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Cells across the body talk to each other about aging

quantamagazine.org

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Re: Cells across the body talk to each other about aging

#61

Post by polishdude20 »

JoshTriplett wrote: post #40
3cats-in-a-coat wrote: post #31

Earlier quoted context omitted.

[flagged]

> Your brain at 90 is mostly useless even if you're not afflicted with a serious condition. You can't learn and adapt You are factually incorrect. You can, in fact, learn and adapt in your 90s. Sometimes (not always) the brain has degraded and can't do so as well , but that's a problem we should work to fix. And there is some evidence to suggest that cause and effect go in both directions there: if you keep learning…

They won't help us change our minds though. The problem with having people in their 90's capable of the same things as people in their 30's is that they'd hold positions of power longer. Old ideas would live on much longer

Re: Cells across the body talk to each other about aging

#63

Post by Kalanos »

LASR wrote: post #3

You know, I've recently wondered quite a bit about aging and how any of it makes sense. What has perplexed me is the notion of honest signals[1] in a world governed by natural selection and the survival of the fittest. Why wouldn't cheating exclusively emerge as the only strategy? Why wouldn't a species evolve a mechanism to survive longer and longer till it completely dominates? Then it dawned on me that the surviva…

because game theory, and we would evolve to recognize cheating

Re: Cells across the body talk to each other about aging

#64

Post by wcoenen »

yarg wrote: post #47
JumpCrisscross wrote: post #41

"As a worm ages, the quality of its eggs or sperm declines — what we refer to as the ticking of a biological clock. The decline is also reflected in the germ cells’ changing ability to transmit signals from the brain’s mitochondria, he suggested. As the worm grows older, its germline transmits the repair signal less effectively, and so its body declines, too. Scientists don’t yet know whether these findings apply to…

> But as the quality of the germ cells declines, there is no evolutionary reason to keep extending life span further; from evolution’s perspective, life exists to reproduce itself. When the individual's survival is the only selection factor, this is true - but it ceases to be the case in social species where reproductively non-viable individuals can still positively influence the reproductive chances of the young. Th…

The survival of the individual is indeed not what natural selection is selecting for.

Otherwise phenomena like eusocial insects with sterile workers would not make sense. What is actually selected for, is genes that somehow promote more copies of themselves. This is the main takeaway from the book "the selfish gene".

However, the example of ants and bees shows that this doesn't exactly promote long lifespan in the sterile workers... Instead, they are mass-produced expendable drones.

Re: Cells across the body talk to each other about aging

#65

Post by Terr_ »

alexschnapp wrote: post #58
Terr_ wrote: post #50

Earlier quoted context omitted.

> There is no more evolutionary pressure on lifespan after you have children since you have successfully passed on the ‘aging’ gene. This assumes, incorrectly, that each generation of children are birthed into a new separate pocket-universe, where absolutely nothing prior generations do next--including suddenly dying--can ever affect their own trajectories. Consider genes Alpha and Beta, where Alpha kills women right…

If your offspring does not survive to reproduce, your genetic lineage disappears, therefore ‘failed’. Others who do not kill their offspring will survive and the species will therefore not exhibit that behavior nor enjoy the benefits of that behavior.

> If your offspring does not survive to reproduce

First you declared genes had no evolutionary pressure on longevity after children existed... but now you're amending it to grand-children existing?

Well, what about great-grandchildren? How many more times must you be forced to move the goalposts before realizing that the logic behind them is simply wrong?

You can't just ignore stuff like kin-selection, which we've known about for over a hundred years already.

Re: Cells across the body talk to each other about aging

#67

Post by mrkstu »

ttoinou wrote: post #60
bhuga wrote: post #52

Earlier quoted context omitted.

> survival of the species is not aligned with the survival of an individual The unit of survival is not the individual or the species, but the gene. Genes maximize their survival by combining via sexual reproduction with other genes over time. Any one combination of genes will be out-competed over time. The reason for honest aging signals is that a gene survives longer by getting out of the way of its offspring's com…

Why would women survive so long after menopause then ?

Happy accident at first, though there are some possibilities around grandparents increasing survival rates of younger children, so that would ultimately feed back into the gene pool.

Re: Cells across the body talk to each other about aging

#68

Post by hwbehrens »

alexschnapp wrote: post #58
Terr_ wrote: post #50

Earlier quoted context omitted.

> There is no more evolutionary pressure on lifespan after you have children since you have successfully passed on the ‘aging’ gene. This assumes, incorrectly, that each generation of children are birthed into a new separate pocket-universe, where absolutely nothing prior generations do next--including suddenly dying--can ever affect their own trajectories. Consider genes Alpha and Beta, where Alpha kills women right…

If your offspring does not survive to reproduce, your genetic lineage disappears, therefore ‘failed’. Others who do not kill their offspring will survive and the species will therefore not exhibit that behavior nor enjoy the benefits of that behavior.

That's precisely the point the parent was trying to make to your GP post, namely that

> "There is no more evolutionary pressure on lifespan after you have children"

is an inaccurate oversimplification.

Re: Cells across the body talk to each other about aging

#70

Post by tarkin2 »

ttoinou wrote: post #60
bhuga wrote: post #52

Earlier quoted context omitted.

> survival of the species is not aligned with the survival of an individual The unit of survival is not the individual or the species, but the gene. Genes maximize their survival by combining via sexual reproduction with other genes over time. Any one combination of genes will be out-competed over time. The reason for honest aging signals is that a gene survives longer by getting out of the way of its offspring's com…

Why would women survive so long after menopause then ?

To help her offspring propogate her genes is one theory I've read, coming from observing post menopausal sharkes
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