期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2015
卷号：112
期号：26
页码：E3318-E3326
DOI：10.1073/pnas.1414463112
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：SignificanceMany species live in socially structured populations, forming cohesive units with kin structure. Yet, sociality has been neglected by population geneticists under the assumption that social groups can be seen as small demes subjected to significant genetic drift. Such demes are usually considered to be susceptible to inbreeding, with inbreeding avoidance becoming a major force explaining dispersal strategies. We find that social structure is highly effective in maintaining high genotypic and genetic diversity levels, without invoking sex-biased dispersal or inbreeding avoidance mechanisms. These findings should change the way we perceive social groups. Many species are spatially and socially organized, with complex social organizations and dispersal patterns that are increasingly documented. Social species typically consist of small age-structured units, where a limited number of individuals monopolize reproduction and exhibit complex mating strategies. Here, we model social groups as age-structured units and investigate the genetic consequences of social structure under distinct mating strategies commonly found in mammals. Our results show that sociality maximizes genotypic diversity, which contradicts the belief that social groups are necessarily subject to strong genetic drift and at high risk of inbreeding depression. Social structure generates an excess of genotypic diversity. This is commonly observed in ecological studies but rarely reported in population genetic studies that ignore social structure. This heterozygosity excess, when detected, is often interpreted as a consequence of inbreeding avoidance mechanisms, but we show that it can occur even in the absence of such mechanisms. Many seemly contradictory results from ecology and population genetics can be reconciled by genetic models that include the complexities of social species. We find that such discrepancies can be explained by the intrinsic properties of social groups and by the sampling strategies of real populations. In particular, the number of social groups and the nature of the individuals that compose samples (e.g., nonreproductive and reproductive individuals) are key factors in generating outbreeding signatures. Sociality is an important component of population structure that needs to be revisited by ecologists and population geneticists alike.
关键词：sociality ; social structure ; mating system ; genotypic diversity ; inbreeding avoidance
