我国6个鲤群体的mtDNA D-loop序列遗传变异分析

探讨当前中国鲤（Cyprinus carpio）野生群体和育成品种的遗传结构及变异情况，以期丰富鲤种质资源的研究数据，为后期鲤的种质挖掘和遗传育种提供更多参考。收集了鲤的４个野生群体（清水江鲤、太湖鲤、黄河鲤和黑龙江鲤）和２个育成品种（福瑞鲤和松浦鲤）共计185尾个体，进行mtDNA D-loop序列测序分析。全长927~930bp的D-loop序列有36个变异位点。所有个体呈27个单倍型，其中清水江鲤和太湖鲤的单倍型数量较多（分别为18和9个），而福瑞鲤和松浦鲤各存在１个优势单倍型（占有率分别为93％和80％）。Fst值检验发现，松浦鲤与黑龙江鲤间遗传分化不显著（P>0.05），其余群体间均呈极显著遗传分化（P<0.01）。基于群体间K2P遗传距离（0.005 ~ 0.013）的NJ树显示，福瑞鲤和黄河鲤首先聚类，然后依次与清水江鲤和太湖鲤聚类；最后与松浦鲤和黑龙江鲤所在的另一支聚类。分子方差分析显示，群体间遗传变异极显著（P<0.01），占总变异的35.59％。研究表明，鲤的野生群体（清水江鲤和太湖鲤）存在较高的遗传多样性，具有进一步选育利用的潜力；而２个育成品种（福瑞鲤和松浦鲤）在选育过程中积累了较高的遗传纯度。

Genetic Variation of Six Cyprinus carpio Populations in China Based on mtDNA D-loop Sequences

The common carp (Cyprinus carpio) is an important economic freshwater fish species in China with abundant wild and breeding populations. To enrich the germplasm resource for common carp and provide additional data for germplasm exploration and genetic breeding, we analyzed the genetic variation among four wild populations (QSJ, TH, HH, and HLJ) and two selection strains (FRL and SPL) based on mtDNA D-loop sequences. Genomic DNA for PCR product amplification and sequencing was extracted from the tail fins of 185 samples. The amplified fragment length of mtDNA D-loop sequences was 927-930bp. All mtDNA D-loop sequences consisted 27 haplotypes and a total of 36 variable loci were detected. The QSJ and TH populations contained more haplotypes (18 and 9) than other populations. There were 14, 5, 1 and 1 specific haplotype observed in QSJ, TH, FRL and SPL populations and one dominant haplotype each in the two selection strains (FRL and SPL), with an occupancy of 93% and 80%, respectively. Pairwise K2P genetic distance of the six common carp populations was at the range of 0.005-0.013, with the shortest genetic distance between FRL and HH and the longest between SPL and FRL. FST testing indicated no significant genetic divergence between SPL and HLJ populations (P>0.05), whereas highly significant genetic divergences were detected among other populations (P<0.01). The NJ phynogenetic tree of the six populations was constructed based on K2P genetic distances, and shows the FRL and HH were initially clustered, then clustered with DSJ and TH and finally assembled with HLJ and SPL. The analysis of molecular variance (AMOVA) indicates significant genetic variation among populations (P<0.01), accounting for 35.59% of total genetic variation. In bref, the two wild population (QSJ and TH) had rich diversity and great hereditary potency for breeding program in the future. Two selection strains (FRL and SPL) have accumulated a high level of genetic homogeneity as a result of selection.