Although it has long been suspected that the ability to perceive the odor of androstenone is genetically determined, this study is the first to identify variations in a single gene that account for a large part of why people perceive androstenone's scent so differently.
With their Duke collaborators, Vosshall and Keller identified two point mutations called single nucleotide polymorphisms along the gene, which gave rise to two variants of the odorant receptor: RT and WM, which differ by two amino acids. As a group, participants with the RT/RT genotype perceive androstenone's odor as foul and intense. Those with the RT/WM genotype, on the other hand, are more likely to perceive androstenone as less unpleasant. Many cannot smell androstenone at all. Although some participants with the RT/WM genotype can smell androstenone, they experience the smell very differently than those with two copies of the fully functional receptor: To them, androstenone doesn't smell like urine; it has a vanilla scent.
"There are two independent things that are interesting about this odor," says first co-author Keller. "One is that it is a potential social signal but the other one is that so many people cannot smell it."
Two additional point mutations in some of the participants influenced their sensitivity to androstenone, one of which may make humans hypersensitive to this odor. Vosshall and Keller are interested in what it is about these amino acid changes that alter one's perception of androstenone's scent, and in whether one's perception of this potent compound can influence behavior.
"Since some mammals clearly use androstenone to communicate sexuality and dominance within a social hierarchy, it's intriguing to think whether the same thing may happen in humans," Vosshall says. "If so, what happens to humans who can't get the signal because they have the nonfunctional copy of the gene" Or the hyperfunctional one" What could be the soci
|Contact: Thania Benois|