基于线粒体COⅠ基因对南海毛颚动物箭虫科的鉴定及系统发育初探

摘要

为提高毛颚动物鉴定的准确性,进一步探索毛颚动物箭虫纲箭虫科各属的系统发育地位,文章采用形态学鉴定与DNA条形码技术相结合,对南海北部采集的部分箭虫种类进行鉴定,并初步探讨其系统分类地位.结果表明包括粗壮猛箭虫(Ferosagitta robusta)、小型滨箭虫(Aidanosagitta neglecta)、规则滨箭虫(Aidanosagitta regularis)在内的箭虫,其形态鉴定结果与分子鉴定的结果一致,其COⅠ(线粒体编码的细胞色素氧化酶第一亚基,cytochrome oxidase subunitⅠ)序列在系统发育树中与GenBank得到的相应箭虫COⅠ序列以91%~100%高支持率形成各自单系枝.种内遗传距离范围为0.000~0.015,平均值为0.004;种间遗传距离范围为0.081~0.173,平均值为0.127;种内遗传距离和种间遗传距离未重叠,存在明显的条形码间隙,证实了COⅠ基因作为毛颚动物DNA条形码标准基因的可行性.本研究首次将DNA条形码技术应用于箭虫科内各属的系统发育分析,首次从分子层面探讨其系统发育地位.%To improve the accuracy of Chaetognatha identification, we combined morphological identification and DNA barcoding based on the mitochondrial COⅠ(cytochrome oxidase subunit Ⅰ) gene to identify some arrow worms from the northern South China Sea. The results showed that the morphologically and molecularly identified results were consistent, for the species of Ferosagitta robusta, Aidanosagitta neglecta and Aidanosagitta regularis. Furthermore, the neighbor-joining phylogenetic tree was constructed with the amplified COⅠ sequences and those homologous sequences from GenBank based on Kimura 2-parameter, and the phylogenetic positions of Sagiitta (Sagittidae, Sagittoidea) were discussed. The results indicated that these COⅠ sequences formed monophylotic clades compared with GenBank (91%~100%). The intraspecific genetic distance ranged from 0.000 to 0.015 with an average value of 0.004, while the interspecific genetic distance ranged from 0.081 to 0.173 with an average value of 0.127. The barcoding gap was detected between intra and interspecific variations,suggesting that the COⅠ gene could be a standard DNA barcode for the Chaetognatha identification. This study was the first to apply DNA barcoding to phylogenetic analysis of Sagittidae, and to discuss the phylogenetic position at molecular level.