Complex patterns of hybridization and introgression across evolutionary timescales in Mexican whiptail lizards (Aspidoscelis)
Complex patterns of hybridization and introgression across evolutionary timescales in Mexican whiptail lizards (Aspidoscelis)
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DOI：
10.1016/j.ympev.2018.12.016
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发表时间：
2019-03-01
影响因子：
4.1
通讯作者：
Thomson, Robert C.
中科院分区：
文献类型：
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作者：
Barley, Anthony J.;Nieto-Montes de Oca, Adrian;Thomson, Robert C.
识别整个生命树的基因渗入模式是理解基因流对物种形成过程影响的一般机制的基础。很少有脊椎动物群体中的杂交与北美鞭尾蜥蜴（Aspidoscelis）的结果的多样性相关。特别令人感兴趣的是，不同鞭尾鱼物种之间的杂交一再导致单性（单性生殖）谱系的形成。要了解这些单性谱系的杂交起源，需要准确了解雌雄异株鞭尾鱼之间的物种边界。这样做在历史上一直是一个极具挑战性的问题，部分原因可能是血统之间广泛的杂交和不完全的生殖隔离。缺乏一个强大的系统发育框架和物种边界的不确定性排除了一般模式和机制的研究鞭尾物种之间的渐渗。在这里，我们使用基因组数据来重建一个强大的估计进化历史的最大分支鞭尾蜥蜴（A。sexlineatus物种组），并使用它来鉴定基因渗入的模式。我们的研究结果表明，大量的渐渗杂交和混合物发生在不同的进化时间尺度的鞭尾多个谱系之间，并说明它们对系统发育推断的影响。因此，鞭尾物种之间的杂交似乎是其整个进化历史中的一个突出特征，这可以部分解释为什么与其他脊椎动物相比，鞭尾动物的单性生殖进化了这么多次。
Identifying patterns of introgression across the tree of life is foundational to understanding general mechanisms that govern the impacts of gene flow on the speciation process. There are few vertebrate groups in which hybridization is associated with as large a diversity of outcomes as in North American whiptail lizards (Aspidoscelis). Of particular interest is that hybridization among divergent whiptail species has repeatedly led to the formation of unisexual (parthenogenetic) lineages. Understanding the hybrid origin of these unisexual lineages requires an accurate understanding of species boundaries among gonochoristic whiptails. Doing so has historically been an extremely challenging problem which, in part, may be a consequence of widespread hybridization and incomplete reproductive isolation among lineages. The lack of a robust phylogenetic framework and uncertainty in species boundaries precludes studies of general patterns and mechanisms of introgression among whiptail species. Here, we use genomic data to reconstruct a robust estimate of evolutionary history in the largest clade of whiptail lizards (A. sexlineatus species group) and use it to identify patterns of introgression. Our results indicate substantial introgressive hybridization and admixture has occurred among multiple lineages of whiptails across diverse evolutionary time scales, and illustrate their impact on phylogenetic inference. Thus, hybridization among whiptail species appears to have been a prominent feature throughout their evolutionary history, which could, in part, explain why parthenogenesis has evolved so many times in whiptails in comparison to other vertebrate groups.