title: Discrimination between Haemaphysalis longicornis and H. qinghaiensis based on the partial 16S rDNA and the second internal transcribed spacer (ITS-2).
abstract: In the present study, two hard tick species, Haemaphysalis longicornis and H. qinghaiensis from North-western China were characterized genetically by the second internal transcribed spacer (ITS-2) of nuclear ribosomal DNA and partial 16S rDNA. Based on a fragment within the hypervariable region of 16S rDNA with the length of approximately 453 bp, the phylogenetic trees were constructed by Neighbor-Joining and Maximum-parsimony methods. The results indicated that the phylogenetic status of H. qinghaiensis was distant from that of H. longicornis and closer to H. flava. Furthermore, the ITS-2 rDNA was amplified by PCR and sequenced from individual ticks. The length of ITS-2 is 1,606 bp for H. longicornis and 1,162 bp for H. qinghaiensis. Although sequence variation between the immature stages of H. longicornis was 0.1-0.4%, nucleotide differences between the tested species ranged 2.1-23.2%, indicating that ITS-2 rDNA sequences are genetic markers for the differentiation of the two hard ticks in China. Hence, a PCR-linked restriction fragment length polymorphism (RFLP) approach was developed for their unequivocal differentiation based on ITS-2 rDNA, which provides the foundation for further studies on ticks in China and has implications for studying the population genetic structure of the ticks and for identification and differentiation of closely related ticks.
authors.affiliation: Key Laboratory of Veterinary Parasitology of Gansu Province, State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 1 Xujianping, 730046 Yanchangbu, Lanzhou, Gansu Province, People's Republic of China.
authors.forename: Zhancheng
authors.initials: Z
authors.lastname: Tian
authors.forename: Guangyuan
authors.initials: G
authors.lastname: Liu
authors.forename: Junren
authors.initials: J
authors.lastname: Xie
authors.forename: Hong
authors.initials: H
authors.lastname: Yin
authors.forename: Jianxun
authors.initials: J
authors.lastname: Luo
authors.forename: Liyan
authors.initials: L
authors.lastname: Zhang
authors.forename: Ping
authors.initials: P
authors.lastname: Zhang
authors.forename: Jin
authors.initials: J
authors.lastname: Luo
mesh_terms: D000818:Animals; D004275:DNA, Ribosomal / Q000737:chemistry; D021903:DNA, Ribosomal Spacer / Q000737:chemistry*; D005819:Genetic Markers; D026863:Ixodidae / Q000145:classification* / Q000235:genetics; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D012336:RNA, Ribosomal, 16S / Q000235:genetics*; D017422:Sequence Analysis, DNA
chemical_list: D004275:DNA, Ribosomal; D021903:DNA, Ribosomal Spacer; D005819:Genetic Markers; D012336:RNA, Ribosomal, 16S