Lack of genetic structure among Eurasian populations of the tick Ixodesricinus contrasts with marked divergence from north-African populations

► The same level of genetic diversity is observed in all Eurasian populations studied. ► Phylogenetic trees indicated an absence of genetic structure among Eurasian ticks. ► The lack of differentiation among Eurasian ticks suggests a high level of gene flow. ► A strong differentiation is observed between north-African and Eurasian tick populations.