Source: Hmwith / Wikimedia Commons
Can you roll your tongue? I can. Most people can. It’s often presented as an example of a genetic trait, but don’t be fooled. It’s possible for maternal twins to differ in their tongue rolling abilities, even though maternal twins are supposed to be genetically identical [1]. Myth busted.
Sorry to disappoint. This post isn’t about the tongue rolling gene (rolled oral factor lingua, or ROFL). Maybe a few genes combine to give us the power to make the tongue tube, possibly genes that offer better muscle control or flexibility. The tongue is a weird muscle too—wiggling around in there, fiddling with that rough spot on your tooth—and it achieves that wiggling and fiddling thanks to this week’s gene of interest: myosin or MYH1.
Muscles can only pull, never push [2]. Think about that for a second. We can achieve so many artful and dexterous movements (fencing, the tango, punching someone in the face) and manage it entirely by a timely contraction of a series of tissues to achieve the desired effect. To me, that’s mind blowing. Even pushing achieved through pulling.
Muscles pull by way of two proteins, actin and myosin, that work together in a chemical tug-of-war [3]. Actin is the rope and myosin is the hand that pulls on that rope. Myosin attaches to actin and (using energy from ATP) pulls on actin sliding it forward. 
Muscle is organized into groups of parallel actin and myosin fibers called sarcomeres [3]. Each muscle has millions of sarcomeres—millions upon millions of molecules pulling against one another to create force.
Pitting muscles against each other, antagonistic pairs, gives us movement. For example, the bicep and the tricep (Did you get your tickets to the gun show? flexes bicep). In the tongue, several antagonistic pairs are woven together, both parallel and perpendicular to the surface. They pull against each other in a soft mass, with anchor points in the jaw, mandible, and the front and back of the throat [4]. And a few of those pairs combine to pull off the tongue roll. What a weird thing to have inside our mouths. Enjoy being aware your tongue for the next hour!
References
[1] “Debunking the Biggest Genetic Myth of the Human Tongue“. PBS. 5 August 2015.
[2] “Why Do Muscles Only Pull And Not Push“. ezinearticles.com. 13 August 2012.
[3] “How Muscle Works“. How Stuff Works. 11 April 2001.
[4] “Anatomy Angel: The Tongue and Balance“. Dr. Dooley Noted. 30 October 2014.
Gene of Interest 