A new algorithm that examines DNA databases for proteins that have a particular structure, as opposed to a particular sequence, represents a novel 'e-genetics' approach to gene discovery. The algorithm has successfully identified new G-protein-coupled receptors, which have a characteristic seven-transmembrane-domain structure, from the Drosophila genome database. In particular, it has revealed novel families of odor receptors and taste receptors, which had long eluded identification by other means. The two new gene families, the Or and Gr genes, are expressed in neurons of olfactory and taste sensilla and are highly divergent from all other known G-protein-coupled receptor genes. Modification of the algorithm should allow identification of other classes of multitransmembrane-domain protein.