贵州野钟分布泉水鱼的分子鉴定

Molecular Identification of a Pseudogyrinocheilus prochilus Population Distributed in Yezhong, Shuicheng County, Guizhou Province in China

摘要: 于2015年6月9日在贵州省六盘水市水城县野钟乡北盘江(珠江水系)中采集到一尾鲤科鱼类标本，经初步形态鉴定为泉水鱼。然而，之前文献多记载泉水鱼主要分布在长江水系，因此有必要使用分子生物学研究方法做进一步的物种界定。对该标本的肌肉样本进行DNA提取及PCR实验，扩增线粒体16S rRNA基因并进行系统发育分析。结果表明，野钟鱼类样本16SrRNA基因序列与3条泉水鱼16S基因序列聚为一个单系，且与其它3序列间的遗传距离(0.016)介于绝大部分泉水鱼及近缘物种种间遗传距离(0.02~0.05)和种内遗传距离(0~0.01)之间。因此，初步判断该标本属泉水鱼(Pseudogyrinocheilus prochilus)，其与其它三个长江水系种群样本有较大的遗传分化，暗示水系差异对于鱼类种群间基因交流有较大的阻隔作用。

Abstract: In June 9, 2015, a Pseudogyrinocheilus prochilus (Cyprinidae) fish specimen was collected from Beipan River (Pearl River System) in Yezhong Township, Shuicheng County, Liupanshui City, Guizhou Province in China. However, the Pseudogyrinocheilus prochilus fishes are usually recorded in the Yangtze River system in most scientific documentation. So, it needs further species delimitation based on molecular biological methods. Then DNA extraction and PCR experiments were conducted with the tissue of the specimen to amplify the mitochondrial 16S rRNA gene for further phylogenetic analysis and molecular identification. The results showed that the 16S rRNA gene sequence from the fish specimen in Yezhong was clustered into a monophyletic group with 3 homologous sequences of Pseudogyrinocheilus prochilus. The genetic distances between the target sequence and the other 3 P. prochilus ones (0.016) are lower than the most distances among related species (0.02 - 0.05) and higher than the ones within this species (0 - 0.01). Therefore, the Yezhong fish specimen was preliminary identified as Pseudogyrinocheilus prochilus. Its great genetic differentiation from other three populations of the Yangtze River system suggested distribution in different river system has a great role in the barrier for gene exchange among fish populations.