Widespread gene flow following range expansion in Anna's Hummingbird
Widespread gene flow following range expansion in Anna's Hummingbird
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DOI：
10.1111/mec.16928
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发表时间：
2023-04-02
影响因子：
4.9
通讯作者：
Bay，Rachael A.
中科院分区：
文献类型：
--
作者：
Adams，Nicole E.;Bandivadekar，Ruta R.;Bay，Rachael A.
人为的变化改变了许多北美类群的历史分布。随着环境的变化，生态和进化过程可以以复杂的方式联合收割机来刺激或抑制范围的扩大。在这里，我们研究了进化在快速范围扩张中的作用，其生态背景已经得到了很好的记录，安娜的蜂鸟（卡利普特安娜）。以前的研究表明，C. annarange扩张是由人为环境变化促进的生态释放的结果，其中获得新的食物来源允许进一步填充非生物生态位。我们研究了从它们的原生加州繁殖范围向北到加拿大，向东到新墨西哥州和美国德克萨斯州的范围扩张过程中基因流动和适应的作用。使用低覆盖率的全基因组测序，我们发现高的遗传多样性，低分歧，并在北方和东部扩展前线的选择的证据很少。此外，没有明显的障碍，基因流动跨越原生和扩大的范围。核心和扩展范围之间缺乏选择信号可能反映了（i）扩展范围中缺乏新的选择压力（支持生态释放假说），（ii）由于高基因流导致的适应性变异的淹没，或（iii）基因组扫描在检测许多基因座等位基因频率的小变化方面的局限性。然而，我们的研究结果提供了一个例子，强选择是不明显的，在一个快速的，当代的范围转移。
Anthropogenic changes have altered the historical distributions of many North American taxa. As environments shift, ecological and evolutionary processes can combine in complex ways to either stimulate or inhibit range expansion. Here, we examined the role of evolution in a rapid range expansion whose ecological context has been well‐documented, Anna's Hummingbird (Calypte anna). Previous studies have suggested that theC. annarange expansion is the result of an ecological release facilitated by human‐mediated environmental changes, where access to new food sources have allowed further filling of the abiotic niche. We examined the role of gene flow and adaptation during range expansion from their native California breeding range, north into Canada and east into New Mexico and Texas, USA. Using low coverage whole genome sequencing we found high genetic diversity, low divergence, and little evidence of selection on the northern and eastern expansion fronts. Additionally, there are no clear barriers to gene flow across the native and expanded range. The lack of selective signals between core and expanded ranges could reflect (i) an absence of novel selection pressure in the expanded range (supporting the ecological release hypothesis), (ii) swamping of adaptive variation due to high gene flow, or (iii) limitations of genome scans for detecting small shifts in allele frequencies across many loci. Nevertheless, our results provide an example where strong selection is not apparent during a rapid, contemporary range shift.