CHROMOSOMAL REDUCTION IN AN OKAPI PEDIGREE (OKAPIA-JOHNSTONI)

The karyotype of a female okapi showing 2n = 44 has been investigated by G-R-C and Ag-NOR banding methods. This animal is the offspring of a captive female ana a wild-caught male, which are both heterozygotes s howing 2n = 45 with centric fusion between two unequal-sized acrocentr ic chromosomes. The okapi karyotype was arranged according to the catt le standard karyorype in consideration of the high degree of banding h omologies found between the two species. The reduction from 2n = 46 to 2 = 45 and 2n = 44 is the result of a Robertsonian translocation invo lving cattle equivalent chromosomes 4 and 26. Other autosomal rearrang ements, like centric fusions and a tandem translocation, as well as st ructural changes in the X and the Y chromosomes, are tentatively ident ified. The location of centromeric heterochromatin and of nucleolus or ganizer regions in the okapi karyotype are described and discussed in relation to the karyotype in other species of Bovidae.