基于线粒体Cytb基因序列探讨花斑鳅三亚种的分类地位

Taxonomic status of three subspecies of Cobitis melanoleuca based on sequences of mitochondrial cytochrome b gene

以线粒体DNA细胞色素b（Cytb）基因的全序列作为遗传标记,探讨花斑鳅3亚种（指名亚种Cobitis melanoleuca melanoleuca、北方鳅亚种C.m.granoei和格氏鳅亚种C.m.gladkovi）的分类地位.基于Kimura双参数法计算河北花斑鳅指名亚种个体间的遗传距离为0.2%~1.1%,俄罗斯花斑鳅指名亚种、北方鳅亚种和格氏鳅亚种之间的平均遗传距离为0.1%~1.5%,而河北花斑鳅指名亚种与俄罗斯花斑鳅3个亚种之间的平均遗传距离为1.7%~2.6%.分子系统树显示,花斑鳅分为两大分支：分支I为河北花斑鳅指名亚种8个单倍型类群,分支Ⅱ含俄罗斯花斑鳅指名亚种、北方鳅亚种和格氏鳅亚种以及辽宁北方鳅亚种.结合已有研究结果得出：花斑鳅指名亚种仅分布于中国,而俄罗斯也仅有北方鳅亚种1个物种,两者的分化时间约为2.50~3.09百万年.

The taxonomic status of three subspecies（Cobitis melanoleuca melanoleuca,C. m. granoei,C. m. gladkovi）of Cobitis melanoleuca was discussed based on the whole sequences of mitochondrial cytochrome b gene taken as hereditary marker. The genetic distance was calculated by the method of Kimura- 2- parameter. The results showed that the individual ge netic distance of C. m. melanoleuca in Hebei Province was 0.2%- 1.1%; the average genetic distance among the three subspecies of Cobitis melanoleuca in Russia was 0.1%- 1.5%. And the average genetic distance between C. m. melanoleuc and the three subspecies of Cobitis melanoleuca in Russia was 1.7%- 2.6%. The molecular phylogenic trees demonstrated that the species of Cobitis melanoleuca was divided into two distinct clades. One clade included eight hyplogroups of C. m. melanoleuca in Hebei Province; the other clade included the three subspecies in Russia and C. m. granoei in Liaoning Province in China.Based on the existing researches and the present study,the conclusion was that C. m. melanoleuca only distributed in China and there was only one subspecies,i.e. C. m. granoei in Russia. The divergence time between these two subspecies was about2.50- 3.09 Mya.