Genes discovered for sensing carbon dioxide.Researchers have tracked down a pair of genes that, together, seem responsible for some insects' ability to sense carbon dioxide carbon dioxide, chemical compound, CO2, a colorless, odorless, tasteless gas that is about one and one-half times as dense as air under ordinary conditions of temperature and pressure. . Because mosquitoes detect the gas to home in on their next blood meal, a means to block this sense could lead to more-effective mosquito repellents. To locate the carbon dioxide-sensing genes, Leslie Vosshall of the Rockefeller Institute in New York New York, state, United States New York, Middle Atlantic state of the United States. It is bordered by Vermont, Massachusetts, Connecticut, and the Atlantic Ocean (E), New Jersey and Pennsylvania (S), Lakes Erie and Ontario and the Canadian province of and her colleagues worked with Drosophila Drosophila: see fruit fly. drosophila Any member of about 1,000 species in the dipteran genus Drosophila, commonly known as fruit flies but also called vinegar flies. Some species, particularly D. melanogaster. Other researchers had previously found that carbon dioxide-sensing cells in this fruit fly's antennae express a gene known as gustatory gus·ta·to·ry or gus·ta·tive adj. Of or relating to the sense of taste. receptor 21a (Gr21a). Using a genetic test, Vosshall's team discovered that these cells also express a related gene known as Gr63a. To see whether the two genes play a role in carbon dioxide detection, the researchers inserted them into fruit fly neurons Neurons Nerve cells in the brain, brain stem, and spinal cord that connect the nervous system and the muscles. Mentioned in: Speech Disorders that normally respond to fruit odors Odors anosmia Medicine. the absence of the sense of smell; olfactory anesthesia. Also called anosphrasia. — anosmic, adj. halitosis bad breath; an unpleasant odor emanating from the mouth. but not to carbon dioxide. When the researchers placed both genes into the neurons, the cells responded to carbon dioxide, but neither of the genes on its own had that effect. Vosshall and her colleagues also created mutant flies missing Gr63a. These flies didn't respond to carbon dioxide. A genetic-database search revealed that mosquitoes have their own versions of Gr21a and Gr63a. The researchers note in the Jan. 4 Nature that if scientists find chemicals that gum up either of the receptors encoded by those genes, those compounds might leave mosquitoes blind to the carbon dioxide emitted by their targets. |
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