Optical mapping of BAC clones from the human Y chromosome DAZ locus

The accurate mapping of clones derived from genomic regions containing comp lex arrangements of repeated elements presents special problems for DNA seq uencers. Recent advances in the automation of optical mapping have enabled us to map a set of 16 BAC clones derived from the DAZ locus of the human Y chromosome long arm, a locus in which the entire DAZ gene as well as subsec tions within the gene copies have been duplicated. High-resolution optical mapping employing seven enzymes places these clones into two contigs repres enting four distinct copies of the DAZ gene and highlights a number of diff erences between individual copies of DAZ.