

PubMed

Wood, Annabel; Morris, Helen; Emery, Jon; Hall, Per N; Cotton, Symon; Prevost, A Toby; Walter, Fiona M

2008-01-01

Pigmented skin lesions or 'moles' are a common presenting problem in general practice consultations: while the majority are benign, a minority are malignant melanomas. The MoleMate system is a novel diagnostic tool which incorporates spectrophotometric intracutaneous analysis (SIAscopy) within a non-invasive scanning technique and utilises a diagnostic algorithm specifically developed for use in primary care. The MoleMate training program is a short, computer-based course developed to train primary care practitioners to operate the MoleMate diagnostic tool. This pre-trial study used mixed methods to assess the effectiveness and acceptability of a computer-based training program CD-ROM, developed to teach primary care practitioners to identify the seven features of suspicious pigmented lesions (SPLs) seen with the MoleMate system. Twenty-five practitioners worked through the MoleMate training program: data on feature recognition and time taken to conduct the assessment of each lesion were collected. Acceptability of the training program and the MoleMate system in general was assessed by questionnaire. The MoleMate training program improved users' feature recognition by 10% (pre-test median 73.8%, p<0.001), and reduced the time taken to complete assessment of 30 SPLs (pre-test median 21 minutes 53 seconds, median improvement 3 minutes 17 seconds, p<0.001). All practitioners' feature recognition improved (21/21), with most also improving their time (18/21). Practitioners rated the training program as effective and easy to use. The MoleMate training program is a potentially effective and acceptable informatics tool to teach practitioners to recognise the features of SPLs identified by the MoleMate system. It will be used as part of the intervention in a randomised controlled trial to compare the diagnostic accuracy and appropriate referral rates of practitioners using the MoleMate system with best practice in primary care.

Computational mate choice: theory and empirical evidence.

PubMed

Castellano, Sergio; Cadeddu, Giorgia; Cermelli, Paolo

2012-06-01

The present review is based on the thesis that mate choice results from information-processing mechanisms governed by computational rules and that, to understand how females choose their mates, we should identify which are the sources of information and how they are used to make decisions. We describe mate choice as a three-step computational process and for each step we present theories and review empirical evidence. The first step is a perceptual process. It describes the acquisition of evidence, that is, how females use multiple cues and signals to assign an attractiveness value to prospective mates (the preference function hypothesis). The second step is a decisional process. It describes the construction of the decision variable (DV), which integrates evidence (private information by direct assessment), priors (public information), and value (perceived utility) of prospective mates into a quantity that is used by a decision rule (DR) to produce a choice. We make the assumption that females are optimal Bayesian decision makers and we derive a formal model of DV that can explain the effects of preference functions, mate copying, social context, and females' state and condition on the patterns of mate choice. The third step of mating decision is a deliberative process that depends on the DRs. We identify two main categories of DRs (absolute and comparative rules), and review the normative models of mate sampling tactics associated to them. We highlight the limits of the normative approach and present a class of computational models (sequential-sampling models) that are based on the assumption that DVs accumulate noisy evidence over time until a decision threshold is reached. These models force us to rethink the dichotomy between comparative and absolute decision rules, between discrimination and recognition, and even between rational and irrational choice. Since they have a robust biological basis, we think they may represent a useful theoretical tool for behavioural ecologist interested in integrating proximate and ultimate causes of mate choice. Copyright © 2012 Elsevier B.V. All rights reserved.

Variance-based selection may explain general mating patterns in social insects.

PubMed

Rueppell, Olav; Johnson, Nels; Rychtár, Jan

2008-06-23

Female mating frequency is one of the key parameters of social insect evolution. Several hypotheses have been suggested to explain multiple mating and considerable empirical research has led to conflicting results. Building on several earlier analyses, we present a simple general model that links the number of queen matings to variance in colony performance and this variance to average colony fitness. The model predicts selection for multiple mating if the average colony succeeds in a focal task, and selection for single mating if the average colony fails, irrespective of the proximate mechanism that links genetic diversity to colony fitness. Empirical support comes from interspecific comparisons, e.g. between the bee genera Apis and Bombus, and from data on several ant species, but more comprehensive empirical tests are needed.

40 CFR 799.9355 - TSCA reproduction/developmental toxicity screening test.

Code of Federal Regulations, 2012 CFR

2012-07-01

... the mating period and, approximately, two weeks post-mating). In view of the limited pre-mating dosing...) Selection of animal species. This test standard is designed for use with the rat. If other species are used... three test groups and a control group should be used. Dose levels may be based on information from acute...

40 CFR 799.9355 - TSCA reproduction/developmental toxicity screening test.

Code of Federal Regulations, 2013 CFR

2013-07-01

... the mating period and, approximately, two weeks post-mating). In view of the limited pre-mating dosing...) Selection of animal species. This test standard is designed for use with the rat. If other species are used... three test groups and a control group should be used. Dose levels may be based on information from acute...

40 CFR 799.9355 - TSCA reproduction/developmental toxicity screening test.

Code of Federal Regulations, 2010 CFR

2010-07-01

... the mating period and, approximately, two weeks post-mating). In view of the limited pre-mating dosing...) Selection of animal species. This test standard is designed for use with the rat. If other species are used... three test groups and a control group should be used. Dose levels may be based on information from acute...

Integrating epigenomic data and 3D genomic structure with a new measure of chromatin assortativity.

PubMed

Pancaldi, Vera; Carrillo-de-Santa-Pau, Enrique; Javierre, Biola Maria; Juan, David; Fraser, Peter; Spivakov, Mikhail; Valencia, Alfonso; Rico, Daniel

2016-07-08

Network analysis is a powerful way of modeling chromatin interactions. Assortativity is a network property used in social sciences to identify factors affecting how people establish social ties. We propose a new approach, using chromatin assortativity, to integrate the epigenomic landscape of a specific cell type with its chromatin interaction network and thus investigate which proteins or chromatin marks mediate genomic contacts. We use high-resolution promoter capture Hi-C and Hi-Cap data as well as ChIA-PET data from mouse embryonic stem cells to investigate promoter-centered chromatin interaction networks and calculate the presence of specific epigenomic features in the chromatin fragments constituting the nodes of the network. We estimate the association of these features with the topology of four chromatin interaction networks and identify features localized in connected areas of the network. Polycomb group proteins and associated histone marks are the features with the highest chromatin assortativity in promoter-centered networks. We then ask which features distinguish contacts amongst promoters from contacts between promoters and other genomic elements. We observe higher chromatin assortativity of the actively elongating form of RNA polymerase 2 (RNAPII) compared with inactive forms only in interactions between promoters and other elements. Contacts among promoters and between promoters and other elements have different characteristic epigenomic features. We identify a possible role for the elongating form of RNAPII in mediating interactions among promoters, enhancers, and transcribed gene bodies. Our approach facilitates the study of multiple genome-wide epigenomic profiles, considering network topology and allowing the comparison of chromatin interaction networks.

Public Housing Relocations and Partnership Dynamics in Areas With High Prevalences of Sexually Transmitted Infections

PubMed Central

Cooper, Hannah L.F.; Bonney, Loida; Luo, Ruiyan; Haley, Danielle F.; Linton, Sabriya; Hunter-Jones, Josalin; Ross, Zev; Wingood, Gina M.; Adimora, Adaora A.; Rothenberg, Richard

2017-01-01

Background We investigated the implications of one structural intervention—public housing relocations—for partnership dynamics among individuals living areas with high sexually transmitted infection (STI) prevalence. High-prevalence areas fuel STI endemicity and are perpetuated by spatially assortative partnerships. Methods We analyzed 7 waves of data from a cohort of black adults (n = 172) relocating from 7 public housing complexes in Atlanta, Georgia. At each wave, data on whether participants’ sexual partners lived in the neighborhood were gathered via survey. Participant addresses were geocoded to census tracts, and measures of tract-level STI prevalence, socioeconomic conditions, and other attributes were created for each wave. “High-prevalence tracts” were tracts in the highest quartile of STI prevalence in Georgia. Descriptive statistics and hierarchical generalized linear models examined trajectories of spatially assortative partnerships and identified predictors of assortativity among participants in high-prevalence tracts. Results All 7 tracts containing public housing complexes at baseline were high-prevalence tracts; most participants relocated to high-prevalence tracts. Spatially assortative partnerships had a U-shaped distribution: the mean percent of partners living in participants’ neighborhoods at baseline was 54%; this mean declined to 28% at wave 2 and was 45% at wave 7. Participants who experienced greater postrelocation improvements in tract-level socioeconomic conditions had a lower odds of having spatially assortative partnerships (adjusted odds ratio, 1.55; 95% confidence interval [95% CI], 1.06–2.26). Conclusions Public housing relocation initiatives may disrupt high-prevalence areas if residents experience significant postrelocation gains in tract-level socioeconomic conditions. PMID:26967298

AlphaMate: a program for optimising selection, maintenance of diversity, and mate allocation in breeding programs.

PubMed

Gorjanc, Gregor; Hickey, John M

2018-05-02

AlphaMate is a flexible program that optimises selection, maintenance of genetic diversity, and mate allocation in breeding programs. It can be used in animal and cross- and self-pollinating plant populations. These populations can be subject to selective breeding or conservation management. The problem is formulated as a multi-objective optimisation of a valid mating plan that is solved with an evolutionary algorithm. A valid mating plan is defined by a combination of mating constraints (the number of matings, the maximal number of parents, the minimal/equal/maximal number of contributions per parent, or allowance for selfing) that are gender specific or generic. The optimisation can maximize genetic gain, minimize group coancestry, minimize inbreeding of individual matings, or maximize genetic gain for a given increase in group coancestry or inbreeding. Users provide a list of candidate individuals with associated gender and selection criteria information (if applicable) and coancestry matrix. Selection criteria and coancestry matrix can be based on pedigree or genome-wide markers. Additional individual or mating specific information can be included to enrich optimisation objectives. An example of rapid recurrent genomic selection in wheat demonstrates how AlphaMate can double the efficiency of converting genetic diversity into genetic gain compared to truncation selection. Another example demonstrates the use of genome editing to expand the gain-diversity frontier. Executable versions of AlphaMate for Windows, Mac, and Linux platforms are available at http://www.AlphaGenes.roslin.ed.ac.uk/AlphaMate. gregor.gorjanc@roslin.ed.ack.uk.

Females Choose Mates Based on Genetic Relatedness in a Small Dasyurid Marsupial, the Agile Antechinus (Antechinus agilis)

PubMed Central

Parrott, Marissa L.; Ward, Simon J.; Temple-Smith, Peter D.; Selwood, Lynne

2015-01-01

Females in a variety of taxa mate with more than one male during a single oestrus and exhibit mate preferences for genetically compatible males, but the influence of female mate choice on siring success is not clearly understood. Whether females choose to mate with more than one male or endure forced copulations is also often unknown. Here, we examined the effects of genetic relatedness on female mate choice and siring success in a small semelparous carnivorous marsupial, the agile antechinus (Antechinus agilis), during two consecutive breeding seasons. Experimental trials were conducted in captivity over periods of 72 hours using interconnected enclosures in which female antechinus could choose to access any of four separated males, but males were only able to access females that entered their quarters. Females had access to two genetically similar and two genetically dissimilar males simultaneously and all behavioural interactions were observed and scored from continuous video recordings. Genetic similarity between mates and paternity of young was determined by microsatellite analyses. Some females chose to enter and mate with more than one male during a single oestrus period. Although females investigated all males, they spent significantly more time visiting, and mated more times with, genetically dissimilar males. Males that were genetically dissimilar to the female sired 88% of subsequent offspring. Whilst males mated readily with most females, they rejected the advances of some receptive females, indicating a previously unexpected level of male mate choice. The results show that genetic relatedness between mates has a significant influence on mate choice, breeding and siring success in the agile antechinus. PMID:25923325

Females Choose Mates Based on Genetic Relatedness in a Small Dasyurid Marsupial, the Agile Antechinus (Antechinus agilis).

PubMed

Parrott, Marissa L; Ward, Simon J; Temple-Smith, Peter D; Selwood, Lynne

2015-01-01

Females in a variety of taxa mate with more than one male during a single oestrus and exhibit mate preferences for genetically compatible males, but the influence of female mate choice on siring success is not clearly understood. Whether females choose to mate with more than one male or endure forced copulations is also often unknown. Here, we examined the effects of genetic relatedness on female mate choice and siring success in a small semelparous carnivorous marsupial, the agile antechinus (Antechinus agilis), during two consecutive breeding seasons. Experimental trials were conducted in captivity over periods of 72 hours using interconnected enclosures in which female antechinus could choose to access any of four separated males, but males were only able to access females that entered their quarters. Females had access to two genetically similar and two genetically dissimilar males simultaneously and all behavioural interactions were observed and scored from continuous video recordings. Genetic similarity between mates and paternity of young was determined by microsatellite analyses. Some females chose to enter and mate with more than one male during a single oestrus period. Although females investigated all males, they spent significantly more time visiting, and mated more times with, genetically dissimilar males. Males that were genetically dissimilar to the female sired 88% of subsequent offspring. Whilst males mated readily with most females, they rejected the advances of some receptive females, indicating a previously unexpected level of male mate choice. The results show that genetic relatedness between mates has a significant influence on mate choice, breeding and siring success in the agile antechinus.

[Genetic demographic study of Shors in Tashtagolskiĭ district of the Kemerovo region: changes in the marriage migration structure].

PubMed

Ul'ianova, M V; Kucher, A N; Lavriashina, M B

2011-01-01

The changes in the marriage structure with respect to the age at marriage, ethnicity, and spouses' birthplaces during the period of time corresponding to two generations have been analyzed in the rural population of Shors of Tashtagolskii raion of Kemerovo oblast. In general, the Shor population had a high assortative marriage rate with respect to these parameters in the period studied, although there was a temporary tendency towards its decrease. The ages of marriage for both the male and the female Shor populations in the years 2000-2005 were significantly older than in 1940-1945 and 1970-1975. The age-assortative marriage rate was r = = 0.60 in 1940-1945, r = 0.73 in 1970-1975, and r = 0.66 in 2000-2005. The birthplace-assortative marriage rate decreased from 79.63% in 1970-1975 to 70.64% in 2000-2005. The ethnic assortative marriage rate of Shors steadily decreased during the time interval studied; it was 96.92, 89.95, and 80.98% in 1940-1945, 1970-1975, and 2000-2005, respectively, for the total rural population of Tashtagolskii raion.

Review: Game theory of public goods in one-shot social dilemmas without assortment.

PubMed

Archetti, Marco; Scheuring, István

2012-04-21

We review the theory of public goods in biology. In the N-person prisoner's dilemma, where the public good is a linear function of the individual contributions, cooperation requires some form of assortment, for example due to kin discrimination, population viscosity or repeated interactions. In most social species ranging from bacteria to humans, however, public goods are usually a non-linear function of the contributions, which makes cooperation possible without assortment. More specifically, a polymorphic state can be stable in which cooperators and non-cooperators coexist. The existence of mixed equilibria in public goods games is a fundamental result in the study of cooperation that has been overlooked so far, because of the disproportionate attention given to the two- and N-person prisoner's dilemma. Methods and results from games with pairwise interactions or linear benefits cannot, in general, be extended to the analysis of public goods. Game theory helps explain the production of public goods in one-shot, N-person interactions without assortment, it leads to predictions that can be easily tested and allows a prescriptive approach to cooperation. Copyright © 2011 Elsevier Ltd. All rights reserved.

The Genetic Architecture Underlying the Evolution of a Rare Piscivorous Life History Form in Brown Trout after Secondary Contact and Strong Introgression.

PubMed

Jacobs, Arne; Hughes, Martin R; Robinson, Paige C; Adams, Colin E; Elmer, Kathryn R

2018-05-31

Identifying the genetic basis underlying phenotypic divergence and reproductive isolation is a longstanding problem in evolutionary biology. Genetic signals of adaptation and reproductive isolation are often confounded by a wide range of factors, such as variation in demographic history or genomic features. Brown trout ( Salmo trutta ) in the Loch Maree catchment, Scotland, exhibit reproductively isolated divergent life history morphs, including a rare piscivorous (ferox) life history form displaying larger body size, greater longevity and delayed maturation compared to sympatric benthivorous brown trout. Using a dataset of 16,066 SNPs, we analyzed the evolutionary history and genetic architecture underlying this divergence. We found that ferox trout and benthivorous brown trout most likely evolved after recent secondary contact of two distinct glacial lineages, and identified 33 genomic outlier windows across the genome, of which several have most likely formed through selection. We further identified twelve candidate genes and biological pathways related to growth, development and immune response potentially underpinning the observed phenotypic differences. The identification of clear genomic signals divergent between life history phenotypes and potentially linked to reproductive isolation, through size assortative mating, as well as the identification of the underlying demographic history, highlights the power of genomic studies of young species pairs for understanding the factors shaping genetic differentiation.

Effects of autozygosity and schizophrenia polygenic risk on cognitive and brain developmental trajectories.

PubMed

Córdova-Palomera, Aldo; Kaufmann, Tobias; Bettella, Francesco; Wang, Yunpeng; Doan, Nhat Trung; van der Meer, Dennis; Alnæs, Dag; Rokicki, Jaroslav; Moberget, Torgeir; Sønderby, Ida Elken; Andreassen, Ole A; Westlye, Lars T

2018-04-27

Cognitive and brain development are determined by dynamic interactions between genes and environment across the lifespan. Aside from marker-by-marker analyses of polymorphisms, biologically meaningful features of the whole genome (derived from the combined effect of individual markers) have been postulated to inform on human phenotypes including cognitive traits and their underlying biological substrate. Here, estimates of inbreeding and genetic susceptibility for schizophrenia calculated from genome-wide data-runs of homozygosity (ROH) and schizophrenia polygenic risk score (PGRS)-are analyzed in relation to cognitive abilities (n = 4183) and brain structure (n = 516) in a general-population sample of European-ancestry participants aged 8-22, from the Philadelphia Neurodevelopmental Cohort. The findings suggest that a higher ROH burden and higher schizophrenia PGRS are associated with higher intelligence. Cognition-ROH and cognition-PGRS associations obtained in this cohort may, respectively, evidence that assortative mating influences intelligence, and that individuals with high schizophrenia genetic risk who do not transition to disease status are cognitively resilient. Neuroanatomical data showed that the effects of schizophrenia PGRS on cognition could be modulated by brain structure, although larger imaging datasets are needed to accurately disentangle the underlying neural mechanisms linking IQ with both inbreeding and the genetic burden for schizophrenia.

