Department of Biology, McMaster University, Life Sciences Building Room 328, 1280 Main Street West, Hamilton, ON, L8S 4K1 Canada.
Mol Ecol. 2011 Oct;20(20):4216-30. doi: 10.1111/j.1365-294X.2011.05262.x. Epub 2011 Sep 20.
The Ethiopian highlands - home to striking species diversity and endemism - are bisected by the Rift Valley, a zone of tectonic divergence. Using molecular data we examined the evolutionary history of two co-distributed species of African clawed frog (Xenopus clivii and X. largeni) that are endemic to this region. Our field collections substantially extend the known distribution of X. largeni, a species formerly known from highlands southeast of the Rift, but that also occurs to the northwest. In both species, analysis of mitochondrial DNA and 19 autosomal loci identifies significant population structure, suggests little or no recent migration across the Rift Valley, and provides divergence time estimates across the Rift of ∼1-3.5 million years. These results indicate that the Ethiopian Rift Valley is a major obstacle to dispersal of highland-adapted amphibians.
埃塞俄比亚高原——拥有引人注目的物种多样性和特有性——被裂谷分割，裂谷是构造发散的地带。我们使用分子数据研究了两种共同分布的非洲爪蟾（Xenopus clivii 和 X. largeni）的进化历史，这两种物种都分布在该地区。我们的实地采集大大扩展了 X. largeni 的已知分布范围，这种物种以前只在裂谷东南部的高地发现，但也出现在西北部。在这两个物种中，线粒体 DNA 和 19 个常染色体基因座的分析表明存在显著的种群结构，表明裂谷地区很少或没有最近的迁徙，并且裂谷的分化时间估计约为 1-350 万年。这些结果表明，埃塞俄比亚裂谷是适应高地的两栖动物扩散的主要障碍。
