University of Nevada, Las Vegas, Las Vegas, NV 89154-4004, USA.
Mol Ecol. 2010 May;19(9):1860-76. doi: 10.1111/j.1365-294X.2010.04616.x. Epub 2010 Apr 6.
Two factors that can lead to geographic structuring in conspecific populations are barriers to dispersal and climatic stability. Populations that occur in different physiographic regions may be restricted to those areas by physical and/or ecological barriers, which may facilitate the formation of phylogeographic clades. Long-term climatic stability can also promote genetic diversification, because new clades are more likely to evolve in areas that experience lesser climatic shifts. We conducted a phylogeographic study of the Puerto Rican lizard Anolis krugi to assess whether populations of this anole show genetic discontinuities across the species' range, and if they do, whether these breaks coincide with the boundaries of the five physiographic regions of Puerto Rico. We also assessed whether interpopulation genetic distances in A. krugi are positively correlated with relative climatic stability in the island. Anolis krugi exhibits genetic structuring, but the phylogroups do not correspond to the physiographic regions of Puerto Rico. We used climatic reconstructions of two environmental extremes of the Quaternary period, the present conditions and those during the last glacial maximum (LGM), to quantify the degree of climatic stability between sampling locations. We documented positive correlations between genetic distances and relative climatic stability, although these associations were not significant when corrected for autocorrelation. Principal component analyses indicated the existence of climatic niche differences between some phylogeographic clades of A. krugi. The approach that we employed to assess the relationship between climatic stability and the genetic architecture of A. krugi can also be used to investigate the impact of factors such as the spatial distribution of food sources, parasites, predators or competitors on the genetic landscape of a species.
导致同种种群地理结构形成的两个因素是扩散障碍和气候稳定性。发生在不同地貌区域的种群可能会受到物理和/或生态障碍的限制，这可能有利于形成系统发育分支。长期的气候稳定性也可以促进遗传多样化，因为在经历较小气候变化的地区，新的分支更有可能进化。我们对波多黎各蜥蜴 Anolis krugi 进行了系统地理学研究，以评估这种石龙子的种群是否在其分布范围内存在遗传不连续性，如果存在，这些间断是否与波多黎各五个地貌区域的边界相对应。我们还评估了 A. krugi 种群间遗传距离是否与岛上相对气候稳定性呈正相关。Anolis krugi 表现出遗传结构，但系统发育群与波多黎各的地貌区域并不对应。我们使用了两种环境极端情况（即现代条件和末次冰期最大值）的气候重建，以量化采样地点之间的气候稳定性程度。我们记录了遗传距离与相对气候稳定性之间的正相关关系，尽管在纠正自相关后，这些关联并不显著。主成分分析表明，A. krugi 的一些系统发育分支之间存在气候生态位差异。我们用来评估气候稳定性与 A. krugi 遗传结构之间关系的方法也可用于研究诸如食物源、寄生虫、捕食者或竞争者的空间分布等因素对物种遗传景观的影响。
