FLICKR, LUKE PRICENearly everyone will smell the same odor a little bit differently, due to variation in the genes encoding the molecular machinery underlying humans’ sense of smell. Taking advantage of this variation, Noam Sobel of the Weizmann Institute of Science in Rehovot, Israel, and colleagues devised a test that can identify this “olfactory fingerprint” that could potentially identify individuals based on how they report different scents. Sobel and his colleagues reported their findings in a study published this week (June 22) in PNAS.
The researchers asked 89 study participants to rate 28 different odors for how strongly they matched 54 adjectives. The test odors included moth balls, eucalyptus, burnt rubber, and strawberries; adjectives included fishy, citrus, sour, and nutty. Sobel and his team then used these descriptions to estimate how similarly an individual perceived different odors.
Given the diversity of subjects’ responses, the researchers estimated that just 7 odors and 11 descriptors would have been sufficient to identify each of the 89 individuals based on their sense of smell. To individually identify any of the world’s 7 billion human inhabitants would require just 34 odors and 35 descriptors.
In addition to just describing a person’s sense of smell, the olfactory fingerprints can also reveal unrelated genetic information, the researchers found—specifically about variation in human leukocyte antigen (HLA) genes, which have been associated with body odor and mate choice. This suggests that people with similar olfactory fingerprints may have similar body odor, study coauthor and Weizmann neuroscientist Lavi Secundo told ScienceNews.
“[O]lfactory fingerprint matching using only four odorants was significantly related to HLA matching,” the authors wrote in their paper. “In conclusion, a precise measure of olfactory perception reveals meaningful nonolfactory genetic information.”