Tongue-rolling myth busted! It's not a single gene you inherit from your parents
The idea of a dominant "tongue-rolling" gene was actually debunked long ago, but many schools still use it as a classic example, says John McDonald, an evolutionary biologist at the University of Delaware who is on a quest to dispel this myth, according to PBS Newshour.Between 65 and 81 percent of people can curl their tongues, and slightly more women than men can do it, studies find.
The notion that a person's ability to roll his or her tongue is determined by a single dominant gene stems from a paper published in 1940 by geneticist Alfred Sturtevant. But a scientist named Philip Matlock disproved the findings in 1952, when a study of identical twins found that 7 out of 33 lacked the ability to roll their tongues. Sturtevant later conceded that he had been wrong.
But the myth persists in textbooks today.
That's not to say that genetics doesn't play any role in the ability, McDonald says. It could be that multiple genes are involved, such as genes that determine the length or muscle tone in the tongue.
Now, you may be wondering, can tongue rolling be learned? Maybe, but it's not easy. McDonald's students did a small study where they asked 33 people who couldn't roll their tongue to practice the feat each day. After a month of practicing, only one person was able to do it.