基于线粒体基因组全序列的鳅科(Cobitidae)鱼类进化关系分析

Molecular Evolution Analysis of Cobitidae Fishes Based on Mitochondrial Genome Sequences

为了解鳅科(Cobitidae)鱼类线粒体全基因组序列的结构特征和系统发育信息,利用生物信息学方法对已知的40种鳅科鱼类线粒体全基因组进行比对分析,用邻接法(NJ)构建系统发育树。结果显示:(1)鳅科鱼类线粒体基因组全序列长度在16553~16937 bp之间,基因组的结构特征及基因排列顺序与其他硬骨鱼类一致。(2)鳅科鱼类线粒体全基因组一致序列长度为17483 bp,变异位点数为8039(45.9%),Kimura双参数平均遗传距离为0.19。在13个蛋白质编码基因中,ND2的变异程度(58.9%)和平均遗传距离(0.28)最大,变异程度最小的是12S rRNA(30.5%),tRNA拼接序列的平均遗传距离最小(0.07)。(3)Cox1、ND5、Cytb基因是进行鳅科鱼类系统发育分析较为理想的分子标记,NJ系统发育树显示,条鳅亚科(Noemacheilinae)是最早分化出来的一枝群系,位于祖先位置,沙鳅亚科(Botiinae)和花鳅亚科(Cobitinae)亲缘关系更近,互为姐妹群系。本研究为鳅科鱼类进化学研究和分子标记的选取提供参考依据。

In order to understand the structural characteristics and phylogenetic information of the mitochondrial genome of Cobitidae,the mitochondrial genome of 40 known Cobitidae are compared and analyzed using Bioinformatics,and a phylogenetic tree is constructed using Neighbor-Joining method.The results show that:(1)The length of the mitochondrial genome of Cobitidae ranges from 16553 to 16937 bp,and the structural characteristics and gene order are consistent with other teleost fishes.(2)The consensus sequence length of the mitochondrial genome of Cobitidae is 17483 bp,the number of variable sites is 8039(45.9%),and the overall mean Kimura 2-Parameter distance genetic distance is 0.19.Among the 13 protein coding genes,ND2 is the highest degree of variation(58.9%)and genetic distance(0.28),the lowest degree of variation is 12S rRNA(30.5%),and the concatenated tRNA sequence is the lowest genetic distance(0.07).(3)Coxl,ND5 and Cytb genes are ideal molecular markers for phylogenetic analysis of Cobitidae.The NJ phylogenetic tree showes that Noemacheilinae is the earliest divergent group and in the ancestral position,Botininae and Cobitinae are closely related and sister groups.This study provides a reference for the evolutionary research of Cobitidae and the selection of molecular markers.