Data from: Post-glacial recolonization of the North American Arctic by Arctic char (Salvelinus alpinus): genetic evidence of multiple northern refugia and hybridization between glacial lineages

Aims: We investigated post-glacial recolonization of the North American Arctic by Arctic char (Salvelinus alpinus) and examined potential hybridization between different glacial lineages upon secondary contact. Location: North American Arctic and adjacent areas. Methods: We collected mtDNA sequence data from 1355 individuals from 110 sampling locations and data from nine microsatellite loci from 931 individuals from 37 locations. We assessed the phylogenetic relationships and geographical distribution of mtDNA haplotypes and conducted historical demographic analyses. We used a Bayesian clustering analysis method to detect potential hybridization between glacial lineages. Results: Two highly divergent mtDNA lineages were identified in the Arctic region with distinct but overlapping geographic distributions: one in Beringia and the other over the entire Arctic Archipelago and coastal mainland east of Alaska. The microsatellite data also implied the existence of these two lineages. Evidence of hybridization was detected between the Arctic lineage and an Atlantic lineage in eastern North America. Main conclusions: Our data suggested survival and recolonization from two northern glacial refugia: one in Beringia and another in a smaller refugium, perhaps in the Arctic Archipelago itself or a separate refugium within Beringia. Patterns of hybridization detected supported the presence of a secondary contact zone between glacial lineages in the eastern Canadian Arctic.研究目标：本研究旨在探究北极红点鲑（Salvelinus alpinus）在北美北极区域的冰期后拓殖过程，并考察不同冰期谱系在二次接触时的潜在杂交现象。 研究区域：北美北极及毗邻区域。 研究方法：本研究从110个采样点的1355个个体中获取线粒体DNA（mtDNA）序列数据，并从37个采样点的931个个体中获取9个微卫星位点的遗传分型数据。我们评估了线粒体DNA单倍型的系统发育关系与地理分布格局，同时开展历史种群动态分析；此外，采用贝叶斯聚类分析方法以检测冰期谱系间的潜在杂交事件。 研究结果：本研究在北极区域发现两个高度分化的线粒体DNA谱系，二者地理分布范围虽有重叠但特征迥异：一支分布于白令陆桥区域，另一支则覆盖整个北极群岛及阿拉斯加以东的沿海大陆地区。微卫星数据亦佐证了这两个谱系的存在。在北美东部区域，研究人员检测到北极谱系与大西洋谱系间的杂交证据。 主要结论：本研究数据表明，北极红点鲑从两处北部冰期避难所完成存续与冰期后拓殖：一处位于白令陆桥区域，另一处为面积较小的避难所，可能位于北极群岛内部，或是白令陆桥内的一处独立避难所。检测到的杂交格局证实，加拿大北极东部区域存在冰期谱系间的二次接触带。