BAC Finishing Strategies

The goal of the International Human Genome Project is to generate a reference sequence of the human genome with an accuracy of <1 error in 10,000 bases. The approach chosen by the International Human Genome Sequencing Consortium is a hierarchical mapping and sequencing strategy similar to that described for other large genomes, including Saccharomyces cerevisiae, Caenorhabditis elegans , and Arabidopsis thaliana (1 –3 ). A physical map of the human genome has been assembled on the basis of “fingerprints” generated by restriction digestion of individual bacterial clones and mapping of individual clones to chromosomes using landmarks from existing genetic maps. At Washington University, St. Louis, more than 300,000 clones from the whole human genome bacterial artificial chromosome (BAC) libraries RPCI-11 and RPCI-13 from P. de Jong (4 ) were fingerprinted, and the resulting maps of these overlapping clones have been integrated with clone maps of individual chromosomes generated by other centers (5 ). Sets of minimal overlapping clones have been selected for sequencing from the resulting maps.