Despite the well-known effects of sexual selection on phenotypes, links between this evolutionary process and reproductive isolation, genomic divergence, and speciation have been difficult to establish. We unravel the genetic basis of sexually selected plumage traits to investigate their effects on reproductive isolation in barn swallows. The genetic architecture of sexual traits is characterized by 12 loci on two autosomes and the Z chromosome. Sexual trait loci exhibit signatures of divergent selection in geographic isolation and barriers to gene flow in secondary contact. Linkage disequilibrium between these genes has been maintained by selection in hybrid zones beyond what would be expected under admixture alone. Our findings reveal that selection on coupled sexual trait loci promotes reproductive isolation, providing key empirical evidence for the role of sexual selection in speciation.

中文翻译：

---

性选择促进谷仓燕子的生殖隔离


尽管众所周知的性选择对表型的影响，但这种进化过程与生殖隔离、基因组分化和物种形成之间的联系一直难以建立。我们揭示了性选择的羽毛特征的遗传基础，以研究它们对谷仓燕子生殖隔离的影响。性状的遗传结构以两个常染色体和 Z 染色体上的 12 个位点为特征。性状位点在地理隔离中表现出不同选择的特征，在二次接触中表现出基因流动的障碍。这些基因之间的连锁不平衡是通过在杂交区中选择来维持的，超出了单独混合下的预期。我们的研究结果表明，对耦合性状位点的选择促进了生殖隔离，为性选择在物种形成中的作用提供了关键的经验证据。