Biological Immortality and the Probability of it in Humans

[digitalSorrow]

A common theme in science fiction media is the idea of immortality - the inability to die. But, it is not as fantastical as it may seem. Even modern scientists predict that immortality will be possible for human within the next 30 years. Though it wouldn't be the first time something has been classified as "immortal."

The process of aging is called senescence, where mental ability declines, physical strength deteriorates, and the immune system weakens, among many other effects. There is cellular senescence and organismal senescence, and cellular senescence is believe to precede organismal senescence.

In cellular senescence, diploid cells (the ones that make up most of the body) cease to split and divide. Though they no longer make more cells, they continue to function normally otherwise. In a lab condition, the average cell can split 50 times before senescence begins to set in. This is know as "replicative senescence," or the Hayflick Limit. When a part of a chromosome called Telomere deteriorates, that is when the Hayflick Limit is reached. What Telomere does is protect the chromosomes from becoming damaged or fusing with other chromosomes. Each time a chromosome is replicated, the Telomere gets progressively shorter and shorter until it can no longer protect the chromosome. Testing on lab rats on lengthening the Telomere have been successful, though only temporary. Some scientists say that is likely possible to permanently lengthen the Telomere in humans.

Organismal senescence can't be described as a single event, as it occurs throughout our entire lifespans. There is also the Gompertz–Makeham law of mortality, which states that mortality rate increases with age. Simply put, death is more likely the older an organism is. Organismal senescence is different for each kind of organism, and each individual of that kind. That's why a hamster is considered elderly at four years old and a parrot at 70. There are some animals, like certain types of fish, have a very long lifespan and age slowly. This is called Negligible Senescence. There are even some species that exhibit a kind of "negative" senescence, where the chance of death gets lower with age rather than higher. If the cause and long-term effects of this behavior can be mapped out, it may be possible to graft it into humans to create immortality.

But that is not the only option for immortality. There is a species of rodent called the naked mole rat, who has long been under study for the exceptional lifespan and cancer resistance. The naked mole rat may look ugly or even scary to some, but it may hold the secret to eternally increasing human lifespans. The rats' longevity is due to one thing - their overdeveloped ribosomes. Ribosomes are the chemicals responsible for turning DNA sequences into proteins, which then make things happen in the body. Most organisms have ribosomes made of two pieces of RNA, an amino acid similar to DNA, but naked mole rats have three pieces. When compared to other rodents with two piece ribosomes, the mole rats' RNA made up to 40% less errors reading the DNA sequences and transcribing them into proteins. The reason they evolved this structure in the first place is due to their habitat. They live almost entirely underground, in large, social colonies. If a normal rodent (or any other prey animal for that matter) were to develop these traits, they would rarely ever come into play, as the animal would likely die from disease or predation long before they would from senescence. Because the mole rats live and evolved as a subterranean species, they weren't commonly hunted or introduced to diseases, so they could evolve more focused on lifespan than basic survival. If science continues advancing at the rate it has in the past decades, within the foreseeable future, it may be possible through DNA genome sequencing and bio-engineering to bring this amazing ability to humans.

And yet another natural wonder has a unique immortal trait to call its own. A species of jellyfish called Turritopsis dohrnii, more commonly known as the immortal jellyfish, has an emergency self defense technique that makes it a true marvel of the aquatic world. If injured or ill, this jellyfish will revert to its earliest stage of life, the polyp. It is capable of doing this no matter its age, from newborn to elder. Though recreated in lab conditions, this behavior has never been observed in the wild, likely due to the speed of the transformation and/or lack of field ops present to see it. The process begins with the body and tentacles retracting and shrinking, then the forming of a perisarc sheet and stolons, and finally feeding polyps, which proceed to grow even more stolons and polyps. As of now, this makes Turritopsis dohrnii the only "immortal" creature on Earth, and much research is being done on how exactly is do this and how to replicate it in other animals.

It's not hard to see that humans aren't the only ones interested in gaining immortality. Even nature and evolution experiment with it from time to time! And even though it remains science fiction for the time being, immortal humans may be in a not-so-distant future after all.

[Delta1212]

Immortality, like cold fusion, is always only 20 years away.

[XingHa]

30 yrs? Im still alive that time. I hope i could've a glimpse of a real thing someday.

[Phi for All]

It's not hard to see that humans aren't the only ones interested in gaining immortality. Even nature and evolution experiment with it from time to time! And even though it remains science fiction for the time being, immortal humans may be in a not-so-distant future after all.

 

I don't think the jellyfish is interested in gaining immortality. Survival is different, and many species have extreme methods for extreme situations.

 

Extending life past normal expectancies is something we've always been interested in. We actually could use more time between birth and adulthood presently, since our knowledge is accumulating at a very rapid pace. What young humans need to know to survive is expanding, and we need longer lives just to keep the same rate of effectiveness.