PRESENCE AND ABUNDANCE OF CENP-B BOX SEQUENCES IN GREAT APE SUBSETS OF PRIMATE-SPECIFIC ALPHA-SATELLITE DNA

CENP-B, a highly conserved centromere-associated protein, binds to alp ha-satellite DNA, the centromeric satellite of primate chromosomes, at a 17-bp sequence, the CENP-B box. By fluorescence in situ hybridizati on (FISH) with an oligomer specific for the CENP-B box sequence, we ha ve demonstrated the abundance of CENP-B boxes on all chromosomes (exce pt the Y) of humans, chimpanzee, pygmy chimpanzee, gorilla, and orangu tan. This sequence motif was not detected in the genomes of other prim ates, including gibbons, Old and New World monkeys, and prosimians. Ou r results indicate that the CENP-B box containing subtype of alpha-sat ellite DNA may have emerged recently in the evolution of the large-bod ied hominoids, after divergence of the phylogenetic lines leading to g ibbons and apes; the box is thus on the order of 15-25 million years o f age. The rapid process of dispersal and fixation of the CENP-B box s equence throughout the human and great ape genomes is thought to be a consequence of concerted evolution of alpha-satellite subsets on both homologous and nonhomologous chromosomes.