Emerging uses for genomic information in drug discovery.

Geneticists who study yeast, worms, and fruit flies have long recognized that an effective way to identify genes with functional relevance to a particular biologic process is to screen large numbers of mutagenized organisms. Researchers have recently used these primitive organisms to pinpoint genetic mechanisms in human diseases. This approach has succeeded mainly because genome-sequencing projects have discovered numerous invertebrate homologues of human genes. The gene involved in basal-cell carcinoma, for example, was cloned in part through its similarity to the patched gene of the fruit fly Drosophila melanogaster. 1,2 New work on two breast-cancer–susceptibility genes, BRCA1 and BRCA2, is . . .