Using demographic model selection to untangle allopatric divergence and diversification mechanisms in the Rheum palmatum complex in the Eastern Asiatic Region
Using demographic model selection to untangle allopatric divergence and diversification mechanisms in the Rheum palmatum complex in the Eastern Asiatic Region
复制标题
利用人口统计模型选择来理清东亚地区掌叶大黄复合体的异域分化和多样化机制
DOI：
10.1111/mec.15448
复制
发表时间：
2020-05-14
影响因子：
4.9
通讯作者：
Wang, Xu-Mei
中科院分区：
文献类型：
--
作者：
Feng, Li;Ruhsam, Markus;Wang, Xu-Mei
异域性分异通常是由地质隆升和对天岛、气候振荡或河流捕获的限制而引发的。然而，很难确定哪种机制最有可能产生一个物种目前的地理结构。最近，基因组数据结合模型测试框架已被应用于解决动物中的这个问题。为了测试这种方法是否也可能在植物中成功，我们使用了来自东亚地区的掌叶大黄复合体的群体基因组数据，结合地理重建和人口模型选择，以确定导致当前分歧水平的潜在机制。我们的结果表明，R. palmatum复合体起源于横断山脉中部，并可能在更远的东部地区，然后向西和向东扩散，导致遗传上不同的谱系。种群很可能在气候振荡期间，随后的扩张和二次接触中，在避难所中发生分歧。然而，在西方血统的R。palmatum复合体不能拒绝限制天空岛屿作为一种可能的多样化机制，由于一个人口的遗传模糊的位置。这突出表明，在某些情况下，基因混合的群体可能会对最佳多样化模式产生模糊性。虽然可能使用其他数据来解决这种模糊性，但有时在复杂的地理区域这可能证明是困难的。
Allopatric divergence is often initiated by geological uplift and restriction to sky-islands, climate oscillations, or river capture. However, it can be difficult to establish which mechanism was the most likely to generate the current phylogeographical structure of a species. Recently, genomic data in conjunction with a model testing framework have been applied to address this issue in animals. To test whether such an approach is also likely to be successful in plants, we used population genomic data of the Rheum palmatum complex from the Eastern Asiatic Region, in conjunction with biogeographical reconstruction and demographic model selection, to identify the potential mechanism(s) which have led to the current level of divergence. Our results indicate that the R. palmatum complex originated in the central Hengduan Mts and possibly in regions further east, and then dispersed westward and eastward resulting in genetically distinct lineages. Populations are likely to have diverged in refugia during climate oscillations followed by subsequent expansion and secondary contact. However, model simulations within the western lineage of the R. palmatum complex cannot reject a restriction to sky-islands as a possible mechanism of diversification due to the genetically ambiguous position of one population. This highlights that genetically mixed populations might introduce ambiguity regarding the best diversification model in some cases. Although it might be possible to resolve this ambiguity using other data, sometimes this could prove to be difficult in complex biogeographical areas.