浙江沿海潮间带多毛类环节动物DNA条形码数据库初建

Development of DNA Barcode Reference Library for Polychaetous Annelids Identified from the Coastal Intertidal Zone of Zhejiang Coastal Sea

多毛纲环节动物是形态学分类鉴定极为困难的一类海洋生物。本研究旨在构建浙江沿海常见多毛类的DNA条形码数据库。2015年1-10月期间,针对多毛类环节动物在浙江沿海潮间带进行了多次定性采样,并对样本进行了形态学鉴定以及线粒体COⅠDNA序列分析。从形态学上共鉴定了8个多毛类物种,隶属于4个科,即双齿围沙蚕Perinereis aibuhitensis、威氏围沙蚕P.wilsoni、独齿围沙蚕P.cultrifera、杂色伪沙蚕Pseudonereis variegata、双管阔沙蚕Platynereis bicanaliculata、短毛海鳞虫Halosydna brevisetosa、岩虫Marphysa sanguinea、四索沙蚕Lumbrineris tetraura。共得到长度为680~930 bp的13条DNA序列,其中2条属于P.wilsoni、2条属于M.sanguinea的片段,这两个物种的序列还未在BOLD中收录;1条H.brevisetosa的COⅠ基因序列与Gen Bank上的同名序列差异较大。计算得到样本的种内平均遗传距离为2.8%,科内种间平均遗传距离为23.9%,科内种间距离远远大于种内距离;从而印证了COⅠ可作为多毛类动物分类的条形码。此外,本研究还设计了一对多毛类动物COⅠ片段的特异性引物,而且适用于扩增A+T含量较高的多毛类物种。

It remains a big challenge for accurate identification of marine polychaetous annelids solely de-pending on morphology.This study aimed to develop a DNA barcode reference library for polychaetes collected from intertidal zones of Zhejiang coastal sea during the period from January to October,2015.Samples were se-lected for mitochondrial COⅠDNA sequence analysis after morphological examination.Eight species from fourfamilies,i.e.Perinereis aibuhitensis,P.wilsoni,P.cultrifera,Pseudonereis variegata,Platynereis bicanaliculata,Halosydna brevisetosa,Marphysa sanguinea and Lumbrineris tetraura were identified from 13 CO Ⅰ DNA sequences at the length of 680-930 bp; two sequences of P.wilsoni and two sequences of M.sanguinea are unavailable in BOLD＇s collection; one sequence shares 88% similarity with a sequence of H.brevisetos on GenBank; The average K-2-P distance within species is 2.8% and between species within family is 23.9%.The significant gap in K-2-P distance between-species and within-species suggests that COⅠsequence is suitable for DNA barcoding in Polychaeta.In addition,we designed a pair of primers for amplifying CO Ⅰ DNA fragment of polychaete species,especially of species that have high A＋T composition in the gene.