内蒙古部分地区全沟硬蜱的遗传多样性研究

Genetic diversity of Ixodes persulcatus in parts of Inner Mongolia

目的了解内蒙古自治区部分地区全沟硬蜱的遗传多样性和种群历史动态,为制定有效的媒介控制方案和揭示全沟硬蜱的传播机制提供科学数据。方法于2021年4月—2023年7月对内蒙古自治区的10个地区采用人工采集法或拖旗法进行采样,基于全沟硬蜱的16S rRNA和COI基因合成特异引物,对呼伦贝尔市阿龙山镇和兴安盟阿尔山市野外采获的游离全沟硬蜱进行PCR扩增,分析其遗传多样性。结果COI基因阳性率为90.00%,16S rRNA阳性率为98.33%;COI基因鉴定出18个单倍型,16S rRNA序列鉴定出15个单倍型;两个基因的单倍型多样性大于0.762,核苷酸多样性小于0.005;中性检验的Tajima’s值与Fu’s Fs值均为负值且达到了显著性水平(P<0.05),且核苷酸错配图显示为单峰。种群的遗传分化指数F ST显示群体的遗传分化程度较小,同时分子方差分析(AMOVA)表明,群体内的变异大于群体间的变异。系统发育树与单倍型网络图显示单倍型之间混杂分布。结论兴安盟地区与呼伦贝尔地区的全沟硬蜱拥有丰富的遗传多样性,能适应环境变化,遗传分化主要集中在群体内部且并未出现地理隔离。

The aim of this study was to clarify the genetic diversity and population history of Ixodes persulcatus in some areas of Inner Mongolia in order to provide accurate data for effective vector control programs and reveal the transmission mechanism.Samples were collected in 10 areas of Inner Mongolia during the active tick season(April 2021—July 2023)using the flag-dragging and manual sampling methods.The 16S rRNA and COI gene were sequenced to clarify genetic diversity of I.persulcatus.The positivity rates for the COI gene and 16S rRNA were 90.00%and 98.33%respectively.Overall,18 and 15 haplotypes were identified for the COI gene and 16S rRNA,respectively,with a total haplotype diversity>0.762 and total nucleotide diversity<0.005.The Tajima’s values and Fu’s Fs were negative for significance.A nucleotide mismatch map was shown as a single peak.The genetic differentiation index F ST of the population indicates a small degree of genetic differentiation of the population,while analysis of molecular variance indicates that the variation within populations was greater than between populations.Phylogenetic tree and haplotype network plots showed confounding distributions between haplotypes.I.persulcatus from the Hinggan League and Hulunbuir regions can adapt to environmental changes and possess abundant genetic diversity.Genetic differentiation is mainly concentrated within the population and no geographical isolation was observed.