应用mtDNA-COⅠ基因序列研究我国大劣按蚊A、D群体的遗传差异

Genetic Variation of Anopheles dirus A and D (Diptera:Culicidae) in China: Inferred by mtDNA-COⅠ Gene Sequences

目的应用线粒体DNA细胞色素氧化酶亚单位Ⅰ(mtDNA-COⅠ)基因序列特征阐明我国大劣按蚊A、D群体的遗传差异和分化水平。方法研究样本包括大劣按蚊A海南群体(n=13),大劣按蚊D云南江城群体(n=17)和勐腊群体(n=17),所有样本均以rDNA-ITS2序列差异为依据,进行分子鉴别确认;扩增和测定mtDNA-COⅠ基因片段,用MEGA(Version2.1)、TCS(Version1.12)、ARLEQUIN(Version2.0)等软件对基因序列进行生物信息学分析。结果分析mtDNA-COⅠ基因中长度为959bp的片段,显示大劣按蚊A的单倍型共3个,大劣按蚊D的单倍型共6个,均匀分布于3个群体。勐腊群体内错配平均数(7.4412)明显大于江城群体(1.2794)和海南群体(1.0513),表明勐腊群体内个体间分化程度最大。分步AMOVA的计算结果显示群体间基因交流有限(Fst=0.7999),群体间变异(79.99%)明显大于群体内变异(20.01%)。结论我国大劣按蚊A、D群体之间的遗传差异较小,个体间的分化水平较高。

Objective To interpret genetic variation and population structure of Anopheles dirus A and D from China by molecular marker. Methods Samples included An. dirus A of Hainan laboratory colony （n=13）, and field specimen from Mengla （n=17） and Jiangcheng （n=17） in Yunnan Province. The specimens were identified by PCR assay before study, mtDNA-CO Ⅰ region was amplified and sequenced. Genetic variation and population structure was estimated according to sequence data. Results The mtDNA-CO Ⅰ gene with a length of 959 bp was analyzed. There were three haplotypes in An. dirus A and six haplotypes in An. dirus D. The above haplotypes distributed in three populations uniformly. The average number of pairwise differences within Mengla population （7.441 2） was greater than that of Jiangcheng （1.2794） and Hainan （1.051 3） populations, which suggested that the level of genetic divergence was the highest within Mengla population. The result of hierarchical AMOVA estimation showed a limited geneflow （Fst=0.799 9）, therefore the variation level in a population （20.01%） was smaller than among the populations （79.99%）. Conclusion The inter-specific genetic variation between An. dirus A and D in China was small and the level of divergence among individuals was high.