YEAST ARTIFICIAL CHROMOSOME CLONING OF THE XQ13.3-Q21.31 REGION AND FINE MAPPING OF A DELETION ASSOCIATED WITH CHOROIDEREMIA AND NONSPECIFIC MENTAL-RETARDATION

Microscopically detectable deletions and X;autosome translocations hav e previously facilitated the construction of a high-resolution interva l map of the Xq21 region, Here, we have generated three yeast artifici al chromosome contigs spanning approximately 7 megabases of the Xq13.3 -q21.31 region. In addition, a novel deletion associated with choroide remia and mental retardation was identified and mapped in detail, The proximal deletion endpoint was positioned between the loci DXS995 and DXS232, which enabled us to confirm the critical region for a locus in volved in mental retardation. The distal deletion endpoint is situated in the Xq21.33 band, which allowed us to refine the order of several markers in this region.