Division of Evolutionary Biology, Zoological Institute, Technical University of Braunschweig, Mendelssohnstr 4, 38106 Braunschweig, Germany.
Mol Phylogenet Evol. 2012 Sep;64(3):618-32. doi: 10.1016/j.ympev.2012.05.018. Epub 2012 Jun 1.
We analyzed the influence of large rivers on the phylogeography of endemic widespread amphibians along Madagascar's east coast, using as models various species and species complexes of Malagasy reed frogs (Heterixalus spp.) that are specialized to either highland or lowland habitats. We assembled a dense sampling across the full species ranges and used mitochondrial (cob) as well as nuclear (Rag-1) DNA sequences to assess their phylogeographies. A multigene mtDNA phylogeny of each species was constructed to establish the relationships among the main phylogroups, in order to understand the geographical regions of clade origins and possible directions of historical range expansions. Distinct intraspecific lineages as diagnosed by mitochondrial haplotype clades were found in highlands and lowlands. Most geographical boundaries among these phylogroups did not coincide with rivers, indicating that the influence of rivers on the primary divergence of phylogroups is probably minor in these frogs. Nevertheless, we found evidence for the influence of one riverine barrier in the lowland species complex, where the most important genetic discontinuity (the border between Heterixalus madagascariensis and H. alboguttatus) coincides with the geographical position of the Mangoro River on Madagascar's central east coast. Analyses of the highland species H. betsileo revealed the existence of six deep haplotype lineages, separated in two major subpopulations which differ largely in altitudinal distribution and do not overlap with the geographical settings of rivers in the highlands. Furthermore, our analyses indicated that most of the major intraspecific lineages of reed frogs show signs of a rather recent population expansion.
我们分析了马达加斯加东海岸特有广布性两栖动物的系统地理学受大河影响的情况，选择适应高地或低地生境的马达加斯加芦苇蛙（Heterixalus 属）的不同种和种复合体作为模型。我们在整个物种分布范围内进行了密集采样，使用线粒体（cob）和核（Rag-1）DNA 序列来评估它们的系统地理学。构建了每个物种的多基因 mtDNA 系统发育树，以确定主要分支之间的关系，从而了解支系起源的地理区域和可能的历史分布扩张方向。通过线粒体单倍型分支诊断出高地和低地的独特种内谱系。这些分支中大多数地理边界与河流不一致，表明河流对分支的主要分化的影响在这些青蛙中可能较小。然而，我们发现了一个河流屏障对低地物种复合体的影响的证据，在该复合体中，最重要的遗传不连续性（马达加斯加芦苇蛙和白足芦苇蛙之间的边界）与马达加斯加中东部沿海的 Mangoro 河的地理位置一致。对高地物种 Heterixalus betsileo 的分析揭示了六个深单倍型谱系的存在，这些谱系分为两个主要的亚种群，它们在海拔分布上有很大的差异，与高地河流的地理环境没有重叠。此外，我们的分析表明，芦苇蛙的大多数主要种内谱系都显示出种群扩张的迹象。
