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,...

利用微卫星（microsatellites）等遗传标记可开展分子水平的近交系数估算，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。本研究以新西兰乌尔瓦岛（Ulva Island）上受严密监测的再引入种群斯图尔特岛鸲鹟（Petroica australis rakiura）为研究对象，探究了谱系确定的近交系数（pedigree-determined inbreeding coefficients, f）与HFCs之间的关联。我们采用全同胞设计（full sibling design），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）的个体间差异对幼体存活率的特定影响。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。不过，该效应主要在发生近交的窝次，或是其谱系历史（即亲本层面）存在近交事件的窝次中被检测到。据此，我们证实……