In 1940, Alfred Sturtevant, one of the pioneers of Drosophila genetics, published a paper in PNAS called A New Inherited Character in Man. He found 280 subjects The author pointed out that these people fall into two categories - some can roll their tongue sideways and some cannot.

Then we treated it as a single-gene trait and did some simple genetic analysis. In most cases, it was in line with expectations (including 2 pairs of twins). In the end, he concluded on his own that retroflexion "is conditioned at least in part by heredity."

Then, this conclusion was included in textbooks and became a typical example of single-gene inheritance. In fact, more subsequent studies have confirmed whether tongue rolling has a genetic influence, but it is not a purely genetic trait. Even Sturtevant himself, who originally proposed this genetic trait, recognized it. In 1965, Sturtevant said, "I am embarrassed to find that in some current articles this is regarded as an established Mendelian inheritance." Therefore, many textbooks now say that whether or not one can roll one's tongue is determined by genetic factors. This is actually a myth.

Tongue rolling is a conditioned reflex that babies have when they are born. This conditioned reflex is used when sucking breast milk or bottles. However, some people degenerate this reflex as they grow up.

There are many muscles in the human body, and some muscles are power muscles, such as the muscles in our arms. If you don't use the strength of your hands, they will not change their shape at will. Some muscles are memory muscles and can move and deform. For example, the muscles on our tongue are memory muscles, which can stretch and deform at will, so they can change into various shapes.

Not only that, the practitioners also summarized the essentials of practicing the tongue-rolling method: the first step: to curl the sides of your tongue toward the middle; the second step: to use the muscles of the base of the tongue to curl the tongue. The raised tongue should try to shrink back; the third step: lower the sides of the originally rolled tongue down, and fix the tongue with teeth and lips at the same time, so that a lotus-shaped tongue comes out.

Perhaps many people who have learned to roll their tongue through acquired practice carry the tongue-rolling gene themselves. As for whether they can roll their tongue, having the gene without practicing is not enough.