Data from: Gene trees, species trees and Earth history combine to shed light on the evolution of migration in a model avian system

The evolution of migration in birds has fascinated biologists for centuries. In this study, we performed phylogenetic-based analyses of Catharus thrushes, a model genus in the study of avian migration, and their close relatives. For these analyses, we used both mitochondrial and nuclear genes, and the resulting phylogenies were used to trace migratory traits and biogeographic patterns. Our results provide the first robust assessment of relationships within Catharus and relatives and indicate that both mitochondrial and autosomal genes contribute to overall support of the phylogeny. Measures of phylogenetic informativeness indicated that mitochondrial genes provided more signal within Catharus than did nuclear genes, whereas nuclear loci provided more signal for relationships between Catharus and close relatives than did mitochondrial genes. Insertion and deletion events also contributed important support across the phylogeny. Across all taxa included in the study, and for Catharus, possession of long-distance migration is reconstructed as the ancestral condition, and a North American (north of Mexico) ancestral area is inferred. Within Catharus, sedentary behaviour evolved after the first speciation event in the genus and is geographically and temporally correlated with Central American distributions and the final closure of the Central American Seaway. Migratory behaviour subsequently evolved twice in Catharus and is geographically and temporally correlated with a recolonization of North America in the late Pleistocene. By temporally linking speciation events with changes in migratory condition and events in Earth history, we are able to show support for several competing hypotheses relating to the geographic origin of migration.数个世纪以来，鸟类迁徙演化始终令生物学家为之着迷。本研究针对鸟类迁徙研究中的模式类群——夜鸫属（Catharus）鸫类及其近缘类群开展了基于系统发育的分析。本次分析同时采用线粒体基因与核基因，所得系统发育树被用于追溯迁徙性状与生物地理格局的演化历史。本研究结果首次对夜鸫属及其近缘类群的系统发育关系给出了稳健的评估，结果表明线粒体基因与常染色体基因均为系统发育树的整体支持度提供了贡献。系统发育信息性指标显示，在线粒体基因与核基因的对比中，线粒体基因在夜鸫属内部提供了更强的系统发育信号，而核基因位点则在夜鸫属与其近缘类群的关系解析中表现更优。插入与缺失突变事件同样为整个系统发育树的节点支持度提供了重要依据。针对本研究涵盖的所有类群以及夜鸫属本身，长距离迁徙性状均被重建为祖先状态，同时推断其祖先分布区为墨西哥以北的北美地区。在夜鸫属内部，留居习性是在该属首次物种形成事件之后演化而来的，其地理与时间分布均与中美洲分布格局以及中美洲海道的最终闭合事件相关联。迁徙性状随后在夜鸫属内独立演化了两次，其地理与时间分布均与更新世晚期对北美地区的重新定殖事件相关联。通过将物种形成事件与迁徙状态变化以及地球历史事件进行时间维度上的关联，本研究为若干关于迁徙性状地理起源的竞争性假说提供了支持依据。