Genetic structure, UV-vision, wing coloration and size coincide with colour polymorphism in Fabriciana adippe butterflies.

Colour polymorphisms have long served as model systems in evolutionary studies and continue to inform about processes involved in the origin and dynamics of biodiversity. Modern sequencing tools allow for evaluating whether phenotypic differences between morphs reflect genetic differentiation rather than developmental plasticity, and for investigating whether polymorphisms represent intermediate stages of diversification towards speciation. We investigated phenotypic and genetic differentiation between two colour morphs of the butterfly Fabriciana adippe using a combination of ddRAD-sequencing and comparisons of body size, colour patterns and optical properties of bright wing spots. The silvery-spotted adippe form had larger and darker wings and reflected UV light, while the yellow cleodoxa form displayed more green scales and reflected very little UV, showcasing that they constitute distinct and alternative integrated phenotypes. Genomic analyses revealed genetic structuring according to source population, and to colour morph, suggesting that the phenotypic differentiation reflects evolutionary modifications. We report 17 outlier loci associated with colour morph, including ultraviolet-sensitive visual pigment (UVRh1), which is associated with intraspecific communication and mate choice in butterflies. Together with the demonstration that the wings of the adippe (but essentially not the cleodoxa) morph reflect UV light, that UV reflectance is higher in females than males and that morphs differ in wing size, this suggests that these colour morphs might represent genetically integrated phenotypes, possibly adapted to different microhabitats. We propose that non-random mating might contribute to the differentiation and maintenance of the polymorphism.

Unifying quantification methods for sexual selection and assortative mating using information theory.

Sexual selection plays a crucial role in modern evolutionary theory, offering valuable insight into evolutionary patterns and species diversity. Recently, a comprehensive definition of sexual selection has been proposed, defining it as any selection that arises from fitness differences associated with nonrandom success in the competition for access to gametes for fertilization. Previous research on discrete traits demonstrated that non-random mating can be effectively quantified using Jeffreys (or symmetrized Kullback-Leibler) divergence, capturing information acquired through mating influenced by mutual mating propensities instead of random occurrences. This novel theoretical framework allows for detecting and assessing the strength of sexual selection and assortative mating. In this study, we aim to achieve two primary objectives. Firstly, we demonstrate the seamless alignment of the previous theoretical development, rooted in information theory and mutual mating propensity, with the aforementioned definition of sexual selection. Secondly, we extend the theory to encompass quantitative traits. Our findings reveal that sexual selection and assortative mating can be quantified effectively for quantitative traits by measuring the information gain relative to the random mating pattern. The connection of the information indices of sexual selection with the classical measures of sexual selection is established. Additionally, if mating traits are normally distributed, the measure capturing the underlying information of assortative mating is a function of the square of the correlation coefficient, taking values within the non-negative real number set [0, +∞). It is worth noting that the same divergence measure captures information acquired through mating for both discrete and quantitative traits. This is interesting as it provides a common context and can help simplify the study of sexual selection patterns.

Divergent warning patterns influence male and female mating behaviours in a tropical butterfly.

Traits under divergent ecological selection that also function during mating can be important in maintaining species boundaries. Few studies have considered mutual mate choice, where both males and females base mating decisions on the same trait. Wing colouration in Heliconius butterflies evolved as a warning signal but also functions as a mating cue. We investigated the contribution of visual preference to assortative mating in an aposematic butterfly Heliconius cydno in the context of reproductive isolation with its sympatric, visually distinct relative Heliconius melpomene. Heliconius cydno have conspicuous white bands on their forewings, whereas those of H. melpomene are red in colour. We predicted that both sexes of H. cydno contributed to assortative mating by exhibiting visual preference towards conspecific wing colouration. We analysed published and new data from preference experiments, in which males were presented with conspecific and H. melpomene females. We also recorded female responses and mating outcomes in choice experiments, involving conspecific males with either the original white or artificially painted red forewing bands. Both sexes of H. cydno responded more positively towards the conspecific colouration, and males strongly preferred females of its own colours. In contrast, male colouration did not predict mating outcomes in female choice experiments. As courtships are initiated by males in butterflies, our findings suggest that female visual preference might be of secondary importance in H. cydno. Our data also suggest that the contribution of visual preference to reproductive isolation might be unequal between H. cydno and its sympatric relative H. melpomene.

