基于线粒体Ctyb基因的滆湖3种黄颡鱼遗传多样性分析

Genetic Diversity of Three Species of Pelteobagrus in Ge Lake Based on Cytb Gene Sequence

为掌握滆湖3种黄颡鱼野生资源的种质遗传状况,采用线粒体Ctyb基因探索黄颡鱼、光泽黄颡鱼和长须黄颡鱼的遗传多样性和进化历史动态。通过PCR扩增、测序和序列分析,获得3种黄颡鱼的Ctyb基因全序列,长度均为1 138 bp。3种黄颡鱼Cytb基因的碱基组成具有偏倚性,碱基A+T的含量(55.6%)高于G+C的含量(44.4%)。49尾黄颡鱼的Cytb基因序列有23个多态位点,定义17种单倍型,单倍型多样性为0.903,核苷酸多样性为0.002 40;40尾光泽黄颡鱼的Cytb基因序列有25个多态位点,定义17种单倍型,单倍型多样性和核苷酸多样性分别为0.936和0.004 59;32尾长须黄颡鱼的Cytb基因序列有20个多态位点,定义11种单倍型,单倍型多样性和核苷酸多样性分别为0.829和0.002 25。整体来看,3种黄颡鱼的单倍型多样性较为丰富,但核苷酸多样性较低。黄颡鱼、光泽黄颡鱼和长须黄颡鱼的种内遗传距离分别为0~0.006、0~0.012和0~0.008。3种黄颡鱼的种间遗传距离为0.078~0.138,长须黄颡鱼与黄颡鱼的亲缘关系较近、与光泽黄颡鱼的亲缘关系较远。Tajima’s D和Fu’s F_s中性检验值均为负值,且核苷酸不配对分布图呈现单峰型,表明3种黄颡鱼经历过明显的种群扩张过程。该研究结果可为滆湖3种黄颡鱼的种质资源保护及开发利用提供参考依据。

In order to understand the wild resources’genetic situations of three species of Pelteobagrus,the genetic diversity and evolution history dynamics of Pelteobagrus fulvidraco,Pelteobagrus nitidus and Pelteobagrus eupogon were studied based on the mitochondrial Cytb gene sequences.By PCR amplification,sequencing and sequence analysis,the whole sequences of Ctyb gene were obtained from three species of Pelteobagrus,the length was 1138 bp.The base composition of Cytb gene in three species of Pelteobagrus was obvious biased,the content of A+T(55.6%)was higher than the content of G+C(44.4%).23 polymorphic sites were detected in Cytb gene sequences of 49 individuals of P.fulvidraco,17 haplotypes were defined,the haplotype diversity was 0.903,nucleotide diversity was 0.00240.25 polymorphic sites were detected in Cytb gene sequences and 17 haplotypes were defined in 40 individuals of P.nitidus,the haplotype diversity was 0.936,the nucleotide diversity was 0.00459.20 polymorphic sites were detected in Cytb gene sequences and 11 haplotypes were defined in 32 individuals of P.eupogon,the haplotype diversity was 0.829,the nucleotide diversity was 0.00225.Overall,three species of Pelteobagrus had rich haplotype diversity and low nucleotide diversity.The genetic distance within three species were 0-0.006,0-0.012,and 0-0.008,respectively.The genetic distance among three species was 0.078-0.138.P.eupogon had closer genetic relationship with P.fulvidraco and farther genetic relationship with P.nitidus.The values of Tajima’s D and Fu’s F s neutrality tests were negative,and the nucleotide pairwise difference distribution showed a unimodal pattern,indicating that these three species of Pelteobagrus had experienced population expansion in evolution history.The results of this study provided reference basis for the germplasm resources’protection,development and utilization of three species of Pelteobagrus in Ge Lake.