REGION-SPECIFIC YAC BANDING AND PAINTING PROBES FOR COMPARATIVE GENOME MAPPING - IMPLICATIONS FOR THE EVOLUTION OF HUMAN-CHROMOSOME-2

To date, several hundred nonchimeric yeast artificial chromosomes (YAC s) from the Centre d'Etude du Polymorphisme Humain containing polymorp hic sequence-tagged sites have been mapped by fluoresence in situ hybr idization (FISH) on human metaphase chromosomes. Because they carry an average of 1 Mb of human genomic DNA, CEPH YACs generate high-intensi ty in situ hybridization signals. The available set of cytogenetically and genetically anchored YACs, approximately one every 5-10 cM evenly spaced over almost the entire human genome, provides complex region-s pecific probes for molecular cytogenetics. YAC probes can be adapted w ith unlimited flexibility to specific FISH applications such as the st udy of chromosomal evolution. We have generated representational probe s for YAC banding and painting of human chromosome 2 and its great ape homologs. Convergent inversions were found in the pericentric region of the gorilla and orangutan homologs of chromosome 2p.