A contig of 36 overlapping yeast artificial chromosome (YAC) clones has been constructed for the complete Duchenne muscular dystrophy (DMD) gene in Xp21. The YACs were isolated from a human 48,XXXX YAC library using the DMD cDNA and brain promoter fragments as hybridization probes. The YAC clones were characterized for exon content using HindIII or EcoRI digests, hybridization of individual DMD cDNA probes, and polymerase chain reaction (PCR) amplification of specific exons near the 5' end of the gene. For comparison to the known long-range restriction map of the DMD gene, YAC clones were digested with SfiI and hybridized with DMD cDNA probes. The combined analysis of the exon content and the SfiI map allowed an approximately 3.2-Mb YAC contig to be constructed. The complete 2.4-Mb DMD gene could be represented in a minimum set of 7 overlapping YAC clones.