Klimova Anastasia, Ortega-Rubio Alfredo, Vendrami David L J, Hoffman Joseph I
Centro de Investigaciones Biologicas del Noroeste S.C. La Paz Baja California Sur Mexico.
Department of Animal Behaviour Bielefeld University Bielefeld Germany.
Ecol Evol. 2018 May 8;8(11):5873-5890. doi: 10.1002/ece3.4125. eCollection 2018 Jun.
Comparative studies can provide powerful insights into processes that affect population divergence and thereby help to elucidate the mechanisms by which contemporary populations may respond to environmental change. Furthermore, approaches such as genotyping by sequencing (GBS) provide unprecedented power for resolving genetic differences among species and populations. We therefore used GBS to provide a genomewide perspective on the comparative population structure of two palm genera, and , on the Baja California peninsula, a region of high landscape and ecological complexity. First, we used phylogenetic analysis to address taxonomic uncertainties among five currently recognized species. We resolved three main clades, the first corresponding to and , the second to and , and the third to from Guadalupe Island. Focusing on the first two clades, we then delved deeper by investigating the underlying population structure. Striking differences were found, with GBS uncovering four distinct populations and identifying a suite of loci associated with temperature, consistent with ecologically mediated divergence. By contrast, individual mountain ranges could be resolved in and few loci were associated with environmental variables, implying a more prominent role of neutral divergence. Finally, evidence was found for long-distance dispersal events in but not , in line with knowledge of the dispersal mechanisms of these palms including the possibility of human-mediated dispersal. Overall, our study demonstrates the power of GBS together with a comparative approach to elucidate markedly different patterns of genomewide divergence mediated by multiple effectors.
比较研究能够为影响种群分化的过程提供强有力的见解，从而有助于阐明当代种群应对环境变化的机制。此外，诸如测序基因分型（GBS）等方法为解析物种和种群间的遗传差异提供了前所未有的能力。因此，我们利用GBS从全基因组角度对下加利福尼亚半岛上的两个棕榈属（ 和 ）的比较种群结构进行研究，该地区具有高度的地貌和生态复杂性。首先，我们利用系统发育分析来解决五个目前公认物种之间的分类学不确定性问题。我们解析出三个主要分支，第一个分支对应 和 ，第二个分支对应 和 ，第三个分支对应来自瓜达卢佩岛的 。聚焦于前两个分支，我们随后通过调查潜在的种群结构进行了更深入的研究。发现了显著差异，GBS揭示了四个不同的 种群，并识别出一组与温度相关的基因座，这与生态介导的分化一致。相比之下，在 中可以分辨出各个山脉，且很少有基因座与环境变量相关，这意味着中性分化起到了更突出的作用。最后，发现了 在长距离扩散事件方面的证据，而 在这方面没有，这与这些棕榈的扩散机制的知识相符，包括人类介导扩散的可能性。总体而言，我们的研究证明了GBS与比较方法相结合的强大作用，能够阐明由多种因素介导的全基因组分化的显著不同模式。
