Genetic Diversity Analysis of Dermacentor Nuttalli within Inner Mongolia, China

Abstract

BackgroundTicks (Arthropoda, Ixodida), after mosquitoes, are the next most prevalent vector of infectious diseases; and are responsible for spreading a multitude of pathogens and threatening the health and welfare of animals and human beings. Yet, given the history of tick-borne pathogen infections in the Inner Mongolia Autonomous region of China, neither the genetic diversity nor the spatial distribution of haplotypes within ticks has been studied. MethodsWe characterized the haplotype distribution of Dermacentor nuttalli in four main pastoral areas of the Inner Mongolia Autonomous region, by sampling 109 individuals (recovered from sheep) in April-August 2019. The 16S rRNA gene, Cytochrome c Oxidase Subunit Ⅰ, and the Internal Transcribed Spacer 2 region were amplified and sequenced from extracted DNA.Results 82 haplotypes were identified, the most prevalent of which was H32. 12 sequences (11 of all sequences) represented the most abundant haplotypes, with a highly scattered distribution. Total haplotype diversity was 0.98318, while total nucleotide diversity was 0.11369. Neutrality tests revealed negative results in the four locations analyzed, which is indicative of an excess of recently derived haplotypes. Fixation index values (FST) indicate that the degree of genetic differentiation amongst some sampled populations were small, while others were moderate. Conclusion The genetic diversity of D.nuttalli populations in our region can likely adapt to different geographical environments, thereby leading to genetic diversity, and creating genetic differentiation amongst different populations. However, genetic differentiation is cryptic and does not form the pedigree geographical structure.