DURHAM, N.C. Why the same sweaty man smells pleasant to one person and repellant to another comes down to the smellers genes.
Duke University Medical Center researchers demonstrated that genetic variants of odor receptors within the nose determine how a particular odor is perceived. The researchers, led by Dukes Hiroaki Matsunami, Ph.D., assistant professor of molecular genetics and microbiology, published the results of their experiments early online Sept. 16 in the journal Nature.
The researchers focused on two chemicals androstenone and androstadienone that are created naturally by the body during the breakdown of the male sex hormone testosterone and are excreted in sweat and urine.
We found that genetic variations of a specific odor receptor determine, to a significant degree, why the same chemicals smell pleasant or unpleasant to different people, Matsunami said. These results demonstrate the first link between the functioning of a human odor receptor gene and how that odor is perceived.
Humans have about 400 odor receptors within the nose that detect various odors or chemicals. Smells typically bind to their corresponding receptors, and the information is then relayed to the brain for processing.
The researchers wanted to uncover the reasons why people react differently when they smell these two sex steroid-derived chemicals. Hanyi Zhuang, a student in the Matsunami laboratory, tested all the known smell receptors in the laboratory and found one that reacted strongly with the two chemicals.
In conjunction with their collaborators at Rockefeller University, the researchers asked 391 volunteers to inhale the two chemicals and describe what they smelled. The results ranged from no smell at all, to descriptions such as vanilla and sweet and sickening and urine. DNA extracted from blood samples from each volunteer were sent to Matsunamis laboratory.
After performing genetic analysis on each of
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Duke University Medical Center