Complete mitochondrial and phylogenetic relationships of Dermacentor everestianus (Acari: Ixodidae) and Alveonasus sp. (Acari: Argasidae)

BACKGROUND: Ticks are hematophagous arthropods capable of transmitting pathogens threatening human and animal health. The use of individual gene markers has limited phylogenetic studies of ticks, but the mitochondrial genome offers critical data for understanding phylogeny and molecular evolution. RESULTS: The mitogenomes of Dermacentor everestianus and Alveonasus sp. were assembled from Illumina 350 bp pair-end reads. In this study, we sequenced the complete mitochondrial genomes of Dermacentor everestianus and Alveonasus sp., which measured 16,413 bp and 14,545 bp, respectively. Both mitogenomes contained 2 ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA) genes, and 13 protein-coding genes (PCGs). Dermacentor everestianus has two similar insertions between tRNA-Phe and tRNA-Gln and between tRNA-Glu and ND1. The adenine + thymine (A + T) content was 78.68% for D. everestianus and 71.60% for Alveonasus sp. Dermacentor everestianus showed negative AT- and GC-skews, whereas Alveonasus sp. exhibited positive AT-skews and negative GC-skews. The nucleotide diversity (Pi) and nonsynonymous (Ka)/synonymous (Ks) mutation rate ratios indicated that NAD1, COX1, and COX3 were the most conserved genes, with COX1 showing the lowest evolutionary rate. Phylogenetic analysis was performed using maximum likelihood (ML) methods based on COI gene and 13 PCGs. The results revealed that D. everestianus belongs to the Ixodidae family, within the Dermacentor genus, while Alveonasus sp. should be classified as a separate evolutionary lineage within the Argasidae family. CONCLUSIONS: These findings provide valuable insights into tick genetic variation, molecular classification, and evolutionary relationships, offering a foundation for future research in these areas.