Snakes evolved to get rid of their limbs or at least that’s what we though. Snakes in reality developed an on-off switch for the protein that causes the development of limbs. Since the proteins are an on and off switch, snakes don’t need to evolve to grow legs. Some snakes already have limbs like boa constrictors and pythons. The gene for limbs on boas and pythons is switched on during their development and that’s how they grow small claws. In other reptiles the protein drives limb development all the way to the animal’s toes.
The sonic hedgehog protein comes from a gene called “SSH”.2 This protein is responsible for shaping eyes, limbs, and other parts of the body. This protein has been found in snakes suggesting that snakes have the potential to grow limbs. “It is seen in pythons that when the protein is active, male pythons grow a talon-like appendage they use during mating.”1 The sonic hedgehog protein functions in snakes like a light switch and it can be on or off. Most of the time the switch remains off but snakes still have the potential for that switch to turn on.
Snakes and legless lizards are two different animals. “Functional limblessness has evolved independently a dozen times in squamate reptiles.”3 The three legless reptiles are lizards, snakes, and worm lizards. Snakes have been the most successful with being limbless. “Snakes have taken
advantage of almost every habitat you can think of, trees, the ocean, and even underground.”3 There are a few key differences to legless lizards and snakes. “Legless lizards have an external ear. This is something that snakes lack. They also do not have a hinged jaw like a snake and are usually limited to eating things that are smaller than their heads. Snakes are usually longer. Some legless lizards sport vestigial legs, and snakes lack eye lidswhile legless lizards have eyelids. There are a few exceptions to the rules though there are types of legless lizards with hinged jaws and with no eye lids. There are as many differences as there are similarities in the way that they move, breed and lay eggs.”3
So snakes can pop up and grow feet one day and its possible for lizards to not have legs at all. There are key differences between snakes and legless lizards and the protein at work that keeps them being limbless is named after one of our beloved cartoon characters.
1.Chambers, Delaney. "Snakes Evolved Out of Their Legs - But They Still Have the ..."National Geographic. National Geographic, 23 Oct. 2016. Web. 24 Oct. 2016.Works Cited
2.NA. "SHH Gene." Genetics Home Reference. U.S. National Library of Medicine, 18 Oct. 2016. Web. 24 Oct. 2016.
3.Wall, Mike. "Are Legless Lizards Snakes? - Live Science." Live Science. Purch, 30 Oct. 2013. Web. 24 Oct. 2016.
