Implications of cellular immortality

a reply to: chr0naut

Also, in comparison to mortal cells, the populations of immortal cells would bloom far more rapidly, causing a resource contention which would swamp mortal cells. This 'fight for food' would negatively affect the immortal cells too, but it wouldn't necessarily cause their extinction as not all cells would starve.

That isn't necessarily correct. Both mortal and immortal cells are resource dependent. Mortal cells have more resources to draw from whereas immortal cells have limited resources.

The "immortal" cells that you have been referring to have a defective telomere gene. They can reproduce ad infinitum in their media. They can even "evolve" give some mutations and be assigned a new species similar to HeLa cells. But they are not immortal in the sense that they can live forever in any environment. There's a difference. There are limitations. Therefore, they are not immortal in the sense you are describing them.

a reply to: chr0naut

Yes, immortal cells would continue to replicate, but again, I'm talking about genetic diversity and passing down genes, which is pretty important to evolution. It's one thing to have replicating cells with mutations to avoid apoptosis in a multi cellular organism, it's much different to have a completely immortal organism with all of their cells and to pass that trait down. For that to happen, the immortal cells would need to affect the gametes that make the zygote, without killing the offspring before puberty. For the cells themselves, there will always be more genetic diversity with cell death, than without it. I don't see any reason why the immortal cells would replicate faster. They would still be competing with other cells, and there is always more diversity with death.

"Biological immortality is a state in which the rate of mortality from senescence is stable or decreasing, thus decoupling it from chronological age. Various unicellular and multicellular species, including some vertebrates, achieve this state either throughout their existence or after living long enough. A biologically immortal living being can still die from means other than senescence, such as through injury or disease.
This definition of immortality has been challenged in the Handbook of the Biology of Aging,[1] because the increase in rate of mortality as a function of chronological age may be negligible at extremely old ages, an idea referred to as the late-life mortality plateau. The rate of mortality may cease to increase in old age, but in most cases that rate is typically very high.[2] As a hypothetical example, there is only a 50% chance of a human surviving another year at age 110 or greater.
The term is also used by biologists to describe cells that are not subject to the Hayflick limit on how many times they can divide."

Wikipedia

Tartigrades were thought to be "immortal". Turns out there are several species of tartigrades with different characteristics of "immortality".

You need to state your definition of immortality because it isn't consistent with what we know.

What is interesting is that all our cells are replaced approximately every 7 years, the aging process is different with different people, but we do know that after that cycle has repeated itself at least 4 times, we see and begin to feel the effects of new cells that come out genetically aged and weaker, the big question is why?

In theory brand new cells should be just as good as the last one in perpetuity, but they aren't, in fact they get progressively worse, why is that a 100 old cells are so degraded compared to 21 year ?

Is there a genetic kill switch biological science has yet to understand ?

What triggered it ? Can it be fixed ?
If it could, theoretically we would live forever.

And then there is this too....

While death is considered a natural part of life, there is no reason why we should die, aside from the fact that at a certain point in one’s life, in the 20s, the regeneration of cells is outpaced by the death of cells, leading us to ageing.

a reply to: Blue_Jay33

Apoptosis (programmed cell death) is a known thing. When it screws up, then yeah it is a problem, its called Cancer. I am not sure "living forever" is something you would want to do that way.