近日,,國際著名雜志Molecular Ecology雜志刊登了中科院成都生物所研究人員的最新研究成果“Coalescence patterns of endemic Tibetan species of stream salamanders (Hynobiidae:Batrachuperus),”,,文章中,,研究者發(fā)現(xiàn)了青藏高原隆起導致山溪鯢種群分化,。
理解地質(zhì)運動和氣候變化等歷史因素是如何驅(qū)動種群片段化、拓殖和擴張等分化過程,,是譜系生物地理學研究的核心,。青藏高原東緣山區(qū)受高原隆起影響,地質(zhì)結(jié)構(gòu)極端復雜,、物種豐富,,為研究地質(zhì)及氣候變化對物種及種群分化的影響提供了得天獨厚的條件。
中科院成都生物研究所曾曉茂研究組博士生呂彬等人利用溯祖模擬方法,,對生活在青藏高原東緣山區(qū)的山溪鯢屬5個物種進行了譜系地理學研究,,結(jié)果顯示該屬物種種內(nèi)的分化可能是由于青藏高原近期的隆起事件導致,且高海拔和低海拔物種可能具有不同的進化歷史:在分化模式上,,受地質(zhì)拓撲結(jié)構(gòu)的影響,,西部高海拔物種主要經(jīng)歷了階段性的分化過程,長距離遷徙后再發(fā)生隔離分化,,東部低海拔物種直接由祖先物種分化而來,,沒有經(jīng)歷遷徙過程,呈現(xiàn)片段化,;在對冰期的反應上,,高、低海拔物種對于冰期的反應也有差異,。耐寒的高海拔物種主要受到近期的冰期的影響(0.016–0.032 Ma),,種群大小經(jīng)歷了下降的過程。與此相對,,生活在溫暖潮濕環(huán)境中的低海拔物種主要受到更強烈的,,持續(xù)時間更長的冰期的影響(0.5–0.175 Ma),,近期的冰期對其影響不大。(生物谷Bioon.com)
doi:10.1111/j.1365-294X.2012.05606.x
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Coalescence patterns of endemic Tibetan species of stream salamanders (Hynobiidae: Batrachuperus)
BIN LU1,2, YUCHI ZHENG1, ROBERT W. MURPHY3,4, XIAOMAO ZENG1
Orogenesis of topographically diverse montane regions often drives complex evolutionary histories of species. The extensive biodiversity of the eastern edge of the Tibetan Plateau, which gradually decreases eastwardly, facilitates a comparison of historical patterns. We use coalescence methods to compare species of stream salamanders (Batrachuperus) that occur at high and low elevations. Coalescent simulations reveal that closely related species are likely to have been influenced by different drivers of diversification. Species living in the western high-elevation region with its northsouth extending mountains appear to have experienced colonization via dispersal followed by isolation and divergence. In contrast, species on the eastern low-elevation region, which has many discontinuous mountain ranges, appear to have experienced fragmentation, sometimes staged, of wide-ranging ancestral populations. The two groups of species appear to have been affected differently by glaciation. High-elevation species, which are more resistant to cooler temperatures, appear to have experienced population declines as recently as the last glaciation (0.016–0.032 Ma). In contrast, salamanders dwelling in the warmer and wetter habitats at low-elevation environs appear to have been affected less by the relatively recent, milder glaciation, and more so by harsher, extensive glaciations (0.5–0.175 Ma). Thus, elevation, topography and cold tolerance appear to drive evolutionary patterns of diversification and demography even among closely related taxa. The comparison of multiple species in genealogical analyses can lead to an understanding of the evolutionary drivers.