Comparative cytogenetics of hamsters of the genus Calomyscus

Karyotypes of Calomyscus from different regions of Turkmenistan, Iran, and Azerbaijan were studied using chromosome banding (G- and C-banding) and ana lyses of meiosis in laboratory hybrids. Extensive variation in the diploid number and the number of autosomal arms (FNa) was revealed (2n = 30, FNa = 44; 2n = 32, FNa = 42; 2n = 44, FNa = 46; 2n = 44, FNa = 58; 2n = 37, FNa = 44; 2n = 50, FNa = 50; 2n = 52, FNa = 56). Centric and tandem fusions and heterochromatin changes were identified as the major modes of karyotype evo lution in this group. Natural hybrids between individuals with different ka ryotypes were recorded, and regular chromosome pairing in meiosis was obser ved in laboratory hybrids. Fluorescence in situ hybridization with a 353-bp BspRI complex tandem repeat indicated that chromosomal repatterning occurr ed recently within the genus. There is no unequivocal evidence suggesting t he role of chromosomal change in the speciation of the populations of Calom yscus examined. Copyright (C) 2000 S. Karger AG, Basel.