基于线粒体DNA序列分析研究泰山赤鳞鱼的分类和进化

Mitochondrial partial DNA sequence analysis of Chi-lin fish Varicorhinus macrolepis from Taishan Mountain:implication for its taxonomy and evolution

泰山赤鳞鱼作为一种古老而分布特异的鲤科鱼种,其分类和进化地位尚存在很多争议.利用PCR方法克隆了泰山赤鳞鱼线粒体DNA的12S,16SrRNA、细胞色素b和ATP酶8/6基因序列,分析了碱基组成变异和核苷酸序列差异,并与鲤科其它属种的同源序列进行比较,发现所有基因都是(A+T)%>(G+C)%.蛋白编码基因在第三位点是G缺失基因,并集中在第三位点发生替换突变.利用最小进化法(ME)和邻接法(NJ)构建了系统进化树.结果表明,泰山赤鳞鱼不属于突吻鱼属,而是更接近倒刺鲃属和鲃属.利用细胞色素b序列计算并推断泰山赤鳞鱼可能起源于1 600万年前的中新世中期.

The Chi-lin fish is an ancient species of Cyprinidae,which specifically distributed in the Taishan mountain.However,the taxonomy and evolution of Chi-lin fish are disputed.In this study,the Mitochondrial 12 SrRNA,16SrRNA,cytochrome b,ATP synthase 8and 6gene fragments of Chi-lin fish from Tai Mountain were amplified by PCR,and the products were purified and sequenced.The sequences and characters of the multiple genes of mitochondrial DNA（mtDNA）were analyzed by MEGA7.0.The results showed that all of the multiple genes were（A＋T）% （G＋C）%.The base compositions of the protein-coding genes were globally G-deficient,especially in the third position.Interestingly,transitions of protein-coding genes were major in the substitution,and largely concentrated in the third position,too.All molecular phylogenetic trees revealed that Chi-lin fish did not belong to genus Varicorhinus,against the former morphological data.And it was comparatively closer to genus Spinibarbus and Barbus.The Cyt b sequence analysis suggested that the divergence time of Chi-lin fish was about 16.0Mya（million years ago）.