Patterns of genetic divergence and demographic history shed light on island-mainland population dynamics and melanic plumage evolution in the white-winged fairywren

The existence of distinct traits in island versus mainland populations offers opportunities to gain insights into how eco-evolutionary processes operate under natural conditions. We used two island colonization events in the white-winged fairywren (Malurus leucopterus) to investigate the genomic and demographic origin of melanic plumage. This avian species is distributed across most of Australia, and males of the mainland subspecies (M. l. leuconotus) exhibit a blue nuptial plumage in contrast to males of two island subspecies – M. l. leucopterus on Dirk Hartog Island and M. l. edouardion Barrow Island – that exhibit a black nuptial plumage. We used reduced-representation sequencing to explore differentiation and demographic history in this species and found clear patterns of divergence between mainland and island populations, with additional substructuring on the mainland. Divergence between the mainland and Dirk Hartog was approximately 10 times more recent than the split between the ...岛屿种群与大陆种群间存在的显著性状差异，为探究自然条件下生态-进化过程的运作机制提供了绝佳研究契机。本研究以白翅细尾鹩莺（white-winged fairywren，*Malurus leucopterus*）的两次岛屿定居事件为研究对象，探究其黑化婚羽的基因组与种群起源。该鸟类广泛分布于澳大利亚大部分区域，大陆亚种（*M. l. leuconotus*）的雄鸟具有蓝色繁殖婚羽；而两个岛屿亚种——德克哈托格岛（Dirk Hartog Island）上的*M. l. leucopterus*与巴罗岛（Barrow Island）上的*M. l. edouardion*——的雄鸟则呈现黑色繁殖婚羽。本研究采用简化基因组测序（reduced-representation sequencing）技术，解析该物种的种群分化与种群历史，结果发现大陆种群与岛屿种群间存在清晰的分化模式，且大陆种群内部还存在额外的亚种群结构。大陆种群与德克哈托格岛种群的分化时间，相较某两分群的分化事件近约10倍……