Biologjia Online

A fundamental principle in the field of olfaction is that each olfactory receptor neuron expresses a single odorant receptor. Goldman et al. have constructed a receptor-to-neuron map for an entire olfactory organ of the fruit fly Drosophila and find that one class of neuron coexpresses two receptors. Both receptors are functional in an in vivo expression system, are encoded by unlinked genes, and are only 16% identical in amino acid sequence. Coexpression of multiple receptors in a cell could provide an additional degree of freedom for odor coding.