Data from: Understanding the mechanisms of anti-tropical divergence in the seabird White-faced Storm-petrel (Procellariiformes: Pelagodroma marina) using a multi-locus approach

Analytical methods that apply coalescent theory to multilocus data have improved inferences of demographic parameters that are critical to understanding population divergence and speciation. In particular, at the early stages of speciation, it is important to implement models that accommodate conflicting gene trees, and benefit from the presence of shared polymorphisms. Here, we employ eleven nuclear loci and the mitochondrial control region to investigate the phylogeography and historical demography of the pelagic seabird White-faced Storm-petrel (Pelagodroma marina) by sampling subspecies across its antitropical distribution. Groups are all highly differentiated: global mitochondrial ΦST = 0.89 (P < 0.01) and global nuclear ΦST varies between 0.22 and 0.83 (all P < 0.01). The complete lineage sorting of the mitochondrial locus between hemispheres is corroborated by approximately half of the nuclear genealogies, suggesting a long-term antitropical divergence in isolation. Coalescent-based estimates of demographic parameters suggest that hemispheric divergence of P. marina occurred approximately 840 000 ya (95% HPD 582 000–1 170 000), in the absence of gene flow, and divergence within the Southern Hemisphere occurred 190 000 ya (95% HPD 96 000–600 000), both probably associated with the profound palaeo-oceanographic changes of the Pleistocene. A fledgling sampled in St Helena (tropical South Atlantic) suggests recent colonization from the Northern Hemisphere. Despite the great potential for long-distance dispersal, P. marina antitropical groups have been evolving as independent, allopatric lineages, and divergence is probably maintained by philopatry coupled with asynchronous reproductive phenology and local adaptation.

将溯祖理论（coalescent theory）应用于多位点数据的分析方法，已提升了对种群分化与物种形成至关重要的种群参数的推断精度。尤其在物种形成的早期阶段，构建能够适配冲突基因树、并利用共享多态性信息的模型尤为关键。本研究通过在白脸风暴海燕（Pelagodroma marina）的反热带分布范围内采集亚种样本，利用11个核基因座与线粒体控制区，探究该远洋海鸟的系统地理学特征与历史种群动态。各群体均呈现高度分化：全球范围线粒体ΦST值为0.89（P < 0.01），核基因座的全球ΦST值介于0.22至0.83之间（所有P值均< 0.01）。约半数核基因谱系证实了半球间线粒体基因座的完全谱系分选现象，表明该类群长期处于隔离状态下的反热带分化。基于溯祖理论的种群参数估算结果显示，白脸风暴海燕的半球分化发生于约84万年前（95%最高后验密度区间（95% HPD）：58.2万–117万年），期间无基因流发生；南半球内部的分化则发生于约19万年前（95%最高后验密度区间（95% HPD）：9.6万–60万年），两次分化均可能与更新世剧烈的古海洋变化相关。在圣赫勒拿岛（南大西洋热带海域）采集到的1只雏鸟，表明该区域近期存在来自北半球的定殖事件。尽管白脸风暴海燕具备极强的长距离扩散能力，但其反热带群体已作为独立的异域支系演化，种群分化可能通过恋巢行为、异步生殖物候与局部适应得以维持。