Cytogenetic characteristics of Microtus dogramacii (Mammalia: Rodentia) around Amasya, Turkey

The banding patterns of chromosomes of Microtus dogramacii, a recently described vole species endemic to Turkey, were studied. G-, C-, and Ag-NOR-banded patterns of this species are reported here for the first time. In this study, 2 karyotypical forms were determined. Each form had the same diploid chromosome numbers (2n = 48), but possessed different autosomal morphologies. For this reason, the samples collected from the research area were karyologically separated into 2 groups, cytotype-1 (NF = 50) and cytotype-2 (NF = 52). All chromosomes possessed centromeric/pericentromeric heterochromatin bands in both karyotypical forms. It was shown that the acrocentric chromosomes of pair 8 in cytotype-1 have been transformed into metacentric chromosomes in cytotype-2 through pericentric inversion. Variation in the number of active NORs was also observed, but the modal number of active NORs was 8. Due to the chromosomal variation found in M. dogramacii, the cytogenetic results presented in this study may represent a process of chromosomal speciation.