Because the gene is found in a wide variety of insect species, the results point to a new strategy for developing insect repellents. Repellents that block the gene, and thus prevent disease-carrying insects from finding human hosts, might eventually help fight malaria and other infectious diseases.
"This finding has a direct applied potential," says assistant professor Leslie B. Vosshall, Ph.D., head of the Laboratory of Neurogenetics and Behavior. "Insects are the primary vectors for malaria, dengue fever, yellow fever, and West Nile encephalitis, and they locate human hosts largely through their exquisitely sensitive olfactory systems."
"We need better insect repellents to use as weapons against the spread of infectious disease," Vosshall adds. "Most insect repellents are based on trial and error, or folk remedies. Now we have a scientific, rational basis for designing insect repellents."
An anomalous smell receptor
The sense of smell is very direct. In order for humans or fruit flies to smell bananas, for example, molecules from the fruit must waft through the air to specialized nerve cells that detect them. In humans these cells are at the top of the nasal passages. In the fruit fly they are located on the antennae and the maxillary palp, an appendage near the fly mouth. The odorant molecules bind to receptors on the neurons, fitting like chemical keys into the lock-like receptors, and set off a series of signals that the brain perceives as smell.
A different gene codes for each kind of receptor, and the Or83b receptor is unusual in two ways. First, nearly all the olfactory neurons in the fly
Contact: Lynn Love