What scents people pick up on — if one person perceives a smell as floral and another thinks it's lemony — offer clues into the similarity of their immune genes, Scientific American reports.
In the 1990s, researchers reported that women who liked the smell of dirty T-shirts from certain men were more likely to have similar immune genes to those men. And now, researchers led by Lavi Secundo from the Weizmann Institute of Science have expanded this to find that measuring what someone can smell can also reflect their immune genes, as they report in the Proceedings of the National Academy of Sciences.
Secundo and his colleagues had 89 people smell various samples and label whether they thought it smelled masculine, lemony, or like coconut, among other descriptors. From this, they generated unique olfactory fingerprints for each person and noted that they could identify people from this cohort based on randomly selected sets of seven odors and 11 descriptors alone.
For a separate set of 130 people, the researchers also generated olfactory fingerprints and associated them with their HLA type. Olfactory fingerprint matching using only four odorants was significantly related to HLA matching, they report.
Secundo tells Scientific American that these olfactory profiles have real-world applications. "For organ donation you can think of this method as a quick, maybe a quick and dirty, method to sift between the best and the rest," he says.
It could also, as the dirty T-shirt test indicates, influence romantic choices. "Which means that some day a smell-based service could challenge eharmony.com for matchmaking supremacy," Scientific American adds.