The Bell Curve Revisited: Testing Controversial Hypotheses with Molecular Genetic Data

PubMed Central

Conley, Dalton; Domingue, Benjamin

2017-01-01

In 1994, the publication of Herrnstein’s and Murray’s The Bell Curve resulted in a social science maelstrom of responses. In the present study, we argue that Herrnstein’s and Murray’s assertions were made prematurely, on their own terms, given the lack of data available to test the role of genotype in the dynamics of achievement and attainment in U.S. society. Today, however, the scientific community has access to at least one dataset that is nationally representative and has genome-wide molecular markers. We deploy those data from the Health and Retirement Study in order to test the core series of propositions offered by Herrnstein and Murray in 1994. First, we ask whether the effect of genotype is increasing in predictive power across birth cohorts in the middle twentieth century. Second, we ask whether assortative mating on relevant genotypes is increasing across the same time period. Finally, we ask whether educational genotypes are increasingly predictive of fertility (number ever born [NEB]) in tandem with the rising (negative) association of educational outcomes and NEB. The answers to these questions are mostly no; while molecular genetic markers can predict educational attainment, we find little evidence for the proposition that we are becoming increasingly genetically stratified. PMID:29130056

Obesity: lessons from evolution and the environment.

PubMed

Heitmann, B L; Westerterp, K R; Loos, R J F; Sørensen, T I A; O'Dea, K; McLean, P; Jensen, T K; Eisenmann, J; Speakman, J R; Simpson, S J; Reed, D R; Westerterp-Plantenga, M S

2012-10-01

The 9th Stock Conference acknowledged the complex background of genetic, cultural, environmental and evolutionary factors of obesity. Gene-environment interactions underlie the flexibility in body-weight and body-fat regulation, illustrated by the hunter-gatherers' feast and famine lifestyle, the variation in physical activity over the lifespan being highest at reproductive age, the variation in energy intake through 'eating in the absence of hunger', while running the risk of exceeding the capacity of triacylglyceride storage, leading to lipotoxicity and metabolic problems. Perinatal metabolic programming for obesity via epigenetic changes in response to a 'Western diet' results in production of lipid-poor milk and metabolically efficient pups, contributing to the perpetuation of obesity throughout generations. Evolutionary insight from comparative physiology and ecology indicates that over generations activity-induced energy expenditure has remained the same compared to wild mammals, that energy balance might be dependant on protein balance, while the function of taste changed from detection of poison or energy to social drinking and social behaviour. At present, the impact of assortative mating on obesity prevalence is unambiguously positive. The complexity that appeared can only be fully appreciated by setting the data into the context of our evolutionary history. © 2012 The Authors. obesity reviews © 2012 International Association for the Study of Obesity.

Complex cytogeographical patterns reveal a dynamic tetraploid–octoploid contact zone

PubMed Central

Castro, Mariana; Castro, Sílvia; Figueiredo, Albano; Husband, Brian; Loureiro, João

2018-01-01

Abstract The distribution of cytotypes in mixed-ploidy species is crucial for evaluating ecological processes involved in the establishment and evolution of polyploid taxa. Here, we use flow cytometry and chromosome counts to explore cytotype diversity and distributions within a tetraploid–octoploid contact zone. We then use niche modelling and ploidy seed screening to assess the roles of niche differentiation among cytotypes and reproductive interactions, respectively, in promoting cytotype coexistence. Two cytotypes, tetraploids and octoploids, were dominant within the contact zone. They were most often distributed parapatrically or allopatrically, resulting in high geographic isolation. Still, 16.7 % of localities comprised two or more cytotypes, including the intermediate hexaploid cytotype. Tetraploids and octoploids had high environmental niche overlap and associated with similar climatic environments, suggesting they have similar ecological requirements. Given the geographical separation and habitat similarity among cytotypes, mixed-ploidy populations may be transitional and subject to the forces of minority cytotype exclusion which lead to pure-ploidy populations. However, seed ploidy analysis suggests that strong reproductive barriers may enforce assortative mating which favours stable cytotype coexistence. High cytogenetic diversity detected in the field suggests that unreduced gamete formation and hybridization events seem frequent in the studied polyploid complex and might be involved with the recurrent polyploid formation, governing, as well, the gene flow between cytogenetic entities. PMID:29593853

Complex cytogeographical patterns reveal a dynamic tetraploid-octoploid contact zone.

PubMed

Castro, Mariana; Castro, Sílvia; Figueiredo, Albano; Husband, Brian; Loureiro, João

2018-03-01

The distribution of cytotypes in mixed-ploidy species is crucial for evaluating ecological processes involved in the establishment and evolution of polyploid taxa. Here, we use flow cytometry and chromosome counts to explore cytotype diversity and distributions within a tetraploid-octoploid contact zone. We then use niche modelling and ploidy seed screening to assess the roles of niche differentiation among cytotypes and reproductive interactions, respectively, in promoting cytotype coexistence. Two cytotypes, tetraploids and octoploids, were dominant within the contact zone. They were most often distributed parapatrically or allopatrically, resulting in high geographic isolation. Still, 16.7 % of localities comprised two or more cytotypes, including the intermediate hexaploid cytotype. Tetraploids and octoploids had high environmental niche overlap and associated with similar climatic environments, suggesting they have similar ecological requirements. Given the geographical separation and habitat similarity among cytotypes, mixed-ploidy populations may be transitional and subject to the forces of minority cytotype exclusion which lead to pure-ploidy populations. However, seed ploidy analysis suggests that strong reproductive barriers may enforce assortative mating which favours stable cytotype coexistence. High cytogenetic diversity detected in the field suggests that unreduced gamete formation and hybridization events seem frequent in the studied polyploid complex and might be involved with the recurrent polyploid formation, governing, as well, the gene flow between cytogenetic entities.

Winning and losing: an evolutionary approach to mood disorders and their therapy.

PubMed

Sloman, Leon; Sturman, Edward D; Price, John S

2011-06-01

To advance a new evolutionary model that examines the effects of winning and losing on mood and physiological variables. Previous studies have focused on the involuntary defeat strategy in de-escalating conflict. Here, we propose that there also exists an involuntary winning strategy (IWS) that is triggered by success and characterized by euphoria and increased self-confidence. It motivates efforts to challenge, and promotes reconciliation. Previous studies are presented, including data on student athletes, demonstrating the impact of winning and losing on mood. Winning is consistently shown to be related to physiological changes such as increased testosterone and serotonin levels in primates. It reliably leads to mood changes that serve to motivate winners to continue their competitive efforts. When the IWS functions optimally, success leads to success in an adaptive cycle. Over time, the initial differences between the winners and losers of agonistic encounters become magnified in a process known as difference amplification. As a result of assortative mating, the children of people who have entered into an adaptive cycle will inherit traits from both parents that will, in turn, give them an increased competitive advantage. In this manner, difference amplification could have accelerated human evolution by natural selection. Vignettes of clinical interventions are also used to illustrate therapeutic strategies designed to disrupt maladaptive cycles and promote adaptive behaviour.

Cytonuclear genetic architecture in mosquitofish populations and the possible roles of introgressive hybridization

USGS Publications Warehouse

Scribner, Kim T.; Avise, John C.

1993-01-01

Spatial genetic structure in populations of mosquitofish (Gambusia) sampled throughout the south-eastern United States was characterized using mitochondrial (mt) DNA and allozyme markers. Both sets of data revealed a pronounced genetic discontinuity (along a broad path extending from south-eastern Mississippi to north-eastern Georgia) that corresponds to a recently recognized distinction between the nominal forms G. affinis to the west and G. holbrookito the east. However, several populations from the general contact region exhibited unusual allelic associations in high frequency, suggestive of evolutionary processes within a zone of introgressive hybridization. These involve: (i) cytonuclear profiles representing combinations of nuclear and mitochondrial genotypes that tended to be more nearly species-specific and concordant elsewhere; and (ii) significant nuclear gametic disequilibria, perhaps attributable to positive assortative mating and/or differential fitnesses of homospecific vs. recombinant genotypes. However, outside this suspected hybrid region, ‘heterospecific’ genetic markers also appeared in low frequency, thus complicating interpretations. These discordant alleles on a broader geographic scale may reflect: (a) the retention of polymorphisms from an ancestral gene pool; (b) occasional evolutionary convergence (especially with respect to electrophoretic mobility of allozyme alleles); (c) the ‘footprints’ of a moving hybrid zone; or (d) differential introgressive penetrance across the current hybrid region.

Persistence of a sugar-rejecting cockroach genotype under various dietary regimes

NASA Astrophysics Data System (ADS)

Jensen, Kim; Wada-Katsumata, Ayako; Schal, Coby; Silverman, Jules

2017-04-01

Glucose-aversion is a heritable trait that evolved in a number of German cockroach (Blattella germanica L.) populations in response to strong selection with glucose-containing insecticide baits. However, in the absence of glucose-containing bait, glucose-averse (GA) cockroaches have lower performance than wild-type (WT) cockroaches in several fitness-determining traits. We allocated 48 caged populations initiated with homozygous GA and WT adults to four dietary treatments consisting of either pure rodent chow, rodent chow mixed to yield a content of either 20% glucose or 20% fructose, or a treatment consisting of choice between the 20% glucose- and the 20% fructose-containing food. After 6 months we found significantly higher frequency of WT individuals in populations restricted to the 20% glucose food, and after 12 months all dietary treatments contained significantly more WT individuals than expected. In accompanying experiments, we found lower survival and longer development time of GA nymphs restricted to glucose-containing food. We furthermore found evidence for assortative mating of females with males from their own genotype, with significant differences within WT cockroaches. Our study shows experimental evidence that within heterogeneous populations, WT German cockroaches will over time prevail in abundance over GA individuals, even when glucose is not a dietary component.

Phenotype-limited distributions: short-billed birds move away during times that prey bury deeply

PubMed Central

Duijns, Sjoerd; van Gils, Jan A.; Smart, Jennifer; Piersma, Theunis

2015-01-01

In our seasonal world, animals face a variety of environmental conditions in the course of the year. To cope with such seasonality, animals may be phenotypically flexible, but some phenotypic traits are fixed. If fixed phenotypic traits are functionally linked to resource use, then animals should redistribute in response to seasonally changing resources, leading to a ‘phenotype-limited’ distribution. Here, we examine this possibility for a shorebird, the bar-tailed godwit (Limosa lapponica; a long-billed and sexually dimorphic shorebird), that has to reach buried prey with a probing bill of fixed length. The main prey of female bar-tailed godwits is buried deeper in winter than in summer. Using sightings of individually marked females, we found that in winter only longer-billed individuals remained in the Dutch Wadden Sea, while the shorter-billed individuals moved away to an estuary with a more benign climate such as the Wash. Although longer-billed individuals have the widest range of options in winter and could therefore be selected for, counterselection may occur during the breeding season on the tundra, where surface-living prey may be captured more easily with shorter bills. Phenotype-limited distributions could be a widespread phenomenon and, when associated with assortative migration and mating, it may act as a precursor of phenotypic evolution. PMID:26543585

Phenotype-limited distributions: short-billed birds move away during times that prey bury deeply.

PubMed

Duijns, Sjoerd; van Gils, Jan A; Smart, Jennifer; Piersma, Theunis

2015-06-01

In our seasonal world, animals face a variety of environmental conditions in the course of the year. To cope with such seasonality, animals may be phenotypically flexible, but some phenotypic traits are fixed. If fixed phenotypic traits are functionally linked to resource use, then animals should redistribute in response to seasonally changing resources, leading to a 'phenotype-limited' distribution. Here, we examine this possibility for a shorebird, the bar-tailed godwit (Limosa lapponica; a long-billed and sexually dimorphic shorebird), that has to reach buried prey with a probing bill of fixed length. The main prey of female bar-tailed godwits is buried deeper in winter than in summer. Using sightings of individually marked females, we found that in winter only longer-billed individuals remained in the Dutch Wadden Sea, while the shorter-billed individuals moved away to an estuary with a more benign climate such as the Wash. Although longer-billed individuals have the widest range of options in winter and could therefore be selected for, counterselection may occur during the breeding season on the tundra, where surface-living prey may be captured more easily with shorter bills. Phenotype-limited distributions could be a widespread phenomenon and, when associated with assortative migration and mating, it may act as a precursor of phenotypic evolution.

No evidence for female discrimination against male house mice carrying a selfish genetic element

PubMed Central

Lindholm, Anna K.

2016-01-01

Meiotic drivers distort transmission to the next generation in their favor, with detrimental effects on the fitness of their homologues and the rest of the genome. Male carriers of meiotic drivers commonly inflict costs on their mates through genetic incompatibility, reduced fecundity, or biased brood sex ratios. Given these costs, evidence for female discrimination against male carriers is surprisingly rare. One of few examples is the t haplotype in house mice, a meiotic driver that shows strong transmission distortion in males and is typically homozygote lethal. As a consequence, mating between 2 t heterozygous (+/t) mice leads to high embryo mortality. Previous experiments showing that +/t females avoid this incompatibility cost by preferring +/+ versus +/t males have inferred preference based on olfactory cues or brief social interactions. Evidence from mating contexts in laboratory settings and semi-natural populations has been inconclusive. Here, we investigated female choice from a large number of no-choice mating trials. We found no evidence for discrimination against +/t males based on mating, remating, and copulatory behavior. Further, we found no evidence for avoidance of incompatibility through selective interactions between gametes. The likelihood of mating showed significant effects of female weight and genotype, suggesting that our test paradigm enabled females to exhibit mate choice. We discuss the strengths and limitations of our approach. By explicitly considering selection at both the individual and gene level, we argue why precopulatory female discrimination by +/t females may be less evolutionarily stable than discrimination by all females based on postcopulatory mechanisms. PMID:29491955

No evidence for female discrimination against male house mice carrying a selfish genetic element.

PubMed

Sutter, Andreas; Lindholm, Anna K

2016-12-01

Meiotic drivers distort transmission to the next generation in their favor, with detrimental effects on the fitness of their homologues and the rest of the genome. Male carriers of meiotic drivers commonly inflict costs on their mates through genetic incompatibility, reduced fecundity, or biased brood sex ratios. Given these costs, evidence for female discrimination against male carriers is surprisingly rare. One of few examples is the t haplotype in house mice, a meiotic driver that shows strong transmission distortion in males and is typically homozygote lethal. As a consequence, mating between 2 t heterozygous (+/ t ) mice leads to high embryo mortality. Previous experiments showing that +/ t females avoid this incompatibility cost by preferring +/+ versus +/ t males have inferred preference based on olfactory cues or brief social interactions. Evidence from mating contexts in laboratory settings and semi-natural populations has been inconclusive. Here, we investigated female choice from a large number of no-choice mating trials. We found no evidence for discrimination against +/ t males based on mating, remating, and copulatory behavior. Further, we found no evidence for avoidance of incompatibility through selective interactions between gametes. The likelihood of mating showed significant effects of female weight and genotype, suggesting that our test paradigm enabled females to exhibit mate choice. We discuss the strengths and limitations of our approach. By explicitly considering selection at both the individual and gene level, we argue why precopulatory female discrimination by +/ t females may be less evolutionarily stable than discrimination by all females based on postcopulatory mechanisms.

Major histocompatibility complex class II compatibility, but not class I, predicts mate choice in a bird with highly developed olfaction

PubMed Central

Strandh, Maria; Westerdahl, Helena; Pontarp, Mikael; Canbäck, Björn; Dubois, Marie-Pierre; Miquel, Christian; Taberlet, Pierre; Bonadonna, Francesco

2012-01-01

Mate choice for major histocompatibility complex (MHC) compatibility has been found in several taxa, although rarely in birds. MHC is a crucial component in adaptive immunity and by choosing an MHC-dissimilar partner, heterozygosity and potentially broad pathogen resistance is maximized in the offspring. The MHC genotype influences odour cues and preferences in mammals and fish and hence olfactory-based mate choice can occur. We tested whether blue petrels, Halobaena caerulea, choose partners based on MHC compatibility. This bird is long-lived, monogamous and can discriminate between individual odours using olfaction, which makes it exceptionally well suited for this analysis. We screened MHC class I and II B alleles in blue petrels using 454-pyrosequencing and quantified the phylogenetic, functional and allele-sharing similarity between individuals. Partners were functionally more dissimilar at the MHC class II B loci than expected from random mating (p = 0.033), whereas there was no such difference at the MHC class I loci. Phylogenetic and non-sequence-based MHC allele-sharing measures detected no MHC dissimilarity between partners for either MHC class I or II B. Our study provides evidence of mate choice for MHC compatibility in a bird with a high dependency on odour cues, suggesting that MHC odour-mediated mate choice occurs in birds. PMID:22951737

Exploitation of insect vibrational signals reveals a new method of pest management.

PubMed

Eriksson, Anna; Anfora, Gianfranco; Lucchi, Andrea; Lanzo, Francesco; Virant-Doberlet, Meta; Mazzoni, Valerio

2012-01-01

Food production is considered to be the main source of human impact on the environment and the concerns about detrimental effects of pesticides on biodiversity and human health are likely to lead to an increasingly restricted use of chemicals in agriculture. Since the first successful field trial, pheromone based mating disruption enabled sustainable insect control, which resulted in reduced levels of pesticide use. Organic farming is one of the fastest growing segments of agriculture and with the continuously growing public concern about use of pesticides, the main remaining challenge in increasing the safety of the global food production is to identify appropriate alternative mating disruption approaches for the numerous insect pests that do not rely on chemical communication. In the present study, we show for the first time that effective mating disruption based on substrate-borne vibrational signals can be achieved in the field. When disruptive vibrational signals were applied to grapevine plants through a supporting wire, mating frequency of the leafhopper pest Scaphoideus titanus dropped to 9 % in semi-field conditions and to 4 % in a mature vineyard. The underlying mechanism of this environmentally friendly pest-control tactic is a masking of the vibrational signals used in mate recognition and location. Because vibrational communication is widespread in insects, mating disruption using substrate vibrations can transform many open field and greenhouse based farming systems.

Overcoming statistical bias to estimate genetic mating systems in open populations: a comparison of Bateman's principles between the sexes in a sex-role-reversed pipefish.

