The cellular differentiation is a biological process existing in nature from the jellyfishes (that appeared in the ediacaric period, 620 million years ago), in embryofit plants (that appeared 450 million years ago, in the siluric period) and is present in all animal and superior plants.

The cellular differentiation is a mechanism, whereby a non-differentiated cell ( fertilized egg) takes cytological modifications to get different kinds of cells. Although different types of cells have the same gens than the original cell, its expression is inhibited, by own genetic mechanisms and the partial reading of the genetic information makes it a specialized cell.

Almost all cnidaries (jellyfishes) have a biological cycle of 9 steps: gamete, fertilized egg, planula larva, escifisatome polyp, gemmed polyp, strobiled polyp, ephyra larva, young jellyfish and adult, that finishing the reproduction, dead. In each one of the 9 phases, it takes place a cellular differentiation, so the new tissues don’t have the option to go back and finally dead.

However, there is an exception of high interest to study the processes of cellular differentiation and the possibility of reversion (refund of something to the previous status). It is Turritopsis nutricola.

Turritopsis nutricola is similar to cnidary, belonging to the Oceanidae family with a vital cycle that reverts to polyp alter sexual maturation. Is the only known case of a pluricellular organism ( so with differenced tissues) , capable to go to a previous status of immaturity after getting sexual maturity, through a trans differentiation cellular process. Its is from Caribbean, measures 5 cm, has an inner cavity , almost 90 tentacles and its vital cycle is repeated indefinitely so it never dies because of its cells aging.