基于线粒体COI序列片段研究华鳈不同地理群体及其他鳈属鱼类的遗传多样性

Investigation on the genetic diversity of Sarcocheilichthys sinensis from diverse geographical populations and other species within the Sarcocheilichthys genus through the analysis of mitochondrial COI sequence segments

鳈属(Sarcocheilichthys)鱼类是东亚地区常见小型淡水鱼类,并具有一定的养殖开发潜力。深入了解鳈属鱼类的遗传结构及其地域变异,对科学制定保护计划和可持续利用野生资源具有重要意义。试验采用鳈属鱼类包括小鳈(S.parvus,XQ)20尾,江西鳈(S.kiangsiensis,JXQ)20尾,黑鳍鳈(S.nigripinnis,HQQ)20尾,东北鳈(S.lacustris,DBQ)24尾,华鳈(S.sinensis)淮河群体(HQ_(HH))20尾、闽江群体(HQ_(MJ))17尾、江西群体(HQ_(JX))15尾和建德群体(HQ_(JD))17尾,并对每个群体的线粒体细胞色素C氧化酶亚基Ⅰ(cytochrome C oxidase subunitⅠ,COI)序列片段进行了测序和分析。试验结果表明,在获得的153个样本序列(668 bp)中,保守位点507个,变异位点154个,简约信息位点150个,碱基缺失或插入位点27个,平均转换与颠换比值为5.2。HQQ群体的单倍型多样性(Hd)最低(0.442),HQHH群体的Hd略高于HQQ群体(0.574),DBQ群体的Hd则稍高于HQHH群体(0.707),而XQ群体的Hd最高(0.963),HQMJ和HQJX群体的Hd则略低于XQ群体(0.860、0.848)。核苷酸多样变化趋势则与Hd结果类似。153尾个体定义了56种单倍型,各群体的单倍型网络中均存在各自群体的主要单倍型,如Hap_2、Hap_33和Hap_37等。基于遗传距离构建的UPGMA分子系统发育树、层次聚类树和NeighborNet分子系统发育网络表明,XQ、HQQ、JXQ和其他鳈属鱼类间遗传关系较远,而DBQ与HQHH群体间遗传关系较近。该研究利用COI序列片段评估了4个华鳈地理群体及其他4种鳈属鱼类的遗传多样性。研究结果将有助于了解华鳈不同地理群体及其他4种鳈属鱼类野生资源的遗传多样性现状,为今后华鳈以及其他4种鳈属鱼类种质资源保护及利用提供参考。

The genus Sarcocheilichthys,commonly found in East Asia,comprises small freshwater fish species with potential for aquaculture and development.Gaining a thorough understanding of the genetic structure and geographic variation of Sarcocheilichthys fish is of great significance for scientifically formulating conservation plans and ensuring sustainable utilization of wild resources.The experimental subjects included S.parvus(XQ)of 20 individuals,S.kiangsiensis(JXQ)of 20 individuals,S.nigripinnis(HQQ)of 20 individuals,S.lacustris(DBQ)of 24 individuals,and multiple geographic populations of S.sinensis,including Huaihe population(HQ HH)of 20 individuals,Minjiang population(HQ_(MJ))of 17 individuals,Jiangxi population(HQ_(JX))of 15 individuals,and Jiande population(HQ_(JD))of 17 individuals.The mitochondrial cytochrome C oxidase subunit I(COI)sequence segments of each population were sequenced and analyzed.Among the 153 obtained sequence samples,there were 507 conserved sites,154 variable sites,150 parsimony informative sites,and 27 sites with base deletions or insertions,with an average transition/transversion ratio of 5.2.The H_(d)(haplotype diversity)of the HQQ population was the lowest(0.442),slightly higher in the HQ HH population(0.574),and further increased in the DBQ population(0.707).The XQ population showed the highest H_(d)(0.963),while HQ_(MJ)and HQ_(JX)populations had slightly lower H_(d)values than XQ(0.860 and 0.848,respectively).Nucleotide diversity exhibited a similar trend to H_(d)results.A total of 153 individuals defined 56 haplotypes,and each population exhibited major haplotypes within their respective haplotype networks,such as Hap_2,Hap_33,and Hap_37,among others.The UPGMA molecular phylogenetic tree,hierarchical clustering tree,and NeighborNet molecular phylogenetic network constructed based on genetic distance indicated that the genetic relationships between XQ,HQQ,JXQ,and other Sarcocheilichthys fish were relatively distant.At the same time,DBQ had a closer genetic relationship with the HQ_(HH)population.This study used COI sequence segments to assess the genetic diversity of four geographic populations of S.sinensis and four other Sarcocheilichthys species.The research results contribute to understanding the current genetic diversity of different geographic populations of S.sinensis and four other Sarcocheilichthys species,providing valuable insights for the conservation and breeding of germplasm resources in S.sinensis and other Sarcocheilichthys fish in the future.