24 November 2009
Turritopsis nutricula is a hydrozoan with a life cycle in which it reverts to the polyp stage after becoming sexually mature. It is the only known case of a metazoan capable of reverting completely to a sexually immature, colonial stage after having reached sexual maturity as a solitary stage. It does this through the cell development process of transdifferentiation. Theoretically, this cycle can repeat indefinitely, rendering it biologically immortal until its nerve center is removed from the rest of the body.