PubMed

Mobley, Kenyon B; Jones, Adam G

2013-03-01

The genetic mating system is a key component of the sexual selection process, yet methods for the quantification of mating systems remain controversial. One approach involves metrics derived from Bateman's principles, which are based on variances in mating and reproductive success and the relationship between them. However, these measures are extremely difficult to measure for both sexes in open populations, because missing data can result in biased estimates. Here, we develop a novel approach for the estimation of mating system metrics based on Bateman's principles and apply it to a microsatellite-based parentage analysis of a natural population of the dusky pipefish, Syngnathus floridae. Our results show that both male and female dusky pipefish have significantly positive Bateman gradients. However, females exhibit larger values of the opportunity for sexual selection and the opportunity for selection compared to males. These differences translate into a maximum intensity of sexual selection (S'max) for females three times larger than that for males. Overall, this study identifies a critical source of bias that affects studies of mating systems in open populations, presents a novel method for overcoming this bias, and applies this method for the first time in a sex-role-reversed pipefish. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

Female mate choice by chemical signals in a semi-terrestrial crab

NASA Astrophysics Data System (ADS)

Sal Moyano, María Paz; Silva, Paola; Luppi, Tomás; Gavio, María Andrea

2014-01-01

Information about the roles of both sexes in pair formation is required to better understand the mechanisms involved in sexual selection. Mate choice could depend on the courtship behavior, involving chemical, tactile and visual signals. We determined if Neohelice granulata mate choice is based on female or male choice, considering visual and chemical with contact and without contact signals between partners and different categories of individuals: receptive and unreceptive females; and large, small, mated or unmated males. Experiments showed that mate selection was based on receptive female's choice using chemical signals, but not visual ones. Since copulation occurs during high and low tides, water-borne chemical signals would be preferentially used during high tide, while contact ones during low tide. Females preferred large and unmated males, while males did not seem to recognize receptive females using chemical neither visual signals. Females were capable of detecting the presence of the chemical signals released by large and unmated males, but not its amount. It is proposed that small and mated males are probably releasing different types of chemical signals, not attractive to females, or that they are not emitting any signal.

Assessing implicit mate preferences among Chinese and Japanese women by providing love, sex, or money cues.

PubMed

Jin, Zheng; Shiomura, Kimihiro; Jiang, Lizhu

2015-02-01

Love, sex, and money are the most direct cues involved in the fundamental forms of mate preferences. These fundamental forms are not mutually exclusive but are interrelated. As a result, humans base their mate choices on multiple cues. In this study, 62 undergraduate women (M age = 20.4 yr., SD = 1.4) from China and Japan served as the participants. They performed a variation of the semantic priming task, in which they were instructed to decide by means of a key-press whether the target was human or non-human. The primes were images that portrayed potent evolutionary factors for mate preference (i.e., love, sex, and money), and the manipulation was based on whether the prime and target matched regarding gender, independent of the target decision task (human vs non-human). Participants gave faster responses to male targets than to female targets under priming. The results generally supported the evolutionary premises that assume mate preference is determined by fundamental forms of providing emotional (love), material (money), and fertility support (sex). The money priming effect was stronger in the Chinese women than in the Japanese women, suggesting that social context may influence mate preferences.

Structural basis for the blockade of MATE multidrug efflux pumps

DOE PAGES

Radchenko, Martha; Symersky, Jindrich; Nie, Rongxin; ...

2015-08-06

Multidrug and toxic compound extrusion (MATE) transporters underpin multidrug resistance by using the H + or Na + electrochemical gradient to extrude different drugs across cell membranes. MATE transporters can be further parsed into the DinF, NorM and eukaryotic subfamilies based on their amino-acid sequence similarity. Here we report the 3.0 Å resolution X-ray structures of a protonation-mimetic mutant of an H +-coupled DinF transporter, as well as of an H +-coupled DinF and a Na +-coupled NorM transporters in complexes with verapamil, a small-molecule pharmaceutical that inhibits MATE-mediated multidrug extrusion. Combining structure-inspired mutational and functional studies, we confirm themore » biological relevance of our crystal structures, reveal the mechanistic differences among MATE transporters, and suggest how verapamil inhibits MATE-mediated multidrug efflux. Our findings offer insights into how MATE transporters extrude chemically and structurally dissimilar drugs and could inform the design of new strategies for tackling multidrug resistance.« less

Coy Males and Seductive Females in the Sexually Cannibalistic Colonial Spider, Cyrtophora citricola.

PubMed

Yip, Eric C; Berner-Aharon, Na'ama; Smith, Deborah R; Lubin, Yael

2016-01-01

The abundance of sperm relative to eggs selects for males that maximize their number of mates and for females that choose high quality males. However, in many species, males exercise mate choice, even when they invest little in their offspring. Sexual cannibalism may promote male choosiness by limiting the number of females a male can inseminate and by biasing the sex ratio toward females because, while females can reenter the mating pool, cannibalized males cannot. These effects may be insufficient for male choosiness to evolve, however, if males face low sequential encounter rates with females. We hypothesized that sexual cannibalism should facilitate the evolution of male choosiness in group living species because a male is likely to encounter multiple receptive females simultaneously. We tested this hypothesis in a colonial orb-weaving spider, Cyrtophora citricola, with a high rate of sexual cannibalism. We tested whether mated females would mate with multiple males, and thereby shift the operational sex ratio toward females. We also investigated whether either sex chooses mates based on nutritional state and age, and whether males choose females based on reproductive state. We found that females are readily polyandrous and exhibit no mate choice related to male feeding or age. Males courted more often when the male was older and the female was younger, and males copulated more often with well-fed females. The data show that males are choosier than females for the traits we measured, supporting our hypothesis that group living and sexual cannibalism may together promote the evolution of male mate choice.

Coy Males and Seductive Females in the Sexually Cannibalistic Colonial Spider, Cyrtophora citricola

PubMed Central

Yip, Eric C.; Berner-Aharon, Na’ama; Smith, Deborah R.; Lubin, Yael

2016-01-01

The abundance of sperm relative to eggs selects for males that maximize their number of mates and for females that choose high quality males. However, in many species, males exercise mate choice, even when they invest little in their offspring. Sexual cannibalism may promote male choosiness by limiting the number of females a male can inseminate and by biasing the sex ratio toward females because, while females can reenter the mating pool, cannibalized males cannot. These effects may be insufficient for male choosiness to evolve, however, if males face low sequential encounter rates with females. We hypothesized that sexual cannibalism should facilitate the evolution of male choosiness in group living species because a male is likely to encounter multiple receptive females simultaneously. We tested this hypothesis in a colonial orb-weaving spider, Cyrtophora citricola, with a high rate of sexual cannibalism. We tested whether mated females would mate with multiple males, and thereby shift the operational sex ratio toward females. We also investigated whether either sex chooses mates based on nutritional state and age, and whether males choose females based on reproductive state. We found that females are readily polyandrous and exhibit no mate choice related to male feeding or age. Males courted more often when the male was older and the female was younger, and males copulated more often with well-fed females. The data show that males are choosier than females for the traits we measured, supporting our hypothesis that group living and sexual cannibalism may together promote the evolution of male mate choice. PMID:27249787

BATEMANATER: a computer program to estimate and bootstrap mating system variables based on Bateman's principles.

PubMed

Jones, Adam G

2015-11-01

Bateman's principles continue to play a major role in the characterization of genetic mating systems in natural populations. The modern manifestations of Bateman's ideas include the opportunity for sexual selection (i.e. I(s) - the variance in relative mating success), the opportunity for selection (i.e. I - the variance in relative reproductive success) and the Bateman gradient (i.e. β(ss) - the slope of the least-squares regression of reproductive success on mating success). These variables serve as the foundation for one convenient approach for the quantification of mating systems. However, their estimation presents at least two challenges, which I address here with a new Windows-based computer software package called BATEMANATER. The first challenge is that confidence intervals for these variables are not easy to calculate. BATEMANATER solves this problem using a bootstrapping approach. The second, more serious, problem is that direct estimates of mating system variables from open populations will typically be biased if some potential progeny or adults are missing from the analysed sample. BATEMANATER addresses this problem using a maximum-likelihood approach to estimate mating system variables from incompletely sampled breeding populations. The current version of BATEMANATER addresses the problem for systems in which progeny can be collected in groups of half- or full-siblings, as would occur when eggs are laid in discrete masses or offspring occur in pregnant females. BATEMANATER has a user-friendly graphical interface and thus represents a new, convenient tool for the characterization and comparison of genetic mating systems. © 2015 John Wiley & Sons Ltd.

Intra-population variation in behavior modification by the acanthocephalan Acanthocephalus dirus: are differences mediated by host condition?

PubMed

Caddigan, Sara C; Barkauskas, Rima T; Sparkes, Timothy C

2014-11-01

The acanthocephalan parasite Acanthocephalus dirus infects the freshwater isopod Caecidotea intermedius as an intermediate host before completing its life cycle in a fish. Male C. intermedius infected by A. dirus parasites are less likely to engage in mating behavior than uninfected males but there is a significant intra-population variation in the occurrence of this behavioral change. Previous studies on uninfected isopods have shown that glycogen content is a predictor of male mating behavior and we examined whether the intra-population variation in the mating behavior of infected male C. intermedius could be explained by this relationship. A field-based behavioral experiment was used to quantify intra-population variation in male mating behavior, which showed that 50% of infected males were responsive to females and 50% were not responsive. Biochemical analysis of responsive and non-responsive males revealed that glycogen content was a predictor of the mating behavior for uninfected males but was not a predictor of mating behavior for infected males. For infected males, parasite intensity was a predictor of mating behavior. Males that contained more A. dirus parasites were less likely to undergo modification of mating behavior. We propose that the intra-population variation in the mating behavior of infected C. intermedius identified in nature was not mediated by host condition.

Quantifying the risk of pandemic influenza virus evolution by mutation and re-assortment.

PubMed

Reperant, Leslie A; Grenfell, Bryan T; Osterhaus, Albert D M E

2015-12-08

Large outbreaks of zoonotic influenza A virus (IAV) infections may presage an influenza pandemic. However, the likelihood that an airborne-transmissible variant evolves upon zoonotic infection or co-infection with zoonotic and seasonal IAVs remains poorly understood, as does the relative importance of accumulating mutations versus re-assortment in this process. Using discrete-time probabilistic models, we determined quantitative probability ranges that transmissible variants with 1-5 mutations and transmissible re-assortants evolve after a given number of zoonotic IAV infections. The systematic exploration of a large population of model parameter values was designed to account for uncertainty and variability in influenza virus infection, epidemiological and evolutionary processes. The models suggested that immunocompromised individuals are at high risk of generating IAV variants with pandemic potential by accumulation of mutations. Yet, both immunocompetent and immunocompromised individuals could generate high viral loads of single and double mutants, which may facilitate their onward transmission and the subsequent accumulation of additional 1-2 mutations in newly-infected individuals. This may result in the evolution of a full transmissible genotype along short chains of contact transmission. Although co-infection with zoonotic and seasonal IAVs was shown to be a rare event, it consistently resulted in high viral loads of re-assortants, which may facilitate their onward transmission among humans. The prevention or limitation of zoonotic IAV infection in immunocompromised and contact individuals, including health care workers, as well as vaccination against seasonal IAVs-limiting the risk of co-infection-should be considered fundamental tools to thwart the evolution of a novel pandemic IAV by accumulation of mutations and re-assortment. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Evaluation of the Mating Competitiveness of the Adult Oriental Fruit Fly Reared as Larvae in Liquid vs. Those Raised on Standard Wheat-based Diets

USDA-ARS?s Scientific Manuscript database

Three strains (standard lab, DTWP pupal color sexing strain and wild strain) of adult oriental fruit flies, which were reared as larvae on a liquid diet, mill feed diet (Tanaka’s diet), or natural host fruit diet, were evaluated for mating competitiveness in both indoor and outdoor Boller’s mating c...

Intrasexual competition facilitates the evolution of alternative mating strategies in a colour polymorphic fish.

PubMed

Hurtado-Gonzales, Jorge L; Uy, J Albert C

2010-12-23

Intense competition for access to females can lead to males exploiting different components of sexual selection, and result in the evolution of alternative mating strategies (AMSs). Males of Poecilia parae, a colour polymorphic fish, exhibit five distinct phenotypes: drab-coloured (immaculata), striped (parae), structural-coloured (blue) and carotenoid-based red and yellow morphs. Previous work indicates that immaculata males employ a sneaker strategy, whereas the red and yellow morphs exploit female preferences for carotenoid-based colours. Mating strategies favouring the maintenance of the other morphs remain to be determined. Here, we report the role of agonistic male-male interactions in influencing female mating preferences and male mating success, and in facilitating the evolution of AMSs. Our study reveals variation in aggressiveness among P. parae morphs during indirect and direct interactions with sexually receptive females. Two morphs, parae and yellow, use aggression to enhance their mating success (i.e., number of copulations) by 1) directly monopolizing access to females, and 2) modifying female preferences after winning agonistic encounters. Conversely, we found that the success of the drab-coloured immaculata morph, which specializes in a sneak copulation strategy, relies in its ability to circumvent both male aggression and female choice when facing all but yellow males. Strong directional selection is expected to deplete genetic variation, yet many species show striking genetically-based polymorphisms. Most studies evoke frequency dependent selection to explain the persistence of such variation. Consistent with a growing body of evidence, our findings suggest that a complex form of balancing selection may alternatively explain the evolution and maintenance of AMSs in a colour polymorphic fish. In particular, this study demonstrates that intrasexual competition results in phenotypically distinct males exhibiting clear differences in their levels of aggression to exclude potential sexual rivals. By being dominant, the more aggressive males are able to circumvent female mating preferences for attractive males, whereas another male type incorporates subordinate behaviours that allow them to circumvent male aggression and female mating preferences. Together, these and previous results indicate that exploiting different aspects of social interactions may allow males to evolve distinct mating strategies and thus the long term maintenance of polymorphisms within populations.

When genes move farther than offspring: gene flow by male gamete dispersal in the highly philopatric bat species Thyroptera tricolor.

PubMed

Buchalski, M R; Chaverri, G; Vonhof, M J

2014-02-01

For species characterized by philopatry of both sexes, mate selection represents an important behaviour for inbreeding avoidance, yet the implications for gene flow are rarely quantified. Here, we present evidence of male gamete-mediated gene flow resulting from extra-group mating in Spix's disc-winged bat, Thyroptera tricolor, a species which demonstrates all-offspring philopatry. We used microsatellite and capture-recapture data to characterize social group structure and the distribution of mated pairs at two sites in southwestern Costa Rica over four breeding seasons. Relatedness and genetic spatial autocorrelation analyses indicated strong kinship within groups and over short distances (<50 m), resulting from matrilineal group structure and small roosting home ranges (~0.2 ha). Despite high relatedness among-group members, observed inbreeding coefficients were low (FIS  = 0.010 and 0.037). Parentage analysis indicated mothers and offspring belonged to the same social group, while fathers belonged to different groups, separated by large distances (~500 m) when compared to roosting home ranges. Simulated random mating indicated mate choice was not based on intermediate levels of relatedness, and mated pairs were less related than adults within social groups on average. Isolation-by-distance (IBD) models of genetic neighbourhood area based on father-offspring distances provided direct estimates of mean gamete dispersal distances (r^) > 10 roosting home range equivalents. Indirect estimates based on genetic distance provided even larger estimates of r^, indicating direct estimates were biased low. These results suggest extra-group mating reduces the incidence of inbreeding in T. tricolor, and male gamete dispersal facilitates gene flow in lieu of natal dispersal of young. © 2013 John Wiley & Sons Ltd.

MHC-correlated mate choice in humans: a review.

PubMed

Havlicek, Jan; Roberts, S Craig

2009-05-01

Extremely high variability in genes of the major histocompatibility complex (MHC) in vertebrates is assumed to be a consequence of frequency-dependent parasite-driven selection and mate preferences based on promotion of offspring heterozygosity at MHC, or potentially, genome-wide inbreeding avoidance. Where effects have been found, mate choice studies on rodents and other species usually find preference for MHC-dissimilarity in potential partners. Here we critically review studies on MHC-associated mate choice in humans. These are based on three broadly different aspects: (1) odor preferences, (2) facial preferences and (3) actual mate choice surveys. As in animal studies, most odor-based studies demonstrate disassortative preferences, although there is variation in the strength and nature of the effects. In contrast, facial attractiveness research indicates a preference for MHC-similar individuals. Results concerning MHC in actual couples show a bias towards similarity in one study, dissimilarity in two studies and random distribution in several other studies. These vary greatly in sample size and heterogeneity of the sample population, both of which may significantly bias the results. This pattern of mixed results across studies may reflect context-dependent and/or life history sensitive preference expression, in addition to higher level effects arising out of population differences in genetic heterogeneity or cultural and ethnic restrictions on random mating patterns. Factors of special relevance in terms of individual preferences are reproductive status and long- vs. short-term mating context. We discuss the idea that olfactory and visual channels may work in a complementary way (i.e. odor preference for MHC-dissimilarity and visual preference for MHC-similarity) to achieve an optimal level of genetic variability, methodological issues and interesting avenues for further research.

Drosophila melanogaster virgins are more likely to mate with strangers than familiar flies.

PubMed

Odeen, Anders; Moray, Clea M

2008-03-01

Recent evidence shows that females of many species can discriminate against males and/or male phenotypes they have mated with previously. However, these studies have not tested whether actual mating is necessary to induce the avoidance behaviour. A preference for strangers may have evolved because it avoids multiple matings with similar genotypes. Alternatively, there may be selection against mating with familiar individuals directly. By choosing its first mate among unfamiliar individuals (which are less likely close relatives than are those encountered early in life), a virgin might disentangle some of the potential benefits of avoiding genetic incompatibility and inbreeding in the offspring from the costs of remating. In this study, we test whether Drosophila melanogaster flies bias their mate choice towards strangers according to previous, non-copulatory, experience. Based on 173 trials over 12 weeks, virgin females presented with two virgin males were 59% more likely to mate with a novel male than the one which she had been housed with for 8 h the day before. Hence we present the first report showing that a dipteran can distinguish between previously encountered and not previously encountered conspecifics.

Drosophila melanogaster virgins are more likely to mate with strangers than familiar flies

NASA Astrophysics Data System (ADS)

Ödeen, Anders; Moray, Clea M.

2008-03-01

Recent evidence shows that females of many species can discriminate against males and/or male phenotypes they have mated with previously. However, these studies have not tested whether actual mating is necessary to induce the avoidance behaviour. A preference for strangers may have evolved because it avoids multiple matings with similar genotypes. Alternatively, there may be selection against mating with familiar individuals directly. By choosing its first mate among unfamiliar individuals (which are less likely close relatives than are those encountered early in life), a virgin might disentangle some of the potential benefits of avoiding genetic incompatibility and inbreeding in the offspring from the costs of remating. In this study, we test whether Drosophila melanogaster flies bias their mate choice towards strangers according to previous, non-copulatory, experience. Based on 173 trials over 12 weeks, virgin females presented with two virgin males were 59% more likely to mate with a novel male than the one which she had been housed with for 8 h the day before. Hence we present the first report showing that a dipteran can distinguish between previously encountered and not previously encountered conspecifics.

