(A) A schematic physical map of the 15q11–q13 PWS/AS common deletion interval is shown with the centromere toward the left and the telomere toward the right. Genes and genomic markers are shown in boxes. Sites of differential methylation are indicated by asterisks (*) over PW71 and SNRPN. Wavy vertical lines represent chromosomal breakpoints. The common PWS and AS deletion breakpoints are near either end of the map, and the Se family centromeric deletion breakpoint maps between SRRPN and UBE3A, defining the PWS and AS candidate regions, indicated over the map. Breakpoints in the 15q non-AS deletion case and the t(14;15) translocation case, together with the Se breakpoint, define the narrowed AS critical region indicated above UBE3A. (B) YAC, PAC, cosmid, STS, and gene map of the ∼1-Mb region surrounding the Se breakpoint. Genomic clones are indicated by horizontal lines; gene and STS markers are indicated by broken vertical lines.
