Insects provide an attractive system for the study of olfactory sensory per
ception. We have identified a novel family of seven transmembrane domain pr
oteins, encoded by 100 to 200 genes, that is likely to represent the family
of Drosophila odorant receptors. Members of this gene family are expressed
in topographically defined subpopulations of olfactory sensory neurons in
either the antenna or the maxillary palp. Sensory neurons express different
complements of receptor genes, such that individual neurons are functional
ly distinct. The isolation of candidate odorant receptor genes along with a
genetic analysis of olfactory-driven behavior in insects may ultimately af
ford a system to understand the mechanistic link between odor recognition a
nd behavior.