Inbreeding depression is ubiquitous, but we still know little about its genetic architecture and precise effects in wild populations. Here, we combine long-term life-history data with 417K imputed SNP genotypes for 5,952 wild Soay sheep to explore inbreeding depression on a key fitness component, annual survival. Inbreeding manifests in long runs of homozygosity (ROH), which make up nearly half of the genome in the most inbred individuals. The ROH landscape varies widely across the genome, with islands where up to 87% and deserts where only 4% of individuals have ROH. The fitness consequences of inbreeding are severe; a 10% increase in individual inbreeding F_ROH is associated with a 60% reduction in the odds of survival in lambs, though inbreeding depression decreases with age. Finally, a genome-wide association scan on ROH shows that many loci with small effects and five loci with larger effects contribute to inbreeding depression in survival.

中文翻译：

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野生哺乳动物近交衰退的遗传结构和终生动态

近交性抑郁症无处不在，但我们对其遗传结构和在野生种群中的精确作用仍然知之甚少。在这里，我们将长期生活史数据与5952种野生Soay绵羊的417K推定SNP基因型相结合，以探索近亲繁殖的关键适应性因素，即年生存率。近交表现为长期的纯合（ROH），在大多数近交个体中，近纯合占基因组的一半。ROH景观在整个基因组中差异很大，其中岛屿占87％，而沙漠中只有4％的人患有ROH。近亲繁殖的适应性后果很严重；一个增加个体近亲繁殖˚F10％_ROH尽管近亲繁殖的抑郁随着年龄的增长而降低，但与羔羊存活几率降低60％有关。最后，在ROH上进行的全基因组关联扫描显示，许多影响较小的基因座和5个影响较大的基因座有助于生存中的近交衰退。