选择线粒体 COⅠ基因作为分子标记,进行沙鳅亚科鱼类(Botiinae)DNA 条形码及其分子系统发育研究。研究获得了沙鳅亚科7属19种共131个个体的COⅠ基因序列,利用MEGA5.0软件分析了沙鳅亚科鱼类COⅠ基因的序列特征,计算了种内及种间遗传距离。沙鳅亚科鱼类的分子系统发育关系的重建分别采用NJ法和Bayesian法。研究发现,沙鳅亚科COⅠ基因的碱基组成为：A 24.4%、T 29.5%、G 18.0%、C 28.1%。沙鳅亚科鱼类种内平均遗传距离为0.002±0.000,种间平均遗传距离为0.148±0.008。DNA条形码研究结果显示,所分析的19种沙鳅鱼类各自分别聚成单系分支,表明 COⅠ基因在本研究中具有100%的物种鉴别率。同时,系统发育分析支持各属的单系性,并且结果显示沙鳅亚科鱼类聚为两个分支,其中一支由薄鳅属和副沙鳅属构成,另一分支则包括：(沙鳅属、色鳅属)和[中华沙鳅属、(缨须鳅属、安彦鳅属)]。因此, COⅠ基因可以作为有效的分子标记对沙鳅亚科进行DNA条形码研究以及分子系统发育研究。%To analyze the characteristics of the sequences and to calculate the genetic distance within and between spe-cies, the 648 bp mitochondrial COⅠ gene was used as DNA barcode to analyze phylogenetic relationships of Botiinae fishes in 131 sequences from 19 species representing 7 genera of Botiinae. MEGA5.0 software was used in the current study. Phylogenetic analyses were carried out using neighbor-joining and Bayesian methods. Our result revealed that the nucleotide compositions were 24.4% A, 29.5% T, 18.0% G, and 28.1% C. The mean inter- and intra-specific genetic distances were 0.148±0.008 and 0.002±0.000, respectively. Individuals of each species were clustered into monophyletic groups based on the molecular phylogenetic tree, indicating that the mitochondria COⅠ gene is suitable for species discrimination. Moreover, the phylogenetic analyses supported monophyly of genera within Botiinae. Two clades were recovered within the subfamily Botiinae:one clade includes the sister-group of Leptobotia and Parabotia and the other contains Botia + Chromobotia and Sinibotia + (Syncrossus, Yasuhikotakia). This study indicated that the mitochondria COⅠ gene is a potentially effective marker for DNA barcoding and phylogenetic studies of Botiinae fishes.
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