基于线粒体COⅠ基因序列的红螯螯虾养殖群体遗传结构分析

Genetics analysis based on mitochondrial COⅠsequences in five cultured populations of red-claw crayfish(Cherax quadricarinatus)

红螯螯虾原产于澳大利亚,是一种具有优良养殖前景的淡水虾类。基于线粒体COⅠ基因序列,对中国5个养殖群体的遗传多样性和结构进行评估,旨在为红螯螯虾的科学引种、良种选育和种质资源保护提供基础数据。结果显示,红螯螯虾线粒体COⅠ区全序列长1534 bp,包含24个变异位点,占分析位点的1.6%,变异位点中含有22个简约信息位点,平均转换与颠换的比值为6.14,序列中(A+T)的含量(58.7%)明显高于(G+C)的含量(41.3%),在143个个体中定义了35种单倍型,来自浙江、海南和台湾的养殖群体具有较多的共享单倍型(COⅠ-01、COⅠ-02和COⅠ-03),这3种单倍型同时也是优势单倍型。来自江苏的养殖群体的单倍型多样性最低(0.739),来自安徽的养殖群体的单倍型多样性最高(0.881)。全部样本的单倍型多样性指数为0.896,核苷酸多样性指数为0.00465。5个养殖群体间的遗传距离为0.00263~0.00681,其中,来自浙江与海南的养殖群体的遗传距离最近,来自海南与安徽的养殖群体的遗传距离最远。5个养殖群体间的遗传分化系数为0.3421(P<0.01),说明5个养殖群体间存在一定程度的遗传分化。综上,5个红螯螯虾养殖群体的遗传多样性存在差异,群体间存在着一定的基因交流。研究结果可为红螯鳌虾种质资源的合理开发利用提供分子生物学依据。

Cherax quadricarinatus is native to Australia with good breeding prospects.In the present study,the genetic diversity and structure of five cultured populations of Cherax quadricarinatus were evaluated based on mitochondrial COⅠsequences,to provide basic data for scientific introduction,variety selection,and germplasm resource protection.The results showed that the complete sequence of the mitochondrial COⅠregion was 1534 bp,of which 24 were variation sites,accounting for 1.6%of the analysis sites.In the 24 variation sites,22 were parsimony-informative sites,and the average transversion ratio was 6.14.The content of(A+T)(58.7%)was higher than that of(G+C)(41.3%).A total of 35 haplotypes were defined in 143 individuals.Zhejiang,Hainan,and Taiwan cultured populations had some shared haplotypes(COⅠ-01,COⅠ-02,and COⅠ-03),and these three haplotypes were dominant also.The haplotype diversity of Jiangsu cultured population(0.739)was the lowest,while the highest was found in Anhui cultured population(0.881).The haplotype diversity index and nucleotide diversity index of whole samples were 0.896 and 0.00465,respectively.The genetic distance between different cultured populations varied from 0.00263 to 0.00681,and the genetic distance between Zhejiang and Hainan cultured populations was the closest,while the genetic distance between Hainan and Anhui cultured populations was the furthest.The genetic differentiation coefficient within populations was 0.3421(P<0.01),indicating genetic differentiation within populations.The genetic diversity of the five cultured populations of C.quadricarinatus was different,indicating that there was some gene exchange among populations.These results provided molecular biological basis for the rational development and utilization of the germplasm resources of C.quadricarinatus.