Inhibition of OCT2, MATE1 and MATE2-K as a possible mechanism of drug interaction between pazopanib and cisplatin.

PubMed

Sauzay, C; White-Koning, M; Hennebelle, I; Deluche, T; Delmas, C; Imbs, D C; Chatelut, E; Thomas, F

2016-08-01

We hypothesized that pazopanib is an inhibitor of cisplatin renal transporters OCT2, MATE1 and MATE2-K based on previous studies demonstrating an interaction between tyrosine kinase inhibitors and these transporters. Because several combinations of targeted therapies and cytotoxics are currently in development for cancer treatment, such an interaction is worth investigating. Experiments on HEK293 cells stably transfected to express OCT2, MATE1, MATE2-K or an empty vector (EV) were conducted. The inhibitory effect of pazopanib on these transporters was measured using the uptake of fluorescent substrate ASP+ and cisplatin in the different cell lines. The effect of pazopanib on cisplatin-induced cytotoxicity was also evaluated. A decrease of ASP+ uptake was observed in OCT2-HEK, MATE1-HEK and MATE2K-HEK cell lines after addition of pazopanib at increasing concentrations. Pazopanib inhibited cisplatin specific uptake in OCT2-HEK, MATE1-HEK and MATE2K-HEK lines. Cytotoxicity experiments showed that co-incubation of cisplatin with pazopanib multiplied up to 2.7, 2.4 and 1.6 times the EC50 values of cisplatin in OCT2-HEK, MATE1-HEK and MATE2K-HEK cell lines respectively, reaching about the same values as in EV-HEK cells. To conclude, pazopanib inhibits OCT2, MATE1 and MATE2-K, which are involved in cisplatin secretion into urine. The combination of these two drugs may lead to an interaction and increase the cisplatin-induced systemic toxicity. Given the wide variability of plasma pazopanib concentrations observed in vivo, the interaction may occur in a clinical setting, particularly in overexposed patients. The existence of a drug-drug interaction should be investigated when pazopanib is associated with a substrate of these transporters. Copyright © 2016 Elsevier Ltd. All rights reserved.

Genome-wide SNP data suggest complex ancestry of sympatric North Pacific killer whale ecotypes

PubMed Central

Foote, A D; Morin, P A

2016-01-01

Three ecotypes of killer whale occur in partial sympatry in the North Pacific. Individuals assortatively mate within the same ecotype, resulting in correlated ecological and genetic differentiation. A key question is whether this pattern of evolutionary divergence is an example of incipient sympatric speciation from a single panmictic ancestral population, or whether sympatry could have resulted from multiple colonisations of the North Pacific and secondary contact between ecotypes. Here, we infer multilocus coalescent trees from >1000 nuclear single-nucleotide polymorphisms (SNPs) and find evidence of incomplete lineage sorting so that the genealogies of SNPs do not all conform to a single topology. To disentangle whether uncertainty in the phylogenetic inference of the relationships among ecotypes could also result from ancestral admixture events we reconstructed the relationship among the ecotypes as an admixture graph and estimated f4-statistics using TreeMix. The results were consistent with episodes of admixture between two of the North Pacific ecotypes and the two outgroups (populations from the Southern Ocean and the North Atlantic). Gene flow may have occurred via unsampled ‘ghost' populations rather than directly between the populations sampled here. Our results indicate that because of ancestral admixture events and incomplete lineage sorting, a single bifurcating tree does not fully describe the relationship among these populations. The data are therefore most consistent with the genomic variation among North Pacific killer whale ecotypes resulting from multiple colonisation events, and secondary contact may have facilitated evolutionary divergence. Thus, the present-day populations of North Pacific killer whale ecotypes have a complex ancestry, confounding the tree-based inference of ancestral geography. PMID:27485668

Comprehensive multi-stage linkage analyses identify a locus for adult height on chromosome 3p in a healthy Caucasian population.

PubMed

Ellis, Justine A; Scurrah, Katrina J; Duncan, Anna E; Lamantia, Angela; Byrnes, Graham B; Harrap, Stephen B

2007-04-01

There have been a number of genome-wide linkage studies for adult height in recent years. These studies have yielded few well-replicated loci, and none have been further confirmed by the identification of associated gene variants. The inconsistent results may be attributable to the fact that few studies have combined accurate phenotype measures with informative statistical modelling in healthy populations. We have performed a multi-stage genome-wide linkage analysis for height in 275 adult sibling pairs drawn randomly from the Victorian Family Heart Study (VFHS), a healthy population-based Caucasian cohort. Height was carefully measured in a standardised fashion on regularly calibrated equipment. Following genome-wide identification of a peak Z-score of 3.14 on chromosome 3 at 69 cM, we performed a fine-mapping analysis of this region in an extended sample of 392 two-generation families. We used a number of variance components models that incorporated assortative mating and shared environment effects, and we observed a peak LOD score of approximately 3.5 at 78 cM in four of the five models tested. We also demonstrated that the most prevalent model in the literature gave the worst fit, and the lowest LOD score (2.9) demonstrating the importance of appropriate modelling. The region identified in this study replicates the results of other genome-wide scans of height and bone-related phenotypes, strongly suggesting the presence of a gene important in bone growth on chromosome 3p. Association analyses of relevant candidate genes should identify the genetic variants responsible for the chromosome 3p linkage signal in our population.

GJB2 Mutations in Mongolia: Complex Alleles, Low Frequency, and Reduced Fitness of the Deaf

PubMed Central

Tekin, Mustafa; Xia, Xia-Juan; Erdenetungalag, Radnaabazar; Cengiz, F. Basak; White, Thomas W.; Radnaabazar, Janchiv; Dangaasuren, Begzsuren; Tastan, Hakki; Nance, Walter E.; Pandya, Arti

2016-01-01

Summary We screened the GJB2 gene for mutations in 534 (108 multiplex and 426 simplex) probands with non-syndromic sensorineural deafness, who were ascertained through the only residential school for deaf in Mongolia and in 217 hearing controls. Twenty different alleles, including four novel changes, were identified. Biallelic GJB2 mutations were found in 4.5% of the deaf probands (8.3% in multiplex, 3.5% in simplex). The most common mutations were c.IVS1+1G>A (c.-3201G>A) and c.235delC with allele frequencies of 3.5% and 1.5%, respectively. The c.IVS1+1G>A mutation appears to have diverse origins based on its association with multiple haplotypes constructed using nearby SNP markers. The p.V27I and p.E114G variants were frequently detected in both deaf probands and hearing controls. The p.E114G variant was always associated with p.V27I, and haplotype analysis confirmed that it was always in cis with the p.V27I variant. Although in vitro experiments using Xenopus oocytes have suggested that p.[V27I;E114G] disturb the gap junction function of Cx26, the equal distribution of this complex allele in both deaf probands and hearing controls makes it a less likely cause of profound congenital deafness. We found a lower frequency of assortative mating (37.5%) and decreased genetic fitness (62%) of the deaf in Mongolia as compared to the western populations, which provides an explanation for lower frequency of GJB2 deafness in Mongolia. PMID:20201936

Genetic, comparative genomic, and expression analyses of the Mc1r locus in the polychromatic Midas cichlid fish (Teleostei, Cichlidae Amphilophus sp.) species group.

PubMed

Henning, Frederico; Renz, Adina Josepha; Fukamachi, Shoji; Meyer, Axel

2010-05-01

Natural populations of the Midas cichlid species in several different crater lakes in Nicaragua exhibit a conspicuous color polymorphism. Most individuals are dark and the remaining have a gold coloration. The color morphs mate assortatively and sympatric population differentiation has been shown based on neutral molecular data. We investigated the color polymorphism using segregation analysis and a candidate gene approach. The segregation patterns observed in a mapping cross between a gold and a dark individual were consistent with a single dominant gene as a cause of the gold phenotype. This suggests that a simple genetic architecture underlies some of the speciation events in the Midas cichlids. We compared the expression levels of several candidate color genes Mc1r, Ednrb1, Slc45a2, and Tfap1a between the color morphs. Mc1r was found to be up regulated in the gold morph. Given its widespread association in color evolution and role on melanin synthesis, the Mc1r locus was further investigated using sequences derived from a genomic library. Comparative analysis revealed conserved synteny in relation to the majority of teleosts and highlighted several previously unidentified conserved non-coding elements (CNEs) in the upstream and downstream regions in the vicinity of Mc1r. The identification of the CNEs regions allowed the comparison of sequences from gold and dark specimens of natural populations. No polymorphisms were found between in the population sample and Mc1r showed no linkage to the gold phenotype in the mapping cross, demonstrating that it is not causally related to the color polymorphism in the Midas cichlid.

Analysis of Copy Number Variation in the Abp Gene Regions of Two House Mouse Subspecies Suggests Divergence during the Gene Family Expansions.

PubMed

Pezer, Željka; Chung, Amanda G; Karn, Robert C; Laukaitis, Christina M

2017-06-01

The Androgen-binding protein ( Abp ) gene region of the mouse genome contains 64 genes, some encoding pheromones that influence assortative mating between mice from different subspecies. Using CNVnator and quantitative PCR, we explored copy number variation in this gene family in natural populations of Mus musculus domesticus ( Mmd ) and Mus musculus musculus ( Mmm ), two subspecies of house mice that form a narrow hybrid zone in Central Europe. We found that copy number variation in the center of the Abp gene region is very common in wild Mmd , primarily representing the presence/absence of the final duplications described for the mouse genome. Clustering of Mmd individuals based on this variation did not reflect their geographical origin, suggesting no population divergence in the Abp gene cluster. However, copy number variation patterns differ substantially between Mmd and other mouse taxa. Large blocks of Abp genes are absent in Mmm , Mus musculus castaneus and an outgroup, Mus spretus , although with differences in variation and breakpoint locations. Our analysis calls into question the reliance on a reference genome for interpreting the detailed organization of genes in taxa more distant from the Mmd reference genome. The polymorphic nature of the gene family expansion in all four taxa suggests that the number of Abp genes, especially in the central gene region, is not critical to the survival and reproduction of the mouse. However, Abp haplotypes of variable length may serve as a source of raw genetic material for new signals influencing reproductive communication and thus speciation of mice. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

JPRS Report, East Europe

DTIC Science & Technology

1987-11-24

of the assortment of manufactured parts for partial and complete frames, as well as abutments , support walls, and bridgehead construction...Uniform Series II Generation based on anticipated spans; and • Increased effectiveness of prefabrication for steel and masonry bridge construction...support structures and abutments . Parallel to and on an equal par with standard primary construction trades already cited, the scientific-technical

Comparison of sexual mixing patterns for syphilis in endemic and outbreak settings.

PubMed

Doherty, Irene A; Adimora, Adaora A; Muth, Stephen Q; Serre, Marc L; Leone, Peter A; Miller, William C

2011-05-01

In a largely rural region of North Carolina during 1998-2002, outbreaks of heterosexually transmitted syphilis occurred, tied to crack cocaine use and exchange of sex for drugs and money. Sexual partnership mixing patterns are an important characteristic of sexual networks that relate to transmission dynamics of sexually transmitted infections (STIs). Using contact tracing data collected by disease intervention specialists, we estimated Newman assortativity coefficients and compared values in counties experiencing syphilis outbreaks to nonoutbreak counties, with respect to race/ethnicity, race/ethnicity and age, and the cases' number of social/sexual contacts, infected contacts, sex partners, and infected sex partners, and syphilis disease stage (primary, secondary, early latent). Individuals in the outbreak counties had more contacts and mixing by the number of sex partners was disassortative in outbreak counties and assortative nonoutbreak counties. Although mixing by syphilis disease stage was minimally assortative in outbreak counties, it was disassortative in nonoutbreak areas. Partnerships were relatively discordant by age, especially among older white men, who often chose considerably younger female partners. Whether assortative mixing exacerbates or attenuates the reach of STIs into different populations depends on the characteristic/attribute and epidemiologic phase. Examination of sexual partnership characteristics and mixing patterns offers insights into the growth of STI outbreaks that complement other research methods.

Comparison of Sexual Mixing Patterns for Syphilis in Endemic and Outbreak Settings

PubMed Central

Doherty, Irene A; Adimora, Adaora A; Muth, Stephen Q; Serre, Marc L; Leone, Peter A; Miller, William C

2015-01-01

Background In a largely rural region of North Carolina during 1998–2002, outbreaks occurred of heterosexually-transmitted syphilis, tied to crack cocaine use and exchange of sex for drugs and money. Sexual partnership mixing patterns are an important characteristic of sexual networks that relate to transmission dynamics of STIs. Methods Using contact tracing data collected by Disease Intervention Specialists, we estimated Newman assortativity coefficients and compared values in counties experiencing syphilis outbreaks to non-outbreak counties, with respect to race/ethnicity, race/ethnicity and age, and the cases' number of social/sexual contacts, infected contacts, sex partners, and infected sex partners, and syphilis disease stage (primary, secondary, early latent). Results Individuals in the outbreak counties had more contacts and mixing by the number of sex partners was disassortative in outbreak counties and assortative non-outbreak counties. Whereas mixing by syphilis disease stage was minimally assortative in outbreak counties, it was disassortative in non-outbreak areas. Partnerships were relatively discordant by age, especially among older White men, who often chose considerably younger female partners. Conclusions Whether assortative mixing exacerbates or attenuates the reach of STIs into different populations depends on the characteristic/attribute and epidemiologic phase. Examination of sexual partnership characteristics and mixing patterns offers insights into the growth of STI outbreaks that complement other research methods. PMID:21217418

Genetic diversity promotes homeostasis in insect colonies.

PubMed

Oldroyd, Benjamin P; Fewell, Jennifer H

2007-08-01

Although most insect colonies are headed by a singly mated queen, some ant, wasp and bee taxa have evolved high levels of multiple mating or 'polyandry'. We argue here that a contributing factor towards the evolution of polyandry is that the resulting genetic diversity within colonies provides them with a system of genetically based task specialization, enabling them to respond resiliently to environmental perturbation. An alternate view is that genetic contributions to task specialization are a side effect of multiple mating, which evolved through other causes, and that genetically based task specialization now makes little or no contribution to colony fitness.

Selection by mating competitiveness improves the performance of Anastrepha ludens males of the genetic sexing strain Tapachula-7.

PubMed

Quintero-Fong, L; Toledo, J; Ruiz, L; Rendón, P; Orozco-Dávila, D; Cruz, L; Liedo, P

2016-10-01

The sexual performance of Anastrepha ludens males of the Tapachula-7 genetic sexing strain, produced via selection based on mating success, was compared with that of males produced without selection in competition with wild males. Mating competition, development time, survival, mass-rearing quality parameters and pheromone production were compared. The results showed that selection based on mating competitiveness significantly improved the sexual performance of offspring. Development time, survival of larvae, pupae and adults, and weights of larvae and pupae increased with each selection cycle. Differences in the relative quantity of the pheromone compounds (Z)-3-nonenol and anastrephin were observed when comparing the parental males with the F4 and wild males. The implications of this colony management method on the sterile insect technique are discussed.

MHC-disassortative mate choice and inbreeding avoidance in a solitary primate.

PubMed

Huchard, Elise; Baniel, Alice; Schliehe-Diecks, Susanne; Kappeler, Peter M

2013-08-01

Sexual selection theory suggests that choice for partners carrying dissimilar genes at the major histocompatibility complex (MHC) may play a role in maintaining genetic variation in animal populations by limiting inbreeding or improving the immunity of future offspring. However, it is often difficult to establish whether the observed MHC dissimilarity among mates drives mate choice or represents a by-product of inbreeding avoidance based on MHC-independent cues. Here, we used 454-sequencing and a 10-year study of wild grey mouse lemurs (Microcebus murinus), small, solitary primates from western Madagascar, to compare the relative importance on the mate choice of two MHC class II genes, DRB and DQB, that are equally variable but display contrasting patterns of selection at the molecular level, with DRB under stronger diversifying selection. We further assessed the effect of the genetic relatedness and of the spatial distance among candidate mates on the detection of MHC-dependent mate choice. Our results reveal inbreeding avoidance, along with disassortative mate choice at DRB, but not at DQB. DRB-disassortative mate choice remains detectable after excluding all related dyads (characterized by a relatedness coefficient r > 0), but varies slightly with the spatial distance among candidate mates. These findings suggest that the observed deviations from random mate choice at MHC are driven by functionally important MHC genes (like DRB) rather than passively resulting from inbreeding avoidance and further emphasize the need for taking into account the spatial and genetic structure of the population in correlative tests of MHC-dependent mate choice. © 2013 John Wiley & Sons Ltd.

An Automated Safe-to-Mate (ASTM) Tester

NASA Technical Reports Server (NTRS)

Nguyen, Phuc; Scott, Michelle; Leung, Alan; Lin, Michael; Johnson, Thomas

2013-01-01

Safe-to-mate testing is a common hardware safety practice where impedance measurements are made on unpowered hardware to verify isolation, continuity, or impedance between pins of an interface connector. A computer-based instrumentation solution has been developed to resolve issues. The ASTM is connected to the circuit under test, and can then quickly, safely, and reliably safe-to-mate the entire connector, or even multiple connectors, at the same time.

The relative importance of different direct benefits in the mate choices of a field cricket.

PubMed

Wagner, William E; Basolo, Alexandra L

2007-03-01

Discussions about the evolution of female mating preferences have often suggested that females should express multiple strong preferences when different male traits are correlated with different mating benefits, yet few studies have directly tested this hypothesis by comparing the strength of female preferences for male traits known to be correlated with different benefits. In the variable field cricket, Gryllus lineaticeps, females receive fecundity and fertility benefits from mating with males with higher chirp rates and life-span benefits from mating with males with longer chirp durations. Although females prefer higher chirp rates and longer chirp durations when the other trait is held constant, it is possible that they give priority to one of these song traits when both vary. In this study, we examined the relative importance of chirp rate and chirp duration in female mate choice using single-stimulus presentations of songs that varied in both chirp rate and chirp duration. Females expressed both directional and stabilizing preferences based on chirp rate, responding most strongly to a chirp rate approximately one standard deviation above the population mean. Females did not express preferences based on chirp duration, and did not express correlational preferences. These results suggest that females may give priority to the reproductive benefits provided by males that produce higher chirp rates.

Mate choice theory and the mode of selection in sexual populations.

