The Reverse Life Cycle of Turritopsis dohrnii

Under certain stressful conditions—such as physical injury, starvation, or an adverse environment—the jellyfish *Turritopsis dohrnii* can reverse from the adult medusa stage to the polyp stage. An intermediate cyst-like stage usually forms; cells change state and reorganize, including through transdifferentiation. The developmental cycle can then begin again, which is why the species is nicknamed the “immortal jellyfish.” This does not mean every individual lives forever: in nature it can die from predators, disease, or other causes, and the molecular details of the mechanism are still being studied. The species name was garbled in the source list; the correct name is *Turritopsis dohrnii*.