Is Mate Choice in Humans MHC-Dependent?

In several species, including rodents and fish, it has been shown that the Major Histocompatibility Complex (MHC) influences mating preferences and, in some cases, that this may be mediated by preferences based on body odour. In humans, the picture has been less clear. Several studies have reported a tendency for humans to prefer MHC-dissimilar mates, a sexual selection that would favour the production of MHC-heterozygous offspring, who would be more resistant to pathogens, but these results are unsupported by other studies. Here, we report analyses of genome-wide genotype data (from the HapMap II dataset) and HLA types in African and European American couples to test whether humans tend to choose MHC-dissimilar mates. In order to distinguish MHC-specific effects from genome-wide effects, the pattern of similarity in the MHC region is compared to the pattern in the rest of the genome. African spouses show no significant pattern of similarity/dissimilarity across the MHC region (relatedness coefficient, R = 0.015, p = 0.23), whereas across the genome, they are more similar than random pairs of individuals (genome-wide R = 0.00185, p<10−3). We discuss several explanations for these observations, including demographic effects. On the other hand, the sampled European American couples are significantly more MHC-dissimilar than random pairs of individuals (R = −0.043, p = 0.015), and this pattern of dissimilarity is extreme when compared to the rest of the genome, both globally (genome-wide R = −0.00016, p = 0.739) and when broken into windows having the same length and recombination rate as the MHC (only nine genomic regions exhibit a higher level of genetic dissimilarity between spouses than does the MHC). This study thus supports the hypothesis that the MHC influences mate choice in some human populations

Démographie, culture et diversité génétique (le cas des populations humaines nomades)

PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Non-random mate choice in humans: insights from a genome scan.

International audienceLittle is known about the genetic factors influencing mate choice in humans. Still, there is evidence for non-random mate choice with respect to physical traits. In addition, some studies suggest that the Major Histocompatibility Complex may affect pair formation. Nowadays, the availability of high density genomic data sets gives the opportunity to scan the genome for signatures of non-random mate choice without prior assumptions on which genes may be involved, while taking into account socio-demographic factors. Here, we performed a genome scan to detect extreme patterns of similarity or dissimilarity among spouses throughout the genome in three populations of African, European American, and Mexican origins from the HapMap 3 database. Our analyses identified genes and biological functions that may affect pair formation in humans, including genes involved in skin appearance, morphogenesis, immunity and behaviour. We found little overlap between the three populations, suggesting that the biological functions potentially influencing mate choice are population specific, in other words are culturally driven. Moreover, whenever the same functional category of genes showed a significant signal in two populations, different genes were actually involved, which suggests the possibility of evolutionary convergences

Where West Meets East: The Complex mtDNA Landscape of the Southwest and Central Asian Corridor

International audienc

Modeling the influence of human social organizations on genetic diversity

International audienceHuman populations display a wide diversity of social organizations. These organizations are shaped by three major rules: the descent rule, the alliance rule and the post-marital residence rule. Nowadays, patrilineal and patrilocal organizations, for which individuals are affiliated to their paternal group and women settle in their husband’s village, are dominant among human populations, but the past history of human social organizations is currently poorly understood. Previous studies have highlighted that social organizations induce sex- biased behaviours and influence the diversity of uniparental markers (mitochondrial DNA and the non recombining portion of the Y chromosome), but also of autosomal markers (X/autosomes diversity ratios). In this study, we modeled different descent and post-marital residence rules to understand better their effects on human genomic diversity and to identify relevant diversity estimators that can be applied to ancient DNA data, in order to trace back the history of human social organizations in space and time

Modeling the influence of human social organizations on genetic diversity

International audienceHuman populations display a wide diversity of social organizations. These organizations are shaped by three major rules: the descent rule, the alliance rule and the post-marital residence rule. Nowadays, patrilineal and patrilocal organizations, for which individuals are affiliated to their paternal group and women settle in their husband’s village, are dominant among human populations, but the past history of human social organizations is currently poorly understood. Previous studies have highlighted that social organizations induce sex- biased behaviours and influence the diversity of uniparental markers (mitochondrial DNA and the non recombining portion of the Y chromosome), but also of autosomal markers (X/autosomes diversity ratios). In this study, we modeled different descent and post-marital residence rules to understand better their effects on human genomic diversity and to identify relevant diversity estimators that can be applied to ancient DNA data, in order to trace back the history of human social organizations in space and time

