Anthropological Institute & Museum, University of Zurich, Zurich, Switzerland.
Mol Biol Evol. 2011 Aug;28(8):2275-88. doi: 10.1093/molbev/msr042. Epub 2011 Feb 18.
The Southeast Asian Sunda archipelago harbors a rich biodiversity with a substantial proportion of endemic species. The evolutionary history of these species has been drastically influenced by environmental forces, such as fluctuating sea levels, climatic changes, and severe volcanic activities. Orangutans (genus: Pongo), the only Asian great apes, are well suited to study the relative impact of these forces due to their well-documented behavioral ecology, strict habitat requirements, and exceptionally slow life history. We investigated the phylogeographic patterns and evolutionary history of orangutans in the light of the complex geological and climatic history of the Sunda archipelago. Our study is based on the most extensive genetic sampling to date, covering the entire range of extant orangutan populations. Using data from three mitochondrial DNA (mtDNA) genes from 112 wild orangutans, we show that Sumatran orangutans, Pongo abelii, are paraphyletic with respect to Bornean orangutans (P. pygmaeus), the only other currently recognized species within this genus. The deepest split in the mtDNA phylogeny of orangutans occurs across the Toba caldera in northern Sumatra and, not as expected, between both islands. Until the recent past, the Toba region has experienced extensive volcanic activity, which has shaped the current phylogeographic patterns. Like their Bornean counterparts, Sumatran orangutans exhibit a strong, yet previously undocumented structuring into four geographical clusters. However, with 3.50 Ma, the Sumatran haplotypes have a much older coalescence than their Bornean counterparts (178 kya). In sharp contrast to the mtDNA data, 18 Y-chromosomal polymorphisms show a much more recent coalescence within Sumatra compared with Borneo. Moreover, the deep geographic structure evident in mtDNA is not reflected in the male population history, strongly suggesting male-biased dispersal. We conclude that volcanic activities have played an important role in the evolutionary history of orangutans and potentially of many other forest-dwelling Sundaland species. Furthermore, we demonstrate that a strong sex bias in dispersal can lead to conflicting patterns in uniparentally inherited markers even at a genus-wide scale, highlighting the need for a combined usage of maternally and paternally inherited marker systems in phylogenetic studies.
东南亚巽他群岛拥有丰富的生物多样性，其中相当一部分是特有物种。这些物种的进化历史受到环境力量的强烈影响，如海平面波动、气候变化和剧烈的火山活动。猩猩（属：Pongo）是亚洲唯一的大型类人猿，由于其有详细记载的行为生态学、严格的栖息地要求和异常缓慢的生命史，非常适合研究这些力量的相对影响。我们根据巽他群岛复杂的地质和气候历史，研究了猩猩的系统地理格局和进化历史。我们的研究基于迄今为止最广泛的遗传采样，涵盖了现存猩猩种群的整个范围。利用来自 112 只野生猩猩的三个线粒体 DNA（mtDNA）基因的数据，我们表明苏门答腊猩猩（Pongo abelii）相对于婆罗洲猩猩（P. pygmaeus）是并系的，婆罗洲猩猩是该属中目前唯一被认可的物种。猩猩 mtDNA 系统发育树中最深的分裂发生在苏门答腊北部的多巴火山口，而不是在两个岛屿之间，这与预期的情况不同。直到最近，多巴地区经历了广泛的火山活动，这塑造了当前的系统地理格局。与它们的婆罗洲同类一样，苏门答腊猩猩表现出强烈的、但以前未被记录的结构，分为四个地理群。然而，苏门答腊的单倍型与婆罗洲的单倍型相比，有一个更古老的合并时间（350 万年前）。与 mtDNA 数据形成鲜明对比的是，18 个 Y 染色体多态性显示，苏门答腊的合并时间比婆罗洲的要近得多（17.8 万年前）。此外，mtDNA 中明显的地理结构在雄性群体历史中并没有反映出来，这强烈表明雄性有偏向的扩散。我们的结论是，火山活动在猩猩的进化历史中发挥了重要作用，可能在许多其他森林栖息的巽他群岛物种中也是如此。此外，我们证明，在属级范围内，扩散中的强烈性别偏见甚至会导致单亲遗传标记的冲突模式，这凸显了在系统发育研究中同时使用母系和父系遗传标记系统的必要性。
