A team of scientists are now using a gene editing Cas9 system to see how the limb producing genome is lost in snakes. The Cas9 system is editing technology that consists of two “key” molecules that introduce a mutation in DNA. This system basically acts as a pair of scissors that can cut two strands of DNA in a specific part of the genome. After this occurs, you can now start to add or remove DNA bits. This is where it gets confusing; there is an “enhancer sequence” in snake and human genomes that regulate which other sequences function.
These “enhancer sequences” are called ZRS. The ZRS are responsible for the faster production of proteins that develop limbs. After researching how the ZRS functions in snakes, scientists have concluded that the snakes ZRS are not functioning. Since this ZRS is not functioning, it leads to the loss of snakes' so called “legs.” This is a science mystery because scientists do not know why humans ZRS function so well, but snakes do not. This will all be found out in time. It is now just a waiting game. ~ Brandon Smith