Complete Mitochondrial Genome Sequence Data Provides Genetic Evidence That the Brown Dog Tick Rhipicephalus sanguineus (Acari: Ixodidae) Represents a Species Complex

Abstract

Ticks are blood-sucking ectoparasites of great medical and veterinary significance that can transmit bacteria, protozoa, fungi and viruses, and cause a variety of human and animal diseases worldwide. In the present study, we sequenced the complete mitochondrial (mt) genome of Rhipicephalus sanguineus from China (RSC) and compared with that of R. sanguineus from USA (RSU). Nucleotide sequence difference in the full mt genome was 11.23% between RSC and RSU. For the 13 protein-coding genes, comparison revealed sequence divergences at both the nucleotide (9.34-15.65%) and amino acid (2.54-19.23%) levels between RSC and RSU. In addition, sequence comparison of the conserved mt cox1 and cytb genes among multiple individual R. sanguineus revealed substantial nucleotide differences between RSC and RSU but limited sequence variation within RSC. Phylogenetic analysis of ticks based on the amino acid sequence data of 13 protein-coding genes revealed that R. sanguineus from China and R. sanguineus from USA represent sister taxa (likely separate species). Taken together, the findings support the recently proposal that R. sanguineus tick may represents a species complex of at least two closely related species.

Morphological and molecular identification of the brown dog tick Rhipicephalus sanguineus and the camel tick Hyalomma dromedarii (Acari: Ixodidae) vectors of Rickettsioses in Egypt

“…Moreover, the evolutionary rate and sequence alignment of mitochondrial genes is faster than that calculated for nuclear genes [94,95]. In addition to, the reference database of complete and partial mitochondrial genomes of several tick species are more available than nuclear genes [44,54-57,95-97]. This is return to the fact that mitochondrial genes have strict and simple maternal inheritance compared to nuclear DNA [98].…”

“…In recent years, the molecular characterization for taxonomic identification and phylogenetic purposes of ticks has been indispensable by DNA markers, including nuclear (18S rRNA) and mitochondrial (12S rRNA and 16S rRNA, and cytochrome c oxidase subunit-1 [CO1]) genes and nuclear regulatory non-translated stretches (second internal transcribed spacer [ITS2]) [44,47-50]. The 18S rRNA is best used for genera level identification [51] while the 16S rRNA, CO1, and ITS2 are the most useful markers for ticks taxonomy at species level [39,44,47-50,52-56].…”

“…The 18S rRNA is best used for genera level identification [51] while the 16S rRNA, CO1, and ITS2 are the most useful markers for ticks taxonomy at species level [39,44,47-50,52-56]. The 12S rRNA is used as a tool for examining relationships among recently diverged branches of tick phylogenies [50,53,57].…”

Infection with Ehrlichia canis and Anaplasma platys (Rickettsiales: Anaplasmataceae) in two lineages of Rhipicephalus sanguineus sensu lato (Acari: Ixodidae) from Argentina

“…Comparative studies performed with tick populations from different geographical origins have demonstrated that ticks previously determined as Rhipicephalus sanguineus sensu stricto belong in fact to different lineages with reproductive incompatibility and significant genetic divergence (Szabó et al, 2005;Burlini et al, 2010;Moraes-Filho et al, 2011;Levin et al, 2012;Nava et al, 2012;Dantas-Torres et al, 2013;Liu et al, 2013). In South America, at least two lineages of R. sanguineus s.l were identified: tropical and temperate.…”

East and west separation of Rhipicephalus sanguineus mitochondrial lineages in the Mediterranean Basin

“…Similarly, R. sanguineus collected in the USA and Mexico were shown to be genetically different [6]. A latitude-linked geographical pattern of the two major R. sanguineus groups has been confirmed by further, global scale studies, which showed with molecular-phylogenetic methods [7–9] or crossbreeding experiments [10] that (at least) two species might exist under this name, and both occur in the New World and in the Old World. These two clades have been designated as “tropical species” or northern lineage and “temperate species” or southern lineage [8, 11].…”