Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK.
Mol Ecol. 2011 Nov;20(21):4533-49. doi: 10.1111/j.1365-294X.2011.05268.x. Epub 2011 Oct 10.
South-East Asia is one of the world's richest regions in terms of biodiversity. An understanding of the distribution of diversity and the factors shaping it is lacking, yet essential for identifying conservation priorities for the region's highly threatened biodiversity. Here, we take a large-scale comparative approach, combining data from nine forest-associated Anopheles mosquito species and using statistical phylogeographical methods to disentangle the effects of environmental history, species-specific ecology and random coalescent effects. Spatially explicit modelling of Pleistocene demographic history supports a common influence of environmental events in shaping the genetic diversity of all species examined, despite differences in species' mtDNA gene trees. Populations were periodically restricted to allopatric northeastern and northwestern refugia, most likely due to Pleistocene forest fragmentation. Subsequent southwards post-glacial recolonization is supported by a north-south gradient of decreasing genetic diversity. Repeated allopatric fragmentation and recolonization have led to the formation of deeply divergent geographical lineages within four species and a suture zone where these intraspecific lineages meet along the Thai-Myanmar border. A common environmental influence for this divergence was further indicated by strong support for simultaneous divergence within the same four species, dating to approximately 900 thousand years ago (kya). Differences in the geographical structuring of genetic diversity between species are probably the result of varying species' biology. The findings have important implications for conservation planning; if the refugial regions and suture zone identified here are shared by other forest taxa, the unique and high levels of genetic diversity they house will make these areas conservation priorities.
东南亚在生物多样性方面是世界上最丰富的地区之一。尽管了解多样性的分布和塑造多样性的因素对于确定该地区高度受威胁的生物多样性的保护重点至关重要，但目前这方面的了解还很缺乏。在这里，我们采用了大规模的比较方法，结合了来自 9 种与森林相关的疟蚊物种的数据，并使用统计系统地理学方法来区分环境历史、物种特有生态学和随机合并效应的影响。对更新世人口历史的空间明确建模支持环境事件对所有被研究物种遗传多样性的共同影响，尽管物种的 mtDNA 基因树存在差异。种群周期性地局限于异质的东北和西北避难所，这很可能是由于更新世森林破碎化所致。随后的冰期后向南再殖民化得到了从北向南遗传多样性逐渐减少的梯度的支持。反复的异域片段化和再殖民化导致了四个物种内部形成了深度分歧的地理谱系，以及在泰国-缅甸边界处这些种内谱系相遇的缝合区。这种分歧的共同环境影响进一步表明，大约 90 万年前（kya），同一四个物种中同时发生了分歧，得到了强烈支持。物种之间遗传多样性地理结构的差异可能是物种生物学差异的结果。这些发现对保护规划具有重要意义；如果这里确定的避难区和缝合区与其他森林分类群共享，那么它们所拥有的独特和高水平的遗传多样性将使这些地区成为保护重点。
