THE GENOMIC SEQUENCE FOR PRADER-WILLI ANGELMAN SYNDROMES LOCI OF HUMAN IS APPARENTLY CONSERVED IN THE GREAT APES/

Chromosomal changes through pericentric inversions play an important r ole in the origin of species. Certain pericentric inversions are too m inute to be detected cytogenetically, thus hindering the complete reco nstruction of hominoid phylogeny. The advent of the fluorescence in si tu hybridization (FISH) technique has facilitated the identification o f many chromosomal segments, even at the single gene level. Therefore the cosmid probe for Prader-Willi (PWS)/Angelman syndrome to the loci on human chromosome 15 [q11-13] is being used as a marker to highlight the complementary sequence in higher primates. We hybridized metaphas e chromosomes of chimpanzee (PTR), gorilla (GGO), and orangutan (PPY) with this probe (Oncor) to characterize the chromosomal segments becau se the nature of these pericentric inversions remains relatively unkno wn, Our observations suggest that a pericentric inversion has occurred in chimpanzee chromosome (PTR 16) which corresponds to human chromoso me 15 at PTR 16 band p11-12, while in gorilla (GGO 15) and orangutan ( PPY 16) the bands q11-13 complemented to human chromosome 15 band q11- 13. This approach has proven to be a better avenue to characterize the pericentric inversions which have apparently occurred during human ev olution. ''Genetic'' divergence in the speciation process which occurs through ''chromosomal'' rearrangement needs to be reevaluated and fur ther explored using newer techniques.