淮安市长角血蜱遗传多样性的线粒体基因COⅠ分析

Analysis of genetic diversity of Haemaphysalis longicornis based on mitochondrial gene COⅠ in Huai'an City

目的 本研究旨在了解淮安市长角血蜱(Haemaphysalis longicornis)的遗传多样性,比较不同地理种群间的进化关系,为本市H.longicornis及蜱传病的预防提供理论基础。方法 在淮安市盱眙县山区采集游离蜱和羊寄生蜱,PCR法扩增细胞色素C氧化酶亚基Ⅰ(mt COⅠ)基因并测序。对mt COⅠ基因序列进行系统进化分析和种群遗传多样性分析。结果 JS-XY种群的mt COⅠ基因的核苷酸同源性为97.00～100.00%,JS-XY种群在进化枝上属于"Compound"进化谱系枝。JS-XY种群共有3单倍型,单倍型多样性Hd=0.439,核苷酸多样性为π=0.001,多态性位点S=2,Tajima's D值为-0.849 71。结论 研究表明,淮安地区的优势蜱种为长角血蜱,H.longicornis JS-XY种群近期可能经历过种群扩张。

[Objective] To determine the genetic diversity of Haemaphysalis longicornis in Huai’an City,compare the molecular evolution and genetic relation with other populations,and provide a theoretical basis for the prevention and control of H.longicornis and tick-borne diseases.[Methods]The free ticks and parasitic ticks were collected in mountainous area of Xuyi County in Huai’an City. Genomic DNA of ticks was extracted for PCR amplification of the mitochondrial cytochrome C oxidase subunitⅠ(mt COⅠ) gene followed by sequencing. The mt COⅠsequences were used for analysis of phylogenetic relationships and genetic variation within H.longicornis. [Results]Nucleotide identity of mt COⅠof H.longicornis of present in JS-XY population was97.00-100.00%,and the phylogenetic tree indicated the population JS-XY clustered together and belonged to a genetic "compound" lineage. Three haplotypes in population JS-XY were identified with the genetic diversity of populations(haplotype diversity Hd =0.439,nucleotide diversity π =0.001,polymorphic site S =2,Tajima’s D =-0.849 71).[Conclusion]The dominant tick species is H.longicornis in Huai’an area. H.longicornis of population JS-XY may undergo population expansion recently.