Genome-wide patterns of divergence and introgression after secondary contact between Pungitius sticklebacks
Genome-wide patterns of divergence and introgression after secondary contact between Pungitius sticklebacks
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DOI：
10.1098/rstb.2019.0548
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发表时间：
2020-07
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通讯作者：
Yo Y. Yamasaki;Ryo Kakioka;Hiroshi Takahashi;A. Toyoda;A. Nagano;Y. Machida;P. Møller;J. Kitano
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文献类型：
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作者：
Yo Y. Yamasaki;Ryo Kakioka;Hiroshi Takahashi;A. Toyoda;A. Nagano;Y. Machida;P. Møller;J. Kitano
物种形成是一个连续的过程。尽管众所周知，即使面对基因流，差异适应也可以引发分化，但我们对驱动完全生殖隔离的机制以及物种形成后期分化和基因渗入的基因组模式知之甚少。刺鱼包含许多对同域物种，其生殖隔离程度和分化历史不同。然而，之前的大多数研究都集中在年轻物种对上。在这里，我们调查了两种同域刺鱼：Pungitius pungitius 和 P. sinensis，它们的栖息地在北海道东部重叠。这些物种表现出杂交雄性不育性，表明它们可能处于物种形成的晚期阶段。我们使用全基因组序列数据进行的人口统计分析表明，这些物种分裂了 1.73 Ma，并在 37 200 年前经过一段异域繁殖后进入二次接触。这种长期的异域异域可能促进了内在不相容性的演变。尽管我们检测到持续的基因流和基因渗入特征，但总体基因组差异很高，整个基因组具有相当大的异质性。异质性与重组率的变化显着相关。这对同域生物为研究刺鱼物种形成连续体的后期阶段提供了新的途径。本文是主题“迈向物种形成的完成：超越第一道障碍的生殖隔离的进化”的一部分。
Speciation is a continuous process. Although it is known that differential adaptation can initiate divergence even in the face of gene flow, we know relatively little about the mechanisms driving complete reproductive isolation and the genomic patterns of divergence and introgression at the later stages of speciation. Sticklebacks contain many pairs of sympatric species differing in levels of reproductive isolation and divergence history. Nevertheless, most previous studies have focused on young species pairs. Here, we investigated two sympatric stickleback species, Pungitius pungitius and P. sinensis, whose habitats overlap in eastern Hokkaido; these species show hybrid male sterility, suggesting that they may be at a late stage of speciation. Our demographic analysis using whole-genome sequence data showed that these species split 1.73 Ma and came into secondary contact 37 200 years ago after a period of allopatry. This long period of allopatry might have promoted the evolution of intrinsic incompatibility. Although we detected on-going gene flow and signatures of introgression, overall genomic divergence was high, with considerable heterogeneity across the genome. The heterogeneity was significantly associated with variation in recombination rate. This sympatric pair provides new avenues to investigate the late stages of the stickleback speciation continuum. This article is part of the theme issue ‘Towards the completion of speciation: the evolution of reproductive isolation beyond the first barriers’.