高体(鱼狮)(Seriola dumerili)线粒体全基因组测定及结构特征分析

为快速有效鉴别(鱼师)属鱼类物种、加强(鱼师)鱼遗传多样性管理与种质资源保护,通过Illumina测序技术,获得了东海海域养殖高体(鱼师)(Seriola dumerili)线粒体基因组全序列(16 530bp),碱基组成为A (26.83%)、G (17.6%)、C (30.04%)和T (25.53%), A+T含量为52.36%,且非编码控制区(D-loop)A+T富含61.64%,表现明显的AT偏好性。与其他硬骨鱼一样,高体(鱼师)线粒体基因组包含13条蛋白编码基因, 22个tRNA基因, 2个rRNA基因,除ND6、tRNA^Gln、tRNA^Ala、tRNA^Asn、tRNA^Cys、tRNA^Tyr、tRNA^Ser、tRNA^Glu、tRNA^Pro基因外,其余均位于H链编码;蛋白编码基因中,除COⅠ、COⅡ和ND5的起始密码子分别为ATC、ATA和ATA外,其余10个蛋白编码基因的起始密码子均为ATG,以典型的TAA和TAG为终止密码子,在ND4和Cytb中存在不完全密码子T;除tRNA^Ser-GCT外,其余21个tRNA均为典型三叶草二级结构。比较中国和日本海域高体(鱼师)线粒体基因组发现, CO Ⅰ、CO Ⅱ和ND5蛋白编码基因在起止位置、片段长度及起止密码子上存在显著差异。此外,与同属的黄条(Seriola aureovittata)和五条(鱼师)(Seriola quinqueradiata)的线粒体基因组13个蛋白编码基因进行两两对比分析,结果表明3种(鱼师)属鱼类的蛋白编码基因的相似性在85%~100%之间。基于线粒体基因组全序列构建的系统发育树,成功将高体(鱼师)与其他(鱼师)属鱼类有效区分,高体(鱼师)与长鳍(鱼师)同属一支,亲缘关系最近;黄条(鱼师)和五条(鱼师)聚为一支,亲缘关系最近。

COMPLETE SEQUENCE AND GENE ORGANIZATION OF THE MITOCHONDRIAL GENOME OF SERIOLA DUMERILI

To identify the species of Seriola and strengthen the management of genetic diversity and protection of germplasm resources of the Seriola, the complete mitochondrial genome sequence of Seriola dumerili cultured in the East China Sea was successfully obtained by second-generation sequencing and bioinformatic analysis. The total length of the mitochondrial genome sequence was 16 530 bp with typical mtDNA components including 13 proteins and 22 tRNAs, 2 rRNAs and a D-Loop region, in which the A content was 26.83%, G was17.6%, C was 30.04% and T was 25.53%. Except for ND6, tRNA^Gln,tRNA^Ala,tRNA^Asn,tRNA^Cys,tRNA^Tyr,tRNA^Ser,、tRNA^Glu,and tRNA^Pro, all the other genes were encoded on the H-strand. The A+T content of the complete mitochondrial genome sequence and the protein coding gene were 52.36%and 51.72%, respectively. Among the 22 tRNA genes, except for tRNA^Ser-GCT, the other 21 tRNA genes contained typical secondary structure of clover. The results show that the similarity of 13 protein coding genes in the whole mitochondrial genome of the three species was over 85% to 100%. The genes encoding CO Ⅰ, COⅡ, and ND5 showed difference at the start point, length, and starting codon between Chinese and Japanese S. dumerili. Furthermore, the phylogenetic tree was constructed with the complete mitochondrial genome sequences of four species from Seriola genus. The phylogenetic tree showed that S. aureovittata and S. quinqueradiata were clustered in one branch, and the phylogenetic tree of S. dumerili and S. rivoliana belonged to the same proximal branch. The phylogenetic relationship between S. aureovittata and S.quinqueradiata, and between S. dumerili and S. rivoliana are the closest.