近日，我国分子进化与基因组多样性实验室博士生周炜帏在张亚平院士和车静副研究员的指导下在Molecular Ecology发表上发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"，证实了青藏高原隆升及气候环境变化促进“中国林蛙复合体”物种的形成。
物种形成是生物进化的重要标志，是生物学领域重要的科学问题之一。影响生物成种的因素很多，例如地质事件以及环境变化均会造成物种的隔离，进而促进物种形成和分化；相反，杂交带来的基因流则促进种群之间的相互融合。此外生物对于不同环境的适应造成的生态位分化，也会起到隔离的作用，限制杂交的频率和范围。
中国林蛙复合体（包括中国林蛙，高原林蛙，桓仁林蛙）沿青藏高原东部和北部向东一直延伸分布到朝鲜半岛，是典型的北方物种类群，已有的研究显示部分物种分布区域有重叠，物种界限不清，通过研究该复合体物种的分化过程，有助于我们深入理解物种形成的过程和机制。
研究人员通过分析中国林蛙复合体92个居群394个个体的线粒体和核基因序列，同时结合GIS数据进行的生态位分析重建了中国林蛙复合体物种分化过程。结果支持四大支系的划分包括桓仁林蛙，中国林蛙秦岭居群（模式标本产地），高原林蛙和中国林蛙黄土高原居群；四大支系之间存在明显的生态位分化且与高原隆起造成的气候变化相关；结合分子钟估计该研究揭示了青藏高原晚新生代以来的隆升以及之后北方的气候环境变化对于该复合体物分化的重要作用。
此外基于IM（Isolation and Migration）模型的基因流分析发现在中国林蛙秦岭居群和高原林蛙之间以及中国林蛙黄土高原居群和桓仁林蛙之间存在基因流，但是基因流被限制在交界区域，强度和范围有限，没有影响成种过程。有意思的是，研究也发现中国林蛙秦岭西部居群存在渐渗杂交现象，线粒体完全被来自高原林蛙的线粒体所替代。杂交带是研究物种形成分子机制的良好模型，研究组将对杂交带的种群动态，渐渗杂交的范围以及生态位分化的分子遗传机制做进一步深入研究。
该研究得到了科技部973项目，国家自然科学基金等的大力支持。（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.
