基于线粒体COⅡ基因和D-loop区序列对江西安南光唇鱼(Acrossocheilus)物种鉴定及系统发育位置分析

Species identification and phylogenetic position of Acrossocheilus fasciatus from Annan in Jiangxi Province based on mitochondrial COⅡ and D-loop region sequences

以采自江西赣州安南的野生鱼为实验材料,分别设计引物扩增其线粒体DNA COⅡ和D-loop序列并进行序列比对分析,经扩增得到的COⅡ序列全长为691 bp,D-loop序列的全长为937～944 bp,其中COⅡ序列中A、T、G、C的平均占比分别为31. 00%、25. 80%、15. 30%和27. 90%,而D-loop序列的占比则分别为35. 60%、32. 30%、12. 00%和20. 00%,两序列都是A+T含量高于G+C,G的含量在4种碱基中最低。COⅡ序列中仅存在6个碱基位点的转换,D-loop则有多个碱基位点存在转换、颠换、缺失或插入,群体内遗传距离分别为0. 0075、0. 0050。用最大似然法构建的COⅡ和D-loop系统发育树显示赣州安南光唇鱼与半刺光唇鱼(Acrossocheilus hemispinus)亲缘性最近,序列相似性分别为98. 70%、98. 69%,遗传距离最近分别为0. 0130、0. 0260,未达到种间分化的水平(0. 05)。2个序列分析结果一致,结合外部形态特征观察,可以断定赣州安南光唇鱼与半刺光唇鱼为同一种,研究为江西赣州安南光唇鱼的资源利用提供了资料。

Using Acrossocheilus fasciatus from Annnan in Jiangxi province, China, as experimental materials, we analyzed the variability of mitochondrial cytochrome oxidase unit Ⅱ(COⅡ) gene and D-loop region, and discussed the phylogenetic positon and species identification of two kinds of A. fasciatus . The results showed that the COⅡ gene was 691 bp in length, and the D-loop gene was 931- 944 bp in length. Regardless of COⅡ, or D-loop, the content of bases A+T was higher than that of bases G+C. Only 6 base sites were transformed in COⅡ sequence, while several base sites in D-loop sequence were transformed, transversed, and insertions/deletions. The genetic distances within the population were 0.0075 and 0.0050, respectively. The COⅡ and D-loop phylogenetic tree constructed by the maximum likelihood method showed the closest relationship between JXAnnan and Arossocheilus hemispinus . The sequence similarities were 98.70% and 98.69%, respectively. The genetic distances were 0.0130 and 0.0260, respectively, indicating that the genetic distance did not reach the level of interspecific divergence (0.05). The results demonstrated that JXAnnan is a geographical group of A. hemispinus . The results of this study can provide information for taxonomic study of Acrossocheilus .