Evolutionary divergence of the oncogenes GLI, HST and INT2.

Almost a quarter of a century ago, the banding patterns of human and other higher primate chromosomes were compared, creating a barrage of speculation. Consequently, a number of approaches have been used to understand human descent. Chromosome modifications are believed to be important in the origin of species, and pericentric inversions account for the majority of evolutionary chromosomal alterations seen in Hominoidea. A comparative mapping fluorescence in situ hybridization technique, using locus-specific DNA probes as phylogenotic markers, was used to decipher the pericentric inversions of human chromosomes 11 and 12. Human-derived (Homo sapiens, HSA) DNA probes for GLI, HST and INT2 protooncogenes were used to identify their homologous locations in the chromosomes of chimpanzee (Pan troglodytes, PTR), gorilla (Gorilla gorilla, GGO) and orangutan (Pongo pygmaeus, PPY). The INT2 and HST loci mapping results confirm the earlier putative claim that a pericentric inversion took place in HSA chromosome 11 and its equivalent PTR and GGO chromosomes. In addition, these data provide additional information regarding the orangutan's position on the evolutionary tree of Pongidae and Hominidae. GLI mapping reveals that a pericentric inversion occurred in the HSA chromosome 12 equivalent in PTR and GGO, but was not seen in HSA or PPY. These pericentric inversions in PTR and GGO may have occurred at a period when both PTR and GGO had branched off from the Hominoidae trunk. The use of loci-specific probes to decipher pericentric inversions has proved to be a formidable approach in characterizing chromosome rearrangements and providing further evidence on human descent.