There is a species of jellyfish that never dies!

Have you ever heard of a creature that seems to defy the laws of aging and mortality? Meet Turritopsis dohrnii, a tiny jellyfish species that has earned the nickname “the immortal jellyfish” due to its extraordinary ability.

Discovered in the Mediterranean Sea in the 1880s, Turritopsis dohrnii has captured the fascination of scientists and nature enthusiasts alike. This remarkable jellyfish, featured in the exhibition “Life at the Limits: Stories of Amazing Species,” possesses a unique survival skill that sets it apart from other marine organisms.

Starting its life as a larva called a planula, Turritopsis dohrnii undergoes a fascinating developmental journey. From a fertilised egg, a planula emerges and swims initially, later settling on the sea floor to grow into a cylindrical colony of polyps. These polyps eventually give rise to genetically identical medusae — the familiar jellyfish we recognise.

What makes this jellyfish truly exceptional is its ability to hit the reset button on its life cycle. In response to threats like physical damage or starvation, these jellyfish undergo a process known as trans-differentiation. Essentially, they revert to their polyp stage, a transformation that appears remarkably like immortality. The born-again polyp colony then produces medusae that are genetically identical to the injured adult, leading to the species being dubbed “the immortal jellyfish.”

Beyond its intriguing survival mechanism, the species has caught the attention of scientists for another reason — its cellular process of trans-differentiation. This rare ability allows adult cells, specialised for specific tissues, to transform into entirely different specialised cells. This phenomenon holds promise for applications in medicine and is a focal point of study in stem cell research, potentially aiding in the replacement of damaged cells due to disease.

However, the immortality comes with a twist. Not only is it an extraordinary survivour, but it’s also proving to be an increasingly aggressive invader. Identified as an “excellent hitchhiker,” these jellyfish are adept at surviving long journeys on cargo ships, spreading across the world’s oceans.

In a fascinating study, researchers discovered genetically identical Turritopsis dohrnii individuals distributed globally, prompting an intriguing question about the nature of mortality. If all cells of an organism can be replaced, is it still the same individual? While the answer remains a topic of debate, the genes remain constant, making this tiny, transparent jellyfish a true marvel in the world of marine biology.