基于线粒体控制区全序列的鄱阳湖水系鲢增殖放流群体与野生群体的遗传多样性分析

采用PCR和DNA测序技术研究鄱阳湖水系增殖放流群体与野生群体白鲢的遗传结构和群体遗传学特征,测定了瑞昌、赣江、增殖放流3个群体54尾鲢线粒体控制区全序列935bp，缺失或插入3个碱基,发现41个变异位点,均为简约信息位点，共检出24个单倍型。转换／颠换比为14.344。在邻接树上来自不同地点的鲢混杂分布于各分支，没有出现明显的谱系结构和地理聚群。AMOVA 分析表明变异主要来自种群内，种群间出现显著分化。FST=0.22388也表明遗传变异主要来自种群内。3个群体间的遗传距离为0.01035～0.01634,Fst值为0.08252～0.39171，表明3个群体间存在显著遗传分化。赣江、瑞昌和增殖放流群体的单倍型多样性分别为0.727、0.978、0.947，核苷酸多样性分别为0.00897、0.01135、0.00978，其中瑞昌群体的单倍型多样性与核苷酸多态性在3个群体中最丰富，其次是增殖放流群体，赣江群体单倍型多样性及核苷酸多样性最低，应加以保护。

Genetic diversity analysis of Hypophthal michthys molitrix between wild and stock enhancement based on mitochondrial control region sequences in the Poyang Lake water system

The aim was to determine whether the enhancement activities will lead to changes genetic structure of natural silver carp in the Poyang Lake River, a 935 bp fragment of the mitochondrial D-Loop complete sequences was used to study the genetic diversity and population structure of Hypophthal michthys molitrix between wild and stock enhancement in the Poyang Lake water system. Complete sequences of the mitochondrial DNA control region （935 bp） of 54 silver carps from Ruichang （RL）, Gan river （RL） and stock enhancement （SL） were directly sequenced, of which 41 mutations of nucleotide acids and a total of 24 haplotypes were indentified, in which only one haplotype （Hap6） was shared by three populations in the Poyang Lake water system. Haplotpic diversity （0.727±0.077） and nucleotide diversity （0.00897±0.00168） of the the populations in Gan river were lower than those of RL and SL population. The AMOVA analysis indicated that the genetic variation mainly occurred within populations instead of among populations. Although on geographic clustering was observed in the phylogenetic tree, significant population subdivision was supported by both of the pairwise Fst values and average pairwise differences. The bimodal mismatch distribution of pairwise haplotype difference and the negatively selective neutrality test （Tajima＇ s D =0.70106, P=0.824〉0.10; Fu＇s Fs=-1.007, P=0.410〉0.10） suggest that a recent population expansion of Poyang Lake water system had not occurred. Based on the above results, the genetic diversity of Gan River population were the very lowest, Gan River should be as priority conservation areas; silver carp of stock enhancement induced the genetic structure differentiation of natural silver carp in the Poyang Lake, the releasing procedure should be standardized and operation procedure should be planed.