绵阳地区部分野生黄鳝mtDNA D-loop多态性分析

Polymorphic Analysis of the mtDNA D-loop of Some Monopteras albus Individuals from Mianyang

从mtDNAD-loop标记探讨绵阳地区野生黄鳝遗传多态性,为中国黄鳝遗传资源研究增添新内容。采用PCR技术对12条绵阳市野生黄鳝mtDNAD-loop区部分序列进行扩增和测序,对所得9个个体606bp的核甘酸片段序列进行遗传变异和系统进化分析:9条野生黄鳝D-loop序列的4种核苷酸组成中,T和C的组成频率为固定值,而A和G的频率有一定的差异;A+T的平均组成频率(57%)显著高于C+G的频率(43%)。从9条D-loop序列中一共检测到了5个多态位点,占总核苷酸序列总数(606bp)的0.83%,核苷酸多样性为0.00413±0.00057。基于发现的5个多态位点将9条D-loop序列定义为5种单倍型,单倍型多样性为0.861±0.087。一共发现到9个突变位点,其中除了1处(15987)为颠换(T→G)外,其余的8处突变位点全部为转换。9条野生黄鳝与标准序列黄鳝个体类聚为2个明显的类群,分子树拓卜分支的置信度百分数达到93%。9条野生黄鳝又可以类聚为2个亚类群,说明绵阳野生黄鳝种群具有一定程度遗传分化,由此推测中国野生黄鳝种群可能具有比较高的遗传多样性。

The aim of this work is to investigate genetic polymorphisms of wild rice field eel from Mianyang Region using mtDNA D-loop molecular marker, which will enrich new achievements to the genetic research of rice field eel in China. The partial sequences of mtDNA D-loop region for 12 individuals of Monopteras albus from Mianyang city were amplified by PCR and 9 out of 12 samples were sequenced. The frequency of C and T were comparatively constant, while the divergence were examined in the composition of A and G. The average frequency of A＋T （57%） was significantly higher than that of G＋C （43%）. Five polymorphic sites were detected from the nine D-loop sequences, with a nucleotide diversity of 0.00413±0.00057, which represented 0.83% of the total DNA sequence analyzed （606 bp）. These sequences belonged to five haplotypes defined by the five polymorphic sites with a haplotype diversity of 0.861 ± 0.087. Nine variable sites were defined from the nine sequences. Among these variations, eight were transitions and the other one was transversion （T→G） at the sites of 15987 in standard sequence. The individual of Monopteras albus （NC_003192） and the nine individuals examined were clustered into two distinct groups, which was supported by 93% of 1000 bootstrap iterations. The nine individuals from Mianyang fell into two distinct sub groups. These results revealed that the comparative genetic differentiation existed among the rice field eels from Mianyang, and thereby, the higher genetic diversity could be found in the population of the rice field eels from all of the country.