A. Delineation of the critical region of loss between in patients 1 and 2.

Marker D5S2634 maps within 30-kb of marker D5S672 (SHGC radiation hybrid map) and is placed centromeric, based on results from our somatic cell hybrid. The ordering of markers is supported by the YAC contig in Figure 3. B. Loss of heterozygosity analysis of polymorphic markers at 5q13.3. Paired samples of DNA from peripheral blood granulocytes or bone marrow blasts and mononuclear cells were PCR amplified for each of the 5q13.3 polymorphic markers. Patient 1 mononuclear cells were short term cultured to select for the leukemic population. The presence of 2 alleles in the control sample rendered a given patient informative for the specific locus. N = normal sample. L = leukemic sample. Arrows mark the location of alleles. Stars indicate allele loss.