Human chromosome 12 constitutes approximately 4.5% of the human genome
and has an estimated size of 135 million base pairs (Mb). We have sta
rted to construct a high-resolution physical map of chromosome 12 as o
verlapping yeast artificial chromosomes (YACs), using as a foundation
the first-generation physical map which contained overlapping clones c
orresponding to 56 markers. Our second-generation map of this chromoso
me covers nearly 102 Mb of DNA and includes 426 highly polymorphic, mo
nomorphic and gene-based markers. We also mapped 119 of the YACs, most
of which are part of the physical map, by cytogenetic methods. Thus t
he map integrates genetic, physical and cytogenetic data and provides
information about the organization of this chromosome and will help in
the localization and cloning of disease-related genes. The strategy u
sed here to generate the chromosome-12 map could be applied for the va
pid construction of physical and expression maps for other human chrom
osomes.