Zebrafish with visible limbs. Image credit: Freitas et al., Developmental Cell

Land animals evolved from sea animals, as the fossil record shows and evolution tells us. From ocean life to amphibians and then developing legs to enable life to harness the vegetation that had already colonized the land.

It was a major event in the history of all life on Earth and took place about 400 million years ago.

Now, a team of researchers has managed to repeat this process. According to a study recently published in the Cell Press journal Developmental Cell. Providing new evidence that the development of hands and feet occurred through DNA mutation.

The team managed to repeat this evolutionary process through manually manipulating genes in zebrafish. Adding the “Hoxd13” gene into an embryo of a zebrafish. This made it develop the limbs that appear on the featured image. Hoxd13 is a gene that is known to play an important role in embryonic development of limbs.

Dr. Fernando Casares said; “We found that in the zebrafish, the mouse Hoxd13 control element was capable of driving gene expression in the distal fin rudiment. This result indicates that molecular machinery capable of activating this control element was also present in the last common ancestor of finned and legged animals and is proven by its remnants in zebrafish,”.

Mutations in Hoxd13 are known to make fingers and toes grow differently and deformed in humans.