Master gene found for insect smell.Bugs use their sense of smell to find food and mates and to avoid predators. New research suggests that a single gene may be behind all that smelling in a broad range of insect species. Many insects detect scents through odor receptors along their antennae. When a particular scent molecule matches the shape of an odor receptor, as a key fits in a lock, nerves transmit information about that smell to the brain. The proteins that make up odor receptors can vary significantly, giving different smelling capabilities even to individual insects within a species. Despite this variability, Leslie Vosshall and her colleagues of Rockefeller University Rockefeller University, philanthropic organization in New York City, founded 1901 as the Rockefeller Institute for Medical Research by John D. Rockefeller for furthering medical science and its allied subjects and to make knowledge of these subjects available to the in New York City New York City: see New York, city. New York City City (pop., 2000: 8,008,278), southeastern New York, at the mouth of the Hudson River. The largest city in the U.S. reported last year that the protein encoded by a single odor-receptor gene, known as Or83b, works in conjunction with almost every odor receptor in fruit flies. When the scientists engineered flies that lacked the gene, the insects were unable to smell. Because genes corresponding to Or83b turn up in a variety of insect species, Vosshall's team investigated whether the genes fill a similar role in overseeing smell. First, the researchers isolated genes analogous to Or83b from three other species: the medfly (Ceratitis capitata), a mosquito mosquito (məskē`tō), small, long-legged insect of the order Diptera, the true flies. The females of most species have piercing and sucking mouth parts and apparently they must feed at least once upon mammalian blood before their eggs can (Anopheles gambiae Anopheles gambiae, refers to a complex of morphologically indistinguishable mosquitoes in the genus Anopheles, which contains the most important vectors of malaria in Sub-Saharan Africa [1], and the most efficient malaria vectors in the world. ), and a moth (Helicoverpa zea The larva of the moth Helicoverpa zea (formerly in the genus Heliothis) is a major agricultural pest. It can feed on many different plants (i.e. it is polyphagous) during the larval stage. ). They inserted these genes into fruit flies engineered to lack their own Or83b gene. Tests showed that the gene trans plants gave the fruit fly recipients a normal sense of smell. The results, published in the Feb. 22 Current Biology, suggest that these genes have retained the same function among even distantly related species. Vosshall says that researchers may eventually apply these findings to developing new insect repellents insect repellent, substance applied to the skin in order to provide protection against biting insects, primarily mosquitoes, ticks, chiggers, fleas, and certain flies. that work by interfering with Or83b.--C.B. |
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