A HIGH-RESOLUTION PHYSICAL MAP OF HUMAN-CHROMOSOME-11

The development of a highly reliable physical map with landmark sites spaced an average of 100 kbp apart has been a central goal of the Huma n Genome Project, We have approached the physical mapping of human chr omosome 11 with this goal as a primary target, We have focused on stra tegies that would utilize yeast artificial chromosome (YAC) technology , thus permitting long-range coverage of hundreds of kilobases of geno mic DNA, yet we sought to minimize the ambiguities inherent in the use of this technology, particularly the occurrence of chimeric genomic D NA clones, This was achieved through the development of a chromosome I i-specific YAC library from a human somatic cell hybrid line that has retained chromosome II as its sole human component, To maximize the ef ficiency of YAC contig assembly and extension, we have employed an Alu -PCR-based hybridization screening system, This system eliminates many of the more costly and time-consuming steps associated with sequence tagged site content mapping such as sequencing, primer production, and hierarchical screening, resulting In greater efficiency with increase d throughput and reduced cost, Using these approaches, we have achieve d YAC coverage for >90% of human chromosome 11, with an average interm arker distance of <100 kbp, Cytogenetic localization has been determin ed for each contig by fluorescent in situ hybridization and/or sequenc e tagged site content, The YAC contigs that we have generated should p rovide a robust framework to move forward to sequence-ready templates for the sequencing efforts of the Human Genome Project as well as more focused positional cloning on chromosome 11.