Pervasive gene flow despite strong and varied reproductive barriers in swordtails.

One of the mechanisms that can lead to the formation of new species occurs through the evolution of reproductive barriers. However, recent research has demonstrated that hybridization has been pervasive across the tree of life even in the presence of strong barriers. Swordtail fishes (genus Xiphophorus) are an emerging model system for studying the interface between these barriers and hybridization. We document overlapping mechanisms that act as barriers between closely related species, X. birchmanni and X. cortezi, by combining genomic sequencing from natural hybrid populations, artificial crosses, behavioral assays, sperm performance, and developmental studies. We show that strong assortative mating plays a key role in maintaining subpopulations with distinct ancestry in natural hybrid populations. Lab experiments demonstrate that artificial F1 crosses experience dysfunction: crosses with X. birchmanni females were largely inviable and crosses with X. cortezi females had a heavily skewed sex ratio. Using F2 hybrids we identify several genomic regions that strongly impact hybrid viability. Strikingly, two of these regions underlie genetic incompatibilities in hybrids between X. birchmanni and its sister species X. malinche. Our results demonstrate that ancient hybridization has played a role in the origin of this shared genetic incompatibility. Moreover, ancestry mismatch at these incompatible regions has remarkably similar consequences for phenotypes and hybrid survival in X. cortezi × X. birchmanni hybrids as in X. malinche × X. birchmanni hybrids. Our findings identify varied reproductive barriers that shape genetic exchange between naturally hybridizing species and highlight the complex evolutionary outcomes of hybridization.

International Cross-Temporal Meta-Analysis of Assortative Mating for Educational Attainment.

Previous studies have found a high degree of assortative mating for educational attainment (r = .56). However, this can be confounded by cohort effects or country effects, where certain nations may have more pronounced assortative mating than others. In addition, method variance regarding how educational attainment is measured may also result in heterogeneity of effect sizes. Effect sizes were gathered from various datasets and from academic literature, resulting in a large collection of effect sizes (k = 1498, n = 9,159,098), spanning 84 different countries. Assortative mating for educational attainment was stronger than what previous literature suggested (r = .66, [.64, .68]), largely due to the fact that assortative mating for educational attainment is stronger when latent methods are used. The strongest predictors of assortative mating for education between countries were individualism (r = -.61, p < .001) and HDI (r = -.56, p < .001). Assortative mating over time was found to vary by region. Capitalist Europe experienced an increase in assortative mating for education, while Communist Europe experienced a decrease. The United States had a non-linear trend in assortative mating for educational attainment, as it decreased from 1875 to 1926, increased from 1926 to 1945, decreased from 1945 to 1958, increased from 1958 to 1977, and decreased from 1977 onwards.

Genomic predictions under different genetic architectures are impacted by mating designs.

Mating in animal communities must be managed in a way that assures the performance increase in the progenies without increasing the rate of inbreeding. It has currently become possible to identify millions of single nucleotide polymorphisms (SNPs), and it is feasible to select animals based on genome-wide marker profiles. This study aimed to evaluate the impact of five mating designs among individuals (random, positive and negative assortative, minimized and maximized inbreeding) on genomic prediction accuracy. The choice of these five particular mating designs provides a thorough analysis of the way genetic diversity, relatedness, inbreeding, and biological conditions influence the accuracy of genomic predictions. Utilizing a stochastic simulation technique, various marker and quantitative trait loci (QTL) densities were taken into account. The heritabilities of a simulated trait were 0.05, 0.30, and 0.60. A validation population that only had genotypic records was taken into consideration, and a reference population that had both genotypic and phenotypic records was considered for every simulation scenario. By measuring the correlation between estimated and true breeding values, the prediction accuracy was calculated. Computing the regression of true genomic breeding value on estimated genomic breeding value allowed for the examination of prediction bias. The scenario with a positive assortative mating design had the highest accuracy of genomic prediction (0.733 ± 0.003 to 0.966 ± 0.001). In a case of negative assortative mating, the genomic evaluation's accuracy was lowest (0.680 ± 0.011 to 0.899 ± 0.003). Applying the positive assortative mating design resulted in the unbiased regression coefficients of true genomic breeding value on estimated genomic breeding value. Based on the current results, it is suggested to implement positive assortative mating in genomic evaluation programs to obtain unbiased genomic predictions with greater accuracy. This study implies that animal breeding programs can improve offspring performance without compromising genetic health by carefully managing mating strategies based on genetic diversity, relatedness, and inbreeding levels. To maximize breeding results and ensure long-term genetic improvement in animal populations, this study highlights the importance of considering different mating designs when evaluating genomic information. When incorporating positive assortative mating or other mating schemes into genomic evaluation programs, it is critical to consider the complex relationship between gene interactions, environmental influences, and genetic drift to ensure the stability and effectiveness of breeding efforts. Further research and comprehensive analyzes are needed to fully understand the impact of these factors and their possible complex interactions on the accuracy of genomic prediction and to develop strategies that optimize breeding outcomes in animal populations.

