Nucleolus-organizer regions and heterochromatin in three species of bovidae.

Ag-NOR staining and a counterstain-enhanced fluorescence technique (chromomycin A3/distamycin A/DAPI staining = CDD-method) have been applied to ibex (Capra ibex L.), chamois (Rupicapra rupicapra L.) and bison (Bison bison L.) chromosomes. Chromomycin A3 visualization led to a well defined R-banding pattern along the chromosome arms and to a clear demonstration of centric heterochromatic bands of variable size. The nucleolus organizer regions (NORs) were found in the telomeric regions of the chromosomes 2, 3, 4, 5 and 28 of the ibex, of the chromosomes 1/3 (short arm), 2, 4, 5 and 28 of the chamois and of the chromosomes 2, 3, 4, 11 and 28 of the bison.