A difference at the smallest level of DNA -- one base pair coded for by one gene -- can determine whether you find a given smell pleasant. A different base pair coded for by the same gene in your friend's body could mean he finds the same odor offensive, according to researchers at Duke University and collaborators from Monell Chemical Sciences Center, the University of Pennsylvania School of Medicine, and Rockefeller University. There are approximately 400 genes coding for the receptors in our noses, and according to the 1000 Genomes Project, there are more than 900,000 variations of those genes. These receptors control the sensors that determine how we smell odors. A given odor will activate a suite of receptors in the nose, creating a specific signal for the brain. But the receptors don't work the same for all of us, said Hiroaki Matsunami, Ph.D., associate professor of molecular genetics and microbiology at the Duke University School of Medicine. In fact, when comparing the receptors in any two people, they should be about 30 percent different, said Dr. Matsunami, who is also a member of the Neurobiology Graduate Program and the Duke Institute for Brain Sciences. "There are many cases when you say you like the way something smells and other people don't. That's very common," Dr. Matsunami said. But what the researchers found is that no two people smell things the same way.Login Or Register To Read Full Story