Rapid evolutionary divergence of a songbird population following recent colonization of an urban area
Rapid evolutionary divergence of a songbird population following recent colonization of an urban area
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DOI：
10.1111/mec.16422
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发表时间：
2022-03-17
影响因子：
4.9
通讯作者：
Mila, Borja
中科院分区：
文献类型：
--
作者：
Friis, Guillermo;Atwell, Jonathan W.;Mila, Borja
少数个体对一个新环境的殖民可以导致快速的进化变化，但很少有证据表明中性和选择性因素在殖民早期阶段对促进分歧的相对贡献。在这里，我们探索中性和选择性力量在一个独特的城市种群的分化中所起的作用。这种独特的城市种群于20世纪80年代初在加州大学圣地亚哥分校(UCSD)成立。以前基于微卫星座位的研究记录了城市种群的显著遗传分化以及相对于附近山地种群的表型特征的差异，但殖民的地理来源和促成因素仍不确定。我们的全基因组单核苷酸多态数据集证实了加州大学洛杉矶分校种群的显著遗传分化，我们将来自加州中部的沿海亚种Pinosus确定为其姊妹群，而不是邻近的山区种群。人口统计推断在经历了一个强烈的瓶颈后，直到20-32代前才恢复了与Pinosus的分离，这表明漂移在遗传分化中发挥了作用。然而，我们也发现栖息地变量和与功能基因相关的全基因组变异之间存在显著的关联，其中一些被报道为对栖息在改良环境中的鸟类具有潜在的适应性。这些结果表明，创始人事件和选择之间的相互作用可能导致整个基因组中中性和适应性基因座的快速转移，并揭示了UCSD Junco种群是人类环境中当代进化分化的案例。
Colonization of a novel environment by a few individuals can lead to rapid evolutionary change, yet there is scarce evidence of the relative contributions of neutral and selective factors in promoting divergence during the early stages of colonization. Here we explore the role of neutral and selective forces in the divergence of a unique urban population of the dark-eyed junco (Junco hyemalis), which became established on the campus of the University of California at San Diego (UCSD) in the early 1980s. Previous studies based on microsatellite loci documented significant genetic differentiation of the urban population as well as divergence in phenotypic traits relative to nearby montane populations, yet the geographical origin of the colonization and the contributing factors remained uncertain. Our genome-wide single nucleotide polymorphism data set confirmed the marked genetic differentiation of the UCSD population, and we identified the coastal subspecies pinosus from central California as its sister group instead of the neighbouring mountain population. Demographic inference recovered a separation from pinosus as recent as 20-32 generations ago after a strong bottleneck, suggesting a role for drift in genetic differentiation. However, we also found significant associations between habitat variables and genome-wide variants linked to functional genes, some of which have been reported as potentially adaptive in birds inhabiting modified environments. These results suggest that the interplay between founder events and selection may result in rapid shifts in neutral and adaptive loci across the genome, and reveal the UCSD junco population as a case of contemporary evolutionary divergence in an anthropogenic environment.