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A yeast artificial chromosome library containing 33,000 clones with an average insert size of one megabase of human genomic DNA was extensively analysed by several different procedures for detecting overlaps and positional information. We developed an analysis strategy that resulted, after confirmatory tests, in a YAC contig map reliably covering about 75% of the human genome in 225 contigs having an average size of about ten megabases.

Sets of ordered overlapping cloned genomic DNA fragments that span each of the human chromosomes are urgently needed for identification of human disease genes. Such a physical map also provides unique material to study the structure and function of the genome. We have therefore exhaustively analysed the CEPH yeast artificial chromosome (YAC) library, which contains 33,000 clones, whose insert size was individually determined. These YACs have an average length of 0.9 megabases and cover the equivalent of 10 haploid genomes. Several mapping techniques were combined to provide multiple sources of structural information for most of these clones. Finally, the library was screened with more than 2,000 genetic markers quasiuniformly distributed over 90% of the genome. These results should allow the scientific community to construct detailed maps of all human chromosomes. Moreover, we propose a data analysis strategy that produces a first-generation integrated map covering most of the human genome.

Sets of ordered overlapping cloned genomic fragments, spanning each of the human chromosomes are urgently needed for identification of human disease genes. Such a physical map provides also a unique source of material to study structure and function of the genome. To achieve this goal we exhaustively analyzed the CEPH yeast artificial chromosome (YAC) library containing 33,000 clones, which insert sizes were individually measured. With 0.9 Mb average lengths these YACs cover an equivalent of 10 haploid genomes. Then, several mapping techniques were combined to generate multiple structural information for most of these clones. Finally, the library was screened with more than 2,000 genetic markers quasi-uniformly distributed along 90% of the genome. These results should allow the scientific community to construct detailed chromosomic maps. Moreover, we propose a data analysis strategy that produces a first generation integrated map covering most of the human genome.

A continuous array of overlapping clones covering the entire human chromosome 21q was constructed from human yeast artificial chromosome libraries using sequence-tagged sites as landmarks specifically detected by polymerase chain reaction. The yeast artificial chromosome contiguous unit starts with pericentromeric and ends with subtelomeric loci of 21q. The resulting order of sequence-tagged sites is consistent with other physical and genetic mapping data. This set of overlapping clones will promote our knowledge of the structure of this chromosome and the function of its genes.

A new approach for the isolation of chromosome-specific subsets from a human genomic yeast artificial chromosome (YAC) library is described. It is based on the hybridization with an Alu polymerase chain reaction (PCR) probe. We screened a 1.5 genome equivalent YAC library of megabase insert size with Alu PCR products amplified from hybrid cell lines containing human chromosome 21, and identified a subset of 63 clones representative of this chromosome. The majority of clones were assigned to chromosome 21 by the presence of specific STSs and in situ hybridization. Twenty-nine of 36 STSs that we tested were detected in the subset, and a contig spanning 20 centimorgans in the genetic map and containing 8 STSs in 4 YACs was identified. The proposed approach can greatly speed efforts to construct physical maps of the human genome.

The recombinant locus ORAgp5 containing the regions homologous to protooncogene mos was previously cloned from the human genome. In order to monitor the expression of this human genome region, we have transfected the recombinant phage gp5 into mouse LMtk cells. One of these transfectants contained several copies of gp5. ORAgp5 sequences were found to be expressed in 1.5 kb RNA from this clone.