Modelling the influence of kinship systems on human genetic diversity

International audienceKinship rules such as descent rules – indicating the group (lineage, clan) to which an individual is affiliated – and post-marital residence rules – determining the place of living of a couple after marriage – vary widely between human populations. In western societies, individuals are generally affiliated to the groups of both their parents (bilateral descent) and choose where to settle after their marriage (neolocality). However, the majority of populations display unilineal descent rules, that is, individuals are affiliated to the group of their father (patrilineal) or to the group of their mother (matrilineal), and are either patrilocal – the wife migrates to her husband’s village – or matrilocal – the husband settles in his wife’s village. Interestingly, human populations are currently mostly patrilineal (~ 40 %) and patrilocal (~ 60 %), but little is known about the evolution of these kinship rules in human history. Hence, we wonder if this overrepresentation of patrilineality and patrilocality always existed and, if not, when they became dominant in human populations. By modelling populations displaying different kinship rules, we evaluate the influence of these cultural practices on genetic diversity and identify relevant diversity estimators that could be applied to ancient DNA, in order to trace back the history of human social organizations in space and time

Modeling the influence of human kinship systems on genetic diversity

International audienceLes organisations sociales humaines sont caractérisées par trois grandes règles : la règle de filiation qui détermine le groupe auquel un individu est apparenté dans une population, la règle d’alliance qui encourage ou interdit certains types de mariages (ex. mariages entre cousins), et la règle de résidence post-maritale qui définit le lieu de résidence d’un couple après le mariage. D’après le Standard Cross-Cultural Sample publié par Murdock et White en 1969, environ 40 % des populations humaines actuelles seraient patrilinéaires, c’est-à-dire que les individus sont affiliés au lignage ou clan de leur père, et 60 % seraient patrilocales, ce qui signifie que les couples s’installent dans le lieu de naissance du mari après le mariage.L’histoire de ces organisations sociales est aujourd’hui méconnue, et nous ignorons depuis quand la patrilinéarité et la patrilocalité sont devenues majoritaires au sein des populations humaines. De précédentes études ont mis en évidence que les organisations sociales humaines induisent des dynamiques démographiques sexe-spécifiques (ex. biais de migration) et ont une influence sur la diversité génétique des populations. Afin de mieux caractériser l’impact de ces règles de parenté sur la diversité génétique des populations humaines, nous avons développé un modèle de populations présentant différentes règles de filiation et de résidence.En calculant plusieurs estimateurs de diversité sur les marqueurs uniparentaux (chromosome Y, ADN mitochondrial) ainsi que sur le chromosome X et les autosomes, nous mettons en évidence des signatures génétiques associées aux différentes règles modélisées. Ces estimateurs pourront ensuite être calculés sur des données d’ADN ancien afin de pouvoir retracer l’histoire des organisations sociales humaines dans le temps et l’espace

Modeling the influence of human kinship systems on genetic diversity

International audienceLes organisations sociales humaines sont caractérisées par trois grandes règles : la règle de filiation qui détermine le groupe auquel un individu est apparenté dans une population, la règle d’alliance qui encourage ou interdit certains types de mariages (ex. mariages entre cousins), et la règle de résidence post-maritale qui définit le lieu de résidence d’un couple après le mariage. D’après le Standard Cross-Cultural Sample publié par Murdock et White en 1969, environ 40 % des populations humaines actuelles seraient patrilinéaires, c’est-à-dire que les individus sont affiliés au lignage ou clan de leur père, et 60 % seraient patrilocales, ce qui signifie que les couples s’installent dans le lieu de naissance du mari après le mariage.L’histoire de ces organisations sociales est aujourd’hui méconnue, et nous ignorons depuis quand la patrilinéarité et la patrilocalité sont devenues majoritaires au sein des populations humaines. De précédentes études ont mis en évidence que les organisations sociales humaines induisent des dynamiques démographiques sexe-spécifiques (ex. biais de migration) et ont une influence sur la diversité génétique des populations. Afin de mieux caractériser l’impact de ces règles de parenté sur la diversité génétique des populations humaines, nous avons développé un modèle de populations présentant différentes règles de filiation et de résidence.En calculant plusieurs estimateurs de diversité sur les marqueurs uniparentaux (chromosome Y, ADN mitochondrial) ainsi que sur le chromosome X et les autosomes, nous mettons en évidence des signatures génétiques associées aux différentes règles modélisées. Ces estimateurs pourront ensuite être calculés sur des données d’ADN ancien afin de pouvoir retracer l’histoire des organisations sociales humaines dans le temps et l’espace