The ancestors of modern-day snakes may have walked on their legs rather than slithering on the ground. Independent researchers concluded in two separate studies that a mutation in the DNA of some snakes switched off the gene responsible for forming limbs.
This gene, known as the "Sonic hedgehog" gene, controls limb development. Scientists tracked the mutation back to the docking site for proteins, known as an enhancer. For whatever reason 100 million years ago that enhancer switched off, causing the snakes to no longer grow limbs.
Some present day snakes even have the remnants of this evolutionary change within them. Certain pythons and boas still have tiny leg bones in their skeletal structure today!
To learn more about this discovery and the snakes we know today, click here!