COMPARATIVE RB1 GENE-MAPPING IN HOMO-SAPIENS, PITHECIA-PITHECIA, MACACA-SYLVANA, AND CERCOPITHECUS-AETHIOPS-TANTALUS

The chromosomal localization of the gene for retinoblastoma (RB1), whi ch has been mapped to band 13q14 in man, was studied by in situ hybrid ization on metaphase chromosomes of selected primates, including Pithe cia pithecia, Macaca sylvana, and Cercopithecus aethiops tantalus. The results allowed us to determine the position of the bands homologous to human chromosome band 13q14 in these species. Hybridization analysi s corroborated the results of previous studies that defined the chromo some homologous to human chromosome 13 (HSA 13) in these species. By c omparing RB1 localizations and banding patterns, it is shown that the rearrangement separating HSA 13 from its homologous chromosome in Cerc opithecidae is not a pericentric inversion, as suggested by earlier st udies. Since the banding pattern and RB1 localization are not changed, the modification of the centromeric index is explained by a centromer ic shift or by two inversions, one pericentric and one paracentric.