A YAC CLONE MAP SPANNING 7.5-MEGABASES OF HUMAN-CHROMOSOME BAND-XQ28

Xq28 has been of special interest in human genetics because a large nu mber of diseases map to this region, As a step in the molecular analys is of the as yet uncloned disease genes, and as a test for the detaile d analysis of larger regions of the genome, we have constructed YAC cl one contigs covering the 7.5 Mb region between IDS to the telomere on the long arm of the human X chromosome. Contigs were assembled and ver ified by an integrated hybridization-based strategy. Data was combined from the physical map, from YAC and cosmid mapping experiments, and f rom the localization of specific transcripts in the region. Two gaps i n the YAC map of 250 and 100 kb were covered in part by the aid of cos mid clones, but small gaps of 50 kb each remain. The cloned region is expected to contain yet unidentified genes for at least ten genetic di seases. The construction of ordered YAC clone contigs of Xq28 represen ts an important step in the molecular identification of these genes, a nd the further analysis of one of the genetically most interesting reg ions of the human genome.