Phenotypic and ancestry-related assortative mating in autism.

BACKGROUND: Positive assortative mating (AM) in several neuropsychiatric traits, including autism, has been noted. However, it is unknown whether the pattern of AM is different in phenotypically defined autism subgroups [e.g., autism with and without intellectually disability (ID)]. It is also unclear what proportion of the phenotypic AM can be explained by the genetic similarity between parents of children with an autism diagnosis, and the consequences of AM on the genetic structure of the population. METHODS: To address these questions, we analyzed two family-based autism collections: the Simons Foundation Powering Autism Research for Knowledge (SPARK) (1575 families) and the Simons Simplex Collection (SSC) (2283 families). RESULTS: We found a similar degree of phenotypic and ancestry-related AM in parents of children with an autism diagnosis regardless of the presence of ID. We did not find evidence of AM for autism based on autism polygenic scores (PGS) (at a threshold of |r|> 0.1). The adjustment of ancestry-related AM or autism PGS accounted for only 0.3-4% of the fractional change in the estimate of the phenotypic AM. The ancestry-related AM introduced higher long-range linkage disequilibrium (LD) between single nucleotide polymorphisms (SNPs) on different chromosomes that are highly ancestry-informative compared to SNPs that are less ancestry-informative (D2 on the order of 1 × 10-5). LIMITATIONS: We only analyzed participants of European ancestry, limiting the generalizability of our results to individuals of non-European ancestry. SPARK and SSC were both multicenter studies. Therefore, there could be ancestry-related AM in SPARK and SSC due to geographic stratification. The study participants from each site were unknown, so we were unable to evaluate for geographic stratification. CONCLUSIONS: This study showed similar patterns of AM in autism with and without ID, and demonstrated that the common genetic influences of autism are likely relevant to both autism groups. The adjustment of ancestry-related AM and autism PGS accounted for < 5% of the fractional change in the estimate of the phenotypic AM. Future studies are needed to evaluate if the small increase of long-range LD induced by ancestry-related AM has impact on the downstream analysis.

Mate selection and current trends in the prevalence of autism.

BACKGROUND: According to the most recent U.S. CDC surveillance data, the rise in prevalence of childhood autism spectrum disorder among minority children has begun to outpace that of non-Hispanic white children. Since prior research has identified possible differences in the extent of mate selection for autistic traits across families of different ethnicity, this study examined variation in autism related traits in contemporaneous, epidemiologically ascertained samples of spousal pairs representing Hispanic and non-Hispanic white populations. The purpose was to determine whether discrepancies by ethnicity could contribute to differential increases in prevalence in the current generation of young children. METHODS: Birth records were used to identify all twin pairs born between 2011 and 2013 in California and Missouri. Families were selected at random from pools of English-speaking Hispanic families in California and Non-Hispanic White families in Missouri. Autistic trait data of parents was obtained using the Adult Report Form of the Social Responsiveness Scale (SRS-2). RESULTS: We did not identify a statistically significant difference in the degree of mate selection for autism related traits between Hispanic and non-Hispanic white spousal pairs. However, the degree of spousal correlation observed in this recent cohort was pronounced (on the order of ICC 0.45) and exceeded that typically reported in prior research (on the order of 0.30), surpassing also widely reported estimates for sibling correlation (also on the order of 0.30). LIMITATIONS: The sample did not allow for a direct appraisal of change in the magnitude of spousal correlation over time and the ascertainments of trait burden were derived from spouse report. CONCLUSION: Across two epidemiologically ascertained samples of spousal pairs representing Hispanic and non-Hispanic white families across two U.S. states (respectively, California and Missouri), the extent of autism-related trait co-variation for parents of the current generation of young children is substantial and exceeds correlations typically observed for siblings. Given the heritability of these traits and their relation to autism risk, societal trends in the degree of mate selection for these traits should be considered as possible contributors to subtle increases in the incidence of autism over time and across generations.

