Integration of physical, genetic and cytogenetic maps of human chromosome 7: isolation and analysis of yeast artificial chromosome clones for 117 mapped genetic markers

An Important goal of the human genome project is to assemblefully integrated physical, genetic and cytogenetic maps foreach human chromosome. Towards that end, we have isolated yeastartificial chromosome (YAC) clones containing 117 of the 119genetic markers that constitute a recently constructed, detailedgenetic map of human chromosome 7. Analysis of these clonesreveals numerous examples where adjacent genetic markers havebeen physically connected, either In Individual YACs or in multi-YACcontigs. At present, the 117 genetic markers are contained Infewer than 80 YAC contigs, with most of these contigs uniquelyordered relative to one another based on the genetic map positionsof the corresponding markers. These YAC and YAC contigs areestimated to contain {small tilde}60–85% of the DNA fromhuman chromosome 7. YACs representing 36 genetic markers weremapped by fluorescence In situ hybridization (FISH) to metaphasechromosomes, allowing assignment of these genetic markers tocytogenetic bands along chromosome 7 and placement of the centromerewithin the genetic map. Together, these studies provide geneticallyand cytogenetically anchored YAC clones covering the majorityof chromosome 7 that will be useful both for the positionalcloning of genes and as a framework for assembling a completeYAC-based physical map of the chromosome.