基于线粒体16S rRNA和COI基因序列探讨对虾属(Penaeus)物种系统发生关系

有关对虾属(Penaeus)的设置及其相互亲缘关系一直是分类学争论的焦点,利用线粒体16S rRNA基因片段及COI基因片段序列分析的方法,以长臂虾科的脊尾白虾(Exopalaemon carinicauda)为外群,对对虾属的6亚属23种对虾进行了分子系统学研究。经ClustalX多重比对和MEGA4.0软件分析,得到种间序列的遗传距离并构建了最大简约(MP)系统树。结果表明:分子系统学数据支持Perez F等将对虾属的6个亚属提升为属级阶元的观点。囊对虾属的日本囊对虾(Marsupenaeus japonicus)和沟对虾属(Melicertus)的深沟对虾(Melicertus canaliculatus)之间的16S遗传距离只有0.007,而且COI遗传距离仅有0.065,比深沟对虾与同为沟对虾属的其他虾类遗传距离还小,说明囊对虾亚属(Marsupenaeus)和沟对虾亚属之间亲缘关系较近。另外美对虾亚属的褐美对虾(Farfantepenaeus aztec-us)和巴西美对虾(Farfantepenaeus brasiliensis)之间的16S rRNA基因序列遗传距离仅为0.012,但是与其他同亚属的虾类遗传距离相对较大,推测美对虾亚属(Farfantepenaeus)中的虾类根据亲缘关系远近和地理分布可以分为2大类群:墨西哥湾类群和南美洲类群。可以为对虾属的6个亚属的分类问题及演化提供一定的分子生物学依据。

The molecular phylogenetic analysis of Penaeus based on 16S rRNA and COI sequences

The setting and genetic relationship of original Penaeus genera was the focus of taxonomy.To clarify the classification and phylogenesis of original Penaeus genera,16SrRNA and COI gene of mitochondrial DNA sequences were used to establish the phylogeny of the Penaeus genus.This phylogeny was used to prove the variety and evolutionary history of species.Sequences of both 16S rRNA and COI genes from 23 species of Penaeus genera were analysed by MEGA 4.0 Beta.The matrix of pair-wise genetic distance and trees of maximum parsimony(MP) was also established.Phylogenetic analysis supported the validity of all the previously created six subgenera.The molecular data showed that the genetic distances of M.japonicus and M.canaliculatus were only 0.007 and 0.065.The genetic distances are smaller than that of the other shrimps of the Melicertus genus.Marsupenaeus and Melicertus were close to each other in evolutional relation.Pairwise distance matrix suggested that the Farfantepenaeus can be divided into two major groups,because the shrimps of Farfantepenaeus have larger evolutional relation.There are the group of Gulf of Mexico and group of South America.This study provided a basis of molecular biology for classification and evolutionary of the six sub-species.