基于线粒体D-loop 基因探讨花鳗鲡的群体遗传多样性及其种群进化历史

通过测定花鳗鲡(Anguillia marmorata)海南群体(HN)和菲律宾群体(PH)共19尾个体的线粒体D-loop基因的核苷酸序列(约1017 bp),分析了花鳗鲡的种群遗传结构。结果表明:A、T、G、C 4种核苷酸的平均含量分别为39.8%、28.3%、12.4%、19.4%,A+T含量(68.1%)明显高于G+C含量(31.8%)。所测序列中存在73个变异位点,共有18个单倍型。其中海南群体的单倍型多样度(Hd)、核苷酸多态性(Pi)、平均核苷酸差异数(k)分别为0.982、0.21577和219.655,而菲律宾群体的单倍型多样度、核苷酸多态性、平均核苷酸差异数分别为1.000、0.26728和271.821,两个群体之间平均遗传距离(P)为0.3203。结果表明2个群体遗传变异较大,菲律宾群体的遗传多样性较海南群体更加丰富。通过构建NJ分子系统树表明2个群体的亲缘关系较近。利用中性检验Tajima’s D(海南群体D=1.35345,P>0.01;菲律宾群体D=0.79220,P>0.01)和Fs(海南群体Fs=3.759;菲律宾群体Fs=2.231)探讨其种群历史,表明花鳗鲡群体进化过程种群数量较为稳定。

Genetic variation and population evolutionary history of the giant mottled eel (Anguillia marmorata) based on the mitochondrial D-loop gene

The population genetic structures of the giant mottled eel from Hainan and Philippines were investigated by sequencing the mitochondrial control region (D-loop) gene for the first time. The average contents of A, T, G and C in the control region were 39.8%, 28.3%, 12.4% and 19.4%, respectively. There were 73 polymorphisms sites from the sequenced samples revealing 18 haplotypes. By calculating the haplotype diversity (Hd), nucleotide diversity (Pi) and average number of pairwise nucleotide difference (k), the Philippines population exhibited higher level of variability (Hd=1.000, Pi=0.26728, k=271.821) than the Hainan population (Hd=0.982, Pi=0.21577, k=219.655 and the genetic distance (P) was 0.3203 between two populations. By constructing the molecular phylogenetic tree with the method of NJ, the two geographic populations of the giant mottled eel did not show significant genetic difference. Besides, neutrality tests indicated a possible stable population in the population history of the giant mottled eel.