Functional characterization of the S-cerevisiae genome by gene deletion and parallel analysis

The functions of many open reading frames (ORFs) identified in genome-seque ncing projects are unknown. New, whole-genome approaches are required to sy stematically determine their function. A total of 6925 Saccharomyces cerevi siae strains were constructed, by a high-throughput strategy, each with a p recise deletion of one of 2026 ORFs (more than one-third of the ORFs in the genome). Of the deleted ORFs, 17 percent were essential for viability in r ich medium. The phenotypes of more than 500 deletion strains were assayed i n parallel. Of the deletion strains, 40 percent showed quantitative growth defects in either rich or minimal medium.