These papers simply present the accumulated damage hypothesis with new window dressing. They do not account for the known facts.
The article about these papers does not present a mechanism that would account for the Hayflick Limit.
Nor does it explain why dogs, for example, age and die more quickly than humans. If there is a mechanism of epigenetic drift that would explain this, I do not see it in the article.
The obvious answer to senescence is that we are programmed to do it. Cells die when they are supposed to die; if they don't, we have a problem.
Likewise, mammals die when they are supposed to. It takes less time to train a puppy to survive on its own than it takes to train a human. Hence, dogs are optimized to age and die more quickly. It's better for the species.
If we were not programmed to get old and die, evolution through natural selection would not work. We would never adapt to changing environments and our species would fail.
Aging and death is not an accident or a deterioration from damage or a drift away from a correct instruction set. It is an absolute hard necessity, without which we would all be long gone.
Stop wasting your time on nonsense articles like this and seek the mechanism that provides us as a species with the flexibility to adapt. Until we see aging and death as an core mechanism, we're going to be looking in the wrong place.
A lot of fallacies and assumptions in this comment.
First of all there is nothing in biology or evolution where the "good of the species" has any kind of bearing on natural selection. This is the group selection hypothesis that has numerous counterexamples. If anything selection happens at the gene level over the long run.
There is also no clear reason we know of yet as to why a human being couldn't simply reach sexual maturity and hunting age faster. In fact, there might be at least some evidence other hominids did reach sexual maturity faster. It is not fully understood why humans take so long, but in animal kingdom terms we take roughly as long as the Asian Elephant to reach reproductive maturity. Almost certainly a tradeoff for achieving greater brain development and intelligence, but this could also simply be the consequences of being intelligent (e.g. it's easier to evolve for bigger skulls once ape intelligence surpasses a threshold where the apes are capable of committing to greater early childcare such that natural selection in absence of intelligence is weakened).
If dogs were optimized to age and die more quickly for the betterment of the canine species, then you could make the same argument for humanity. That's simply not what's going on. Human ancestors in the past who traded generation time for greater intelligence, likely selfishly outcompeted those who did not, and those other hominids either died off or represent a much smaller allelic contribution to the extant human gene pool.
For evolutionary biologists, aging and death similarly likely represent evolutionary tradeoffs. After reaching sexual maturity, as the probability of producing more offspring declines, so too does natural selection as alluded to in the article. Women are born with their entire compliment of ova and the rate of errors increases dramatically as they get older. Men have similar but more subtle issues with sperm generation. These error rate absolutely can be driven by mechanical stresses over time, and I would imagine could be driving much of the selective pressure that puts a cap on human longevity in the long run.
> Do we currently have the ability to do targeted methylation or de methylation at sites in cells?
No, and you probably wouldn’t want it if you could. You don’t know what mutations are lurking in the genes that have been switched off or the consequences of turning them back on.
I’ve thought about this a bit, and what resetting the methylation map really requires, in addition to actually resetting that map, is resetting your genome to a known good state.
That’s pretty radical, but to selectively switch methylation on and off with precision you’re already talking about science beyond anything we have, featuring custom engineered constellations of proteins that unwrap your chromatin from around histones and then walk along it changing methylation state, then pack everything back.
And doing it for each cell type, without applying the wrong map anywhere.
And knowing what all the cell types and their correct methylation maps actually are.
And assuming that methylation isn’t used anywhere, for example in the brain, in a way we don’t expect.
And methylation isn’t the only kind of epigenetic modification.
So, if we’ve solved all of those problems, rebuilding your DNA to a clean, mutation free state at the same time should be a breeze.
We really do need AI for this if any of it is going to be remotely feasible.
Cancer is the price we pay for complex multicellular life. It’s not a failsafe, it’s the failure of all failsafes to regulate cellular growth within an organism.
> We really do need AI for this if any of it is going to be remotely feasible.
Would you give your life into the hands of AI skynet slop?
I understand your rationale, of course, but I for one don't want big fat mega-corporations dictate over our life here. Naturally, all of this hinges whether AI can even solve this problem. I assume it can, but I doubt it can do so initially - and the legal implications are still enormous. I really am not ready to turn my hands to claude's gene therapy slop.
It makes me concerned on many levels, but perhaps also more hopeful. It was inevitable that we would eventually develop AI if we didn't go extinct first, and while there are myriad risks and challenges, there is also massive potential, which seems like it could be a source of hope. As the earlier comment said, the only way that therapies like these could be remotely viable on any kind of near to medium timeframe would be with AI assistance, and this is just one example.
What about Xanax or medication. Hypothetically ignoring the ill effects of the drugs themselves will chemical stress relief have the same anti-aging benefits?
I just don't understand. Wouldn't we have evolved in an environment with constant stress? Constant fear of disease, starvation, predation, attacks by neighboring tribes? Why would our body's natural response to our environment be to immediately grenade itself.
The idea that pre-agricultural societies are subjected to constant stress reflects modern biases somewhat. I remember years ago I saw a talk from Spencer Wells where he described how pre-agricultural life might have been like in Anatolia. Fields and fields of wild wheat stretching across the horizon. Long periods of seasonal abundance. Occasional periods of hunger and privation where families would often have to rely on the help of friends and acquantainces, with the understanding that one day the debt would be repaid if similar ill circumstances befell your neighbors.
