From ancient myths to science fiction literature, our fascination with eternal youth is well documented.
But there are creatures that seem to have cracked the code to stop, or even reverse, aging, and they are very real.
They are, or we believe they may be, biologically immortal. This means that unless killed by a predator, disease, or drastic changes in their environment, they can live indefinitely.
Scientists are trying to unlock the secrets of these mysterious organisms to see if they can help us control our own aging process.
Here are three of these amazing creatures:
The ability of these worms to regenerate if split in two has been known since the end of the 19th century, but these animals went viral in 2012, when the University of Nottingham published a study on their potential immortality.
The planaria is a type of flatworm found throughout the world and has a unlimited ability to regenerate stem cells.
There are two types of planaria: some reproduce sexually and others asexually by dividing in two.
Scientists at the University of Nottingham studied both types and found that asexuals may be able to “rejuvenate” their DNA.
At some point in our lives, our DNA, like that of most animals, reaches its limit in cell division and our body begins to deteriorate.
Planarians, on the other hand, have higher amounts of an enzyme that protects their cells from aging, and can replenish these stores when they reproduce, leading scientists to believe they may be immortal.
to the hydra
This alien-looking creature is a freshwater invertebrate with a tubular body and tentacles around its mouth.
It uses these tentacles to sting its prey, which are worms, small crustaceans, and other invertebrates.
Hydras were one of the first organisms examined by the Dutch scientist Antonie van Leeuwenhoek, who built a microscope with a single spherical lens with significant magnification in order to see these creatures.
Shortly thereafter, Swiss scientist Abraham Trembley’s observations of hydras and their “regenerative superpowers” ushered in a new era in biology.
Like the planarians, the hydras are also capable of regenerating parts of their body. The key to understanding their potential immortality lies in their stem cells, which can self-renew indefinitely.
In fact, the entire body of a hydra appears to be made up of self-renewing stem cells.
Scientists who observed groups of hydras for years could not detect any signs of aging in them.
In 2018, researchers at the University of California, Davis (UC Davis) hypothesized that hydras might be immortal thanks to their ability to control something called transposon genesalso known as “jumping genes”.
These are genes that can “jump” from one part of the genome to another, giving rise to mutations.
When we are young, our body is able to control these genes, but as we get older we have a hard time keeping them under control.
Hydras, on the other hand, may be able to repress these genes forever.
Turritophis dohrnii: the immortal jellyfish
The so-called immortal jellyfish -or, to use its scientific name, Turritopsis dohrnii– lives in marine waters.
First discovered in the 1880s in the Mediterranean Sea, it can now be found in many other places due to ballast water discharged from ships.
It is tiny and loves to eat plankton, fish eggs and small mollusks.
The surprising thing about this type of jellyfish is that it can restart its life cycle. When the jellyfish is stressed, it transforms at an earlier life stage.
This is sometimes compared to a frog turning back into a tadpole or a butterfly turning into a caterpillar, and is due to a process called transdifferentiation.
Transdifferentiation occurs when a fully formed, specialized adult cell changes into another type of adult cell. This process remains a mystery to scientists.
When the jellyfish returns to its previous life stage as a polyp, it also creates more organisms with the same genetic code, so basically by rejuvenating it also clones itself.
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