Hundred million years ago the snake came into existence, by slowly going from an animal with limbs to the slithering creature as we know it today. You might think that evolution worked the other way around, but if you take an x-ray of a phyton or a boa constrictor you can still see rudimentary legs in their bodies. Scientist are now trying to reverse evolution by inserting the mutated leg snake DNA into the DNA of a mouse. The test result is striking: a mouse without limbs.
The research was done by a Swiss University and Californian team of researchers, using the DNA editing technique called CRISPR. The scientists replaced part of the mouse DNA, a small sequence known as ZRS - the equivalent sequence from a snake. This change stopped the mouse from developing any limbs. They repeated the test with ZRS of other species, like fish and even humans, giving the mouse perfect developed legs. Because of this difference the researchers were able to prove that this specific piece of snake DNA got mutated. To wrap up the research snake ZRS and ZRS of other species got compared, concluding that only 17 codes of the DNA inside ZRS got changed; a small mutation but big enough to ‘serpentize’ a mouse.
When we speak about genetic modification, we are temped to think only about future applications, like the creation of the micro pigs and CRISPRy cabbage. Whereas this research shows how genetic modification can also be used to reconstruct the evolutionary changes of the past, by turning back the clock to hundred millions years ago.