Mitochondrial genetic markers based phylogenetic analyses of Hyalomma dromedarii Koch, 1844 (Acari: Ixodidae)

The hard tick Hyalomma dromedarii, a vector for numerous animal and human pathogens, was investigated for genetic diversity using the mitochondrial cytochrome C oxidase subunit I (cox I) and 16S ribosomal RNA (16S rRNA) genes. Hyalomma dromedarii sequences (n = 11 cox I; n = 7 16S rRNA) were deposited in GenBank (LC761179-89, LC761173-78, LC654692), showing 99.52-100 % (cox I) and 98.15-100 % (16S rRNA) similarity to existing GenBank sequences. Phylogenetic analysis revealed monophyletic clades for H. dromedarii sequences from this study and GenBank. Haplotype network analysis identified 34 and 11 haplotypes for the cox I and 16S rRNA genes, respectively, displaying stellate configurations. The overall cox I dataset showed very low nucleotide diversity (0.0019 ± 0.0002) and high haplotype diversity (0.535 ± 0.052). In contrast, the 16S rRNA gene dataset displayed low nucleotide (0.00211 ± 0.00071) and haplotype (0.351 ± 0.079) diversities. Neutrality tests showed significant negative values (Tajima's D, Fu and Li's D, and Fu and Li's F), indicating recent population expansion or selective sweep. Pairwise F_ST values (-0.00942 to 0.02007 for cox I; -0.04878 to 0 for 16S rRNA) suggested non-significant genetic differentiation between populations, supported by high gene flow (Nm) values. This study provided novel insights into H. dromedarii population genetics, revealing recent expansion, weak population differentiation, and high gene flow. These findings have implications for understanding the tick's evolutionary history and epidemiological significance.