Investigation of genetic diversity of Dermacentor reticulatus ticks in Europe using microsatellite genetic markers

Abstract

Dermacentor reticulatus ticks are important vectors of tick-borne diseases in humans, livestock and wild animals in Europe. Geographic distribution of these ticks is fragmented, usually divided into two groups: Western Europe and Eastern Europe with extension to Asia. In this study we applied fourteen microsatellite markers previously developed for D. variabilis, D. albipictus and D. andersoni in USA. All loci amplified with varying success in D. reticulatus, and six of them were selected for further analyses, based on reliable amplification of the expected fragment length and presence of polymorphism. Polymorphic microsatellites were further characterized in 173 adult D.reticulatus individuals collected from 17 locations along the distribution range of D. reticulatus in Eastern (Latvia, Lithuania, Eastern Poland, Slovakia, Croatia and Ukraine) and Western Europe (Spain and Czech Republic), using capillary electrophoresis. Results of analysis showed that most of the molecular variability is contained within populations, and that populations cluster together similarly to known geographic distribution. All unique alleles were found in Spain and Czech Republic populations. Bayesian-clustering and PCoA analyses showed two genetic groups of D. reticulatus ticks: Western Europe and Eastern Europe. Eastern Europe group showed no evidence of clusterization according to geographical distribution patterns with low molecular variability between populations. Low genetic differences between Lithuanian, Latvian, Poland and Slovak populations of D. reticulatus show close relatedness among these populations.