Filling the gap: the common hamster, Cricetus cricetus, phylogeography – a case study of Ukraine as potential refugial area

Abstract. The phylogeographic analyses of the common hamster revealed the existence of five mitochondrial DNA (mtDNA) lineages. However, the analyses did not include Ukraine and the area outside Carpathian arch located in Romania that is important for the species as presumably refugial territory. We investigated both areas and described phylogeographic relationships of the populations on the basis of a partial cytochrome b (cytb, 904 bp) region of the mtDNA. Haplotype network and gene tree analyses did not produce a clear phylogeographic pattern for investigated territories that is typical for refugial populations. The highest diversity was found at the left bank of the River Dnieper and the area was called the Dnieper Lowland Refugial Area. Moreover only three from five described phylogeographic lineages (North, Pannonia and Caucasus) were fully separate on the network and gene trees. The haplotypes of other two lineages described previously from Eastern Europe (E1 and E0 lineages) mixed together with haplotypes from Ukraine and Moldovian Plateau. This study highlights the need for a re-examination of the phylogeography divisions of the common hamster.