Data from: Inbreeding influences within-brood heterozygosity-fitness correlations (HFCs) in an isolated passerine population

Molecular estimates of inbreeding may be made using genetic markers such as microsatellites, however the interpretation of resulting heterozygosity-fitness correlations (HFCs) with respect to inbreeding depression is not straightforward. We investigated the relationship between pedigree-determined inbreeding coefficients (f) and HFCs in a closely monitored, reintroduced population of Stewart Island robins (Petroica australis rakiura) on Ulva Island, New Zealand. Using a full sibling design, we focused on differences in juvenile survival associated specifically with individual sibling variation in standardized multilocus heterozygosity (SH) when expected f was identical. We found that within broods, siblings with higher SH at microsatellite loci experienced a higher probability of juvenile survival. This effect, however, was detected primarily within broods that experienced inbreeding or when inbreeding had occurred in their pedigree histories (i.e., at the parents’ level). Thus we show, for the first time in a wild population, that the strength of an HFC is partially dependent on the presence of inbreeding events in the recent pedigree history. Our results illustrate the importance of realized effects of inbreeding on genetic variation and fitness and the value of full-sibling designs for the study of HFCs in the context of small, inbred populations.

利用微卫星（microsatellites）等遗传标记可估算分子水平近交系数，但针对近交衰退解读所得的杂合度-适合度相关性（heterozygosity-fitness correlations, HFCs）并非易事。我们对新西兰乌尔瓦岛（Ulva Island）上一个受严密监测的再引入斯图尔特岛鸲鹟（Petroica australis rakiura）种群展开研究，探讨系谱确定的近交系数（f）与HFCs之间的关联。本研究采用全同胞设计，聚焦于当个体的预期近交系数f相同时，标准化多位点杂合度（standardized multilocus heterozygosity, SH）的个体间同胞差异与幼体存活率的具体关联。研究发现，在同窝幼鸟中，微卫星位点上SH值更高的同胞个体拥有更高的幼体存活概率。然而，该效应主要在发生过近交的窝，或是其系谱历史（即亲本层面）存在近交事件的窝中被检测到。据此，我们在野生种群中首次证实，HFCs的强度部分取决于近期系谱历史中是否存在近交事件。本研究结果阐明了近交对遗传变异与适合度的实际影响的重要性，以及全同胞设计在小型近交种群的HFCs研究中的应用价值。