Data from: Fine-scale spatiotemporal patterns of genetic variation reflect budding dispersal coupled with strong natal philopatry in a cooperatively breeding mammal

The relatedness structure of animal populations is thought to be a critically important factor underlying the evolution of mating systems and social behaviours. While previous work has shown that population structure is shaped by many biological processes, few studies have investigated how these factors vary over time. Consequently, we explored the fine-scale spatiotemporal genetic structure of an intensively studied population of cooperatively breeding banded mongooses (Mungos mungo) over a ten-year period. Overall population structure was strong (average Fst = 0.129) but groups with spatially overlapping territories were not more genetically similar to one another than non-contiguous groups. Instead, genetic differentiation was associated with historical group-fission (budding) events, with new groups diverging from their parent groups over time. Within groups, relatedness was high within but not between the sexes, although the latter increased over time since group formation due to group founders being replaced by philopatric young. This trend was not mirrored by a decrease in average offspring heterozygosity over time, suggesting that close inbreeding may often be avoided, even when immigration into established groups is virtually absent and opportunities for extra-group matings are rare. Fine-scale spatiotemporal population structure could have important implications in social species, where relatedness between interacting individuals is a vital component in the evolution of patterns of inbreeding avoidance, reproductive skew and kin-selected helping and harming.

动物种群的亲缘关系结构，被视作交配系统演化与社会行为演变的关键影响因子。尽管既往研究已表明种群结构受诸多生物过程塑造，但鲜有研究探讨这些因子随时间的动态变化规律。为此，本研究针对一个被长期深度研究的合作繁殖缟獴（Mungos mungo）种群，探究了其十年间的精细尺度时空遗传结构。整体种群结构显著（平均Fst=0.129），但领地空间重叠的种群集群，其遗传相似性并未高于非邻接集群。与之相反，遗传分化与历史上的群体分裂（出芽式）事件相关，新集群会随时间推移与其亲本群体产生遗传分化。在集群内部，两性内部的亲缘性较高，但两性之间的亲缘性则较低；不过后者随集群形成后的时间推移逐渐升高，这是由于集群创建者会被留居后代所替代。这一趋势并未伴随子代平均杂合度随时间下降的现象，这表明即便几乎没有外来个体迁入已建立的集群，且集群外交配的机会极少，种群仍往往能够避免紧密近亲交配。精细尺度的时空种群结构对社会性生活物种具有重要意义：在这类物种中，相互作用个体间的亲缘性，是近亲交配规避模式、生殖偏倚以及亲缘选择下互助与伤害行为演化的核心驱动因子。