基于线粒体基因组的东方鲀属系统发育学及群体遗传学

为了探究东方鲀属内系统发育关系,本研究首次基于群体尺度对东方鲀属物种进行系统发育分析。利用线粒体基因组,在包含10个种的124尾东方鲀中,挖掘了1 488个单核苷酸多态性(SNP)位点和4个插入缺失(INDEL),使用这些遗传变异位点进行了系统发育及群体遗传学分析。发现网纹东方鲀与铅点东方鲀可能是同种异名,且二者形成的姊妹群位于东方鲀属基部;暗纹东方鲀与红鳍东方鲀、菊黄东方鲀与双斑东方鲀各自亲缘关系较近。此外,实验发现了4尾可疑的双斑东方鲀和菊黄东方鲀杂交个体,以及2尾可疑的横纹东方鲀杂交个体。遗传多样性方面,弓斑东方鲀遗传多样性最低。此外,实验在10种东方鲀中共找到595个种间特异性SNP位点。Ka/Ks分析表明,nd6基因的Ka/Ks最高(平均为1.19),说明在东方鲀属中nd6可能经历了正选择,而ATP合成酶基因可能在东方鲀适应淡水环境中受到选择。研究表明,东方鲀属内系统发育关系较为复杂,且在野生环境下东方鲀物种间广泛存在自然杂交现象,该研究为东方鲀物种快速鉴定提供可靠的分子标记,加速东方鲀属系统发育研究进展,并为东方鲀野生种质资源保护提供了理论依据。

Phylogeny and population genetics of species in Takifugu genus based on mitochondrial genome

Takifugu, belongs to Tetraodontidae in Tetraodontiformes, is the typical adaptive radiation species, there were about twenty Takifugu species around the coast of China. In this study, phylogeny and population genetics of Takifugu species were analyzed based on population scale for the first time. Using mitochondrial genome, we obtained 1,488 SNPs and 4 INDELs in 124 individuals of 10 Takifugu species. The Phylogeny and population genetics analysis showed that T. poechilonotus and T. alboplumbeus could be synonym, and the sister group of these two species was located at the base of phylogeny tree. Besides, we found that the relationships between T. rubripes and T. fasciatus, T. flavidus and T. bimaculatus were closely. In addition, we detected 4 T. bimaculatus individuals which possibly were the hybrid progenies with T. flavidus, and 2 hybrid suspect T. oblongus individuals. For genetic diversity, we found that T. alboplumbeus has the lowest diversity. Moreover, we identified 595 species Species-specific SNPs in 10 Takifugu species. The Ka/Ks analysis showed that cox1 had the lowest Ka/Ks, and the Ka/Ks of nd6 was 1.19, which indicated that nc6 possibly under strong positive selection. Besides, the ATP synthetase may under selection in the process of adapting to fresh water of T. ocalletus and T. fasciatus. This study showed that the phylogenetic relationship of the Takifugu was complicated. Although the natural hybridization between species was common in the wild, this study can provide reliable molecular markers for the rapid identification of Takifugu species, and provide a solid foundation for the study of the Takifugu phylogeny in the future.