PubMed

Carson, Hampton L

2003-05-27

Indirect new data imply that mate and/or gamete choice are major selective forces driving genetic change in sexual populations. The system dictates nonrandom mating, an evolutionary process requiring both revised genetic theory and new data on heritability of characters underlying Darwinian fitness. Successfully reproducing individuals represent rare selections from among vigorous, competing survivors of preadult natural selection. Nonrandom mating has correlated demographic effects: reduced effective population size, inbreeding, low gene flow, and emphasis on deme structure. Characters involved in choice behavior at reproduction appear based on quantitative trait loci. This variability serves selection for fitness within the population, having only an incidental relationship to the origin of genetically based reproductive isolation between populations. The claim that extensive hybridization experiments with Drosophila indicate that selection favors a gradual progression of "isolating mechanisms" is flawed, because intra-group random mating is assumed. Over deep time, local sexual populations are strong, independent genetic systems that use rich fields of variable polygenic components of fitness. The sexual reproduction system thus particularizes, in small subspecific populations, the genetic basis of the grand adaptive sweep of selective evolutionary change, much as Darwin proposed.

Final Steps in Mating NuSTAR to its Rocket

NASA Image and Video Library

2012-02-23

Inside an environmental enclosure at Vandenberg Air Force Base processing facility in California, technicians complete the final steps in mating NASA Nuclear Spectroscopic Telescope Array NuSTAR and its Orbital Sciences Pegasus XL rocket.

Influence of mating disruption on the reproductive biology of the vine mealybug, Planococcus ficus (Hemiptera: Pseudococcidae), under field conditions.

PubMed

Cocco, Arturo; Muscas, Enrico; Mura, Alessandra; Iodice, Andrea; Savino, Francesco; Lentini, Andrea

2018-05-08

Although mating disruption is increasingly being used to control the worldwide grapevine pest vine mealybug, Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), its mode of action remains unclear. A three-year field experiment was carried out to investigate the effects of mating disruption on the development and reproduction of the vine mealybug. The influence of mating disruption applied over consecutive years on the pest population density was also evaluated. The percentage of ovipositing females was significantly reduced in disrupted plots by 18.8-66.2%, depending on the year. The absence of ovipositing females in disrupted plots in the autumn of the second and third year indicates the effectiveness of mating disruption throughout the whole growing season. Mating disruption consistently prolonged the pre-oviposition period in all years by up to 12.5 days. Our findings provide new insights into the mechanisms underlying the pheromone-based control of the vine mealybug and indicate that the reduction of the pest population density is due to both a decrease and delay in female mating. In addition, the population density of vine mealybugs under mating disruption decreased over years, indicating that consecutive applications of this control strategy would significantly increase the effectiveness of controlling the vine mealybug by mating disruption. This article is protected by copyright. All rights reserved.

USSR Report, Consumer Goods and Domestic Trade, No. 68.

DTIC Science & Technology

1983-06-20

assortment (garments and knitwear , leather footwear and others) they account for more than 70 percent. The possibilities of increasing the warehouse...commodity attributes, spe- cial delivery dates and the labeling of the goods. The assortment should also be specified in a similar fashion in the...steps of pres- sure must be taken against the producer. Here it is necessary to use fully the right, which is granted by the Statute on Deliveries of

An Evaluation of the Proposed Marine Corps Expeditionary Food Service System Concept

DTIC Science & Technology

1982-01-01

81.5 40.4 $ * Test was compromised. ** Combined. Beverapes were purchased already blended; thus no water was required to prepare beverages during this...test. The average water consumption for food preparation, excluding beverages , in each mode for A-ration operations per meal, would be: larre Galley...Bread Apple Crisp Butter Assorted Beverages Chocolate Coconut Pudding Assorted Beverages 23 July Lunch D’.nner Baked Beef and Noodles Spaghetti with

Two-population dynamics in a growing network model

NASA Astrophysics Data System (ADS)

Ivanova, Kristinka; Iordanov, Ivan

2012-02-01

We introduce a growing network evolution model with nodal attributes. The model describes the interactions between potentially violent V and non-violent N agents who have different affinities in establishing connections within their own population versus between the populations. The model is able to generate all stable triads observed in real social systems. In the framework of rate equations theory, we employ the mean-field approximation to derive analytical expressions of the degree distribution and the local clustering coefficient for each type of nodes. Analytical derivations agree well with numerical simulation results. The assortativity of the potentially violent network qualitatively resembles the connectivity pattern in terrorist networks that was recently reported. The assortativity of the network driven by aggression shows clearly different behavior than the assortativity of the networks with connections of non-aggressive nature in agreement with recent empirical results of an online social system.

Heritability analyses of IQ scores: science or numerology?

PubMed

Layzer, D

1974-03-29

Estimates of IQ heritability are subject to a variety of systematic errors. The IQ scores themselves contain uncontrollable, systematic errors of unknown magnitude. These arise because IQ scores, unlike conventional physical and biological measurements, have a purely instrumental definition. The effects of these errors are apparent in the very large discrepancies among IQ correlations measured by different investigators. Genotype-environment correlations, whose effects can sometimes be minimized, if not wholly eliminated, in experiments with plants and animals, are nearly always important in human populations. The absence of significant effects arising from genotype-environment correlations is a necessary condition for the applicability of conventional heritability analysis to phenotypically plastic traits. When this condition fails, no quantitative inferences about heritability can be drawn from measured phenotypic variances and covariances, except under special conditions that are unlikely to be satisfied by phenotypically plastic traits in human populations. Inadequate understanding of the precise environmental factors relevant to the development of specific behavioral traits is an important source of systematic errors, as is the inability to allow adequately for the effects of assortative mating and gene-gene interaction. Systematic cultural differences and differences in psychological environment among races and among sociocco-nomic groups vitiate any attempt to draw from IQ data meaningful inferences about genetic differences. Estimates based on phenotypic correlations between separated monozygotic twins-usually considered to be the most reliable kind of estimates-are vitiated by systematic errors inherent in IQ tests, by the presence of genotype-environment correlation, and by the lack of detailed understanding of environmental factors relevant to the development of behavioral traits. Other kinds of estimates are beset, in addition, by systematic errors arising from incomplete allowance for the effects of assortative mating and from gene-gene interactions. The only potentially useful data are phenotypic correlations between unrelated foster children reared together, which could, in principle, yield lower limits for e(2). Available data indicate that, for unrelated foster children reared together, the broad heritability (h(2)) may lie between 0.0 and 0.5. This estimate does not apply to populations composed of children reared by their biological parents or by near relatives. For such populations the heritability of IQ remains undefined. The only data that might yield meaningful estimates ot narrow heritability are phenotypic correlations between half-sibs reared in statistically independent environments. No useful data of this kind are available. Intervention studies like Heber's Milwaukee Project afford an alternative and comparatively direct way of studying the plasticity of cognitive and other behavioral traits in human populations. Results obtained so far strongly suggest that the development of cognitive skills is highly sensitive to variations in environmental factors. These conclusions have three obvious implications for the broader issues mentioned at the beginning of this article. 1) Published analyses of IQ data provide no support whatever for Jensen's thesis that inequalities in cognitive performance are due largely to genetic differences. As Lewontin (8) has clearly shown, the value of the broad heritability of IQ is in any case only marginally relevant to this question. I have argued that conventional estimates of the broad heritability of IQ are invalid and that the only data on which potentially valid estimates might be based are consistent with a broad heritability of less than 0.5. On the other hand, intervention studies, if their findings prove to be replicable, would directly establish that, under suitable conditions, the offspring of parents whose cognitive skills are so poorly developed as to exclude them from all but the most menial occupations can achieve what are regarded as distinctly high levels of cognitive performance. Thus, despite the fact that children differ suibstantially in cognitive aptitudes and appetites, and despite the very high probability that these differences have a substantial genetic component, available scientific evidence strongly suggests that environmental factors are responsible for the failure of children not suffering from specific neurological disorders to achieve adequate levels of cognitive performance. 2) Under prevailing social conditions, no valid inferences can be drawn from IQ data concerning systematic genetic differences among races or socioeconomic groups. Research along present lines directed toward this end-whatever its ethical status-is scientifically worthless. 3) Since there are no suitable data for estimating the narrow heritability of IQ, it seems pointless to speculate about the prospects for a hereditary meritocracy based on IQ.

Population-based familial aggregation of eosinophilic esophagitis suggests a genetic contribution.

PubMed

Allen-Brady, Kristina; Firszt, Rafael; Fang, John C; Wong, Jathine; Smith, Ken R; Peterson, Kathryn A

2017-10-01

Prior familial clustering studies have observed an increased risk of eosinophilic esophagitis (EoE) mostly among first-degree relatives, suggesting a genetic contribution to EoE, and twin studies have suggested a powerful contribution from environmental factors. This study sought to clarify the contribution of genetic factors to EoE through estimation of familial aggregation and risk of EoE in extended relatives. The Utah Population Database, a population-based genealogy resource linked to electronic medical records for health care systems across the state of Utah, was used to identify EoE cases and age, sex, and birthplace-matched controls at a 5:1 ratio. Logistic regression was used to determine the odds of EoE among relatives of EoE probands compared with the odds of EoE among relatives of controls. There were 4,423 EoE cases and 24,322 controls. The population-attributable risk of EoE was 31% (95% CI, 28% to 34%), suggesting a relatively strong genetic contribution. Risks of EoE were significantly increased among first-degree relatives (odds ratio [OR], 7.19; 95% CI, 5.65-9.14), particularly first-degree relatives of EoE cases diagnosed <18 years of age (OR, 16.3; 95% CI, 9.4-28.3); second-degree relatives (OR, 1.99; 95% CI, 1.49-2.65); and first cousins (OR, 1.35; 95% CI, 1.03-1.77), providing evidence of a genetic contribution. However, spouses of EoE probands were observed to be at increased risk of EoE (OR, 2.86; 95% CI, 1.31-6.25), suggesting either positive assortative mating or a shared environmental contribution to EoE. This study supports a significant genetic contribution to EoE as evidenced by increased risk of EoE in distant relatives. Copyright © 2017 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Exploring the Genes of Yerba Mate (Ilex paraguariensis A. St.-Hil.) by NGS and De Novo Transcriptome Assembly

PubMed Central

Aguilera, Patricia M.; Bubillo, Rosana E.; Otegui, Mónica B.; Ducasse, Daniel A.; Zapata, Pedro D.; Marti, Dardo A.

2014-01-01

Yerba mate (Ilex paraguariensis A. St.-Hil.) is an important subtropical tree crop cultivated on 326,000 ha in Argentina, Brazil and Paraguay, with a total yield production of more than 1,000,000 t. Yerba mate presents a strong limitation regarding sequence information. The NCBI GenBank lacks an EST database of yerba mate and depicts only 80 DNA sequences, mostly uncharacterized. In this scenario, in order to elucidate the yerba mate gene landscape by means of NGS, we explored and discovered a vast collection of I. paraguariensis transcripts. Total RNA from I. paraguariensis was sequenced by Illumina HiSeq-2000 obtaining 72,031,388 pair-end 100 bp sequences. High quality reads were de novo assembled into 44,907 transcripts encompassing 40 million bases with an estimated coverage of 180X. Multiple sequence analysis allowed us to predict that yerba mate contains ∼32,355 genes and 12,551 gene variants or isoforms. We identified and categorized members of more than 100 metabolic pathways. Overall, we have identified ∼1,000 putative transcription factors, genes involved in heat and oxidative stress, pathogen response, as well as disease resistance and hormone response. We have also identified, based in sequence homology searches, novel transcripts related to osmotic, drought, salinity and cold stress, senescence and early flowering. We have also pinpointed several members of the gene silencing pathway, and characterized the silencing effector Argonaute1. We predicted a diverse supply of putative microRNA precursors involved in developmental processes. We present here the first draft of the transcribed genomes of the yerba mate chloroplast and mitochondrion. The putative sequence and predicted structure of the caffeine synthase of yerba mate is presented. Moreover, we provide a collection of over 10,800 SSR accessible to the scientific community interested in yerba mate genetic improvement. This contribution broadly expands the limited knowledge of yerba mate genes, and is presented as the first genomic resource of this important crop. PMID:25330175

Multi-species mating disruption in Wisconsin cranberries

USDA-ARS?s Scientific Manuscript database

Previous work has shown pheromone-based mating disruption to be a promising method of pest control in cranberries. Three moth species, cranberry fruitworm, Acrobasis vaccinii Riley (Lepidoptera: Pyralidae), Sparganothis fruitworm, Sparganothis sulfureana Clemens (Lepidoptera: Tortricidae), and black...

Status and Mating Success Amongst Visual Artists

PubMed Central

Clegg, Helen; Nettle, Daniel; Miell, Dorothy

2011-01-01

Geoffrey Miller has hypothesized that producing artwork functions as a mating display. Here we investigate the relationship between mating success and artistic success in a sample of 236 visual artists. Initially, we derived a measure of artistic success that covered a broad range of artistic behaviors and beliefs. As predicted by Miller’s evolutionary theory, more successful male artists had more sexual partners than less successful artists but this did not hold for female artists. Also, male artists with greater artistic success had a mating strategy based on longer term relationships. Overall the results provide partial support for the sexual selection hypothesis for the function of visual art. PMID:22059085

Description of a novel mating plug mechanism in spiders and the description of the new species Maeota setastrobilaris (Araneae, Salticidae)

PubMed Central

Garcilazo-Cruz, Uriel; Alvarez-Padilla, Fernando

2015-01-01

Abstract Reproduction in arthropods is an interesting area of research where intrasexual and intersexual mechanisms have evolved structures with several functions. The mating plugs usually produced by males are good examples of these structures where the main function is to obstruct the female genitalia against new sperm depositions. In spiders several types of mating plugs have been documented, the most common ones include solidified secretions, parts of the bulb or in some extraordinary cases the mutilation of the entire palpal bulb. Here, we describe the first case of modified setae, which are located on the cymbial dorsal base, used directly as a mating plug for the Order Araneae in the species Maeota setastrobilaris sp. n. In addition the taxonomic description of Maeota setastrobilaris sp. n. is provided and based on our findings the geographic distribution of this genus is extended to the Northern hemisphere. PMID:26175601

Multiple mating and clutch size in invertebrate brooders versus pregnant vertebrates

PubMed Central

Avise, John C.; Tatarenkov, Andrey; Liu, Jin-Xian

2011-01-01

We summarize the genetic literature on polygamy rates and sire numbers per clutch in invertebrate animals that brood their offspring and then compare findings with analogous data previously compiled for vertebrate species displaying viviparity or other pregnancy-like syndromes. As deduced from molecular parentage analyses of several thousand broods from more than 100 “pregnant” species, invertebrate brooders had significantly higher mean incidences of multiple mating than pregnant vertebrates, a finding generally consistent with the postulate that clutch size constrains successful mate numbers in species with extended parental care. However, we uncovered no significant correlation in invertebrates between brood size and genetically deduced rates of multiple mating by the incubating sex. Instead, in embryo-gestating animals otherwise as different as mammals and mollusks, polygamy rates and histograms of successful mates per brooder proved to be strikingly similar. Most previous studies have sought to understand why gestating parents have so many mates and such high incidences of successful multiple mating; an alternative perspective based on logistical constraints turns the issue on its head by asking why mate numbers and polygamy rates are much lower than they theoretically could be, given the parentage-resolving power of molecular markers and the huge sizes of many invertebrate broods. PMID:21709247

From kissing to belly stridulation: comparative analysis reveals surprising diversity, rapid evolution, and much homoplasy in the mating behaviour of 27 species of sepsid flies (Diptera: Sepsidae).

PubMed

Puniamoorthy, N; Ismail, M R B; Tan, D S H; Meier, R

2009-11-01

Our understanding of how fast mating behaviour evolves in insects is rather poor due to a lack of comparative studies among insect groups for which phylogenetic relationships are known. Here, we present a detailed study of the mating behaviour of 27 species of Sepsidae (Diptera) for which a well-resolved and supported phylogeny is available. We demonstrate that mating behaviour is extremely diverse in sepsids with each species having its own mating profile. We define 32 behavioural characters and document them with video clips. Based on sister species comparisons, we provide several examples where mating behaviour evolves faster than all sexually dimorphic morphological traits. Mapping the behaviours onto the molecular tree reveals much homoplasy, comparable to that observed for third positions of mitochondrial protein-encoding genes. A partitioned Bremer support (PBS) analysis reveals conflict between the molecular and behavioural data, but behavioural characters have higher PBS values per parsimony-informative character than DNA sequence characters.

Genetic evidence for polygynandry in the black-striped pipefish Syngnathus abaster: a microsatellite-based parentage analysis.

PubMed

Hübner, Kerstin; Gonzalez-Wanguemert, Mercedes; Diekmann, Onno E; Serrão, Ester A

2013-01-01

Sexual selection theory predicts that, in organisms with reversed sex roles, more polyandrous species exhibit higher levels of sexual dimorphism. In the family Syngnathidae (pipefish, seahorses, and seadragons), males provide all parental care by carrying developing embryos on their ventral surfaces, and females develop secondary sex characters. Syngnathids exhibit a variety of genetic mating patterns, making them an ideal group to test predictions of sexual selection theory. Here, we describe the mating system of the black-striped pipefish Syngnathus abaster, using 4 highly variable microsatellites to analyze parentage of 102 embryos. Results revealed that 1) both sexes mate multiple times over the course of a pregnancy (polygynandrous mating system), 2) eggs are spatially segregated by maternity within each brood pouch, and 3) larger females have higher mating success (Kolmogorov-Smirnov test; P < 0.05). Together with similar studies of other syngnathid species, our results support the hypothesis that the mating system is related to the intensity of sexual dimorphism.

Genetic quality and sexual selection: an integrated framework for good genes and compatible genes.

PubMed

Neff, Bryan D; Pitcher, Trevor E

2005-01-01

Why are females so choosy when it comes to mating? This question has puzzled and marveled evolutionary and behavioral ecologists for decades. In mating systems in which males provide direct benefits to the female or her offspring, such as food or shelter, the answer seems straightforward--females should prefer to mate with males that are able to provide more resources. The answer is less clear in other mating systems in which males provide no resources (other than sperm) to females. Theoretical models that account for the evolution of mate choice in such nonresource-based mating systems require that females obtain a genetic benefit through increased offspring fitness from their choice. Empirical studies of nonresource-based mating systems that are characterized by strong female choice for males with elaborate sexual traits (like the large tail of peacocks) suggest that additive genetic benefits can explain only a small percentage of the variation in fitness. Other research on genetic benefits has examined nonadditive effects as another source of genetic variation in fitness and a potential benefit to female mate choice. In this paper, we review the sexual selection literature on genetic quality to address five objectives. First, we attempt to provide an integrated framework for discussing genetic quality. We propose that the term 'good gene' be used exclusively to refer to additive genetic variation in fitness, 'compatible gene' be used to refer to nonadditive genetic variation in fitness, and 'genetic quality' be defined as the sum of the two effects. Second, we review empirical approaches used to calculate the effect size of genetic quality and discuss these approaches in the context of measuring benefits from good genes, compatible genes and both types of genes. Third, we discuss biological mechanisms for acquiring and promoting offspring genetic quality and categorize these into three stages during breeding: (i) precopulatory (mate choice); (ii) postcopulatory, prefertilization (sperm utilization); and (iii) postcopulatory, postfertilization (differential investment). Fourth, we present a verbal model of the effect of good genes sexual selection and compatible genes sexual selection on population genetic variation in fitness, and discuss the potential trade-offs that might exist between mate choice for good genes and mate choice for compatible genes. Fifth, we discuss some future directions for research on genetic quality and sexual selection.

