Mitochondrial Gene Heterogeneity and Population Genetics of Haemaphysalis longicornis (Acari: Ixodidae) in China.

Abstract

Haemaphysalis longicornis is an important ectoparasite of domestic and wild animals that can transmit many pathogens including viruses, fungi, bacteria and protozoa. In this study, we examined genetic variation and population genetics in three mitochondrial (mt) genes [cox1 (cytochrome c subunit 1), rrnL (large subunit ribosomal RNA) and nad5 (NADH dehydrogenase 5)] among four H. longicornis populations from China. The sizes of the partial sequences of cox1, rrnL and nad5 were 776bp, 409bp, 510bp, respectively. Among the obtained sequences, we identified 22 haplotypes for cox1, 2 haplotypes for rrnL and 17 haplotypes for nad5. Low gene flow and significant genetic differentiation (66.2%) were detected among H. longicornis populations. There was no rapid expansion event in the demographic history of four H. longicornis populations in China. In addition, phylogenetic analyses confirmed that all the Haemaphysalis isolates were H. longicornis which were segregated into two major clades. The mt DNA genes provide a potential novel genetic marker for molecular epidemiology of H. longicornis and assist in the control of tick and tick-borne diseases in humans and animals.