If you don't mind the smell of rotting fish, you might be one of the rare people to possess a just-discovered gene mutation that hints at just how different people's smell and taste senses can be. Researchers in Iceland set out to learn more about the variants that influence odor perception and in doing so discovered that about 2% of study participants could not only tolerate the stench of fish but in some cases enjoyed it. They asked 9,122 Icelanders to describe what they smelled when sniffing a pen-like device that emitted synthetic odors similar to cinnamon, peppermint, banana, licorice, lemon, and fish, per the New York Times. Most participants could recognize the fish scent, which received the lowest rating of pleasantness. But a small number of participants had a hard time identifying it and used words including "potatoes," "caramel," and "rose," per a release.
That's because they have a mutation in a gene known as TAAR5, one of 400 olfactory genes humans use, that makes fish odor less intense and less unpleasant, according to the study published Thursday in Current Biology. It affects the perception of trimethylamine, a compound found in rotten fish, other animal odors, and bodily secretions. Researchers found the mutation was even rarer in populations outside of Iceland, where fermented shark is a delicacy. They also found more common variants that intensified perceptions of trans-cinnamaldehyde, found in cinnamon, and trans-anethole, found in black licorice, fennel, and anise. The latter variant is "much more common in East Asia than in Europe," says study author Rosa Gisladottir, who notes "these variants likely influence whether we like food containing these odors." (Read more gene mutation stories.)