第四纪更新世的冰川运动及气候变化对中国鸟类物种演化和分布产生了重大影响。近日，中科院动物研究所研究员雷富民带领“鸟类学研究组”，通过对青藏高原两种特有类群白腰雪雀和地山雀的比较研究发现：两个物种都经历了更新世冰期的瓶颈效应和冰后的种群快速扩张，且扩张时间（0.05-0.16 Ma）和最后一次最大冰期撤退的时间基本一致（0.5-0.175 Ma）。但是，两个物种具有不同的谱系地理分布格局：白腰雪雀种群扩张自青藏高原东部边缘的避难地；而地山雀扩张自青藏高原东北及东南边缘两个独立的避难地。这两种不同的避难地模式，两个物种不同的扩散能力，及其不同的空间分布特征是造成这两种不同谱系格局形成的主要原因。该研究结果发表于Molecular Phylogenetics Evolution上。

而对华南分布及东南亚特有物种灰眶雀鹛线粒体Cytb和COI基因片段的种群遗传结构和历史动态研究，却发现了不同谱系格局和形成机制。灰眶雀鹛种群出现了多个明显的种群遗传结构深度分歧，其分歧模式和不同动物地理亚区基本一致。该物种进化历史非常久远，推测最近祖先可能存在于晚中新世的中国南方地区。在其漫长的进化过程中，青藏高原隆升所导致的周边区域环境植被变化、全球范围内的植被演替以及第四纪冰期回旋等一系列地质历史事件和生态环境演变可能是导致灰眶雀鹛种群分化的主要原因。中国南方的复杂地形可能为灰眶雀鹛提供了不同的冰期避难地，而在冰期后这些避难地又阻碍了种群的扩散，从而造成了地理种群之间深度的遗传分歧和基因流中断。灰眶雀鹛的东部地理组群中存在明显的晚更新世种群扩张，反映了晚更新世冰期的气候变化对中国南方东部的环境影响十分显著。扩张时间应在晚更新世早期的最大冰盛期，而非末次冰盛期。该研究结果发表于《BMC进化生物学》（BMC Evolutionary Biology）。

这些研究工作得到了国家自然基金与科学院创新项目的支持。

原始出处：

BMC Evolutionary Biology 2009, 9:143doi:10.1186/1471-2148-9-143

Phylogeography of the Alcippe morrisonia (Aves: Timaliidae): long population history beyond late Pleistocene glaciations

Gang Song1,2 , Yanhua Qu1 , Zuohua Yin1 , Shouhsien Li3 , Naifa Liu4  and Fumin Lei1

1Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101 PR China
2Graduate School of the Chinese Academy of Sciences, Beijing, 100039 PR China
3Department of Life Science, National Taiwan Normal University, Taibei, Taiwan, 116 ROC
4School of Life Science, Lanzhou University, Lanzhou, 730000 PR China

Background

The role of Pleistocene glacial oscillations in current biodiversity and distribution patterns varies with latitude, physical topology and population life history and has long been a topic of discussion. However, there had been little phylogeographical research in south China, where the geophysical complexity is associated with great biodiversity. A bird endemic in Southeast Asia, the Grey-cheeked Fulvetta, Alcippe morrisonia, has been reported to show deep genetic divergences among its seven subspecies. In the present study, we investigated the phylogeography of A. morrisonia to explore its population structure and evolutionary history, in order to gain insight into the effect of geological events on the speciation and diversity of birds endemic in south China.

Results

Mitochondrial genes cytochrome b (Cytb) and cytochrome c oxidase I (COI) were represented by 1236 nucleotide sites from 151 individuals from 29 localities. Phylogenetic analysis showed seven monophyletic clades congruent with the geographically separated groups, which were identified as major sources of molecular variance (90.92%) by AMOVA. TCS analysis revealed four disconnected networks, and that no haplotype was shared among the geographical groups. The common ancestor of these populations was dated to 11.6 Mya and several divergence events were estimated along the population evolutionary history. Isolation by distance was inferred by NCPA to be responsible for the current intra-population genetic pattern and gene flow among geographical groups was interrupted. A late Pleistocene demographic expansion was detected in the eastern geographical groups, while the expansion time (0.2–0.4 Mya) was earlier than the Last Glacial Maximum.

Conclusion

It is proposed that the complicated topology preserves high genetic diversity and ancient lineages for geographical groups of A. morrisonia in China mainland and its two major islands, and restricts gene exchange during climate oscillations. Isolation by distance seems to be an important factor of genetic structure formation within geographical populations. Although glacial influence to population fluctuation was observed in late Pleistocene, it seems that populations in eastern China were more susceptible to climate change, and all geographical groups were growing stably through the Last Glacial Maximum. Coalescence analysis suggested that the ancestor of A. morrisonia might be traced back to the late Miocene, and the current phylogeographical structure of A. morrisonia is more likely to be attributable to a series geological events than to Pleistocene glacial cycles.