Center for Environmental Studies, Virginia Commonwealth University, Richmond, Virginia.
Department of Biology, Virginia Commonwealth University, Richmond, Virginia.
Mol Ecol. 2019 May;28(9):2122-2135. doi: 10.1111/mec.15083. Epub 2019 May 27.
Understanding migratory connectivity is essential for determining the drivers behind population dynamics and for implementing effective conservation strategies for migratory species. Genetic markers provide a means to describe migratory connectivity; however, they can be uninformative for species with weak population genetic structure, which has limited their application. Here, we demonstrated a genomic approach to describing migratory connectivity in the prothonotary warbler, Protonotaria citrea, a Neotropical songbird of conservation concern. Using 26,189 single nucleotide polymorphisms (SNPs), we revealed regional genetic structure between the Mississippi River Valley and the Atlantic Seaboard with overall weak genetic differentiation among populations (F = 0.0055; 95% CI: 0.0051-0.0059). Genetic variation had a stronger association with geographic rather than environmental factors, with each explaining 14.5% and 8.2% of genetic variation, respectively. By varying the numbers of genomic markers used in population assignment models with individuals of known provenance, we identified a maximum assignment accuracy (89.7% to site, 94.3% to region) using a subset of 600 highly differentiated SNPs. We then assigned samples from nonbreeding sites to breeding region and found low migratory connectivity. Our results highlight the importance of filtering markers for informative loci in models of population assignment. Quantifying migratory connectivity for weakly structured species will be useful for expanding studies to a wider range of migratory species across taxonomic groups and may contribute to a deeper understanding of the evolution of migratory strategies.
了解迁徙连通性对于确定种群动态的驱动因素以及实施针对迁徙物种的有效保护策略至关重要。遗传标记为描述迁徙连通性提供了一种手段；然而，对于遗传结构较弱的物种，它们可能没有信息，这限制了它们的应用。在这里，我们展示了一种基因组方法来描述 Protonotaria citrea（一种受保护的新热带鸣禽）的迁徙连通性。使用 26,189 个单核苷酸多态性（SNP），我们揭示了密西西比河流域和大西洋海岸之间的区域遗传结构，总体上种群间的遗传分化较弱（F = 0.0055；95%置信区间：0.0051-0.0059）。遗传变异与地理因素的相关性强于与环境因素的相关性，分别解释了 14.5%和 8.2%的遗传变异。通过在具有已知起源的个体中使用不同数量的基因组标记来改变种群分配模型中的标记数量，我们使用一组 600 个高度分化的 SNP 确定了最大的分配准确性（89.7%到站点，94.3%到区域）。然后，我们将非繁殖地的样本分配到繁殖区，并发现迁徙连通性较低。我们的研究结果强调了在种群分配模型中筛选标记以获得信息性基因座的重要性。量化遗传结构较弱的物种的迁徙连通性将有助于将研究扩展到更广泛的分类群中的迁徙物种，并可能有助于深入了解迁徙策略的进化。
