近日,，我國(guó)分子進(jìn)化與基因組多樣性實(shí)驗(yàn)室博士生周煒幃在張亞平院士和車(chē)靜副研究員的指導(dǎo)下在Molecular Ecology發(fā)表上發(fā)表了其最新研究成果"Speciation in the Rana chensinensis species complex and its relationship to the uplift of the Qinghai–Tibetan Plateau",，證實(shí)了青藏高原隆升及氣候環(huán)境變化促進(jìn)“中國(guó)林蛙復(fù)合體”物種的形成。
物種形成是生物進(jìn)化的重要標(biāo)志,，是生物學(xué)領(lǐng)域重要的科學(xué)問(wèn)題之一。影響生物成種的因素很多,，例如地質(zhì)事件以及環(huán)境變化均會(huì)造成物種的隔離,，進(jìn)而促進(jìn)物種形成和分化；相反,，雜交帶來(lái)的基因流則促進(jìn)種群之間的相互融合,。此外生物對(duì)于不同環(huán)境的適應(yīng)造成的生態(tài)位分化，也會(huì)起到隔離的作用,，限制雜交的頻率和范圍,。
中國(guó)林蛙復(fù)合體（包括中國(guó)林蛙，高原林蛙,，桓仁林蛙）沿青藏高原東部和北部向東一直延伸分布到朝鮮半島,，是典型的北方物種類(lèi)群，已有的研究顯示部分物種分布區(qū)域有重疊,，物種界限不清,，通過(guò)研究該復(fù)合體物種的分化過(guò)程，有助于我們深入理解物種形成的過(guò)程和機(jī)制,。
研究人員通過(guò)分析中國(guó)林蛙復(fù)合體92個(gè)居群394個(gè)個(gè)體的線粒體和核基因序列,，同時(shí)結(jié)合GIS數(shù)據(jù)進(jìn)行的生態(tài)位分析重建了中國(guó)林蛙復(fù)合體物種分化過(guò)程。結(jié)果支持四大支系的劃分包括桓仁林蛙,，中國(guó)林蛙秦嶺居群（模式標(biāo)本產(chǎn)地）,，高原林蛙和中國(guó)林蛙黃土高原居群；四大支系之間存在明顯的生態(tài)位分化且與高原隆起造成的氣候變化相關(guān),；結(jié)合分子鐘估計(jì)該研究揭示了青藏高原晚新生代以來(lái)的隆升以及之后北方的氣候環(huán)境變化對(duì)于該復(fù)合體物分化的重要作用,。
此外基于IM（Isolation and Migration）模型的基因流分析發(fā)現(xiàn)在中國(guó)林蛙秦嶺居群和高原林蛙之間以及中國(guó)林蛙黃土高原居群和桓仁林蛙之間存在基因流，但是基因流被限制在交界區(qū)域,，強(qiáng)度和范圍有限,，沒(méi)有影響成種過(guò)程。有意思的是,，研究也發(fā)現(xiàn)中國(guó)林蛙秦嶺西部居群存在漸滲雜交現(xiàn)象,，線粒體完全被來(lái)自高原林蛙的線粒體所替代。雜交帶是研究物種形成分子機(jī)制的良好模型,，研究組將對(duì)雜交帶的種群動(dòng)態(tài),，漸滲雜交的范圍以及生態(tài)位分化的分子遺傳機(jī)制做進(jìn)一步深入研究。
該研究得到了科技部973項(xiàng)目,，國(guó)家自然科學(xué)基金等的大力支持,。（生物谷Bioon.com）
doi:10.1111/j.1365-294X.2011.05411.x
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Speciation in the Rana chensinensis species complex and its relationship to the uplift of the Qinghai–Tibetan Plateau
WEI-WEI ZHOU1, YANG WEN1,2, JINZHONG FU3, YONG-BIAO XU6, JIE-QIONG JIN1, LI DING4, MI-SOOK MIN5, JING CHE1, YA-PING ZHANG1,6
Speciation remains a fundamental issue in biology. Herein, we report an investigation into speciation in the Rana chensinensis species complex using DNA sequence data from one mitochondrial and five nuclear genes. A phylogenetic analysis of the data revealed four major clades in the complex, and each of them was found to likely represent a species, including one cryptic species. Ecological niche models were generated from 19 climatic variables for three of the four major clades, which were represented by widespread sampling, including R. chensinensis, Rana kukunoris and the potential cryptic species. Each clade is associated with a unique ecological unit, and this indicates that ecological divergence probably drove speciation. Ecological divergence is likely related to the late Cenozoic orogenesis of the Qinghai–Tibetan Plateau. In addition, gene flow between species was detected but only in peripheral portions of the ranges of the four major clades, thus likely had little influence on the speciation processes. Discordances between mitochondrial and nuclear genes were also found; the nominal species, R. chensinensis, contains multiple maternal clades, suggesting potential mitochondrial introgression between R. chensinensis and R. kukunoris.
