Comparative RB1 gene mapping in Homo sapiens, Pithecia pithecia, Macaca sylvana, and Cercopithecus aethiops tantalus.

The chromosomal localization of the gene for retinoblastoma (RB1), which has been mapped to band 13q14 in man, was studied by in situ hybridization on metaphase chromosomes of selected primates, including Pithecia 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 analysis corroborated the results of previous studies that defined the chromosome homologous to human chromosome 13 (HSA 13) in these species. By comparing RB1 localizations and banding patterns, it is shown that the rearrangement separating HSA 13 from its homologous chromosome in Cercopithecidae is not a pericentric inversion, as suggested by earlier studies. Since the banding pattern and RB1 localization are not changed, the modification of the centromeric index is explained by a centromeric shift or by two inversions, one pericentric and one paracentric.