Characterization of the complete mitochondrial genomes of five hard ticks and phylogenetic implications

Abstract

Abstract Ticks are blood-sucking ectoparasites of great medical and veterinary significance that can transmit bacteria, protozoa, fungi and viruses, and cause a variety of human and animal diseases worldwide. In the present study, we sequenced the complete mitochondrial (mt) genomes of five hard tick species and analyzed features of their gene contents and genome organizations. The complete mt genomes of Haemaphysalis verticalis, Haemaphysalis flava, Haemaphysalis longicornis, Rhipicephalus sanguineus and Hyalomma asiaticum were 14,855 bp, 14,689 bp, 14,693 bp, 14,715 bp and 14,722 bp in size, respectively. Their gene content and arrangement are the same as those of most species of metastriate Ixodida, but distinct from species of genus Ixodes. Phylogenetic analyses using concatenated amino acid sequences of 13 protein-coding genes with two different computational algorithms (Bayesian inference and maximum likelihood) revealed the monophylies of the genera Rhipicephalus, Ixodes and Amblyomma, however, rejected the monophylies of the genus Haemaphysalis. To our knowledge, this is the first report of the Haemaphysalis verticalis mt genome. These datasets provide useful mtDNA markers for further studies of the identification and classification of hard ticks.