摘要
测定了绒螯近方蟹和肉球近方蟹线粒体16S rRNA基因部分片段的序列,其长度分别为529bp和525bp。二者的核苷酸序列A、T、G、C的含量相似,分别为36.3%、37.2%、15.9%、10.6%,35.2%、37.5%、17.1%、10.2%;不包括4处插入/缺失位点,两序列间有31个变异位点,核苷酸差异率为5.91%,其中转换18个、颠换13个,转换与颠换比约为1.4。对国外3种近方蟹的16S rRNA基因序列与本文的2种近方蟹序列一起比对获得512bp的同源序列(含插入/缺失位点)进行分析,A+T的平均含量为73.5%,明显高于G+C的平均含量,共检测到变异位点67个,简约信息位点19个。基于已知的弓蟹科43种蟹类的16S rRNA基因502bp同源序列获得的系统发生树的拓扑结构表明,Helicana、Eriocheir、Helice、Cyrtograpsus、Metaplax、Brachynotus属的蟹类各自聚为一支,且与形态学分类结果一致,表明其分别为一单系;但Hemigrapsus、Gaetice、Cyclograpsus属的蟹类却没有各自聚为一支,分子数据不支持它们分别为一单系。
Partial sequences of the mitochondrial 16S rRNA gene were determined for Hemigrapsus penicillatus and H.sanguineus,and the sequence lengths of them were 529bp and 525bp respectively.The A,T,G and C contents were similar,which were 36.3%,37.2%,15.9%,10.6% and 35.2%,37.5%,17.1%,10.2% respectively.There were 31 different sites（excluding 4 deletion/insertion sites） between two species,including 18 transition sites and 13 transversion sites.The si/sv and ratio of sequence divergence were about 1.4 and 5.91% respectively.Furthermore,512bp homologous segments of five Hemigrapsus species were analyzed.The results showed that the average A＋T content（73.5%） was higher than G＋C content,and there were 67 variable sites and 19 parsimony-information sites in the nucleotides of the data.Topological structure of the molecular phylogenetic tree constructed by 502bp homologous segments of 16S rRNA gene from 43 species of Varunid crabs with Neighbor-Joining method showed that the species of Helicana,Eriocheir,Helice,Cyrtograpsus,Metaplax and Brachynotusspecies were clustered into distinct clades respectively,which indicated the monophyly of the genera respectively.But,the species of Hemigrapsus,Gaetice and Cyclograpsus were not clustered into distinct clades respectively,which revealed that the genera might not be monophyletic respectively.
出处
《海洋通报》
CAS
CSCD
北大核心
2010年第6期638-642,共5页
Marine Science Bulletin
基金
重庆文理学院引进人才专项(No.200803)
