“Tongue rolling ability is a simple genetic trait”

The idea that the ability to roll one's tongue (Review) into a tube is a simple, dominant genetic trait is a persistent misconception, widely taught in biology classrooms for decades. This common myth originated with a 1940 paper by geneticist Alfred Sturtevant, who proposed it as a straightforward example of Mendelian inheritance. Its apparent simplicity made it an easy and memorable illustration for introductory genetics, often used to demonstrate dominant and recessive alleles.

However, scientific evidence quickly emerged to challenge this notion. Just twelve years after Sturtevant's initial paper, a 1952 study by Philip Matlock involving identical twins provided crucial evidence against the simple genetic model. Matlock found that some pairs of identical twins, who share the exact same genetic material, differed in their ability to roll their tongues. If it were purely a simple genetic trait, identical twins should always share the same ability. Sturtevant himself later acknowledged his mistake, famously stating in his 1965 book, "A History of Genetics," that he was "embarrassed to see it listed in some current works as an established Mendelian case".

Despite this early debunking and the original researcher's retraction, the myth has continued to be perpetuated in textbooks and classrooms, contributing to its enduring belief. The truth is more complex: tongue rolling is influenced by multiple genes, not just one, and environmental factors also play a significant role. For instance, studies have shown that some individuals, particularly children, can learn to roll their tongues with practice, further demonstrating that it is not solely determined by a single inherited gene.