The age-defying secrets of the 'Immortal jellyfish'

The secret to immortality and the key to stopping ageing has haunted humans for nearly all of our existence.

Spanish scientists may be one step closer to understanding how to halt our inevitable demise thanks to the humble jellyfish.

Photo by: Dr. Karen J. Osborn, Wikimedia Commons

A group of Spanish scientists published a study last week explaining how they unlocked the immortal jellyfish's genetic code. This remarkable creature can revert back to a younger state after reaching maturity.

Maria Pascual-Torner, Victor Quesada, and their colleagues from the University of Oviedo published their study on the subject in the Proceedings of the National Academy of Sciences.

The group successfully mapped the genetic sequence of the Turritopsis dohrnii, the only jellyfish known to revert back to a larva after having sexually reproduced.

Photo by: Bachware, Wikimedia Commons

At first glance, the Turritopsis dohrnii jellyfish seems similar to other kinds of jellyfish as it also has a two-part life cycle.

All jellyfish begin their lives as larvae drifting along until they attach to the seafloor and turn into sprout-like polyps.

Photo: Zina Deretsky, National Science Foundation, Wikimedia Commons

Slowly, these little bottom-dwellers clone themselves into sedentary, stacked colonies that eventually break off into the free-swimming jellyfish many of us fear at the beach.

For many jellyfish, once they break off by themselves, this is the beginning of the end for them.

The scientists from the University of Oviedo point out that while several kinds of jellyfish can reverse aging to a certain degree back to the larval stage, the majority lose this capability once they are sexually mature.

Turritopsis dohrnii is unique in this aspect, thus earning it the nickname of the "immortal jellyfish."

If the environment gets too harsh or Turritopsis dohrnii gets injured, it can melt its body into an amorphous cyst, reattach to the seafloor once again, and turn back into a polyp.

Amazingly, as the magazine New Scientist points out, Turritopsis dohrnii "can restart the cycle indefinitely to skirt death by old age."

The Spanish scientists studied how Turritopsis dohrnii differed from its close cousin Turritopsis rubra (pictured) by comparing their genetic sequences.

Photo by: Tony Wills, Wikimedia Commons

The study's authors found that Turritopsis dohrnii is better at copying and repairing its DNA than other jellyfish due to variations in its genome.
Photo: screenshot, YouTube, Animal Educate

The scientists also discovered that Turritopsis dohrnii had double the amount of genes associated with DNA repair and protection.

Photo: warren-umoh--qycBqByWIY-unsplash

In addition, Turritopsis dohrnii is also superior at preserving its telomeres, the ends of its chromosomes, which in humans and other species tend to shorten with age.

Photo: screenshot YouTube, Real Science

During their study, scientists determined exactly how Turritopsis dohrnii managed to revert into polyp form by identifying the active genes during the reverse metamorphosis.

They found that this particular jellyfish "turned off" or silenced developmental genes so as to be able to revert back to its more primitive state while at the same time re-activating developing cells.

The head of the study Maria Pascual-Torner says that the combination of these two genetic alterations protects the immortal jellyfish from the passage of time.

Photo: screenshot YouTube, Real Science

While this discovery is fascinating, scientists are still a long way from finding the key or magic elixir that will stop us from aging.

However, as the authors of this scientific paper point out, the identification of these genes could be helpful in medicine for humans.

Perhaps they may help in the development of regenerative medicine or help doctors better understand age-related diseases such as neurodegeneration.

Naturally, as Maria Pascual-Torner says, "The next step is to explore these gene variants in mice or in humans."