Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut 06520, USA.
Evolution. 2013 Apr;67(4):1011-25. doi: 10.1111/evo.12017. Epub 2012 Dec 20.
Climatic and geological processes associated with glaciation cycles during the Pleistocene have been implicated in influencing patterns of genetic variation and promoting speciation of temperate flora and fauna. However, determining the factors promoting divergence and speciation is often difficult in many groups because of our limited understanding of potential vicariant barriers and connectivity between populations. Pleistocene glacial cycles are thought to have significantly influenced the distribution and diversity of subterranean invertebrates; however, impacts on subterranean aquatic vertebrates are less clear. We employed several hypothesis-driven approaches to assess the impacts of Pleistocene climatic and geological changes on the Northern Cavefish, Amblyopsis spelaea, whose current distribution occurs near the southern extent of glacial advances in North America. Our results show that the modern Ohio River has been a significant barrier to dispersal and is correlated with patterns of genetic divergence. We infer that populations were isolated in two refugia located north and south of the Ohio River during the most recent two glacial cycles with evidence of demographic expansion in the northern isolate. Finally, we conclude that climatic and geological processes have resulted in the formation of cryptic forms and advocate recognition of two distinct phylogenetic lineages currently recognized as A. spelaea.
与更新世冰川周期相关的气候和地质过程被认为影响了温带动植物的遗传变异模式，并促进了它们的物种形成。然而，由于我们对潜在的地理隔离障碍和种群之间的连通性了解有限，因此在许多群体中，确定促进分化和物种形成的因素往往很困难。更新世冰川周期被认为对地下无脊椎动物的分布和多样性有重大影响；然而，对地下水生脊椎动物的影响则不太清楚。我们采用了几种假设驱动的方法来评估更新世气候和地质变化对北方洞穴鱼（Amblyopsis spelaea）的影响，其当前分布在北美洲冰川推进的南部边缘附近。我们的研究结果表明，现代俄亥俄河是一个重要的扩散障碍，与遗传分化模式相关。我们推断，在最近的两次冰川周期中，俄亥俄河以北和以南的地区存在两个避难所，北方的避难所存在人口扩张的证据。最后，我们得出结论，气候和地质过程导致了隐种的形成，并主张承认目前被认为是 A. spelaea 的两个不同的系统发育谱系。
