Georgia – Snakes don’t have legs or arms, although they do have the ability in their DNA to develop them, a new study suggests. The discovery was made at the University of Georgia.

If snakes don’t grow limbs, what’s the point of having this genetic information? Researchers found that the gene is crucial for developing the snake’s phalluses while they are on the embryonic stage. Eventually, this phallic structure becomes a penis or a clitoris, according to the study published in the journal Developmental Cell.

A new study revealed that the same genetic snippets that control the outgrowth of limbs during embryonic development in mammals are crucial to the development of the phallus in both mammals and reptiles, including legless snakes. Credit: Live Science

These genes that normally should do the work of growing limbs are also used for growing phalluses. There are enhancers on the DNA that control the expression of the gene in these structures and were found both on limbs development of other lizards and also in the phallic structures of the snake.

Doug Menke, lead author of the study, said that, “We’ve really been thinking of these as limb enhancers, but more broadly, these genetic components are actually also participating in development and driving gene expression in other body tissues,” according to Tech Science.

Scientists say that the process behind the genes and how they work is very complex: “Does each gene have a different enhancer for each place and time in development, or are some enhancers read again and again?” asks Kim Cooper, a biologist from UC San, specialist in the subject.

These genetic segments were found by the researchers primarily through studies in mice, looking for a better way to explain how the limb enhancers were involved in the evolution of other types of limbs. They also examined anole lizards (limbed reptiles) and found the same enhancers.

“There have been many millions of snake generations since they evolved a legless body, and we would generally expect the DNA associated with limb development to fade away or mutate to do another job, but that doesn’t seem to have happened,” Menke added.

Researchers say that mice and other lizards used the genetic information to develop extremities, as the snake used the enhancer in their genitalia. They concluded that the proper name for this DNA regions are “appendage enhancers”, and that snakes retained this information with a purpose.

They studied the genomes of three snake species: boa constrictor, Burmese python, and the king cobra. Since a couple of years ago the genome sequences of the snakes have been available, more research like this is in order to be made. Researchers have a long way ahead investigating the role of DNA enhancers in the particular development of different genital shapes in nature.

Source: Discovery News