After-School Programs. The Progress of Education Reform, 2005. Volume 6, Number 5

ERIC Educational Resources Information Center

Weiss, Suzanne; Ed.

2005-01-01

Opportunities for children and youth to engage in activities during out-of-school hours come in various shapes, sizes and flavors. At one end of the spectrum are highly structured, five-day-a-week, school-based programs focused broadly on encouraging and supporting academic and social development. At the other end are assorted activities and…

Mate choice could be random in female rats (Rattus norvegicus).

PubMed

Le Moëne, Olivia; Snoeren, Eelke M

2018-02-01

Female mate choice is often investigated in terms of reproductive success in order to understand how male characteristics contribute to sexual attractiveness. Previous studies have found that females rats prefer mating with their first encounter rather than males visited subsequently, suggesting that the rewarding value of this first encounter is enough to reinforce mating with the first partner. Using a multiple chambers paradigm, we allowed female rats to copulate freely with three males placed each in a different chamber. Then, we switched the males' position, and let the female interact with them freely again within the same session. We tested whether female mate choice was relying rather on a preferred male rat or on a preferred mating location. The results showed that females spent most time with the male in the chamber of 1st entry in the beginning, but as soon as male rats switched chambers, the female rat continued to copulate with the new male in the same chamber of 1st entry, instead of mating with her previously preferred male rat. This suggests that the male preference is an artefact of location preference. Therefore, female mate choice seems to be rather random than the consequence of an individual choice based on male characteristics. This finding, although contradictory with the intuitive feeling that mate choice is a crucial feature in sexual and reproductive behavior, is supported by several recent observations. In the coming years, behavioral neuroscience should bring light to the brain processes at work in random mate choice. Copyright © 2017 Elsevier Inc. All rights reserved.

Validation of Bateman's principles: a genetic study of sexual selection and mating patterns in the rough-skinned newt.

PubMed Central

Jones, Adam G; Arguello, J Roman; Arnold, Stevan J

2002-01-01

Few studies have influenced thought on the nature of sexual selection to the extent of the classic paper of A. J. Bateman on mating patterns in Drosophila. However, interpretation of his study remains controversial, and a lack of modern empirical evidence prevents a consensus with respect to the perceived utility of Bateman's principles in the study of sexual selection. Here, we use a genetic study of natural mating patterns in the rough-skinned newt, Taricha granulosa, to investigate the concordance between Bateman's principles and the intensity of sexual selection. We found that males experienced strong sexual selection on tail height and body size, while sexual selection was undetectable in females. This direct quantification of sexual selection agreed perfectly with inferences that are based on Bateman's principles. Specifically, males (in comparison with females) exhibited greater standardized variances in reproductive and mating success, as well as a stronger relationship between mating success and reproductive success. Overall, our results illustrate that Bateman's principles provide the only quantitative measures of the mating system with explicit connections to formal selection theory and should be the central focus of studies of mating patterns in natural populations. PMID:12573067

Male wing color properties predict the size of nuptial gifts given during mating in the Pipevine Swallowtail butterfly ( Battus philenor)

NASA Astrophysics Data System (ADS)

Rajyaguru, Parth K.; Pegram, Kimberly V.; Kingston, Alexandra C. N.; Rutowski, Ronald L.

2013-06-01

In many animals, males bear bright ornamental color patches that may signal both the direct and indirect benefits that a female might accrue from mating with him. Here we test whether male coloration in the Pipevine Swallowtail butterfly, Battus philenor, predicts two potential direct benefits for females: brief copulation duration and the quantity of materials the male passes to the female during mating. In this species, males have a bright iridescent blue field on the dorsal hindwing surface, while females have little or no dorsal iridescence. Females preferentially mate with males who display a bright and highly chromatic blue field on their dorsal hindwing. In this study, we show that the chroma of the blue field on the male dorsal hindwing and male body size (forewing length) significantly predict the mass of material or spermatophore that a male forms within the female's copulatory sac during mating. We also found that spermatophore mass correlated negatively with copulation duration, but that color variables did not significantly predict this potential direct benefit. These results suggest that females may enhance the material benefits they receive during mating by mating with males based on the coloration of their dorsal hindwing.

Genetic incompatibility drives mate choice in a parasitic wasp.

PubMed

Thiel, Andra; Weeda, Anne C; de Boer, Jetske G; Hoffmeister, Thomas S

2013-07-30

Allelic incompatibility between individuals of the same species should select for mate choice based on the genetic make-up of both partners at loci that influence offspring fitness. As a consequence, mate choice may be an important driver of allelic diversity. A complementary sex determination (CSD) system is responsible for intraspecific allelic incompatibility in many species of ants, bees, and wasps. CSD may thus favour disassortative mating and in this, resembles the MHC of the vertebrate immune system, or the self-incompatibility (SI) system of higher plants. Here we show that in the monogamous parasitic wasp Bracon brevicornis (Wesmael), females are able to reject partners with incompatible alleles. Forcing females to accept initially rejected partners resulted in sex ratio distortion and partial infertility of offspring. CSD-disassortative mating occurred independent of kin recognition and inbreeding avoidance in our experiment. The fitness consequences of mate choice are directly observable, not influenced by environmental effects, and more severe than in comparable systems (SI or MHC), on individuals as well as at the population level. Our results thus demonstrate the strong potential of female mate choice for maintaining high offspring fitness in this species.

Ultimate Drivers and Proximate Correlates of Polyandry in Predatory Mites

PubMed Central

Schausberger, Peter; Patiño-Ruiz, J. David; Osakabe, Masahiro; Murata, Yasumasa; Sugimoto, Naoya; Uesugi, Ryuji; Walzer, Andreas

2016-01-01

Polyandry is more widespread than anticipated from Bateman’s principle but its ultimate (evolutionary) causes and proximate (mechanistic) correlates are more difficult to pinpoint than those of polygyny. Here, we combined mating experiments, quantification of reproductive traits and microsatellite genotyping to determine the fitness implications of polyandry in two predatory mite species, where males are highly polygynous (up to 45 fertilized females during life), whereas females range from monandry to various polyandry levels. The medium-level polyandrous (up to eight male mates possible) Neoseiulus californicus received clear direct and indirect benefits: multiply mated females produced more offspring with higher survival chances over longer times than singly mated females. In contrast, singly and multiply mated females of the low-level polyandrous (commonly two male mates at maximum) Phytoseiulus persimilis produced similar numbers of offspring having similar survival chances. In both species, multiple mating resulted in mixed offspring paternities, opening the chance for indirect fitness benefits such as enhanced genetic compatibility, complementarity and/or variability. However, the female re-mating likelihood and the paternity chance of non-first male mates were lower in P. persimilis than in N. californicus. Regarding proximate factors, in both species first mating duration and female re-mating likelihood were negatively correlated. Based on occasional fertilization failure of first male mates in P. persimilis, and mixed offspring paternities in both species, we argue that fertilization assurance and the chance to gain indirect fitness benefits are the ultimate drivers of polyandry in P. persimilis, whereas those of N. californicus are higher offspring numbers coupled with enhanced offspring viability and possibly other indirect fitness benefits. Overall, the adaptive significance and proximate events well reflected the polyandry levels. Our study provides a key example for linking behavioral experiments, quantification of reproductive traits and paternity analysis via offspring genotyping to explain the evolution of differing levels of polyandry. PMID:27100395

Ultimate Drivers and Proximate Correlates of Polyandry in Predatory Mites.

PubMed

Schausberger, Peter; Patiño-Ruiz, J David; Osakabe, Masahiro; Murata, Yasumasa; Sugimoto, Naoya; Uesugi, Ryuji; Walzer, Andreas

2016-01-01

Polyandry is more widespread than anticipated from Bateman's principle but its ultimate (evolutionary) causes and proximate (mechanistic) correlates are more difficult to pinpoint than those of polygyny. Here, we combined mating experiments, quantification of reproductive traits and microsatellite genotyping to determine the fitness implications of polyandry in two predatory mite species, where males are highly polygynous (up to 45 fertilized females during life), whereas females range from monandry to various polyandry levels. The medium-level polyandrous (up to eight male mates possible) Neoseiulus californicus received clear direct and indirect benefits: multiply mated females produced more offspring with higher survival chances over longer times than singly mated females. In contrast, singly and multiply mated females of the low-level polyandrous (commonly two male mates at maximum) Phytoseiulus persimilis produced similar numbers of offspring having similar survival chances. In both species, multiple mating resulted in mixed offspring paternities, opening the chance for indirect fitness benefits such as enhanced genetic compatibility, complementarity and/or variability. However, the female re-mating likelihood and the paternity chance of non-first male mates were lower in P. persimilis than in N. californicus. Regarding proximate factors, in both species first mating duration and female re-mating likelihood were negatively correlated. Based on occasional fertilization failure of first male mates in P. persimilis, and mixed offspring paternities in both species, we argue that fertilization assurance and the chance to gain indirect fitness benefits are the ultimate drivers of polyandry in P. persimilis, whereas those of N. californicus are higher offspring numbers coupled with enhanced offspring viability and possibly other indirect fitness benefits. Overall, the adaptive significance and proximate events well reflected the polyandry levels. Our study provides a key example for linking behavioral experiments, quantification of reproductive traits and paternity analysis via offspring genotyping to explain the evolution of differing levels of polyandry.

Model-assisted template extraction SRAF application to contact holes patterns in high-end flash memory device fabrication

NASA Astrophysics Data System (ADS)

Seoud, Ahmed; Kim, Juhwan; Ma, Yuansheng; Jayaram, Srividya; Hong, Le; Chae, Gyu-Yeol; Lee, Jeong-Woo; Park, Dae-Jin; Yune, Hyoung-Soon; Oh, Se-Young; Park, Chan-Ha

2018-03-01

Sub-resolution assist feature (SRAF) insertion techniques have been effectively used for a long time now to increase process latitude in the lithography patterning process. Rule-based SRAF and model-based SRAF are complementary solutions, and each has its own benefits, depending on the objectives of applications and the criticality of the impact on manufacturing yield, efficiency, and productivity. Rule-based SRAF provides superior geometric output consistency and faster runtime performance, but the associated recipe development time can be of concern. Model-based SRAF provides better coverage for more complicated pattern structures in terms of shapes and sizes, with considerably less time required for recipe development, although consistency and performance may be impacted. In this paper, we introduce a new model-assisted template extraction (MATE) SRAF solution, which employs decision tree learning in a model-based solution to provide the benefits of both rule-based and model-based SRAF insertion approaches. The MATE solution is designed to automate the creation of rules/templates for SRAF insertion, and is based on the SRAF placement predicted by model-based solutions. The MATE SRAF recipe provides optimum lithographic quality in relation to various manufacturing aspects in a very short time, compared to traditional methods of rule optimization. Experiments were done using memory device pattern layouts to compare the MATE solution to existing model-based SRAF and pixelated SRAF approaches, based on lithographic process window quality, runtime performance, and geometric output consistency.

The Space Shuttle Atlantis is towed from the runway at Edwards Air Force Base to NASA Dryden's Mate-Demate Device (MDD) for post-flight processing

NASA Image and Video Library

2007-06-22

Following its landing on June 22, 2007, the Space Shuttle Atlantis is towed from the runway at Edwards Air Force Base to NASA Dryden's Mate-Demate Device (MDD) for post-flight processing in preparation for its return to the Kennedy Space Center in Florida.

Genome-wide estimates of inbreeding in unrelated individuals and their association with cognitive ability.

PubMed

Power, Robert A; Nagoshi, Craig; DeFries, John C; Plomin, Robert

2014-03-01

The consequence of reduced cognitive ability from inbreeding has long been investigated, mainly restricted to cousin-cousin marriages. Molecular genetic techniques now allow us to test the relationship between increased ancestral inbreeding and cognitive ability in a population of traditionally unrelated individuals. In a representative UK sample of 2329 individuals, we used genome-wide SNP data to estimate the percentage of the genome covered by runs of homozygous SNPs (ROH). This was tested for association with general cognitive ability, as well as measures of verbal and non-verbal ability. Further, association was tested between these traits and specific ROH. Burden of ROH was not associated with cognitive ability after correction for multiple testing, although burden of ROH was nominally associated with increased non-verbal cognitive ability (P=0.03). Moreover, although no individual ROH was significantly associated with cognitive ability, there was a significant bias towards increased cognitive ability in carriers of ROH (P=0.002). A potential explanation for these results is increased positive assortative mating in spouses with higher cognitive ability, although we found no evidence in support of this hypothesis in a separate sample. Reduced minor allele frequency across the genome was associated with higher cognitive ability, which could contribute to an apparent increase in ROH. This may reflect minor alleles being more likely to be deleterious.

Measuring quantitative autism traits in families: informant effect or intergenerational transmission?

PubMed

De la Marche, Wouter; Noens, Ilse; Kuppens, Sofie; Spilt, Jantine L; Boets, Bart; Steyaert, Jean

2015-04-01

Autism spectrum disorders (ASD) have a high degree of heritability, but there is still much debate about specific causal genes and pathways. To gain insight into patterns of transmission, research has focused on the relatedness of quantitative autism traits (QAT) between family members, mostly using questionnaires. Yet, different kinds of bias may influence research results. In this paper, we focus on possible informant effects and, taking these into account, on possible intergenerational transmission of QAT. This study used multiple informant data retrieved via the Social Responsiveness Scale from 170 families with at least one member with ASD. Using intraclass correlations (ICCs) and mixed model analyses, we investigated inter-informant agreement and differences between parent and teacher reports on children and between self- and other-reports on adults. Using structural equation modelling (SEM), we investigated the relatedness of QAT between family members in ASD families. Parent-teacher agreement about social responsiveness was poor, especially for children with ASD, though agreement between parents was moderate to strong for affected and unaffected children. Agreement between self- and other-report in adult men was good, but only moderate in women. Agreement did not differ between adults with and without ASD. While accounting for informant effects, our SEM results corroborated the assortative mating theory and the intergenerational transmission of QAT from both fathers and mothers to their offspring.

Genome-wide estimates of inbreeding in unrelated individuals and their association with cognitive ability

PubMed Central

Power, Robert A; Nagoshi, Craig; DeFries, John C; Donnelly, Peter; Barroso, Ines; Blackwell, Jenefer M; Bramon, Elvira; Brown, Matthew A; Casas, Juan P; Corvin, Aiden; Deloukas, Panos; Duncanson, Audrey; Jankowski, Janusz; Markus, Hugh S; Mathew, Christopher G; Palmer, Colin NA; Plomin, Robert; Rautanen, Anna; Sawcer, Stephen J; Trembath, Richard C; Viswanathan, Ananth C; Wood, Nicholas W; Spencer, Chris C A; Band, Gavin; Bellenguez, Céline; Freeman, Colin; Hellenthal, Garrett; Giannoulatou, Eleni; Pirinen, Matti; Pearson, Richard; Strange, Amy; Su, Zhan; Vukcevic, Damjan; Donnelly, Peter; Langford, Cordelia; Hunt, Sarah E; Edkins, Sarah; Gwilliam, Rhian; Blackburn, Hannah; Bumpstead, Suzannah J; Dronov, Serge; Gillman, Matthew; Gray, Emma; Hammond, Naomi; Jayakumar, Alagurevathi; McCann, Owen T; Liddle, Jennifer; Potter, Simon C; Ravindrarajah, Radhi; Ricketts, Michelle; Waller, Matthew; Weston, Paul; Widaa, Sara; Whittaker, Pamela; Barroso, Ines; Deloukas, Panos; Mathew, Christopher G; Blackwell, Jenefer M; Brown, Matthew A; Corvin, Aiden; Spencer, Chris C A; Plomin, Robert

2014-01-01

The consequence of reduced cognitive ability from inbreeding has long been investigated, mainly restricted to cousin–cousin marriages. Molecular genetic techniques now allow us to test the relationship between increased ancestral inbreeding and cognitive ability in a population of traditionally unrelated individuals. In a representative UK sample of 2329 individuals, we used genome-wide SNP data to estimate the percentage of the genome covered by runs of homozygous SNPs (ROH). This was tested for association with general cognitive ability, as well as measures of verbal and non-verbal ability. Further, association was tested between these traits and specific ROH. Burden of ROH was not associated with cognitive ability after correction for multiple testing, although burden of ROH was nominally associated with increased non-verbal cognitive ability (P=0.03). Moreover, although no individual ROH was significantly associated with cognitive ability, there was a significant bias towards increased cognitive ability in carriers of ROH (P=0.002). A potential explanation for these results is increased positive assortative mating in spouses with higher cognitive ability, although we found no evidence in support of this hypothesis in a separate sample. Reduced minor allele frequency across the genome was associated with higher cognitive ability, which could contribute to an apparent increase in ROH. This may reflect minor alleles being more likely to be deleterious. PMID:23860046

Spawning behaviour of Allis shad Alosa alosa: new insights based on imaging sonar data.

PubMed

Langkau, M C; Clavé, D; Schmidt, M B; Borcherding, J

2016-06-01

Spawning behaviour of Alosa alosa was observed by high resolution imaging sonar. Detected clouds of sexual products and micro bubbles served as a potential indicator of spawning activity. Peak spawning time was between 0130 and 0200 hours at night. Increasing detections over three consecutive nights were consistent with sounds of mating events (bulls) assessed in hearing surveys in parallel to the hydro acoustic detection. In 70% of the analysed mating events there were no additional A. alosa joining the event whilst 70% of the mating events showed one or two A. alosa leaving the cloud. In 31% of the analysed mating events, however, three or more A. alosa were leaving the clouds, indicating that matings are not restricted to a pair. Imaging sonar is suitable for monitoring spawning activity and behaviour of anadromous clupeids in their spawning habitats. © 2016 The Fisheries Society of the British Isles.

Pest persistence and eradication conditions in a deterministic model for sterile insect release.

