A species of “immortal” jellyfish can age backward. The Turritopsis dohrnii jelly fish can revert back to its juvenile stage from its adult stage, doing it several times over, making it the only known officially immortal creature. When starvation, physical damage or other crises arise, instead of sure death, Turritopsis turns itself into a bloblike cyst, which then develops into a polyp colony (the first stage in jellyfish life) which can spawn hundreds of genetically identical jellyfish – near perfect copies of the original adult.
Fully grown, Turritopsis dohrnii is only about 4.5 mm (0.18 inches) across, smaller than a pinky nail. A bright-red stomach is visible in the middle of its transparent bell, and the edges are lined with up to 90 white tentacles. These tiny, transparent creatures have an extraordinary survival skill, though. In response to physical damage or even starvation, they take a leap back in their development process, transforming back into a polyp. In a process that looks remarkably like immortality, the born-again polyp colony eventually buds and releases medusae that are genetically identical to the injured adult. In fact, since this phenomenon was first observed in the 1990s, the species has come to be called “the immortal jellyfish.”
The cellular mechanism behind it—a rare process known as transdifferentiation—is of particular interest to scientists for its potential applications in medicine. By undergoing transdifferentiation, an adult cell, one that is specialized for a particular tissue, can become an entirely different type of specialized cell. It’s an efficient way of cell recycling and an important area of study in stem cell research that could help scientists replace cells that have been damaged by disease.
As for Turritopsis dohrnii, this jelly is not only an extraordinary survivor. It’s also an increasingly aggressive invader. Marine species have long been known to hitch rides around the world in the ballasts of ships. Researchers have recently identified the immortal jellyfish as an “excellent hitchhiker,” particularly well-suited to surviving long trips on cargo ships.
Credit : AMNH
Picture Credit : Google
