Variation in C-heterochromatin and NOR distribution among chromosomal races of mole rats (Spalacidae) from Central Anatolia, Turkey

Abstract

In this study, the 2n=40, 58, 60 chromosome races of mole rats of the Nannospalax nehringi superspecies from the Konya province in Turkey were investigated. Conventional chromosome staining, Ag-NOR staining and C-banding analysis was carried out on 25 specimens of mole rats from 13 localities. The description of conventional karyotypes revealed the detailed pattern of geographic distribution of individual races of mole rats in Central Anatolia. The C-positive regions were localized in centromeric areas, and/or in short arms of submetacentric and subtelocentric autosomes. In the 2n=40 race, C-heterochromatin regions were found in whole short arms of four biarmed autosomal pairs whereas C-heterochromatin was localized in pericentromeric areas of biarmed and acrocentric autosomes in the karyotypes of the other races. Autosomal pairs heteromorphic possibly due to deletion/addition of heterochromatin and euchromatin material in short arms were recorded in some populations of both the 2n=58 and 60 chromosome races. The distribution of nucleolar organizer regions (NORs) was described for the first time in the 2n=40 and 58 races. The NORs were localized in four pairs of biarmed autosomes in all the studied chromosomal races in distal heterochromatic and euchromatic areas of the short arms. The results demonstrate the considerable extent of variation in C-heterochromatin and NORs distribution in karyotypes of mole rats from Anatolia.