基于mtDNA D-loop进行四种鲤科鱼类种间鉴定研究

为研究鲤科鱼类的遗传变异和种间鉴定,采用线粒体D环（mitochondrial DNA,mtDNAD-loop）作为分子标记,测定了四种常见鲤科鱼类（草鱼,Ctenopharyngodon idellus;鲢,Hypophthalmichthys molitri;鲤,Cyprinus carpio;鲫,Carassius cuvieri）mtDNAD-loop核苷酸序列。结果表明：四种鱼类mtDNAD-loop区碱基组成A＋T的平均含量（71.4%）明显高于G＋C（28.6%）。在108个个体中,共检测到132个多态位点（22个单一多态位点和110个简约信息位点）,由此界定了57个单倍型（H1-H57）。鲫的单倍型多样度（1.000±0.017）和核苷酸多样度（0.03593）最高,而草鱼最低（分别为0.499±0.071,0.00817）。四种鱼类可以通过53个特征性碱基严格区分。基于遗传变异分析表明：四种鱼类没有共享单倍型,种间特异性单倍类的特征性碱基可以作为种间鉴别的依据。通过mtDNA控制区的分子标记,可以为鱼类鉴定、种质资源保护及其产品的真伪鉴别提供依据。

Species Identification by mtDNA D-loop among Four Cyprinid Fishes

In order to identify genetic variation and species identification between the cyprinid fishes, mtDNA D-loop was selected as a marker to determine mtDNA D-loop nucleotide sequence of four common cyprinid fishes (Ctenopharyngodoni dellus; Hypophthalmichthys molitri; Cyprinus carpio; Carassius cuvieri ) in the study. The nucleotide composition A+T (averagely 71.4%) are much more abundant than G+C (averagely 28.6%) in the four kinds of fish. 132 polymorphic sites(22 singleton variable sites and 110 parsimony informative sites) was detected in 108 fishes . Based on the research, we defined 57 haplotypes (H1-H57) in these fishes. Haplotype diversity and nucleotide diversity were the highest in Carassius cuvieri( haplotype diversity: 1.000±0.017, nucleotide diversity: 0.03593) and the lowest in Ctenopharyngodoni dellus ( haplotype diversity: 0.499±0.071, nucleotide diversity: 0.00817). The four kinds of fish also could be identified clearly by 53 characteristic nucleotides. According to the genetic variation analysis we can include that the haplotypes were different among four fish populations. No common haplotype was shared between them. Characteristic nucleotides as a method used to identify four kinds of fish. Marking mtDNA D-loop can provide the germplasm resources conservation of fish and the authenticity of fish products.