Before the zebrafish’s fins regenerate, the wound is closed with multiple layers of tissue. The cells beneath the stump then lose their identity and form what is called blastema.
Researchers found that the fish uses a special genetic trick that allows the retinoic acid to control the formation of blastema, which means the animal is able to produce a store of cells that can rebuild the fin.
Retinoic acid is produced by animals, including humans, from vitamin A and can activate the necessary genes for regeneration.
It has been shown that pregnant women who do not take enough vitamin A in their diet can have underdeveloped foetuses.