Some strains are less sensitive to sweet taste than others, and scientists had found the approximate location of the responsible gene on a mouse chromosome. In the new work, the scientists surveyed that region of the mouse chromosome and the corresponding region of human DNA, eventually identifying a gene that looked like it could give rise to a taste receptor. Margolskee's group proposed how a version found in insensitive mice might lead to a malfunctioning receptor. The scientists found that, in both mice and people, the gene is active only in taste bud cells known to contain taste receptors. But it will take more work to nail down the idea that the gene gives rise to a sweet receptor, Buck and Margolskee said.
Sweetness is one of five recognized tastes.
Genes for apparent bitter taste receptors were identified by Buck and others last year. Salty and sour tastes are detected by a different kind of sensor, and the identity of the sour-detecting system isn't yet known for sure. A fifth taste, called umami, is found in the flavoring monosodium glutamate and many protein-rich foods like meat, fish and cheese. Researchers reported last year that they'd found a probable umami receptor. The Associated Press .