厦门海域真刺唇角水蚤mtCOI序列分析

Mitochondrial COI Sequence Analysis of Labidocera euchaeta Habitated in Xiamen Waters

采用PCR扩增、克隆和序列测定等技术对厦门海域真刺唇角水蚤(Labidocera euchaetaGiesbrecht)线粒体细胞色素氧化酶I亚基基因(mitochondrial COI,mtCOI)进行了初步研究,得到3个雌性个体的mtCOI基因片段序列,序列的长度为709 bp,其A,T,C,G平均含量分别为23%、37%、15%和25%.三条核苷酸序列经比较后,得到其遗传相似性(i-dentity)为99.29%,共有15个差异位点,核苷酸差异均为颠换(transversion)类型.比较了厦门海域真刺唇角水蚤与GenBank数据库中的角水蚤科(Pontellidae)6个种的mtDNA COI基因片段序列(索引号AY145428、AY145429、AB206443、AB206444、AB206445、AB206446),其同源性为87.34%.文中讨论了上述7种桡足类的系统发生关系.

Labidocera euchaeta Giesbrecht is a dominant planktonic Copepod of the coastal waters of China. The specimens in the present study were collected from Xiamen Waters in February of 2004. Mitochondrial COI gene fragment of Labidocera euchaeta was amplified via PCR,the PCR products were ligated into T-vector （Promega Co. ）, cloned and sequenced. MtCOI gene fragment sequences of three female individual were obtained. The sequence length was 709 of base pairs, and the average contents of A, T, C, G were 23 %, 37 % 15 % and 25 %, respectively. Genetic identity, 99.29 %, was calculated by comparison of sequences of Labidocera euchaeta. MtCOI sequence variation sites were found as much as 15 loci and variation types were transversion. The sequences of Labidocera euchaeta collected from Xiamen waters and the sequences of Labidocera rotunda （accession no. AY145428） ,Calanopia thompsoni （ accession no. AY145429）, Pontellina plumata （ accession no. AB206443）, Pontellopsis regalis （ accession no. AB206444）, Pontellopsis tenuicauda （accession no. AB206445）, Pontella rostraticauda （accession no. AB206446） from GenBank were compared and the result showed that the genetic identity was about 87. 34% in the 625 base pair region. In the present study, the software programs DNAMAN and MEGA3.1 were used to make gene trees showing the systematic relationships of Labidocera euchaeta collected from Xiamen waters and Labidocera rotunda, Calanopia thompsoni , Pontellina plumata , Pontellopsis regalis , Pontellopsis tenuicauda , Pontella rostraticauda.