Callahan Melissa S, McPeek Mark A
Department of Biological Sciences, Dartmouth College, 78 College Street, Hanover, NH 03755, United States.
Mol Phylogenet Evol. 2016 Jan;94(Pt A):182-95. doi: 10.1016/j.ympev.2015.08.013. Epub 2015 Aug 28.
Reconstructing evolutionary patterns of species and populations provides a framework for asking questions about the impacts of climate change. Here we use a multilocus dataset to estimate gene trees under maximum likelihood and Bayesian models to obtain a robust estimate of relationships for a genus of North American damselflies, Enallagma. Using a relaxed molecular clock, we estimate the divergence times for this group. Furthermore, to account for the fact that gene tree analyses can overestimate ages of population divergences, we use a multi-population coalescent model to gain a more accurate estimate of divergence times. We also infer diversification rates using a method that allows for variation in diversification rate through time and among lineages. Our results reveal a complex evolutionary history of Enallagma, in which divergence events both predate and occur during Pleistocene climate fluctuations. There is also evidence of diversification rate heterogeneity across the tree. These divergence time estimates provide a foundation for addressing the relative significance of historical climatic events in the diversification of this genus.
重建物种和种群的进化模式为探讨气候变化的影响提供了一个框架。在此，我们使用一个多位点数据集，在最大似然法和贝叶斯模型下估计基因树，以获得北美豆娘属（Enallagma）关系的稳健估计。使用宽松分子钟，我们估计了该类群的分歧时间。此外，考虑到基因树分析可能高估种群分歧的时间，我们使用多群体溯祖模型来更准确地估计分歧时间。我们还使用一种允许多样化速率随时间和谱系变化的方法来推断多样化速率。我们的结果揭示了Enallagma复杂的进化历史，其中分歧事件既早于更新世气候波动，也发生在更新世气候波动期间。同时也有证据表明整个谱系存在多样化速率的异质性。这些分歧时间估计为探讨历史气候事件在该属多样化中的相对重要性奠定了基础。
