Data from: Genomic consequences of genetic rescue in an insular population of bighorn sheep (Ovis canadensis)

Genetic rescue is a management intervention whereby a small population is supplemented with individuals from other populations in an attempt to reverse the effects of inbreeding and increased genetic load. One such rescue was recently documented in the population of bighorn sheep (Ovis canadensis) within the National Bison Range wildlife refuge (Montana, USA). Here we examine the locus-specific effects of rescue in this population using a newly developed genome-wide set of 195 microsatellite loci and first-generation linkage map. We found that the rate of introgression varied among loci, and that 111 loci, 57% of those examined, deviated from patterns of neutral inheritance. The most common deviation was an excess of homozygous genotypes relative to neutral expectations, indicative of directional selection. As in previous study of this rescue, individuals with more introduced alleles had higher lifetime reproductive success and longevity. In addition, we found 30 loci, spread throughout the genome, which seem to have individual effects on these life history traits. Though the potential for outbreeding depression is a major concern when translocating individuals between populations, we found no evidence of such effects in this population.

遗传拯救（genetic rescue）是一种种群管理干预手段，指通过向小型种群引入其他种群的个体，以逆转近交（inbreeding）加剧与遗传负荷（genetic load）带来的负面影响。近期在美国蒙大拿州国家野牛野生动物保护区（National Bison Range wildlife refuge）内的大角羊（Ovis canadensis）种群中，便记录到了一例此类拯救事件。本研究依托新开发的包含195个微卫星位点（microsatellite loci）的全基因组标记集与第一代连锁图谱（linkage map），探究了该种群中遗传拯救的位点特异性效应。研究结果显示，基因渐渗（introgression）的速率在不同位点间存在显著差异，其中111个位点（占检测位点总数的57%）的遗传模式偏离中性演化预期。最常见的偏离模式为纯合子基因型数量超出中性预期，这一结果指向定向选择。与此前针对该拯救事件的研究结论一致，携带更多外来引入等位基因的个体具有更高的终生繁殖成功率与更长的寿命。此外，本研究还发现了分布于全基因组的30个位点，这些位点似乎对上述生活史性状存在独立调控效应。尽管在种群间移植个体时，远交衰退（outbreeding depression）的潜在风险是一项核心顾虑，但本研究未在该种群中发现此类效应的相关证据。