Determination of the phylogenetic lineage of the species microtus arvalis from the Republic of Moldova based on CYTB gene sequencing

Resolving phylogenetic structure in cryptic rodent species is essential for understanding evolutionary history, population connectivity, and informing conservation strategies. In the Republic of Moldova, Microtus arvalis co-occurs with the morphologically similar M. levis, complicating species-level identification based on external traits alone. To determine the phylogenetic affiliation of local M. arvalis populations, we sequenced the mitochondrial cytochrome b (CYTB) gene (1106 bp) from five individuals identified molecularly from a total of 13 vole samples collected in central Moldova. These sequences were analyzed alongside 26 reference sequences retrieved from GenBank, representing the major phylogenetic lineages of M. arvalis across Europe. Phylogenetic reconstruction, performed using the Neighbor-Joining method in R software environment, revealed that the samples from Moldova form a highly homogeneous cluster and group with sequences from Poland, Slovakia, Finland, and Hungary. This pattern indicates a clear affiliation with the eastern phylogenetic lineage. The results expand the phylogeographic understanding of M. arvalis in Eastern Europe and underscore the utility of mitochondrial markers in distinguishing closely related species and supporting regional biodiversity assessments