厚蟹线粒体16S rRNA基因序列分析及系统发育研究

Molecular phylogeny of the crab genera Helice and Helicana (Crustacea,Decapoda) based on the partial sequences of mitochondrial 16S rRNA gene

对我国沿海天津厚蟹6个群体、侧足厚蟹4个群体、伍氏仿厚蟹2个群体和日本仿厚蟹1个群体的线粒体16S rRNA基因片段进行了序列测定;结合从GenBank下载的其他厚蟹序列,分析了厚蟹分子系统发育关系。除天津厚蟹丹东群体的2个个体16S rRNA基因片段长度为526 bp外,其他天津厚蟹和侧足厚蟹均为525 bp;除日照群体和丹东群体外,其他每个群体的个体之间没有序列差异,天津厚蟹和侧足厚蟹共有5个单倍型。伍氏仿厚蟹16S rRNA基因片段长度均为525 bp,群体、个体之间均无序列差异。日本仿厚蟹16S rRNA基因片段长度均为523 bp,个体之间无序列差异。其A,T,G,C含量只有略微的差异,A+T含量(72.3%～73.7%)明显高于G+C含量。4种厚蟹所有序列比对,在526 bp序列上共有变异位点36处和4处插入/缺失,其中简约信息位点26处,转换/颠换的平均值为2.8。在5个单倍型中,侧足厚蟹泉州、宁波群体的6个个体与天津厚蟹宁波、日照群体的4个个体的序列都相同,共享1个单倍型;而且5个单倍型之间的遗传距离很小,仅为0.19%～1.15%,表明二者为同一物种的不同形态类型。采用NJ法,ML法和MP法构建的厚蟹/张口蟹复合群系统进化树的拓扑结构基本一致。结果显示,天津厚蟹和侧足厚蟹的10个群体的5个单倍型和台湾厚蟹首先聚到一起,形成侧足厚蟹复合体后,再与三齿厚蟹聚为一支;日本仿厚蟹与德氏仿厚蟹先聚在一起,然后再与伍氏仿厚蟹聚为一支;均得到99%置信度的支持,表明厚蟹属蟹类和仿厚蟹属蟹类均为单系,支持将厚蟹亚属和仿厚蟹亚属分别提升为属。分子数据及系统树的拓扑结构亦支持将假厚蟹亚属和拟厚蟹亚属分别提升为属,以及形态学上将厚蟹/张口蟹复合群分为7个属的结论。

The partial sequences of mitochondrial 16S rRNA gene of Helice tientsinensis（six populations）,H.latimera（four populations）,Helicana wuana（two populations） and H.japonica（one population） from the coast of China were determined and subjected to phylogenetic analysis with the inclusion of other species of Helice and Helicana obtained from the GenBank.The length of sequence of Helice tientsinensis and H.latimera was 525 bp,excluding 526 bp of two individuals from Dandong population of H.tientsinensis.Five haplotypes were found in them.The lengths of sequence of Helicana wuana and H.japonica were 525bp and 523bp respectively.There were no differences of sequence among individuals within populations of them,except Rizhao and Dandong populations.The A,T,G and C contents of them were similar,and the AT content（72.3%～73.7%）was higher than GC content.The resultant sequences of H.tientsinensis,H.latimera,H.wuana and H.japonica were 526bp long with 4 indels,of which 36 sites were variable and 26 sites were parsimoniously informative,and average transition/transversion ratio was 2.8.Among the five haplotypes,six individuals of H.latimera from Quanzhou and Ningbo populations and four individuals of H.tientsinensis from Ningbo and Rizhao populations shared one haplotype,and genetic distances among them were very small（0.19%～1.15%）,implying that they may represent different morphotypes of the same species.Molecular phylogenetic trees indicated that the genera Helice and Helicana were monophyletic respectively,the large net genetic distances between them supported that they were updated from subgenus to genus.The molecular data also supported that the Pseudohelice and Parahelice were updated from subgenus to genus,and Helice/Chasmagnathus complex was divided into seven genera by morphology.