鳅科鱼类DNA条形码鉴定及系统进化研究

DNA Barcodes for Species Identification and Systematic Evolution of Cobitidae Fish

【目的】为了探讨线粒体COI基因作为DNA条形码在鳅科鱼类物种鉴定中的有效性及在系统进化关系分析中的适用性,对鳅科鱼类3亚科18属61种共358条线粒体COI基因序列进行了分析。【结果】61种鳅科鱼类的种内和种间的平均遗传距离分别为0.010和0.162,种间平均遗传距离是种内平均遗传距离的16.2倍。鳅科鱼类遗传距离在种内、种间重叠较少,能形成一定的DNA条形码间隙。ABGD分类把61个物种划分为66个OTUs,OTUs的划分与距离法基本一致。系统聚类中,有6组鱼类物种个体间相互混杂,不能按各自的物种聚类,有4个物种分化成明显的两支,46个物种能按各自的形态学分类分别聚成单支。南鳅属、花鳅属、似鳞头鳅属、瘦身鳅属和泥鳅属中部分物种没有按其形态学分类的属聚在一起。沙鳅亚科能形成单系,但条鳅亚科和花鳅亚科不能形成单系。在研究中,COI条形码可以鉴定鳅科鱼类75.41%的物种,另外,COI条形码也能够明确大多鳅科鱼类属和亚科的分类地位,研究结果可为鳅科鱼类的物种鉴定和系统分类提供参考。

In order to study the validity of mitochondrial COI gene as a DNA barcoding in identification of species and the applicability of phylogenetic framework for Cobitidae fish,358 mitochondrial COI gene sequences of 61 morphological species belonging to 18 genera and 3 subfamilies were studied.In this study,the average genetic distances of intraspecific and interspecific species were 0.010 and 0.162,respectively.The average genetic distance of interspecific species was 16.2 times that of the average intraspecific species.DNA barcode was an efficient method for the identification of Cobitidae fish by the presence of barcode gaps.ABGD results defined 61 species as 66 operational taxonomic units(OTUs),which was roughly consistent with the distance method.In the systematic clustering,the members of 6 groups of fish species mixed with each other and could not assembled into their own taxa,four species differentiated into two branches,respectively,and the members of 46 species could grouped into one single branches according to their morphological classification.Some species in Schistura,Cobitis,Lepidocephalichthys,Canthophrys and Misgurnuswere did not group together according to their morphologic genus.Botiinae could form monophyletic system,but Nemacheilinae and Cobitinae could not form monophyletic system.In this study,75.41%species of Cobitidae could be successfully identified.In addition,COI gene barcode could clarified taxon status of most genera and subfamilies.These results will provide a reference for identification and phylogenetic framework for Cobitidae fish.