青海湖裸鲤和花斑裸鲤线粒体基因组比较及其系统进化分析

Comparison and Phylogenetic Analysis of Mitochondrial Genomes Between Gymnocypris przewalskii and Gymnocypris eckloni

为正确区分青海湖裸鲤和花斑裸鲤,向科学研究及偷捕鱼货物的司法鉴定提供相应的数据支撑。对青海湖裸鲤和花斑裸鲤的线粒体基因组进行测序和生物信息学分析。此外,基于36种鲤科鱼类的线粒体全基因组序列用最大似然法(ML)构建鲤科鱼类系统发育树。结果表明,青海湖裸鲤线粒体基因组全序列全长为16 720 bp,包括13个蛋白编码基因,22个tRNA基因,2个rRNA基因和1个D-Loop控制区,整个青海湖裸鲤线粒体基因组的核苷酸组成为28.68%A、27.29%T、18.16%G及25.87%C,AT偏向性显著(55.97%)。花斑裸鲤线粒体基因组全序列全长为16 760 bp,包括13个蛋白编码基因,22个tRNA基因,2个rRNA基因和1个D-Loop控制区,整个花斑裸鲤线粒体基因组的核苷酸组成为28.63%A、27.22%T、18.26%G及25.88%C,同样具有明显的AT偏向性(55.85%)。青海湖裸鲤和花斑裸鲤线粒体基因组所有蛋白编码基因以ATG作为起始密码子,绝大多数蛋白编码基因以TAG或TAA作为终止密码子,少数以不完全密码子(T--)作为终止密码子,所有的tRNA基因均能形成典型的三叶草结构。系统发育分析结果显示,裸鲤属所有物种都聚为一个类群,并与光倒刺鲃、大理裂腹鱼和扁吻鱼的亲缘关系较近。该研究基于线粒体基因组的系统发育分析未将青海湖裸鲤和花斑裸鲤准确区分,但为重新建立更清晰的鲤科鱼类分类体系奠定了基础。

The study aims to correctly distinguish between Gymnocypris przewalskii and Gymnocypris eckloni,and to provide corresponding data support to scientific research and judicial identification of fish poaching cargo.The mitochondrial genomes of Gymnocypris przewalskii and Gymnocypris eckloni were sequenced and bioinformatics analyzed.In addition,a cyprinid phylogenetic tree was constructed using the maximum likelihood(ML)method based on the complete mitochondrial genome sequences of 36 cyprinid species.The results showed that the total length of the mitochondrial genome of Gymnocypris przewalskii was 16720 bp,including 13 protein-coding genes,22 tRNA genes,2 rRNA genes and 1 D-Loop control region.The nucleotide composition of the entire mitochondrial genome was A(28.68%),T(27.29%),G(18.16%)and C(25.87%),with a significant AT-bias(55.97%).The total sequence of the mitochondrial genome of Gymnocypris eckloni was 16760 bp,including 13 protein-coding genes,22 tRNA genes,2 rRNA genes and 1 D-Loop control region.The nucleotide composition of whole mitochondrial genome was A(28.63%),T(27.22%),G(18.26%)and C(25.88%).There was also a significant AT bias(55.85%).All protein-coding genes in the mitochondrial genome of Gymnocypris przewalskii and Gymnocypris eckloni took ATG as the initiation codon,the vast majority of protein-coding genes took TAG or TAA as the termination codon,and a few took incomplete codons(T--)as the termination codon.All tRNA genes could form a typical clover structure.Phylogenetic analysis showed that all species of the genus Gymnocypris were clustered together and were closely related to the Spinibarbus hollandi,Schizothorax taliensis and Aspiorhynchus laticeps.The mitochondrial genome-based phylogenetic analysis of this experimental study did not accurately distinguish the Gymnocypris przewalskii and Gymnocypris eckloni,but laid the foundation for re-establishing a clearer taxonomic system for Cyprinidae.