沙鳅科鱼类的起源演化

Origin and evolution of botiid loaches (Teleostei: Cypriniformes: Botiidae)

摘要:

目的 厘清沙鳅科鱼类的系统发育关系和起源演化。方法 本实验通过PCR扩增和公共数据库搜集，共获得240条序列，涵盖了8属20种沙鳅科鱼类，采用2个线粒体基因 (COⅠ、Cytb)和3个核基因 (IRBP、RAG1和RH)联合的方法，进行了系统发育树重建、分化时间和生物地理学分析。结果 基于不同数据集构建的最大似然树 (Maximum Likelihood, ML)和贝叶斯树 (Bayesian Inference, BI)的拓扑结构一致，沙鳅科及各属均为单系类群，沙鳅科分为沙鳅亚科和薄鳅亚科2大支，其中，沙鳅亚科包括华鳅属、安巴鳅属、安彦鳅属、缨须鳅属、沙鳅属和色鳅属，薄鳅亚科包括副沙鳅属和薄鳅属，且基于不同数据集构建的ML和BI树均有较高的支持度。结论 沙鳅科鱼类在渐新世[约28.85 百万年前]起源于东南亚地区，中新世 (约24.15 百万年前)各属开始分化，中新世和上新世 (约17.17 百万年—3.79 百万年前)属内种的分化明显；随着喜马拉雅山脉的运动，沙鳅科鱼类从东南亚地区向西和向北扩散和演化。其中，沙鳅属向西进入南亚地区，薄鳅属、副沙鳅属和华鳅属向北进入我国长江、珠江流域，这说明沙鳅科鱼类的物种分化和喜马拉雅山脉的运动有着密切的关系。本研究为进一步研究鳅超科鱼类起源演化提供参考资料。

Abstract:

Botiidae (Actinopterygii: Cypriniformes) is a group of small and medium-sized fish with eight genera and 62 species, which is widely distributed in Southeast Asia, East Asia and South Asia. A total of 240 sequences were obtained by PCR amplification and downloading from GenBank, covering eight genera and 20 species of Botiidae to clarify the phylogenetic relationships and the origin evolution of the family Botiidae. In this study, phylogenetic tree reconstruction, divergence time estimation and biogeographic analysis were performed using the combination of two mitochondrial genes (CO I, Cytb) and three nuclear genes (IRBP, RAG1, RH). The topology of Maximum Likehood (ML) and Bayesian inference (BI) trees based on different datasets consistently showed that the family Botiidae was a monophyletic taxa and all genera were also monophyletic taxa. The family Botiidae was divided into two major brances of the subfamily Botiinae and Leptobotiinae, of which Botiinae included Sinibotia, Ambastaia, Yasuhikotakia, Syncrossus, Botia and Chromobotia and Leptobotiinae included Parabotia and Leptobotia. The above results were well supported. The results of divergence time and geographic ancestral reconstruction indicated that the family Botiidae originated in Southeast Asia in the Early Oligocene (about 28.85 million years ago), and the genera began to diverge in the Miocene (about 24.25 million years ago), with obvious divergence of species within genera in the Late Miocene and Pliocene (about 17.17-3.79 million years ago). With the movement of the Himalayas, the family Botiidae spread and evolved westward and northward from Southeast Asia, among which the genus Botia entered the South Asian region westward, and the genera of Leptobotia, Parabotia, and Sinibotia entered the Yangtze River and Pearl River basin in China to the north. The differentiation of the family Botiidae was closely related to the movement of the Himalayas. This research has important implications for the phylogenetic relationships and evolutionary processes in the origin of Botiidae.