A 2ND-GENERATION YAC CONTIG MAP OF HUMAN-CHROMOSOME-12

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.