基于Cytb和D-Loop基因对中国少鳞鳜种群遗传多样性的分析

Analysis of Genetic Diversity of Little Scale Mandarinfish Coreoperca whiteheadi Population Based on Cytb and D-Loop Genes

为探究贵州省中国少鳞鳜野生资源多样性状况,利用线粒体DNA Cytb基因和D-Loop基因分析评价沅江上游铜仁锦江、平塘县平舟河及荔波县樟江3个自然群体的86尾中国少鳞鳜的遗传多样性、遗传结构及种群历史动态。测序结果表明,中国少鳞鳜Cytb基因的序列长度为1141 bp,D-Loop为822 bp。在Cytb区段共检测出11个变异位点,界定了18种单倍型,3个群体平均的单倍型多样性、平均核苷酸差异数和核苷酸多样性分别为0.918、3.342和0.00293;在D-Loop区段中共检测出17个变异位点,其中有3个缺失和2个插入,界定了23种单倍型,3个群体平均的单倍型多样性、平均核苷酸差异数和核苷酸多样性分别为0.903、3.343和0.00410。遗传分化指数显示出3个群体间存在极大的遗传分化;中性检验和核苷酸不配对分布分析表明,本试验的中国少鳞鳜未经历过种群扩张。中国少鳞鳜属迁徙能力弱、较封闭的小群体,因近交衰退效应,种群结构较为原始,长江流域群体生境理想,进化潜力较大。荔波樟江种群面临生存危机,而锦江更适宜中国少鳞鳜栖息繁育。本试验从分子水平评价贵州省中国少鳞鳜遗传多样性水平,将为其种质资源的保护和开发利用提供依据。

The genetic diversity,genetic structure and population history of little scale mandarinfish(Coreoperca whiteheadi)were investigated in 86 samples collected in Tongren Jinjiang River in the upper Yuanjiang River,Pingzhou River in Pingtang County and Zhangjiang River in Libo County by mitochondrial DNA Cytb gene and D-Loop gene analysis in order to explore the diversity of wild resources of little scale mandarinfish in Guizhou Province.The sequence was found to be 1141 bp in Cytb and 822 bp in D-Loop in length.In the Cytb region,11 haplotypes were detected and 18 haplotypes were defined,with mean haplotype diversity of 0.918,mean nucleotide difference of 3.342 and mean nucleotide diversity of 0.00293.A total of 17 mutation sites were detected in the D-Loop region,including 3 deletions and 2 insertions,and 23 haplotypes were found,with mean haplotype diversity of 0.903,mean nucleotide difference of 3.343,and mean nucleotide diversity of 0.00410.The genetic differentiation index indicated that there was significant genetic differentiation among the three populations,and both the neutral test and the nucleotide mismatch analysis revealed that little scale mandarinfish had not experienced population expansion.The findings showed that the population structure of little scale mandarinfish in Guizhou Province was primitive due to inbreeding decline.The habitat of the population in the Yangtze River Basin is ideal,with great evolutionary potential.The population in Libo Zhangjiang River is at risk,and Jinjiang River is more suitable for little scale mandarinfish breeding.In this paper,the genetic diversity of little scale mandarinfish in Guizhou Province was evaluated at molecular level,which provides reference for the protection and utilization of its germplasm resources.