People With This Mutation Can’t Smell Stinky Fish
A very small percentage of people don’t mind the pungent odor of fish, a genetic study found.
A small contingent of the world’s population carries a mutation that makes them immune to the odious funk that wafts off fish, according to a study of some 11,000 people published Thursday in the journal Current Biology. The trait is rare, but potent: When faced with a synthetic odor that would put many people off their lunch, some test subjects smelled only the pleasant aroma of caramel, potato or rose.
The vast majority of people aren’t so lucky. Nearly 98 percent of Icelanders, the research said, are probably as put off by the scent as you’d expect. The mutation is thought to be even rarer in populations in other countries. ...
Study participants were asked to take a whiff of six Sniffin’ Sticks — pens imbued with synthetic odors resembling the recognizable scents of cinnamon, peppermint, banana, licorice, lemon and fish. They were asked to identify the smell, then rate its intensity and pleasantness. ...
The older the study subjects were, the more they struggled to accurately pinpoint the scents. That’s unsurprising ... But even younger people didn’t always hit the mark ...
The reek of fish, however, was mostly recognizable and received by far the lowest pleasantness ratings among the six sticks. But a small group of people consistently tolerated or even welcomed the piscine perfume: those born with a genetic mutation that incapacitated a gene called TAAR5.
TAAR5 helps make a protein that recognizes a chemical called trimethylamine, or TMA, that is found in rotten and fermented fish and certain animal bodily fluids, including human sweat and urine.
Most people carry an intact version of TAAR5, and easily recognize the fishy fragrance as mildly repulsive — an ability that might have evolved to help our ancestors avoid spoiled food. But a small number of the Icelanders in the study carried at least one “broken” copy of the gene that appeared to render them insensitive to the scent. When asked to describe it, some even mistook it for a sugary dessert, ketchup or something floral. ...