PubMed

Gordillo, Luis F

2015-01-01

The release of sterile insects is an environment friendly pest control method used in integrated pest management programmes. Difference or differential equations based on Knipling's model often provide satisfactory qualitative descriptions of pest populations subject to sterile release at relatively high densities with large mating encounter rates, but fail otherwise. In this paper, I derive and explore numerically deterministic population models that include sterile release together with scarce mating encounters in the particular case of species with long lifespan and multiple matings. The differential equations account separately the effects of mating failure due to sterile male release and the frequency of mating encounters. When insects spatial spread is incorporated through diffusion terms, computations reveal the possibility of steady pest persistence in finite size patches. In the presence of density dependence regulation, it is observed that sterile release might contribute to induce sudden suppression of the pest population.

Mate-sampling costs and sexy sons.

PubMed

Kokko, H; Booksmythe, I; Jennions, M D

2015-01-01

Costly female mating preferences for purely Fisherian male traits (i.e. sexual ornaments that are genetically uncorrelated with inherent viability) are not expected to persist at equilibrium. The indirect benefit of producing 'sexy sons' (Fisher process) disappears: in some models, the male trait becomes fixed; in others, a range of male trait values persist, but a larger trait confers no net fitness advantage because it lowers survival. Insufficient indirect selection to counter the direct cost of producing fewer offspring means that preferences are lost. The only well-cited exception assumes biased mutation on male traits. The above findings generally assume constant direct selection against female preferences (i.e. fixed costs). We show that if mate-sampling costs are instead derived based on an explicit account of how females acquire mates, an initially costly mating preference can coevolve with a male trait so that both persist in the presence or absence of biased mutation. Our models predict that empirically detecting selection at equilibrium will be difficult, even if selection was responsible for the location of the current equilibrium. In general, it appears useful to integrate mate sampling theory with models of genetic consequences of mating preferences: being explicit about the process by which individuals select mates can alter equilibria. © 2014 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

Hotshots, hotspots, and female preference in the organization of lek mating systems

USGS Publications Warehouse

Beehler, B.M.; Foster, M.S.

1988-01-01

We critically review the female-preference and hotspot models, the two most widely accepted recent explanations of lek organization. On the basis of what we believe are the inadequacies of these models-too great a reliance on the presumed acuity of female discrimination, the assumption that females have full freedom of choice within the lek, and insufficient recognition of the importance of male-male interactions-we develop an alternative set of hypotheses, which we call the hotshot model, to explain the development and maintenance of lek behavior. Our model attributes strong male mating skew to the interaction between (1) simplified and conservative mating rules of females and (2) social dominance among males. We demonstrate the importance of male-male dominance relationships in lek and non-lek court mating systems. We then argue that a strong mating skew among males forces novice males entering a population to adopt a long-term mating strategy that involves delayed breeding (floating) and subordinate lek behavior. The structure of leks is created by a complex of malemale interactions, with conflict between hotshots (who attempt to control lek mating) and subordinates, who may benefit from disrupting lek activities. Explanations for the number of males in an arena and inter-arena distances are based on modifications of the hotspot and female-preference models. We suggest specific field tests to help distinguish which hypothesis best models the behavioral interactions that produce lek mating.

Effects of Cyclic Feeding and Starvation, Mating, and Sperm Condition on Egg Production and Fertility in the Common Bed Bug (Hemiptera: Cimicidae).

PubMed

Matos, Yvonne K; Osborne, Jason A; Schal, Coby

2017-11-07

Bed bugs (Cimex lectularius L.) are now endemic in most major cities, but information regarding their basic biology is still largely based on research done over four decades ago. We investigated the effects of starvation, mating, sperm storage, and female and male age on egg production and hatch. Egg production cycles varied with the number of bloodmeals that females received. Once-mated females fed every 5 d had constant egg production for ∼75 d followed by a monotonic decline to near zero. Percentage egg hatch was high and constant, but declined after ∼30 d to near zero. To determine whether the age of the female, male, or sperm affected these patterns, we mated newly eclosed females to 60-d-old virgin males, 60-d-old mated males, or newly eclosed males. Females produced the most eggs when mated to young males, followed by old mated males, and then old virgin males; percentage hatch followed a similar pattern, suggesting that sperm stored within males for long was deficient. To examine effects of sperm stored within females, we mated newly eclosed females, starved them for 30 or 60 d, then fed them every 5 d. The 60-d starved group produced fewer eggs than the 30-d starved group, and both produced fewer eggs than young females mated to old or young males. Longer periods of sperm storage within females caused lower corresponding percentage hatch. These findings indicate egg production and hatch are governed by complex interactions among female and male age, frequency of feeding and mating, and sperm condition. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Effects of polygamy on the activity/rest rhythm of male fruit flies Drosophila melanogaster

NASA Astrophysics Data System (ADS)

Vartak, Vivek Rohidas; Varma, Vishwanath; Sharma, Vijay Kumar

2015-02-01

Although polygamy is common in insects, its extent varies enormously among natural populations. Mating systems influence the evolution of reproductive traits and the difference in extent of polygamy between males and females may be a key factor in determining traits which come under the influence of sexual selection. Fruit flies Drosophila melanogaster are promiscuous as both males and females mate with multiple partners. Mating has severe consequences on the physiology and behaviour of flies, and it affects their activity/rest rhythm in a sex-specific manner. In this study, we attempted to discern the effects of mating with multiple partners as opposed to a single partner, or of remaining unmated, on the activity/rest rhythm of flies under cyclic semi-natural (SN) and constant dark (DD) conditions. The results revealed that while evening activity of mated flies was significantly reduced compared to virgins, polygamous males showed a more severe reduction compared to monogamous males. In contrast, though mated females showed reduction in evening activity compared to virgins, activity levels were not different between polygamous and monogamous females. Although there was no detectable effect of mating on clock period, power of the activity/rest rhythm was significantly reduced in mated females with no difference seen between polygamous and monogamous individuals. These results suggest that courtship motivation, represented by evening activity, is successively reduced in males due to mating with one or more partners, while in females, it does not depend on the number of mating partners. Based on these results we conclude that polygamy affects the activity/rest rhythm of fruit flies D. melanogaster in a sex-dependent manner.

An Assessment of a Beowulf System for a Wide Class of Analysis and Design Software

NASA Technical Reports Server (NTRS)

Katz, D. S.; Cwik, T.; Kwan, B. H.; Lou, J. Z.; Springer, P. L.; Sterling, T. L.; Wang, P.

1997-01-01

A typical Beowulf system, such as the machine at the Jet Propulsion Laboratory (JPL), may comprise 16 nodes interconnected by 100 base T Fast Ethernet. Each node may include a single Inter Pentium Pro 200 MHz microprocessor, 128 MBytes of DRAM, 2.5 GBytes of IDE disk, and PCI bus backplane, and an assortment of other devices.

Using computerised decision support to improve compliance of cancer multidisciplinary meetings with evidence-based guidance

PubMed Central

Patkar, Vivek; Acosta, Dionisio; Davidson, Tim; Jones, Alison; Fox, John

2012-01-01

Objectives The cancer multidisciplinary team (MDT) meeting (MDM) is regarded as the best platform to reduce unwarranted variation in cancer care through evidence-compliant management. However, MDMs are often overburdened with many different agendas and hence struggle to achieve their full potential. The authors developed an interactive clinical decision support system called MATE (Multidisciplinary meeting Assistant and Treatment sElector) to facilitate explicit evidence-based decision making in the breast MDMs. Design Audit study and a questionnaire survey. Setting Breast multidisciplinary unit in a large secondary care teaching hospital. Participants All members of the breast MDT at the Royal Free Hospital, London, were consulted during the process of MATE development and implementation. The emphasis was on acknowledging the clinical needs and practical constraints of the MDT and fitting the system around the team's workflow rather than the other way around. Delegates, who attended MATE workshop at the England Cancer Networks' Development Programme conference in March 2010, participated in the questionnaire survey. Outcome measures The measures included evidence-compliant care, measured by adherence to clinical practice guidelines, and promoting research, measured by the patient identification rate for ongoing clinical trials. Results MATE identified 61% more patients who were potentially eligible for recruitment into clinical trials than the MDT, and MATE recommendations demonstrated better concordance with clinical practice guideline than MDT recommendations (97% of MATE vs 93.2% of MDT; N=984). MATE is in routine use in breast MDMs at the Royal Free Hospital, London, and wider evaluations are being considered. Conclusions Sophisticated decision support systems can enhance the conduct of MDMs in a way that is acceptable to and valued by the clinical team. Further rigorous evaluations are required to examine cost-effectiveness and measure the impact on patient outcomes. The decision support technology used in MATE is generic and if found useful can be applied across medicine. PMID:22734113

Performance measures from the explorer platform berthing experiment

NASA Technical Reports Server (NTRS)

Leake, Stephen

1993-01-01

The Explorer Platform is a Modular Mission Spacecraft: it has several subunits that are designed to be replaced on orbit. The Goddard Space Flight Center Robotics Lab undertook an experiment to evaluate various robotic approaches to replacing one of the units; a large (approximately 1 meter by 1 meter by 0.5 meter) power box. The hardware consists of a Robotics Research Corporation K-1607 (RRC) manipulator mounted on a large gantry robot, a Kraft handcontroller for teleoperation of RRC, a Lightweight Servicing Tool (LST) mounted on the RRC, and an Explorer Platform mockup (EP) with a removable box (MMS) that has fixtures that mate with the LST. Sensors include a wrist wrench sensor on the RRC and Capaciflectors mounted on the LST and the MMS. There are also several cameras, but no machine vision is used. The control system for the RRC is entirely written by Goddard; it consists of Ada code on three Multibus I 386/387 CPU boards doing the real-time robot control, and C on a 386 PC processing Capaciflector data. The gantry is not moved during this experiment. The task is the exchange of the MMS; it is removed and replaced. This involves four basic steps: mating the LST to the MMS, demating the MMS from the EP, mating the MMS to the EP, and demating the LST form the MMS. Each of the mating steps must be preceeded by an alignment to bring the mechanical fixtures within their capture range. Two basic approaches to alignment are explored: teleoperation with the operator viewing thru cameras, and Capaciflector based autonomy. To evaluate the two alignment approaches, several runs were run with each approach and the final pose was recorded. Comparing this to the ideal alignment pose gives accuracy and repeatability data. In addition the wrenches exerted during the mating tasks were recorded; this gives information on how the alignment step affects the mating step. There are also two approaches to mating; teleoperation, and impedance based autonomy. The wrench data taken during mating using these two approaches is used to evaluate them. Section 2 describes the alignment results, section 3 describes the mating results, and finally Section 4 gives some conclusions.

Male but not female olfaction is crucial for intermolt mating in European lobsters (Homarus gammarus L.).

PubMed

Skog, Malin

2009-02-01

Chemical signals are common in most crustacean social interactions and are often perceived via chemosensory (olfactory) organs on the first antenna. Intermolt courtship behaviors and mating were investigated in size-matched pairs of intermolt European lobsters (Homarus gammarus) where the olfactory receptors of either the male or the female were lesioned with distilled water (olfactory ablation) or seawater (control). Matings or advanced male courtship behaviors (mounting and turning) were common in seawater controls and olfactory-ablated females. In contrast, when male olfaction was ablated with distilled water, there was not a single mating, and the only male courtship behaviors seen were a few very brief and unsuccessful mounting attempts. Individual females mated up to 5 times with different males, showing that previously inseminated females were still attractive to males. Thus, male but not female olfaction is crucial for intermolt mating in H. gammarus, indicating the presence of a female sex pheromone during the entire female molt cycle, not only at the time of molting. Female sex discrimination may be based on other cues from the male in combination with typical male behaviors.

Mating systems and sexual selection in male-pregnant pipefishes and seahorses: insights from microsatellite-based studies of maternity.

PubMed

Jones, A G; Avise, J C

2001-01-01

In pipefishes and seahorses (family Syngnathidae), the males provide all postzygotic care of offspring by brooding embryos on their ventral surfaces. In some species, this phenomenon of male "pregnancy" results in a reversal of the usual direction of sexual selection, such that females compete more than males for access to mates, and secondary sexual characteristics evolve in females. Thus the syngnathids can provide critical tests of theories related to the evolution of sex differences and sexual selection. Microsatellite-based studies of the genetic mating systems of several species of pipefishes and seahorses have provided insights into important aspects of the natural history and evolution of these fishes. First, males of species with completely enclosed pouches have complete confidence of paternity, as might be predicted from parental investment theory for species in which males invest so heavily in offspring. Second, a wide range of genetic mating systems have been documented in nature, including genetic monogamy in a seahorse, polygynandry in two species of pipefish, and polyandry in a third pipefish species. The genetic mating systems appear to be causally related to the intensity of sexual selection, with secondary sex characters evolving most often in females of the more polyandrous species. Third, genetic studies of captive-breeding pipefish suggest that the sexual selection gradient (or Bateman gradient) may be a substantially better method for characterizing the mating system than previously available techniques. Finally, these genetic studies of syngnathid mating systems have led to some general insights into the occurrence of clustered mutations at microsatellite loci, the utility of linked loci in studies of parentage, and the use of parentage data for direct estimation of adult population size.

Prenatal development of the agouti (Dasyprocta prymnolopha Wagler, 1831): External features and growth curves.

PubMed

Fortes, Eunice Anita de Moura; Ferraz, Maíra Soares; Bezerra, Dayseanny Oliveira; Júnior, Aírton Mendes Conde; Cabral, Rosa Maria; Sousa, Francisco das Chagas Araújo; Almeida, Hatawa Melo; Pessoa, Gerson Tavares; Menezes, Danilo José Ayres de; Guerra, Sérgio Paulo Lima; Sampaio, Ivan Barbosa Machado; Assis Neto, Antônio Chaves; Carvalho, Maria Acelina Martins de

2013-08-01

The gestation period in agoutis can range from 104 to 120 days. Knowledge regarding the morphological characteristics of embryos and fetuses is important as a base for studies in reproduction biotechnology, such as in vitro fertilization, embryo transfer and helps in determining congenital anomalies during the development phase. Thus, given the importance and lack of information about agouti embryology, the objective of this study was to characterize the external morphology and define the biometry of embryos and fetuses, at different days of development. Nine females were submitted to daily colpocytology to identify the estrus, confirm mating and identify day zero of the gestation. When the mating was confirmed they were weighed, underwent abdominal ultrasonography and surgery was conducted on the females at the gestational ages of 25, 30, 35, 40, 45, 50, 75 and 100 days. Sixteen embryos/fetuses were weighed and measured. Agouti embryos at 25 days after mating are "C" shaped, with primitive structures, 0.4±0.01cm crown-rump and weighed 0.06±0.01g; at 30 days after mating the crown-rump was 0.95±0.07cm and weighed 0.28±0.00g; at 35 days after mating the crown-rump was 155±0.07cm and weighed 0.38±0.01g; at 40 days after mating the crown-rump was 2.25±0.21cm and weighed 1.25±0.07g; at 45 days after mating the crown-rump was 3.45±0.35cm and weighed 2.75±0.64g; at 50 days after mating the crown-rump was 5.0±0.3cm and weighed 7.01±2.6g; at 75 days after mating, the skin was dark, the crown-rump was 10.0±0.14cm and weighed 55.2±0.07g. At 100 days after mating, the crown-rump was 13.8±0.49cm and fetuses weighed 136.7±9.40g. Based on the morphological data assessed the embryo and fetus age could be assessed and the size and average weight of agouti embryos was established. Copyright © 2013 Elsevier B.V. All rights reserved.

Sexual communication in Tephritidae-current knowledge and potential applications for integrated pest management

USDA-ARS?s Scientific Manuscript database

Diptera Tephritidae are an enormous threat to fruit and vegetable production throughout the world, causing both quantitative and qualitative losses. Investigating mating behavioural sequences could help to unravel mate choice dynamics, adding useful information to build behaviour-based control strat...

Characterization of Phytophthora infestans populations in northwestern Algeria during 2008-2014.

PubMed

Rekad, Fatma Zohra; Cooke, David Edward Llewelyn; Puglisi, Ivana; Randall, Eva; Guenaoui, Yamina; Bouznad, Zouaoui; Evoli, Maria; Pane, Antonella; Schena, Leonardo; Magnano di San Lio, Gaetano; Cacciola, Santa Olga

2017-05-01

A total of 161 Phytophthora infestans isolates, collected from infected potato and tomato plants during 2008-2014, were characterized based on mating type, metalaxyl sensitivity and polymorphism at 12 simple sequence repeat (SSR) loci, in order to investigate the population of P. infestans in the north-west of Algeria, an emerging potato production region. The majority of isolates were of A2 mating type (112 isolates). A high percentage (89 %) of resistance to metalaxyl among isolates was detected. The metalaxyl resistant phenotype was present in both mating types with a higher percentage in A2 mating type isolates. SSR-based genotypic analysis of P. infestans population showed a low diversity. Genotype 13_A2 was the predominant in the population with a frequency of 67 % followed by 2_A1 (21 %) and 23_A1 (5 %). Genotype 23_A1 was detected only in tomato and potato isolates collected in 2013 and 2014. Copyright © 2017 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

Grandmothering life histories and human pair bonding.

PubMed

Coxworth, James E; Kim, Peter S; McQueen, John S; Hawkes, Kristen

2015-09-22

The evolution of distinctively human life history and social organization is generally attributed to paternal provisioning based on pair bonds. Here we develop an alternative argument that connects the evolution of human pair bonds to the male-biased mating sex ratios that accompanied the evolution of human life history. We simulate an agent-based model of the grandmother hypothesis, compare simulated sex ratios to data on great apes and human hunter-gatherers, and note associations between a preponderance of males and mate guarding across taxa. Then we explore a recent model that highlights the importance of mating sex ratios for differences between birds and mammals and conclude that lessons for human evolution cannot ignore mammalian reproductive constraints. In contradiction to our claim that male-biased sex ratios are characteristically human, female-biased ratios are reported in some populations. We consider the likelihood that fertile men are undercounted and conclude that the mate-guarding hypothesis for human pair bonds gains strength from explicit links with our grandmothering life history.

Seminal fluid protein depletion and replenishment in the fruit fly, Drosophila melanogaster: an ELISA-based method for tracking individual ejaculates

PubMed Central

Sirot, Laura K.; Wolfner, Mariana F.