Diferencia de edad entre cónyuges por nivel educativo en América Latina. El caso de Bolivia, Ecuador y Uruguay / Diferença de idade entre cônjuges por nível de escolaridade na América Latina. O caso de Bolívia, Equador e Uruguai / Spousal age difference by education in Latin America. The case of Bolivia, Ecuador and Uruguay

Resumen El objetivo del estudio es hacer un análisis descriptivo de la asociación entre la educación y la diferencia de edad entre los cónyuges en uniones de distinto sexo y conocer cómo ha evolucionado esta relación a lo largo de las cohortes en las últimas décadas a la luz del incremento del nivel educativo de la población en América Latina, en particular de las mujeres. Se hizo un análisis descriptivo utilizando muestras de rondas censales desde 1970 hasta 2010 de tres países de la región, Bolivia, Ecuador y Uruguay, seleccionando a hombres y a mujeres de 25 a 29 años de edad. Tanto en hombres como en mujeres, no se observa en general un descenso significativo de la diferencia etaria a lo largo de las cohortes. Mientras en las mujeres se observó una relación negativa entre la diferencia etaria entre cónyuges y nivel educativo, en los hombres se constató mayor heterogeneidad entre los países.

Resumo O objetivo do estudo é realizar uma análise descritiva da associação entre escolaridade e diferença de idade entre cônjuges em uniões de diferente sexo e como essa relação evoluiu ao longo das coortes nas últimas décadas em função do aumento da escolaridade da população da América Latina, especialmente para as mulheres. Foram utilizadas amostras de rodadas dos censos de 1970 a 2010 de três países da região − Bolívia, Equador e Uruguai −, selecionando homens e mulheres de 25 a 29 anos de idade. Para o total da amostra, não foi observada diminuição significativa na diferença de idade ao longo das coortes. Para as mulheres, verificou--se relação negativa entre a diferença de idade entre os cônjuges e a escolaridade. Para os homens, observou-se maior heterogeneidade entre os países.

Abstract The purpose of this study is to investigate the association between education and the age gap between spouses in heterosexual unions. The study also examines how this association has changed over time in different cohorts, especially among women, in the context of educational expansion in Latin America. The research used the data collected from census rounds conducted between 1970 and 2010 in Bolivia, Ecuador, and Uruguay. The sample included men and women aged between 25 to 29. The findings reveal that there was no significant decrease in the age difference throughout the cohorts for both men and women. However, a negative relationship was observed between the spousal age difference and educational level in women. On the other hand, men showed greater heterogeneity between countries.

Marital Satisfaction in Spanish and Dominican Couples / Satisfacción Marital en Parejas Españolas y Dominicanas

Abstract Marriage is an appreciated worldwide institution, although nearly half of first marriages end in divorce. Thus, the relevance of understanding how people choose their partners and what features can predict a satisfactory relationship. More specifically, in search of data supporting similarity or complementarity approaches on marital satisfaction, the current study analyzes the association between different assortative mating options (homogamy, and heterogamy) and marital satisfaction in Spanish and Dominican couples. A stratified quota sampling of 600 participants was selected, corresponding to 300 married couples (50% Spanish and 50% Dominicans). Data were gathered by means of an interview with the 10-item scale on Marital Satisfaction and a 7-item scale on Status. Results suggest that spouses are matched by similarity in their health and education and by the perception of similarity in intelligence and the financial advantages of staying together. Dominican couples experienced higher marital satisfaction than Spanish couples. Findings on hypergamy reveals the persistence of some traditional roles' distribution among Spanish speaking cultures. The association between status and marital satisfaction revealed that heterogamy rather than homogamy is associated to such satisfaction. These results stress the relevance of taking into account social and cultural differences, beyond biological and psychological factors, to fully understand couples' satisfaction.

