These jellyfish are biologically immortal, which means that at any point in their development they can reverse aging.
Nature’s creatures have one constant: they are born, they grow, they reproduce, and they die. It is a mantra that we have learned in school over and over again, and that biologists know perfectly well since it is the behavior of all creatures on Earth or almost all of them. There is a jellyfish that defies this law of nature; it is the immortal jellyfish whose scientific name is Turritopsis dohrnii, and it never seems to age.
Researchers from the University of Oviedo have finally managed to decipher the genome of the immortal jellyfish and with this, they are close to understanding the cause of the strange immortality of the jellyfish. How T. dohrnii has managed to avoid death by aging is a question that has experts amazed and eager to find more answers.
The immortal jellyfish, a small-sized species, inhabits the Mediterranean Sea and the waters of Japan. These creatures begin their lives like other jellyfish species, as tiny, free-swimming larvae (planulae) in the sea. Then they become polyps until they grow large enough to reach sexual maturity, and finally, they can be observed as small jellyfish in the ocean.
But their main characteristic is that they are biologically immortal, which means that at any point in their development they can reverse aging, returning to their polyp stage. The cycle can repeat itself over and over again until eventually, some predator ends the jellyfish’s life.
The genome that defies death
Researchers discovered the key to the biological immortality of the tiny jellyfish; they found that the key is, of course, in the genome. The genes of T. dohrnii are mostly associated “with DNA replication and repair, telomere maintenance, stem cell population renewal, intercellular communication and reduction of the oxidative cellular environment,” explain the authors of the paper.
In other words, the processes that take place naturally in jellyfish are associated with longevity and healthy aging. Before jellyfish reach the advanced age that eventually leads to death, they generate changes in gene expression and reverse aging through gene silencing mediated by the so-called ‘Polycomb’ pathway. That is, they can reverse aging thanks to their specialized cells that manage to dedifferentiate (reverse) and thus acquire the ability to become any other type of cell.
The mechanisms by which the immortal jellyfish defy the law of nature remain to be investigated. However, this research opens a new avenue to understanding how the genome behaves to evade aging.
Story originally published in Spanish in Ecoosfera