10种石斑鱼系统发育的线粒体细胞色素b基因序列分析

Molecular phylogeny of 10 species of groupers(Serranidae: Epinephelinae)based on mitochondrial cytochrome b gene sequences

为探讨石斑鱼亚科鱼类的系统发育关系,测定了此亚科中具有代表性的石斑鱼属、鳃棘鲈属、九棘鲈属、驼背鲈属和白线光腭鲈属等5个属10种石斑鱼的细胞色素b基因全序列,分析了这些序列的特性,运用Kimura 2-parameter模型,以邻接法构建了分子系统树。结果表明,九棘鲈属与鳃棘鲈属位于系统进化树的基部,与石斑鱼类其它类群亲缘关系较远;驼背鲈属与白线光腭鲈属网结于石斑鱼属构成的分支中。

Groupers are edible fish of highly economic values. Owing to enormous number of the subfamily Epinephelinae and the lack of unified morphologic speciation characters, species identification for groupers is very difficult, and phylogenetic relationships among some taxa are not yet determined, playing negative effects on the sustainable exploitation and conservation of groupers. In this study sequences of mitochondrial cytochrome b gene of 10 species from genera Epinephelus,Cephalopholis, Plectropomus, Comileptes and Anyperodon were analyzed to infer phylogenetic relationships within the subfamily Epinephelinae. Neighbour-Joining unrooted tree based on the Kimura 2-parameter model indicated that Epinephelus was paraphyletic with the in- clusion of two morphologically distinct monotypic genus slender grouper Anyperodon and humpback hind Cromileptes. Compared to other groupers, Cromilepetes had slot nostrils, humpbacked body and the unique number of dorsal spines, nevertheless the Cytb gene sequence similarity between Cromileptes and Epinephelus was so high that their genetic distance was even closer than those between some Epinephelus fish. More molecular data and additional ontogenic development investigations are required to confirm phylogenetic status of Cromileptes. Unlike other groupers, Anyperodon lacked palatine teeth; whereas Anyperodon shared 11 dorsal spines with Epinephelus, indicating that the moving of A. leucogrammicus to the Epinephelus clade was not unexpected. Cephalopholis and Plectropomus were basal in the NJ tree,revealing their primitivity, in the Epinephelinae, which was consistent with former researches on Epinephelinae larvae.