ddRAD-seq data of two Goldeneye species

Delineation of population structure provides valuable information for conservation and management of species. Here, we measure population genetic structure and connectivity across the respective ranges of two sister species of Goldeneye, Barrows and Common Goldeneye. Sampling 3,678 ddRAD-seq loci across 61 samples, we recover strong population structure between these two sister species. Next, although inter-specific brood parasitism was expected to cause some level of gene flow, we only identified a single F1 hybrid with no further evidence of contemporary or historical gene flow. Despite ddRAD-seq demographic analyses which recovered an optimum evolutionary model of split with migration (i.e., secondary contact), estimates of gene flow were <<1 migrant per generation in both directions. Together, we conclude that either strong ecological barriers or assortative mating are likely playing a role in preventing further backcrossing. Finally, demographic analyses estimated a relatively deep divergence time between Barrows Goldeneye and Common Goldeneye of ~1.6 million years before present and that the genomes of both species have been under similar evolutionary constraints.

种群结构解析可为物种的保护与管理提供重要参考依据。本研究针对两种鹊鸭姐妹种——巴氏鹊鸭（Barrows Goldeneye）与普通鹊鸭（Common Goldeneye）的分布范围，开展了种群遗传结构与连通性分析。本研究对61份样本进行测序，获取了3678个ddRAD-seq位点，结果显示这两种鹊鸭姐妹种间存在显著的种群遗传分化。尽管此前推测种间巢寄生可能会导致一定程度的基因交流，但本研究仅发现1例F1杂交个体，未发现当代或历史基因交流的其他证据。尽管基于ddRAD-seq的种群历史动态分析筛选出了最优的分化伴基因流进化模型（即次生接触模型），但双向的基因流估计值均远低于每世代1个迁移个体的阈值。综合以上结果，我们认为强烈的生态屏障或选型交配可能是阻止后续回交发生的关键因素。最后，种群历史动态分析估计，巴氏鹊鸭与普通鹊鸭的分化时间相对较深，约为160万年前，且两个物种的基因组均受到相似的进化约束。