古地質(zhì)和古氣候變遷是影響生物多樣性和群體結(jié)構(gòu)的兩個重要因素。例如,，影響北美洲和歐洲生物多樣性的主要因素是第四紀(jì)冰期氣候波動,。然而中國南方孕育著復(fù)雜的地形，第四紀(jì)時并沒有發(fā)育大規(guī)模的冰川,，氣候波動對于該地區(qū)生物的影響希待探究,。另外，青藏高原的多次隆升造成中國西南地區(qū)地形和水系的巨大變動,。其中,，古長江流域的四川段原向西南流入南海，由于地形改變其逐漸流向東北方向,，2-3個百萬年時在三峽地區(qū)與長江中游水系連通,，形成現(xiàn)代長江的雛形。古水系變遷對于生物的影響也是系統(tǒng)地理學(xué)近年來的研究熱點,。
分子進(jìn)化與基因組多樣性研究組博士生顏芳在張亞平院士和車靜研究員的指導(dǎo)下,，以中國南方特有兩棲類棘腹蛙（Quasipaa boulengeri）為研究對象,，使用線粒體和核基因為分子標(biāo)記，發(fā)現(xiàn)棘腹蛙類群有四個分化較深的進(jìn)化支系,。
這四個支系的分化發(fā)生于較為古老的兩個時期,，大致對應(yīng)于青藏高原的第二三次隆升時期，遠(yuǎn)早于第四紀(jì)冰期,。而長江水系在三峽地區(qū)的連通介導(dǎo)了該物種從上游地區(qū)向中游地區(qū)的擴(kuò)散,，形成現(xiàn)今廣泛的分布模式。雖然經(jīng)歷了第四紀(jì)的氣候波動,，但棘腹蛙種群基本保持穩(wěn)定,，沒有經(jīng)歷過群體擴(kuò)張或收縮等事件。這些結(jié)果證明地質(zhì)變動是影響該群體演化的主要因素,，而第四紀(jì)氣候波動并沒有對該物種產(chǎn)生顯著作用,。另外還發(fā)現(xiàn)四川盆地的東南地區(qū)是四個支系的二次接觸地，并有基因流現(xiàn)象,。
本研究揭示,，在中國南方地區(qū)，第四紀(jì)冰期氣候波動對山區(qū)兩棲類的群體演化并沒有顯著的影響,，而這可能是中國南方山區(qū)物種較為普遍的模式,，對于今后的研究具有指導(dǎo)意義。該研究結(jié)果已發(fā)表于國際著名雜志Molecular Ecology,。(生物谷Bioon.com)
DOI: 10.1111/mec.12153
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PMID:
Geological events play a larger role than Pleistocene climatic fluctuations in driving the genetic structure of Quasipaa boulengeri (Anura: Dicroglossidae)
Fang Yan, Weiwei Zhou, Haitao Zhao, Zhiyong Yuan, Yunyu Wang, Ke Jiang, Jieqiong Jin, Robert W-Murphy, Jing Che, Yaping Zhang.
Paleoclimatic and paleogeological events have been identified as being the two main drivers of genetic structuring in extant organisms. We used a montane stream-dwelling frog, Quasipaa boulengeri, to explore the relative roles played by these drivers on species in southern China, a region needing thorough studies. We detected four major matrilines, and no broadly distributed haplotypes occurred. The complex orogenesis of south-western China drove matrilineal divergence in Q. boulengeri into highly structured geographical units. These matrilines subsequently persisted in situ with stable populations rather than undergoing expansions during glacial cycling. The unification of the upper and middle Yangtze River in the Three Gorges mountain region mediated downstream colonization of this frog. Analyses identified geological events as playing a larger role than climatic fluctuations in driving the population history of Q. boulengeri. Nuclear allele analyses indicated gene flow; this maintained genetic cohesion of the species. South-eastern Sichuan Basin was identified as the area of secondary contact for several matrilines, and this area deserves further study and special protection.
