Introgression and the fate of domesticated genes in a wild mammal population

When domesticated species are not reproductively isolated from their wild relatives, the opportunity arises for artificially selected variants to be re-introduced into the wild. However, the evolutionary consequences of introgression of domesticated genes back into the wild are poorly understood. By combining high-throughput genotyping with 25 years of long-term ecological field data, we describe the occurrence and consequences of admixture between a primitive sheep breed, the free-living Soay sheep of St Kilda, and more modern breeds. Utilizing data from a 50 K ovine SNP chip, together with forward simulations of demographic scenarios, we show that admixture occurred between Soay sheep and a more modern breed, consistent with historical accounts, approximately 150 years ago. Haplotype-sharing analyses with other breeds revealed that polymorphisms in coat colour and pattern in Soay sheep arose as a result of introgression of genetic variants favoured by artificial selection. Because the...

若驯化物种与其野生近缘类群未形成生殖隔离，则人工选育的遗传变异便有机会重新回流至野生种群中。然而，驯化基因渐渗（introgression）回野生种群所带来的演化后果，目前仍鲜有深入阐释。本研究结合高通量基因分型（high-throughput genotyping）技术与25年的长期野外生态监测数据，揭示了原始绵羊品种——圣基尔达岛野生索伊羊（Soay sheep）与现代培育品种间的遗传混杂（admixture）现象及其演化效应。依托50K绵羊单核苷酸多态性（Single Nucleotide Polymorphism, SNP）芯片数据，并结合种群历史动态情景的正向模拟分析，本研究证实索伊羊与某现代培育品种的遗传混杂事件发生于约150年前，这与历史记载完全吻合。通过与其他绵羊品种的单倍型共享分析，本研究发现索伊羊的毛色与毛色模式多态性，正是源于人工选育青睐的遗传变异的渐渗。由于……