Resumen El matrimonio es una institución apreciada a nivel mundial, pese a que casi la mitad de los primeros matrimonios terminan en divorcio. De ahí la importancia de comprender cómo las personas eligen a sus parejas y qué factores contribuyen a predecir una relación satisfactoria. Más concretamente, en busca de datos que ofrezcan apoyo a los enfoques de semejanza o de complementariedad en su relación con la satisfacción marital, el presente estudio analiza diferentes alternativas de emparejamiento selectivo (homogamia y heterogamia) y su relación con dicha satisfacción marital en parejas españolas y dominicanas. Para llevar a cabo el estudio se ha empleado un muestreo estratificado por cuotas compuesto por un total de 600 participantes, que se corresponden con 300 parejas casadas (un 50% procedente de España y el otro 50% procedente de República Dominicana). Los datos se recogieron a través de entrevista la escala de 10 ítems de Satisfacción Marital y la escala de 7 ítems de Status. Los resultados sugieren que los emparejamientos se caracterizan por la semejanza en salud, formación, inteligencia, y por la percepción compartida de las ventajas económicas asociadas a su permanencia. Las parejas dominicanas experimentan una mayor satisfacción marital que las españolas. Los resultados obtenidos sobre hipergamia revelan la persistencia de una distribución de roles tradicional en países de habla hispana. La asociación entre estatus y satisfacción marital indicaron que la heterogamia más que la homogamia, se asocia a tal satisfacción. Todos estos resultados subrayan la importancia de tener en cuenta diferencias sociales y culturales, además de factores biológicos y psicológicos, para comprender plenamente la satisfacción en las parejas.

Padrões de seletividade relacionados aos casais homossexuais e heterossexuais no Brasil / /Assortative mating patterns of homosexual and heterosexual couples in Brazil / /Patrones de selectividad de las parejas homosexuales y heterosexuales en Brasil

Esse artigo tem por objetivo analisar os padrões de seletividade marital entre os casais heterossexuais e os casais homossexuais no Brasil, investigando os níveis de escolaridade, cor/raça e grupo etário. Inicialmente foi feita uma análise descritiva dos dados com o intuito de caracterizar a população estudada e os diferenciais entre os tipos de casais. Além disso, esse artigo utiliza tabelas de contingência e modelos log-lineares para compreender as formas de associações entre os casais e quais variáveis influenciam a seletividade dos parceiros. Os resultados mostram que cor/raça e escolaridade têm maior influência na seletividade dos casais heterossexuais, enquanto cor/raça e grupo etário são mais relevantes para os casais homossexuais em relação aos seus padrões de seletividade. Portanto, é possível identificar a existência de diferenças entre as características de seletividade entre esses casais e seus padrões, o que abre margem para estudos posteriores que possam aprofundar a compreensão das distinções entre esses padrões, no sentido de encontrar formas de tentar explicá-las e suas possíveis consequências no Brasil.

El objetivo de este artículo es analizar los patrones de selectividad marital entre las parejas heterosexuales y homosexuales en Brasil, investigando para ello los niveles de escolaridad, color/raza y grupo etario. Inicialmente se realizó un análisis descriptivo de los datos con el fin de caracterizar a la población estudiada y los diferenciales entre los tipos de parejas. Además, el estudio utiliza tablas de contingencia y modelos log-lineares para entender las formas de asociación entre las parejas y las variables que influyen en la selectividad de sus miembros. En relación con los patrones de selectividad, los resultados muestran que el color/raza y la escolaridad tienen mayor influencia en las parejas heterosexuales, mientras que el color/raza y el grupo etario al que se pertenece son más relevantes para las parejas homosexuales. Por lo tanto, se pueden identificar diferencias entre las características de la selectividad de estas parejas y sus patrones, lo que abre un espacio para estudios posteriores que puedan profundizar la comprensión de las diferencias entre estos patrones, con el fin de intentar explicar estas distinciones y sus posibles consecuencias en el país.

Interethnic variability and admixture in Latin America-social implications: [review]

Past and present attempts to classify and characterize the human biological variability are examined, considering the race concept, ethnic identification problems, assortative mating based on ethnicity, and historical genetics. In relation to the latter, a review is made of the methods presently available for admixture quantification and of previous studies aimed at the characterization of the parental continental contributions to Latin American populations, with emphasis in global evaluations of the Costa Rican and Brazilian gene pools. Finally, the question of racism and discrimination is considered, including the relation between human rights and affirmative actions. The right to equal opportunity should be strictly respected. Biological inequality has nothing to do with the ethical principle that someone's position in a given society should be an accurate reflection of her/his individual ability.