GENERATION OF SEQUENCE-TAGGED SITES FROM XP22.3 BY ISOLATING COMMON ALU-PCR PRODUCTS OF RADIATION HYBRIDS RETAINING OVERLAPPING HUMAN X-CHROMOSOME FRAGMENTS

Several human diseases have been mapped to Xp22.3 on the distal short arm of the human X chromosome, and many genes in this area have been f ound to be expressed from the inactive X chromosome. To facilitate phy sical mapping and characterization of this interesting region, we have constructed a battery of radiation hybrids containing human X chromos omal fragments, and isolated two hybrid clones with overlapping fragme nts of Xp22.3. Alu-PCR on these hybrids and identification of sequence s common to both hybrids allowed the isolation of six sequence-tagged sites (STSs) from Xp22.3. Five of the STSs were mapped to individual Y ACs comprising a recently constructed contig of this region. These nov el STSs are useful markers for further physical characterization of th is part of the genome.