Inferring phylogenetic relationships in the common vole (Microtus arvalis) based on mitochondrial and nuclear sequence diversities

Abstract

The common vole Microtus arvalis (Pallas, 1778) is the most widespread Microtus species. It has two forms – the European arvalis form (2n: 46, NF: 84) and the Asian obscurus form (2n: 46, NF: 72). The present study aimed to clarify the taxonomic status of M. arvalis populations distributed in Eastern Turkey, Europe and Asia by analysing two mitochondrial (CYTB and COX1) and one nuclear (IRBP) markers. Phylogenetic dendrograms (median-joining networks and Bayesian trees) constructed using the mitochondrial markers clearly separated the Anatolian population from the European and Asian populations. Contrarily, any explicit differentiation was not shown in IRBP analyses. Mean and net genetic distance values (d) were found to be notably low for three markers. Species delimitation test (Automatic Barcode Gap Discovery Method) supported these results. Our results indicate that the arvalis and obscurus forms are not sufficiently differentiated to be considered different species, while the Anatolian population has only recently split from the Asian population. Together, these findings demonstrate that the speciation process is ongoing.