Species identification of zooplankton resting eggs based on DNA barcode technology: A case study of Lake Liuye (Changde), Lake Dongting Basin

Abstract

以洞庭湖流域的典型城市湖泊常德柳叶湖表层沉积物中浮游动物休眠卵为研究对象，采用DNA条形码技术进行种类鉴定，从191个休眠卵中成功获得101条有效序列，鉴定成功率约为53%.根据NCBI数据库比对成功鉴定休眠卵9科12属11种，另有6个样品鉴定到属或科；3个类群的种间遗传距离平均为种内遗传距离的68倍，表明可以利用线粒体细胞色素c氧化酶第一亚基编码基因（COⅠ）对休眠卵进行有效物种鉴定.通过Neighbor-Joining树进行系统发育分析，发现所鉴定的物种与其参比序列聚类为一支，所有物种分别聚为独立的一个支系，不同物种可有效区分.研究结果均表明，COⅠ基因作为DNA条形码可以实现沉积物中浮游动物休眠卵的物种鉴定.;With the rapid development of modern molecular biology tools, especially DNA barcoding technology, a rapid, accurate and efficient identification method for species of zooplankton resting eggs is possible. In this study, zooplankton resting eggs, including copepods,cladocerans and rotifers in the surface sediments of Lake Liuye (Changde), a typical urban lake in Lake Dongting Basin, were studied. Using DNA barcode technology for species identification, 101 valid DNA sequences were successfully obtained from 191 resting eggs, and the identification success rate was 53%. According to the NCBI database comparison, 9 families, 12 genera and 11 species of resting eggs were successfully identified, and 6 samples were only identified to the genus or family level. The inter-species genetic distance of the three taxa was 68 times that of the intra-species genetic distance, indicating that the cytochrome oxidase Ⅰ (COⅠ) gene could be used for effective species identification of zooplankton resting eggs. Through the phylogenetic analysis by Neighbour-Joining tree, it was found that the identified species and their reference sequences were clustered into one branch, and all different species were clustered into independent branches respective. Therefore, different species could be effectively distinguished. The above results all indicate that the mitochondrial COⅠ gene, as a DNA barcode, can be used to identify the species of zooplankton resting eggs in sediment of lakes.