Turritopsis Dohrnii: This "Immortal Jellyfish" Can Age In Reverse And Possibly Live Forever

The quest for immortality has been a timeless human obsession. Humans have explored every possible avenue, from the mystical realms of religion to the scientific frontiers of cryogenics, and even the mythical fountain of youth. But, as it turns out, the secret to cheating death might have been hiding in plain sight - or rather, floating in the ocean. Meet the Turritopsis dohrnii, also known as the "immortal jellyfish", which has a remarkable ability to reverse its ageing process and avoid death.

Under normal conditions, the life cycle of the immortal jellyfish is similar to that of other jellyfish. It begins as a larva, develops into a polyp (a small, stationary form that looks a bit like a tiny anemone), and then matures into the adult medusa. However, when faced with environmental stress or physical damage, this jellyfish can revert to an earlier stage of its life cycle, transforming its adult cells back into a polyp stage (youth form), according to Natural History Museum.

This transformation process is called "transdifferentiation" and allows the jellyfish to start its life cycle over again. Through this process, the jellyfish's specialized cells transform into more generalised, unspecialized cells which can then regenerate into new types of cells and rebuild the body back to its youthful, polyp form. Once the jellyfish has regressed into a polyp, it essentially restarts its life cycle. It can then grow into an adult medusa all over again, avoiding death by old age

In theory, this cycle of reverting and re-growing can continue indefinitely, allowing the jellyfish to "cheat" biological ageing. 

The creature was first described by scientists in 1883, but it wasn't until a century later that experts accidentally discovered its eternal life cycle while keeping it in captivity. Originally discovered in the Mediterranean Sea and found in oceans worldwide, this jellyfish is small, typically around 4-5 millimetres in diameter, roughly the size of a pinky nail. 

While theoretically immortal, Turritopsis dohrnii is far from indestructible. In the wild, it faces the same threats as other marine creatures, including predation, disease, and environmental hazards. Though it can biologically "start over" indefinitely, many die before they can use this ability to extend their lifespan dramatically. 

Nevertheless, this phenomenon has left scientists fascinated and eager to unravel the secrets of its immortality. Scientists are investigating whether understanding the jellyfish's molecular mechanisms could lead to advances in anti-aging treatments, cancer research, and regenerative medicine. For example, if scientists can learn how to safely "reprogram" human cells, it might open pathways to therapies for repairing damaged tissues or even slowing down ageing.