东黄海沙海蜇与口冠水母分类关系的辨析-基于核糖体18 SrDNA基因序列

Taxonomic relationship between Nemopilema nomurai(in the Yellow Sea of China and the East China Sea) and Stomolophus meleagris based on the analysis of 18 SrDNA partial sequences

近年在东黄海形成大规模暴发的大型水母沙海蜇(Nemopilema nomurai)在大量文献中常被等同于口冠水母(Stomolophus meleagris)的同物异名,为澄清沙海蜇与口冠水母之间一直混淆不清的分类关系,现首次从分子遗传学水平进行辨析,采用聚合酶链式反应(PCR)技术对东黄海沙海蜇的18SrDNA(核糖体18 SrRNA的编码基因)进行扩增,PCR产物经纯化后进行测序,结果经比对拼接校正后,获得沙海蜇的18 SrDNA片段序列,长度为1 758 bp;碱基T、C、A、G平均组成分别为27.2%、20.1%、26.6%和26.2%,其A+T含量(53.8%)与G+C含量(46.2%)差别不大,AT/GC为1.16。利用18SrDNA序列构建的NJ系统发育树表明,东黄海野生沙海蜇与越前水母的亲缘关系很近,与海蜇的亲缘关系较远,与口冠水母的关系更远,首次从分子水平提供证据支持东黄海暴发性大型水母沙海蜇与口冠水母为不同物种。

The giant jellyfish Nemopilema nomurai which has formed blooms in the Yellow Sea and East ChinaSeas（YECS） in recent years was regarded as a synonym of Stomolophus meleagrisin many research literatures.In order to clarify the confused taxonomic relationship between N.nomurai（YECS） and S.meleagris,polymerase chain reaction（PCR） technique has been used to amplify the 18SrDNA gene for N.nomurai（YECS）.The PCR products were purified and sequenced.After being aligned,1 758 bp sequences of 18SrDNA have been obtained and analyzed.The average nucleotide composition of T,C,A,G were27.2%,20.1%,26.6% and 26.2% respectively.The phylogenetic tree based on 18SrDNA gene partial sequences showed that N.nomurai（YECS） was more closely related with N.nomurai in Japan（sequence from NCBI’s Genbank） than with Rhopilema esculentum（sequences from NCBI’s Genbank）,further more than with S.meleagris（sequences from NCBI’s Genbank）,which indicated that N.nomurai（YECS） was different from S.meleagrisat molecular genetic level.