Am Nat. 2021 Jun;197(6):658-676. doi: 10.1086/714079. Epub 2021 Apr 19.
AbstractInbreeding depression is often found in small, inbred populations, but whether it can be detected in and have evolutionary consequences for large, wide-ranging populations is poorly known. Here, we investigate the possibility of inbreeding in a large population to determine whether mild levels of inbreeding can still have genetic and phenotypic consequences and how genomically widespread these effects can be. We apply genome-wide methods to investigate whether individual and parental heterozygosity is related to morphological, growth, or life-history traits in a pelagic seabird, Leach's storm-petrel (). Examining 560 individuals as part of a multiyear study, we found a substantial effect of maternal heterozygosity on chick traits: chicks from less heterozygous (relatively inbred) mothers were significantly smaller than chicks from more heterozygous (noninbred) mothers. We show that these heterozygosity-fitness correlations were due to general genome-wide effects and demonstrate a correlation between heterozygosity and inbreeding, suggesting inbreeding depression. We used population genetic models to further show that the variance in inbreeding was probably due to past demographic events rather than the current mating system and ongoing mate choice. Our findings demonstrate that inbreeding depression can be observed in large populations and illustrate how the integration of genomic techniques and fieldwork can elucidate its underlying causes.
摘要
近亲繁殖衰退通常在小而近交的群体中发现，但在大而广泛分布的群体中是否能够检测到并具有进化后果尚不清楚。在这里，我们研究了一个大群体中近亲繁殖的可能性，以确定轻度的近亲繁殖是否仍然会产生遗传和表型后果，以及这些影响在多大程度上具有全基因组的普遍性。我们应用全基因组方法来研究个体和父母的杂合性是否与海洋海鸟（Leach's storm-petrel）的形态、生长或生活史特征有关。通过一项多年的研究，我们对 560 只个体进行了研究，发现母体杂合性对雏鸟特征有很大影响：来自杂合性较低（相对近交）母亲的雏鸟明显比来自杂合性较高（非近交）母亲的雏鸟小。我们表明，这些杂合性与适应度的相关性是由于全基因组的普遍影响，并证明了杂合性与近交之间的相关性，表明存在近交衰退。我们使用群体遗传模型进一步表明，近交方差可能是由于过去的人口事件而不是当前的交配系统和正在进行的配偶选择造成的。我们的研究结果表明，近亲繁殖衰退可以在大群体中观察到，并说明了如何整合基因组技术和实地工作来阐明其潜在原因。
