Comparative mitogenomics elucidates the population genetic structure of <i>Amblyomma testudinarium</i> in Japan and a closely related <i>Amblyomma</i> species in Myanmar

Abstract

Ticks are the second most important vector capable of transmitting diseases affecting the health of both humans and animals. <i>Amblyomma testudinarium</i> Koch 1844 (Acari: Ixodidae), is a hard tick species having a wide geographic distribution in Asia. In this study, we analyzed the composition of <i>A. testudinarium</i> whole mitogenomes from various geographical regions in Japan and investigated the population structure, demographic patterns, and phylogeographic relationship with other ixodid species. In addition, we characterized a potentially novel tick species closely related to <i>A. testudinarium</i> from Myanmar. Phylogeographic inference and evolutionary dynamics based on the 15 mitochondrial coding genes supported that <i>A. testudinarium</i> population in Japan is resolved into a star-like haplogroup and suggested a distinct population structure of <i>A. testudinarium</i> from Amami island in Kyushu region. Correlation analysis using Mantel test statistics showed that no significant correlation was observed between the genetic and geographic distances calculated between the <i>A. testudinarium</i> population from different localities in Japan. Finally, demographic analyses, including mismatch analysis and Tajima's <i>D</i> test, suggested a possibility of recent population expansion occurred within Japanese haplogroup after a bottleneck event. Although <i>A. testudinarium</i> has been considered widespread and common in East and Southeast Asia, the current study suggested that potentially several cryptic <i>Amblyomma</i> spp. closely related to <i>A. testudinarium</i> are present in Asia.