A LINKAGE MAP OF MICROSATELLITE MARKERS ON THE HUMAN X-CHROMOSOME

The efficiency of mapping and diagnosis of X-linked disorders by linka ge depends upon the existence of a high-density genetic map of polymer ase chain reaction (PCR)-based markers. DXS1120, DXS1122, DXS1123, DXS 1124, DXS1125, DXS1126, and DXS1153 were randomly isolated from a flow -sorted lambda bacteriophage library of the human X chromosome. The CC N (N = A or G) repeat within the androgen receptor was also found to b e polymorphic and primers were designed for genotyping the CCN polymor phism in addition to the AGC polymorphism. The above markers, together with microsatellite polymorphisms at DXS237 (GMGX9), 5'DYS-II and 3'D YS MS (within the dystrophin locus), DXS538 (XL27B), PGK1P1, DXS300 (V K29AC), DXS294 (VK17AC), and DXS102 (cX38.1AC), were genotyped in the 40 CEPH reference families. One marker, DXS1153, was found to include cryptic alleles that amplify only in homozygotes and hemizygotes but n ot heterozygotes. A PCR-based linkage map was constructed using all of the above markers plus PCR-based markers from the CEPH database and t hose PCR-based markers previously typed in our laboratory: ALAS2, DXS2 99 (VK14AC), DXS297 (VK23AC), FRAXAC1, and FRAXAC2. The genetic map of the X chromosome incorporates 62 PCR-based marker loci, integrates th e Weissenbach markers, and extends from XG near Xpter to DXS52 near Xq ter, a distance of 236 cM. (C) 1994 Academic Press, Inc.