The geographic distribution of phenotypic variation among closely related populations is a valuable source of information about the evolutionary processes that generate and maintain biodiversity. Leapfrog distributions, in which phenotypically similar populations are disjunctly distributed and separated by one or more phenotypically distinct populations, represent geographic replicates for the existence of a phenotype, and are therefore especially informative. These geographic patterns have mostly been studied from phylogenetic perspectives to understand how common ancestry and divergent evolution drive their formation. Other processes, such as gene flow between populations, have not received as much attention. Here, we investigate the roles of divergence and gene flow between populations in the origin and maintenance of a leapfrog distribution in Phyllobates poison frogs. We found evidence for high levels of gene flow between neighbouring populations but not over long distances, indicating that gene flow between populations exhibiting the central phenotype may have a homogenizing effect that maintains their similarity, and that introgression between ‘leapfroging’ taxa has not played a prominent role as a driver of phenotypic diversity in Phyllobates. Although phylogenetic analyses suggest that the leapfrog distribution was formed through independent evolution of the peripheral (i.e. leapfrogging) populations, the elevated levels of gene flow between geographically close populations poise alternative scenarios, such as the history of phenotypic change becoming decoupled from genome‐averaged patterns of divergence, which we cannot rule out. These results highlight the importance of incorporating gene flow between populations into the study of geographic variation in phenotypes, both as a driver of phenotypic diversity and as a confounding factor of phylogeographic inferences.

中文翻译：

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散度，基因流和越级地理分布的起源：毛叶毒蛙的颜色模式变化历史。

表型变异在密切相关的人群中的地理分布是有关生成和维持生物多样性的进化过程的宝贵信息来源。跨越表型分布，其中表型相似的种群被一个或多个表型不同的种群离散地分布和分隔，代表了表型存在的地理复制，因此特别有用。这些地理模式主要是从系统发育的角度进行研究的，以了解共同的祖先和发散的进化如何驱动它们的形成。其他过程，例如群体之间的基因流动，并未引起足够的重视。在这里，我们调查人口之间的分歧和基因流在起源和维持跨越式分布中的作用。叶状毒蛙。我们发现有证据表明邻近种群之间存在高水平的基因流动，但距离却不是很长，这表明表现出中心表型的种群之间的基因流动可能具有均化作用，保持了它们的相似性，而“跨越”类群之间的基因渗入并未发挥作用作为叶状表型多样性驱动因素的重要作用。尽管系统发育分析表明，越级分布是通过外围（即越级）种群的独立进化形成的，但地理上紧密的种群之间的基因流水平升高却构成了替代方案，例如表型变化的历史与基因组平均模式脱钩。分歧，我们不能排除。这些结果凸显了将种群之间的基因流整合到表型地理变异研究中的重要性，这既是表型多样性的驱动力又是系统地理学推断的混杂因素。