喜馬拉雅-橫斷山區(qū)是世界上最重要的生物多樣性核心地區(qū)之一,，該地區(qū)豐富的生物多樣性的起源一直是生物學(xué)家研究的熱點。其中包括數(shù)量和種類眾多的食蟲類哺乳動物,。
蹼足鼩族（Nectogalini）是歐亞大陸小型食蟲類哺乳類中重要的一員,，現(xiàn)在主要棲息于東喜馬拉雅-橫斷山區(qū)，臺灣地區(qū)和歐洲,。 該族群中的各物種有著多樣化的生態(tài)適應(yīng)性,，包括樹棲，穴居和水棲等,。因此是研究哺乳類生態(tài)適應(yīng)以及與之相關(guān)的形態(tài)和生理進化的極好材料。
蔣學(xué)龍研究組成員對蹼足鼩族進行了詳細的系統(tǒng)發(fā)育和生物地理研究,，在系統(tǒng)進化,、生理進化和生物歷史地理各方面都取得了新的進展。結(jié)合系統(tǒng)進化的結(jié)果,，化石和古氣候記錄,，該研究組詳細地論證了全球歷史氣候變化對蹼足鼩族的分布以及進化的影響：東喜馬拉雅－橫斷山區(qū)的蹼足鼩首先從歐洲遷移到亞洲北部地區(qū)，由于全球氣候的變化,，在中新世末上新世初蹼足鼩在該地區(qū)發(fā)生快速分化,。到上新世末、更新世初,，隨著全球變冷和青藏高原的隆升,，歐洲的蹼足鼩大量滅絕，而亞洲的類群則向南遷徙,。并在第四紀冰期的影響下最終形成今天的分布格局,。此研究為氣候環(huán)境對小型食蟲類的進化的影響提供了可靠的依據(jù)，并且為喜馬拉雅－橫斷山區(qū)生物多樣性的起源提供了線索,。另外,，本研究還闡明了一些在前人研究中有爭議的或者不清楚的發(fā)育關(guān)系，首次證明了蹼足鼩族對水生生活的多次適應(yīng)性進化并闡明了長尾鼩屬（Episoriculus）的并系問題,。該研究成果發(fā)表在Molecular Phylogenetics and Evolution,。(生物谷Bioon.com)
生物谷推薦原文出處：
Molecular Phylogenetics and Evolution doi:10.1016/j.ympev.2010.03.039
A multi-locus phylogeny of Nectogalini shrews and influences of the paleoclimate on speciation and evolution
Kai Hea, b, Ya-Jie Lia, b, Matthew C. Brandleyc, Liang-Kong Lind, Ying-Xiang Wanga, Ya-Ping Zhanga and Xue-Long Jiang a
a State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China
b Graduate School of Chinese Academy of Sciences, Beijing, China
c Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, USA
d Laboratory of Wildlife Ecology, Department of Life Science, Tunghai University, Taichung, Taiwan
Nectogaline shrews are a major component of the small mammalian fauna of Europe and Asia, and are notable for their diverse ecology, including utilization of aquatic habitats. So far, molecular phylogenetic analyses including nectogaline species have been unable to infer a well-resolved, well-supported phylogeny, thus limiting the power of comparative evolutionary and ecological analyses of the group. Here, we employ Bayesian phylogenetic analyses of eight mitochondrial and three nuclear genes to infer the phylogenetic relationships of nectogaline shrews. We subsequently use this phylogeny to assess the genetic diversity within the genus Episoriculus, and determine whether adaptation to aquatic habitats evolved independently multiple times. Moreover, we both analyze the fossil record and employ Bayesian relaxed clock divergence dating analyses of DNA to assess the impact of historical global climate change on the biogeography of Nectogalini. We infer strong support for the polyphyly of the genus Episoriculus. We also find strong evidence that the ability to heavily utilize aquatic habitats evolved independently in both Neomys and Chimarrogale + Nectogale lineages. Our Bayesian molecular divergence analysis suggests that the early history of Nectogalini is characterized by a rapid radiation at the Miocene/Pliocene boundary, thus potentially explaining the lack of resolution at the base of the tree. Finally, we find evidence that nectogalines once inhabited northern latitudes, but the global cooling and desiccating events at the Miocene/Pliocene and Pliocene/Pleistocene boundaries and Pleistocene glaciation resulted in the migration of most Nectogalini lineages to their present day southern distribution.
