基于线粒体COⅡ基因的大豆蚜不同地理种群遗传分化研究
Analysis of genetic differentiation among different geographic populations of Aphis glycines (Hemiptera: Aphididae) based on mtDNA COⅡ gene sequences
李 冉** 韩岚岚** 王 红 赵奎军*** 莽逸伦 张红玉 樊 东
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DOI：10.7679/j.issn.2095-1353.2015.144
作者单位：东北农业大学农学院，哈尔滨 150030
中文关键词：大豆蚜，线粒体COⅡ，地理种群，遗传分化，基因流（Nm）
英文关键词：Aphis glycines, mtDNA COⅡ, geographic population, genetic differentiation, gene flow (Nm)
中文摘要： 【目的】 大豆蚜Aphis glycines逐渐成为栽培大豆上的世界性重要害虫，为明确大豆蚜不同地理种群的遗传分化及遗传多样性，本研究探讨其在中国的种群遗传变异。【方法】 测定了采自7个省共14个地理种群339头大豆蚜的线粒体COⅡ基因的673 bp序列，利用DnaSP 5.0、Arlequin 3.5.1.2、Network 4.6.1.3等软件对地理种群间的大豆蚜的遗传多样性、遗传分化程度及分子变异进行分析，并建立了单倍型网络图及单倍型系统进化树。【结果】 在所分析的339个COⅡ序列中，共检测出7个单倍型，其中H1为各种群所共享。种群内遗传多样性较低（Hd=0.479±0.030，Pi=0.00166±0.00018），种群内遗传分化相对较大（Fst=0.1985），基因流水平较高（Nm=2.019）。中性检验结果不显著（Tajima’s D=﹣0.931，P>0.10，Fu’s Fs=0.220，P>0.10），说明中国地区大豆蚜在较近的历史时期内没有出现种群扩张现象。分子变异分析（AMOVA）结果表明，大豆蚜遗传变异主要来自种群内部（80.15%），而种群间未发生明显的遗传分化。根据各地理种群的单倍型建立的系统发育树、单倍型网络图表明，各单倍型散布在不同的地理种群中，无明显的地理分布格局。【结论】 大豆蚜不同地理种群的遗传多样性不高，各种群的遗传距离与地理距离之间没有显著线性相关性，各种群间的基因交流并未受到地理距离的影响。
英文摘要： [Objectives] To investigate genetic variation among different geographic populations of soybean aphids, Aphis glycines, in China. [Methods] The genetic diversity, genetic differentiation, and molecular variance of 339 individual soybean aphids from 14 geographic populations in 7 Chinese provinces were analyzed based on 673 bp segments of the mitochondrial cytochrome c oxidase subunit Ⅱ (COⅡ) gene using DnaSP 5.0, Arlequin 3.5.1.2 and Network 4.6.1.3. Phylogenetic trees and the networks of COⅡ haplotypes were constructed from the resultant data. [Results] A total of 7 haplotypes were identified; haplotype No.1 (H1) was shared by all 14 populations. A low level of genetic diversity (Hd=0.479±0.030, Pi=0.00166±0.00018) in the total population was detected and higher genetic differentiation (Fst=0.1985) and a high level of gene flow (Nm=2.019) was apparent among different geographic populations. The results of a Neutral test (Tajima's D=﹣0.931, P>0.10, Fu’s Fs=0.220, P>0.10) were not significant, indicating that there is no evidence of recent population expansion. The analysis of molecular variance (AMOVA) showed no obvious genetic differentiation among populations with a high proportion of the total genetic variance attributable to variation within populations (80.15%). A phylogenetic tree and a haplotype network based on haplotypes of the different geographic populations shows no obvious geographical structure in different clades. [Conclusion] Genetic diversity of different geographical populations of soybean aphids is low, and there is no significant linear correlation between geographic distance and genetic differentiation; gene flow between different geographic populations is not affected by geographic distance.