Yi J N, Jin Y C, Liu J H, Li F, Li Z B, Cheng T Y
Hunan Provincial Key Laboratory of Protein Engineering in Animal Vaccines, College of Veterinary Medicine, Hunan Agricultural University, Changsha, Hunan Province 410128, P.R. China.
Hunan Co-Innovation Center of Animal Production Safety, Changsha, Hunan province 410128, P.R. China.
Trop Biomed. 2019 Mar 1;36(1):297-303.
The cattle tick, Rhipicephalus microplus (formerly Boophilus microplus), is the most important blood-feeding ectoparasite of cattle in tropical and subtropical regions of the world. In this study, we examined sequence variability in three mitochondrial (mt) DNA (cox1, nad1, nad4) among cattle tick R. microplus originating from four provinces of China. A portion of cox1 (pcox1), nad1 (pnad1) and nad4 (pnad4) genes were amplified by polymerase chain reaction (PCR) separately from adult R. microplus individuals and the amplicons were subjected to sequence from both directions. The sequence of mt cox1, nad1, nad4 genes was 817 bp, 350 bp, and 794 bp in size, respectively. The intraspecific sequence variations within R. microplus were 0-8.6% for cox1, 0-4.9% for nad1 and 0-10.3% for nad4. However, the interspecific sequence differences among the members of the Rhipicephalus [R. sanguineus (JX416325) and R. turanicus (NC035946)] were significantly higher, being 16.9-20.5%, 18- 22.8%, 22.8-25.3% for pcox1, pnad1 and pnad4, respectively. In addition, genetic differences were 7.9-8.6% for cox1, 4.3-4.9% for nad1 and 10-10.3% for nad4 between the two detected lineages (R. microplus clade A and clade B). Phylogenetic analyses indicated that all the Rhipicephalus isolates from the present study represents R. microplus, supporting that R. microplus represents species complex. Our result provided an additional genetic evidence for the existence of species complex within R. microplus in China.
微小牛蜱（Rhipicephalus microplus，原名微小扇头蜱Boophilus microplus）是世界热带和亚热带地区牛最重要的吸血外寄生虫。在本研究中，我们检测了来自中国四个省份的微小牛蜱线粒体（mt）DNA的三个基因（cox1、nad1、nad4）的序列变异性。分别从成年微小牛蜱个体中通过聚合酶链反应（PCR）扩增cox1（pcox1）、nad1（pnad1）和nad4（pnad4）基因的一部分，并对扩增产物进行双向测序。mt cox1、nad1、nad4基因的序列大小分别为817 bp、350 bp和794 bp。微小牛蜱种内cox1的序列变异为0 - 8.6%，nad1为0 - 4.9%，nad4为0 - 10.3%。然而，扇头蜱属成员[血红扇头蜱（R. sanguineus，JX416325）和图兰扇头蜱（R. turanicus，NC035946）]之间的种间序列差异显著更高，pcox1、pnad1和pnad4分别为16.9 - 20.5%、18 - 22.8%、22.8 - 25.3%。此外，两个检测谱系（微小牛蜱A分支和B分支）之间cox1的遗传差异为7.9 - 8.6%，nad1为4.3 - 4.9%，nad4为10 - 10.3%。系统发育分析表明，本研究中的所有扇头蜱分离株均代表微小牛蜱，支持微小牛蜱代表物种复合体的观点。我们的结果为中国微小牛蜱中存在物种复合体提供了额外的遗传证据。
