The complete mitogenome of Hyalomma anatolicum: novel insights into the phylogenetics of Hyalomma.

Ticks are obligate blood-sucking ectoparasite and common vector of a wide variety of zoonotic pathogens. In this research, we sequenced and assembled the circular complete mitogenome information of Chinese isolates of Hyalomma anatolicum maintained at the Laboratory. The 14,714 bp mitogenome consists of 37 genes, including 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes and 2 ribosomal RNA (rRNA). The nucleotide sequence of Hy. anatolicum mitogenome includes approximately A (35.05%), G (8.70%), T (41.20%) and C (11.26%), the proportion of A + T (80.04%) is substantially higher than G + C (19.96%). We compared mitogenome selection pressure of the Hy. anatolicum and found that positive selection signatures were detected in atp8, contrasting sharply with the strong purifying selection observed in cox1. Phylogenomic reconstruction using concatenated PCGs robustly placed Hy. anatolicum within a clade sister to Hy. excavatum. We further validated cox3, cytb, nad1, nad2, nad3, nad4, nad4L, nad5 and nad6 as lineage-specific markers mirroring full mitogenome topology, proposing their cost-effective use in Hyalomma systematics. The divergence time analysis suggests that Hy. anatolicum was the most recent species in Hyalomma, 1.95 Mya. As far as we know, this is the first study exploring the complete mitogenome for Hy. anatolicum. Here, we obtained the whole mitogenome sequence for the species Hy. anatolicum, which enriched the mitogenome data of ticks, provided new idea for future research on the molecular evolution, population heredity and systematics of ticks.