To understand the process and mechanism of speciation, a detailed analysis of origin and demographic history of recently diverged species pairs is necessary. Here, we investigate the evolutionary history of Actaea purpurea (P.K. Hsiao) J. Compton and its closest relatives, A. japonica Thunb. and A. biternata (Siebold and Zuccarini) Prantl. We aim to estimate important parameters of the divergence event, and to lay the foundation for further investigation of the speciation mechanism of this system. Floral and vegetative traits were measured and analyzed. Genetic structure, divergence history, and historical gene flow were also inferred from the plastid and single nucleotide polymorphism data. Floral traits were divergent, and a strong match between pollinator and floral traits was revealed. Genetically the two species were also well diverged, and the time of divergence was dated to the Pleistocene. The demographic modelling results suggest that A. purpurea had continuous limited gene flow with A. japonica and A. biternata since divergence. More work is now needed to confirm that floral trait divergence was selected by pollinators, as well as to understand how pollinator isolation acts in conjunction with other reproductive barriers to reduce gene flow between the two species.

中文翻译：

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毛茛科及其近缘种的形态分化和第四纪物种形成

要了解物种形成的过程和机制，有必要对最近分化的物种对的起源和人口历史进行详细分析。在这里，我们调查了Actaea purpurea (PK Hsiao) J. Compton 及其近亲A. japonica Thunb的进化史。和A. biternata（西博尔德和祖卡里尼）普兰特尔。我们旨在估计分歧事件的重要参数，并为进一步研究该系统的物种形成机制奠定基础。测量和分析花卉和植物性状。还从质体和单核苷酸多态性数据推断出遗传结构、分歧历史和历史基因流。花性状存在差异，传粉者和花性状之间存在很强的匹配性。从基因上讲，这两个物种也有很好的分歧，分歧的时间可以追溯到更新世。人口统计学建模结果表明，A. purpurea与A. japonica和A. biternata的基因流动持续受限由于分歧。现在需要做更多的工作来确认传粉媒介选择了花性状差异，以及了解传粉媒介隔离如何与其他生殖障碍一起发挥作用，以减少两个物种之间的基因流动。