Abstract

Publisher Summary Complete genome sequences are available for three model organisms—Escherichia coli, Saccharomyces cerevisiae, and Caenorhabditis elegans—and for several pathogenic microorganisms such as Helicobacter pylori. Complete genome sequences are expected to become available soon for other model organisms and for humans. This information is expected to revolutionize the way biological questions can be addressed. Molecular mechanisms should now be approachable on a more global scale in the context of (nearly) complete sets of genes, rather than by analyzing genes individually. However, most open reading frames (ORFs) predicted from sequencing projects have remained completely uncharacterized at the functional level. The emerging field of functional genomics addresses this limitation by developing methods to characterize the function of large numbers of predicted ORFs simultaneously.