基于线粒体COI基因分析广州市15个白纹伊蚊种群的遗传多样性

目的 探讨广州市白纹伊蚊不同地理种群的遗传多样性、遗传分化和系统发育关系。方法 本实验于2020年9月至2020年11月期间,采集广州市11个行政区的共计15个白纹伊蚊种群。单只蚊虫提取基因组DNA,通过PCR法扩增COI基因序列并测序,获得的序列在GenBank上经过BLAST比对。BioEdit 7.2软件观察序列峰图。MEGA X软件对齐序列,分析碱基组成,构建系统发育树(NJ法)。DNAsp 6.12软件分析位点多态性,单倍型及其多样性,进行错配分布分析。Arlequin 3.5软件进行分子变异分析、进行中性检验。DAMBE 7.2软件分析序列的系统发育信号。 PopART 1.7软件构建单倍型网络图(Median joining法)。结果 广州市15个白纹伊蚊种群共获得642条序列,其长度为603 bp。A碱基加T碱基平均含量是67.5%,符合线粒体DNA的AT偏向性。单倍型分析共检出45种单倍型,其中单倍型1为优势单倍型。中性检验表明广州市部分种群不符合中性理论,但大部分种群都经历过种群扩张,而错配分布却表明仅有少部分种群经历过种群扩张。Mantel检验表明15个白纹伊蚊种群不存在地理隔离现象。种群遗传分化显示各种群间交流较频繁,且种群间的遗传分化很低,差异更多来自于个体间。结论 广州市的白纹伊蚊种群间基因交流较频繁,遗传分化小,遗传多样性偏低。这可能使不同地理种群的白纹伊蚊具有相似的媒介能力。

Analysis of the genetic diversity of 15 Aedes albopictus populations in Guangzhou based on the mitochondrial COI gene

This study aimed to investigate the genetic diversity, genetic differentiation, and phylogenetic relationship of the mitochondrial cytochrome c oxidase subunit I (COI) gene among 15 Aedes albopictus populations in Guangzhou. A total of 15 Ae. albopictus populations were collected from 11 districts of Guangzhou from September 2020 to November 2020. Genomic DNA was extracted from a single mosquito. The COI gene sequences were amplified by PCR methodology and sequenced afterwards. Sequences were blasted against GenBank. Chromatograms of sequences were observed with BioEdit 7.2 software. Sequence alignment, nucleotide composition analysis, and phylogenetic tree construction were conducted with MEGA X. Analysis of polymorphic sites, haplotype morphism and mismatch distribution was performed with DNAsp 6.12. A figure of the mismatch distribution was drawn with R 4.0.3 using the “ggplot2” and “cowplot” packages. The results of the molecular variance test and neutral hypothesis test were obtained with Arlequin 3.5. Substitution saturation was checked with DAMBE 7.2 and the haplotype network was drawn with PopART 1.7. In total, 642 sequences were obtained from the 15 Ae. albopictus populations in Guangzhou, and the length of the COI gene was 603 bp, with an average A+T content of 67.5%, which conforms to the mitochondrial AT bias. Forty-five haplotypes were detected and haplotype 1 was the dominant haplotype. Haplotype diversity (Hd) was 0.499 and nucleotide diversity (Π) was 0.00108. Neutrality tests showed that half of the Ae. albopictus populations (7/15) did not fit the neutrality theory and most (12/15) had experienced population expansion. However, the mismatch distribution showed that only a few of the Ae. albopictus populations had undergone population growth. The Mantel test showed that 15 Ae. albopictus populations were not geographically isolated. Population differentiation revealed a common occurrence of gene flow and greater variation within populations than between populations. In conclusion, gene flow has commonly occurred in Ae. albopictus populations in Guangzhou. Genetic differentiation and genetic diversities among populations were not significant. Therefore, Ae. albopictus populations in Guangzhou might have similar vector competence. The control of Ae. albopictus necessarily needs effort applied to all aspects of its biology.