Ecology and Evolutionary Biology Department, Yale University, 21 Sachem Street, New Haven, CT 06511, USA.
J Hered. 2013 Jan-Feb;104(1):23-35. doi: 10.1093/jhered/ess083. Epub 2012 Nov 5.
We conducted a mitochondrial phylogeographic study of the endemic dry forest rodent Eliurus carletoni (Rodentia: Nesomyinae) in an ecological transition zone of northern Madagascar (Loky-Manambato) and 2 surrounding regions (Ankarana and Analamerana). The main goal was to assess the evolutionary consequences on this taxon of the complex landscape features and Quaternary ecological vicissitudes. Three haplogroups were identified from the 215 specimens obtained from 15 populations. High levels of genetic diversity and significant genetic differentiation among populations were observed. The different geographical subdivisions of the study area by regions, by river catchment zones, and the physical distance between populations are not correlated with genetic patterns. In contrast, population structure is mostly explained by the geographic distribution of the samples among existing forest blocks. E. carletoni experienced a genetic bottleneck between 18 750 and 7500 years BP, which correlates with periods when moister climates existed on the island. Overall, our data suggest that the complex genetic patterns of E. carletoni can be explained by Quaternary climatic vicissitudes that resulted in habitat fluctuations between dry and humid forests, as well as subsequent human-induced fragmentation of forest habitat.
我们对马达加斯加北部生态过渡区（洛基-曼塔巴托）及周边两个地区（安卡拉纳和阿纳拉梅纳拉）的特有干森林啮齿动物伊柳利厄斯·卡雷托尼（Rodentia：Nesomyinae）进行了线粒体系统地理学研究。主要目标是评估该分类群在复杂景观特征和第四纪生态变迁方面的进化后果。从 15 个种群中获得的 215 个标本中鉴定出了 3 个单倍型群。观察到种群之间存在高水平的遗传多样性和显著的遗传分化。研究区域的不同地理分区（按地区、河流集水区和种群之间的物理距离）与遗传模式没有相关性。相反，种群结构主要由现有森林斑块之间的样本地理分布来解释。E. carletoni 在 18750 至 7500 年前经历了遗传瓶颈，这与岛上存在更湿润气候的时期相对应。总体而言，我们的数据表明，E. carletoni 的复杂遗传模式可以通过第四纪气候变迁来解释，这些变迁导致了干森林和湿森林之间的栖息地波动，以及随后人为导致的森林栖息地碎片化。
