The Immortal Jellyfish
The Elusive Secret to Eternal Life
Diving beneath the shimmering waves of the tropical oceans may grant one a chance encounter with one of the most fascinating creatures alive. Though it certainly won’t look like much- a mere plankton no bigger than your pinky nail, spurred on by the whims of the ocean currents - rest assured, this tiny jellyfish contains the secret to genetic immortality.
Upon this instance, “plankton” refers not to microscopic unicellular life, but to small lifeforms (plant or animal) that drift along with ocean currents; either with very minimal or entirely lacking any independent swimming abilities. In the case of our Turritopsis Dohrnii (more lovingly referred to as the “Immortal Jellyfish”), independent abilities as a whole are incredibly limited due to the fact that even a fully grown medusa is but a mere 4.5mm in average length. Additionally, the title of “Immortal” is a misnomer, as these translucent jellies are sadly susceptible to both disease and predation (via tuna, sharks, swordfish, other jellyfish, etc.).
Yet, not all is doom & gloom for these fragile creatures; should they become injured or their generous food supply of fish eggs and brine shrimp dry up, they have a clever little trick up their sleeves- or, tentacles rather; reverting from fully-grown medusa right back to a juvenile polyp.
The immortal jellyfish (Turritopsis dohrnii)
Though this may sound laughably similar to the tale of Benjamin Button, it is very much real- and is a phenomenon entirely unique to the Immortal Jellyfish. Though science does not fully understand the mechanisms which allow this intriguing clump of mesoglea and collagen to live indefinitely, it is believed that trans-differentiation is a vital mechanism. Trans-differentiation is the term describing the process by which a fully-specialised cell switches to become a completely different cell with an entirely different function.
Scientists have developed a somewhat-similar method to this, known as induced-pluripotency. This is the process by which samples of cells are reverted from their specialised state (skin, liver, kidney, blood cells, etc.) back to an unspecialised stem cell. However, this process is costly, imperfect, and can in no way be performed in vivo. Firstly, life as a jellyfish is far simpler; there’s no need for complex systems such as a brain, heart, or gastrointestinal tract. Furthermore, a jellyfish’s genome is approximately 17,000 genes long whereas the human genome ranges from anywhere between 20,000 to 80,000 genes. As a result, a jellyfish has far fewer proteins to worry about balancing when swapping from one cell type to another- whereas we humans contain a vast array of complex intermingling mechanisms which can be incredibly difficult to both dismantle and initiate.
Yet, if it is immortality for humanity one seeks, then rest assured, it can be achieved- but in a far less desirable way. Cancer is, sadly, the closest we will come to functional immortality until we crack the jellyfish’s secret. Immortality in this case is due to a failure to control, rather than a means of survival.
“The true immortal mechanism of Turritopsis Dohrnii eludes our understanding. Though some day, with a bit of luck, we may crack the code to their cellular-reset mechanism”
There are numerous contributing factors which lead to the development of immortal cells, the majority of which fall under the typical results of normal aging. As a cell grows older, the protective string of non-coding regions on the ends of the genome- telomeres -become worn down due to the imperfections in replication; as every time a copy of a genome is made, a little bit of code is lost from the ends. Usually, this is fine- but becomes quickly problematic when the telomeres are worn away and the continual loss begins to affect coding-regions of the genome.
However, alongside the loss of telomeres with age, the cell will also have to deal with the accumulation of random (somatic) mutations to the genetic code. A majority of these mutations will be banal thanks to the copious amount of non-coding regions within our genome. However, upon the rare occasion that an important gene is mutated- particularly those pertinent to cell proliferation –then the anti-tumour proteins are kicked into high gear.
Usually, from this point, the mutation is either fixed or the cell is killed (via apoptosis). Yet, when mutations occur to the anti-tumour proteins themselves then this could open the gates for tumour formation. Additionally, should a mutation occur to switch on telomerase- an enzyme used to regenerate the lengths of the telomeres, meant only for use in embryo cells –then the cell will effectively live on infinitely, with the code a genetic free-for-all for mutations.
But, it is upon this point that we return to our familiar friend, the Immortal Jellyfish. Cancer amongst aquatic sea life is exceptionally rare. In 2019, a study conducted upon extracts from aquatic sea life- including jellyfish -found a great presence of anti-metastasising compounds within their bodies, which act to prevent the formation and spreading of cancerous cells through tissue. This in essence means that a tumour within these jellies is far less of a concern than it would be to a human body.
However, much to the dismay of science, the true immortal mechanism of Turritopsis Dohrnii eludes our understanding. Though some day, with a bit of luck, we may crack the code to their cellular-reset mechanism, allowing it to be isolated and repurposed to aid humanity.
And so that is how the story goes; the immortal jellyfish is helping to cure humanity of their immortal cells!