2014-01-01

In many species, seminal fluid proteins (SFPs) affect female post-mating behavioral patterns, including sperm storage, egg laying, feeding, and remating. Yet, few studies have investigated the patterns of allocation, depletion, and replenishment of SFPs in male animals, despite the importance of these proteins to male and female reproductive success. To investigate such SFP dynamics, it is necessary to have a sensitive method for quantifying SFP levels in males and mated females. We developed such a method by adapting the enzyme-linked immunosorbent assay (ELISA) using anti-SFP antibodies. Here, we first use two Drosophila melanogaster SFPs (ovulin and sex peptide) to demonstrate that ELISAs provide accurate measures of SFP levels. We find that, consistent with previous data from Western blotting or immunofluorescence studies, levels of both ovulin and sex peptide decline in the mated female with time since mating, but they do so at different rates. We then use ELISAs to show that males become depleted of SFPs with repeated matings, but that previously mated males are able to transfer “virgin” levels of SFPs after 3 days of sexual inactivity. Finally, we demonstrate that ELISAs can detect SFPs from wild-caught D. melanogaster males and, thus, potentially can be used to track mating patterns in the wild. This method of measuring SFP dynamics can be used in a wide range of species to address questions related to male reproductive investment, female mating history, and variation in female post-mating behavioral changes. PMID:24733957

Pheromonal Cues Deposited by Mated Females Convey Social Information about Egg-Laying Sites in Drosophila Melanogaster.

PubMed

Duménil, Claire; Woud, David; Pinto, Francesco; Alkema, Jeroen T; Jansen, Ilse; Van Der Geest, Anne M; Roessingh, Sanne; Billeter, Jean-Christophe

2016-03-01

Individuals can make choices based on information learned from others, a phenomenon called social learning. How observers differentiate between which individual they should or should not learn from is, however, poorly understood. Here, we showed that Drosophila melanogaster females can influence the choice of egg-laying site of other females through pheromonal marking. Mated females mark territories of high quality food by ejecting surplus male sperm containing the aggregation pheromone cis-11-vaccenyl acetate (cVA) and, in addition, deposit several sex- and species-specific cuticular hydrocarbon (CHC) pheromones. These pheromonal cues affect the choices of other females, which respond by preferentially laying eggs on the marked food. This system benefits both senders and responders, as communal egg laying increases offspring survival. Virgin females, however, do not elicit a change in the egg-laying decision of mated females, even when food has been supplemented with ejected sperm from mated females, thus indicating the necessity for additional cues. Genetic ablation of either a female's CHC pheromones or those of their mate results in loss of ability of mated females to attract other females. We conclude that mated females use a pheromonal marking system, comprising cVA acquired from male ejaculate with sex- and species-specific CHCs produced by both mates, to indicate egg-laying sites. This system ensures information reliability because mated, but not virgin, females have both the ability to generate the pheromone blend that attracts other flies to those sites and a direct interest in egg-laying site quality.

Games among relatives revisited.

PubMed

Allen, Benjamin; Nowak, Martin A

2015-08-07

We present a simple model for the evolution of social behavior in family-structured, finite sized populations. Interactions are represented as evolutionary games describing frequency-dependent selection. Individuals interact more frequently with siblings than with members of the general population, as quantified by an assortment parameter r, which can be interpreted as "relatedness". Other models, mostly of spatially structured populations, have shown that assortment can promote the evolution of cooperation by facilitating interaction between cooperators, but this effect depends on the details of the evolutionary process. For our model, we find that sibling assortment promotes cooperation in stringent social dilemmas such as the Prisoner's Dilemma, but not necessarily in other situations. These results are obtained through straightforward calculations of changes in gene frequency. We also analyze our model using inclusive fitness. We find that the quantity of inclusive fitness does not exist for general games. For special games, where inclusive fitness exists, it provides less information than the straightforward analysis. Copyright © 2015 Elsevier Ltd. All rights reserved.

Artificial selection reveals sex differences in the genetic basis of sexual attractiveness.

PubMed

Gosden, Thomas P; Reddiex, Adam J; Chenoweth, Stephen F

2018-05-07

Mutual mate choice occurs when males and females base mating decisions on shared traits. Despite increased awareness, the extent to which mutual choice drives phenotypic change remains poorly understood. When preferences in both sexes target the same traits, it is unclear how evolution will proceed and whether responses to sexual selection from male choice will match or oppose responses to female choice. Answering this question is challenging, as it requires understanding, genetic relationships between the traits targeted by choice, mating success, and, ultimately, fitness for both sexes. Addressing this, we applied artificial selection to the cuticular hydrocarbons of the fly Drosophila serrata that are targeted by mutual choice and tracked evolutionary changes in males and females alongside changes in mating success. After 10 generations, significant trait evolution occurred in both sexes, but intriguingly there were major sex differences in the associated fitness consequences. Sexually selected trait evolution in males led to a genetically based increase in male mating success. By contrast, although trait evolution also occurred in females, there was no change in mating success. Our results suggest that phenotypic sexual selection on females from male choice is environmentally, rather than genetically, generated. Thus, compared with female choice, male choice is at best a weak driver of signal trait evolution in this species. Instead, the evolution of apparent female ornamentation seems more likely due to a correlated response to sexual selection on males and possibly other forms of natural selection.

QTLs Regulating the Contents of Antioxidants, Phenolics, and Flavonoids in Soybean Seeds Share a Common Genomic Region.

PubMed

Li, Man-Wah; Muñoz, Nacira B; Wong, Chi-Fai; Wong, Fuk-Ling; Wong, Kwong-Sen; Wong, Johanna Wing-Hang; Qi, Xinpeng; Li, Kwan-Pok; Ng, Ming-Sin; Lam, Hon-Ming

2016-01-01

Soybean seeds are a rich source of phenolic compounds, especially isoflavonoids, which are important nutraceuticals. Our study using 14 wild- and 16 cultivated-soybean accessions shows that seeds from cultivated soybeans generally contain lower total antioxidants compared to their wild counterparts, likely an unintended consequence of domestication or human selection. Using a recombinant inbred population resulting from a wild and a cultivated soybean parent and a bin map approach, we have identified an overlapping genomic region containing major quantitative trait loci (QTLs) that regulate the seed contents of total antioxidants, phenolics, and flavonoids. The QTL for seed antioxidant content contains 14 annotated genes based on the Williams 82 reference genome (Gmax1.01). None of these genes encodes functions that are related to the phenylpropanoid pathway of soybean. However, we found three putative Multidrug And Toxic Compound Extrusion (MATE) transporter genes within this QTL and one adjacent to it (GmMATE1-4). Moreover, we have identified non-synonymous changes between GmMATE1 and GmMATE2, and that GmMATE3 encodes an antisense transcript that expresses in pods. Whether the polymorphisms in GmMATE proteins are major determinants of the antioxidant contents, or whether the antisense transcripts of GmMATE3 play important regulatory roles, awaits further functional investigations.

Social pairing of Seychelles warblers under reduced constraints: MHC, neutral heterozygosity, and age.

PubMed

Wright, David J; Brouwer, Lyanne; Mannarelli, Maria-Elena; Burke, Terry; Komdeur, Jan; Richardson, David S

2016-01-01

The prevalence and significance of precopulatory mate choice remains keenly debated. The major histocompatibility complex (MHC) plays a key role in vertebrate adaptive immunity, and variation at the MHC influences individual survival. Although MHC-dependent mate choice has been documented in certain species, many other studies find no such pattern. This may be, at least in part, because in natural systems constraints may reduce the choices available to individuals and prevent full expression of underlying preferences. We used translocations to previously unoccupied islands to experimentally reduce constraints on female social mate choice in the Seychelles warbler ( Acrocephalus sechellensis ), a species in which patterns of MHC-dependent extrapair paternity (EPP), but not social mate choice, have been observed. We find no evidence of MHC-dependent social mate choice in the new populations. Instead, we find that older males and males with more microsatellite heterozygosity are more likely to have successfully paired. Our data cannot resolve whether these patterns in pairing were due to male-male competition or female choice. However, our research does suggest that female Seychelles warblers do not choose social mates using MHC class I to increase fitness. It may also indicate that the MHC-dependent EPP observed in the source population is probably due to mechanisms other than female precopulatory mate choice based on MHC cues.

Above and beyond short-term mating, long-term mating is uniquely tied to human personality.

PubMed

Holtzman, Nicholas S; Strube, Michael J

2013-12-16

To what extent are personality traits and sexual strategies linked? The literature does not provide a clear answer, as it is based on the Sociosexuality model, a one-dimensional model that fails to measure long-term mating (LTM). An improved two-dimensional model separately assesses long-term and short-term mating (STM; Jackson and Kirkpatrick, 2007). In this paper, we link this two-dimensional model to an array of personality traits (Big 5, Dark Triad, and Schizoid Personality). We collected data from different sources (targets and peers; Study 1), and from different nations (United States, Study 1; India, Study 2). We demonstrate for the first time that, above and beyond STM, LTM captures variation in personality.

Female guppies agree to differ: phenotypic and genetic variation in mate-choice behavior and the consequences for sexual selection.

PubMed

Brooks, R; Endler, J A

2001-08-01

Variation among females in mate choice may influence evolution by sexual selection. The genetic basis of this variation is of interest because the elaboration of mating preferences requires additive genetic variation in these traits. Here we measure the repeatability and heritability of two components of female choosiness (responsiveness and discrimination) and of female preference functions for the multiple ornaments borne by male guppies (Poecilia reticulata). We show that there is significant repeatable variation in both components of choosiness and in some preference functions but not in others. There appear to be several male ornaments that females find uniformly attractive and others for which females differ in preference. One consequence is that there is no universally attractive male phenotype. Only responsiveness shows significant additive genetic variation. Variation in responsiveness appears to mask variation in discrimination and some preference functions and may be the most biologically relevant source of phenotypic and genetic variation in mate-choice behavior. To test the potential evolutionary importance of the phenotypic variation in mate choice that we report, we estimated the opportunity for and the intensity of sexual selection under models of mate choice that excluded and that incorporated individual female variation. We then compared these estimates with estimates based on measured mating success. Incorporating individual variation in mate choice generally did not predict the outcome of sexual selection any better than models that ignored such variation.

Intrasexual competition in females: evidence for sexual selection?

PubMed

Rosvall, Kimberly A

2011-11-01

In spite of recent interest in sexual selection in females, debate exists over whether traits that influence female-female competition are sexually selected. This review uses female-female aggressive behavior as a model behavioral trait for understanding the evolutionary mechanisms promoting intrasexual competition, focusing especially on sexual selection. I employ a broad definition of sexual selection, whereby traits that influence competition for mates are sexually selected, whereas those that directly influence fecundity or offspring survival are naturally selected. Drawing examples from across animal taxa, including humans, I examine 4 predictions about female intrasexual competition based on the abundance of resources, the availability of males, and the direct or indirect benefits those males provide. These patterns reveal a key sex difference in sexual selection: Although females may compete for the number of mates, they appear to compete more so for access to high-quality mates that provide direct and indirect (genetic) benefits. As is the case in males, intrasexual selection in females also includes competition for essential resources required for access to mates. If mate quality affects the magnitude of mating success, then restricting sexual selection to competition for quantity of mates may ignore important components of fitness in females and underestimate the role of sexual selection in shaping female phenotype. In the future, understanding sex differences in sexual selection will require further exploration of the extent of mutual intrasexual competition and the incorporation of quality of mating success into the study of sexual selection in both sexes.

Intrasexual competition in females: evidence for sexual selection?

PubMed Central

2011-01-01

In spite of recent interest in sexual selection in females, debate exists over whether traits that influence female–female competition are sexually selected. This review uses female–female aggressive behavior as a model behavioral trait for understanding the evolutionary mechanisms promoting intrasexual competition, focusing especially on sexual selection. I employ a broad definition of sexual selection, whereby traits that influence competition for mates are sexually selected, whereas those that directly influence fecundity or offspring survival are naturally selected. Drawing examples from across animal taxa, including humans, I examine 4 predictions about female intrasexual competition based on the abundance of resources, the availability of males, and the direct or indirect benefits those males provide. These patterns reveal a key sex difference in sexual selection: Although females may compete for the number of mates, they appear to compete more so for access to high-quality mates that provide direct and indirect (genetic) benefits. As is the case in males, intrasexual selection in females also includes competition for essential resources required for access to mates. If mate quality affects the magnitude of mating success, then restricting sexual selection to competition for quantity of mates may ignore important components of fitness in females and underestimate the role of sexual selection in shaping female phenotype. In the future, understanding sex differences in sexual selection will require further exploration of the extent of mutual intrasexual competition and the incorporation of quality of mating success into the study of sexual selection in both sexes. PMID:22479137

Interspecific aggression, not interspecific mating, drives character displacement in the wing coloration of male rubyspot damselflies (Hetaerina)

PubMed Central

Drury, J. P.; Grether, G. F.

2014-01-01

Traits that mediate intraspecific social interactions may overlap in closely related sympatric species, resulting in costly between-species interactions. Such interactions have principally interested investigators studying the evolution of reproductive isolation via reproductive character displacement (RCD) or reinforcement, yet in addition to reproductive interference, interspecific trait overlap can lead to costly between-species aggression. Previous research on rubyspot damselflies (Hetaerina spp.) demonstrated that sympatric shifts in male wing colour patterns and competitor recognition reduce interspecific aggression, supporting the hypothesis that agonistic character displacement (ACD) drove trait shifts. However, a recent theoretical model shows that RCD overshadows ACD if the same male trait is used for both female mate recognition and male competitor recognition. To determine whether female mate recognition is based on male wing coloration in Hetaerina, we conducted a phenotype manipulation experiment. Compared to control males, male H. americana with wings manipulated to resemble a sympatric congener (H. titia) suffered no reduction in mating success. Thus, female mate recognition is not based on species differences in male wing coloration. Experimental males did, however, experience higher interspecific fighting rates and reduced survival compared to controls. These results greatly strengthen the case for ACD and highlight the mechanistic distinction between ACD and RCD. PMID:25339724

The dilemma of female mate selection in the brown bear, a species with sexually selected infanticide

PubMed Central

Bellemain, Eva; Zedrosser, Andreas; Manel, Stéphanie; Waits, Lisette P; Taberlet, Pierre; Swenson, Jon E

2005-01-01

Because of differential investment in gametes between sexes, females tend to be the more selective sex. Based on this concept, we investigate mate selection in a large carnivore: the brown bear (Ursus arctos). We hypothesize that, in this species with sexually selected infanticide (SSI), females may be faced with a dilemma: either select a high-quality partner based on phenotypic criteria, as suggested by theories of mate choice, or rather mate with future potentially infanticidal males as a counter-strategy to SSI. We evaluated which male characteristics were important in paternity assignment. Among males available in the vicinity of the females, the largest, most heterozygous and less inbred and also the geographically closest males were more often the fathers of the female's next litter. We suggest that female brown bears may select the closest males as a counter-strategy to infanticide and exercise a post-copulatory cryptic choice, based on physical attributes, such as a large body size, reflecting male genetic quality. However, male–male competition either in the form of fighting before copulation or during the post-copulatory phase, in the form of sperm competition, cannot entirely be ruled out. PMID:16543170

Association between Autozygosity and Major Depression: Stratification due to Religious Assortment

PubMed Central

Abdellaoui, Abdel; Hottenga, Jouke-Jan; Xiao, Xiangjun; Scheet, Paul; Ehli, Erik A.; Davies, Gareth E.; Hudziak, James J.; Smit, Dirk J.A.; Bartels, Meike; Willemsen, Gonneke; Brooks, Andrew; Sullivan, Patrick F.; Smit, Johannes H.; de Geus, Eco J.; Penninx, Brenda W.J.H.; Boomsma, Dorret I.

2013-01-01

The effects of inbreeding on the health of offspring can be studied by measuring genome-wide autozygosity as the proportion of the genome in runs of homozygosity (Froh) and relate Froh to outcomes such as psychiatric phenotypes. To successfully conduct these studies, the main patterns of variation for genome-wide autozygosity between and within populations should be well understood and accounted for. Within population variation was investigated in the Dutch population by comparing autozygosity between religious and non-religious groups. The Netherlands have a history of societal segregation and assortment based on religious affiliation, which may have increased parental relatedness within religious groups. Religion has been associated with several psychiatric phenotypes, such as major depressive disorder (MDD). We investigated whether there is an association between autozygosity and MDD, and the extent to which this association can be explained by religious affiliation. All Froh analyses included adjustment for ancestry-informative principal components (PCs) and geographic factors. Religious affiliation was significantly associated with autozygosity, showing that Froh has the ability to capture within population differences that are not captured by ancestry-informative PCs or geographic factors. The non-religious group had significantly lower Froh values and significantly more MDD cases, leading to a nominally significant negative association between autozygosity and depression. After accounting for religious affiliation, MDD was not associated with Froh, indicating that the relation between MDD and inbreeding was due to stratification. This study shows how past religious assortment and recent secularization can have genetic consequences in a relatively small country. This warrants accounting for the historical social context and its effects on genetic variation in association studies on psychiatric and other related traits. PMID:23978897

Dating Choices of High School Students

ERIC Educational Resources Information Center

Hansen, Sally L.

1977-01-01

Dating is experienced by most adolescents in our society as a prelude to mate selection. White and black youth (N=354) were studied to measure their dating-mating choices. Implications for teachers and practitioners, based on racial and gender differences, as well as perceived peer group influences are discussed. (Author)

Methyl bromide determination in selected foods by headspace technique.

PubMed

Daft, J L

1993-01-01

A headspace method used earlier for determining methyl bromide (MB) in assorted nuts and peanut butters has been successfully applied to other foods that could potentially contain traces of this toxic fumigant. The foods tested include 63 off-the-shelf spices and seasonings, 83 table-ready items (grain-based, dried, or highly seasoned), 30 dried fruits and trail mixes, and 38 oil-based items (oil-seeds, cooking oils, or spicy oil-based dressings). Sample headspace gas is produced by blending < or = 50 g sample in 250 +/- 50 mL aqueous solution in a sealed 1000 mL blender cup. After equilibration at 25 degrees C, the headspace is sampled with a gas-tight syringe and injected into a dual column-dual detector gas chromatograph. One determination is made with a 20% OV-101 packed column and a 63Ni electron capture detector (ECD), the other with a GS-Q wide-bore capillary column and a Hall electrolytic conductivity detector (HECD). Of the approximately 200 samples tested, none contained detectable MB residue at a quantitation limit < 100 ng/g sample. All fortified samples yielded MB recovery. Samples were fortified at levels ranging from 78 to 3250 ng MB/g. Recoveries ranged from a mean high of 56% for spices and seasonings to a mean low of 30% for oil-based foods. The overall recovery and CV, including the results from assorted nuts and peanut butters, were 46 and 33%, respectively.

The Impact of Online or F2F Lecture Choice on Student Achievement and Engagement in a Large Lecture-Based Science Course: Closing the Gap

ERIC Educational Resources Information Center

Murphy, Cheryl A.; Stewart, John C.

2015-01-01

Blended learning options vary and universities are exploring an assortment of instructional combinations, some involving video lectures as a replacement for face-to-face (f2f) lectures. This methodological study investigates the impact of the provision of lecture choice (online or f2f) on overall student achievement and course engagement. This…