You can see some of how life might have been like in modern Papua New Guinea. War is nothing like modern warfare with artillery and guns. Its two groups of people firing arrows at each other from stand off distances while shouting at each other with minimal casualties. If you look at casualty rates from some of the early Greek warfare during the hoplite era, it's also surprisingly low.
Also note that in this post, and from research, caloric restriction counteracts some of these inflammatory effects. In many ways modern life can be stressful in its own ways, especially as we remove ourselves more and more from the active lifestyles that necessitated survival in previous eras.
I suppose the stress was running away from a lion, not having the all-eating thought of meeting deadlines, a bad boss, backstabbing coworkers and so on, i.e. intense, but short, not persistent and chronic.
I'm no biologist, but it's pretty easy to imagine a plausible mechanism.
Stress doesn't cause your body to "immediately grenade itself", it causes gradual problems over an extended period. But you can imagine that evolutionarily speaking, a stressful situation would frequently be a situation involving imminent danger. A response that prioritizes short-term survival (e.g. releasing adrenaline and cortisol) regardless of the long-term consequences could easily improve evolutionary fitness.
Considering that aging only happens later in life, it wouldn't have much of an effect on how efficient humans produce offspring, so it wouldn't be selected against. It is the same explanation for why Huntington's and Alzheimer's are still around.
> Wouldn't we have evolved in an environment with constant stress?
Well, humans did not reach an old age if you look back to history.
Only in recent times, say, 2000 years or so, or, if you want to be
strict, the last 100 years, did humans reach very old ages. Back
in older days, 30 years was considered old. Then 40 or so.
I heard that is mostly a myth due to misunderstanding what life expectancy means. It's an average over populations, pulled down mostly by enormous infant mortality. If you made it to 15 then there was a good chance you'll make it to 60.
I suspect that epigenetic aging is adaptive; a deliberately programmed sequence wherein genes more likely to contribute to age-related mortality are shut down progressively. This being in response to random genetic damage accumulating at a predictable rate.
What we think of as aging then becomes primarily the epigenetic response to the problem of DNA damage, much like the symptoms of a virus are mostly the result of the immune response rather than the virus’s direct effects.
There's a lot of indirect evidence for this from the fact that some naive attempts at stopping aging give you cancer, like turning telomerase on indiscriminately.
Almost everything in nature has multiple functions or causes, but one cause of aging is probably an evolutionary compromise between longevity and not getting cancer.
One option, I guess, would be turning the guard rails off and just getting incredibly good at treating cancer or inventing some extraneous cancer detection and killing mechanism.
It’s rarely such a simple tradeoff that only two things are being optimized. Modern humans live way longer than wolves for example despite being of similar body mass. However that’s fairly new in our evolutionary history as wild chimps for example cap our at ~63.
Cancer is extremely rare as a cause of death in wild animals. Again is more common but late enough that reproduction has produced multiple offspring.
Energy expenditure isn’t something we’re concerned with but drives a great deal of evolutionary optimization.
Can you state which genes these are that do that? Because I don't know of any.
Plus, many genes have pleiotropic effects. There is no specific aging gene.
On top of that, aging is a word that combines to many different factors. For
instance, progeria was called accelerated aging. Well, turns out you have a
mutation in lamin A. So, it is about cytoskeletal structure that is defect, rather than aging in itself. Of course the effects that this has, looks like an older person then, so it is related to aging. But one can not say it is "accelerated aging" as such. People having a normal lamin A allele still age nonetheless. So the whole term is problematic. And you can find many more such descriptions where xyz is about aging. Well, most of that it is about damage rather than aging. The Hayflick limit, though, is not about damage; that's just that cells fatigue for some reason when their telomeres shorten, but I have not yet read a sound explanations about why that is the case - after all there must be a mechanism in place.
31 comments:
The two papers:
* https://www.nature.com/articles/s41586-026-10955-0
* https://www.cell.com/cell/abstract/S0092-8674(25)00853-0
These papers simply present the accumulated damage hypothesis with new window dressing. They do not account for the known facts.
The article about these papers does not present a mechanism that would account for the Hayflick Limit.
Nor does it explain why dogs, for example, age and die more quickly than humans. If there is a mechanism of epigenetic drift that would explain this, I do not see it in the article.
The obvious answer to senescence is that we are programmed to do it. Cells die when they are supposed to die; if they don't, we have a problem.
Likewise, mammals die when they are supposed to. It takes less time to train a puppy to survive on its own than it takes to train a human. Hence, dogs are optimized to age and die more quickly. It's better for the species.
If we were not programmed to get old and die, evolution through natural selection would not work. We would never adapt to changing environments and our species would fail.
Aging and death is not an accident or a deterioration from damage or a drift away from a correct instruction set. It is an absolute hard necessity, without which we would all be long gone.
Stop wasting your time on nonsense articles like this and seek the mechanism that provides us as a species with the flexibility to adapt. Until we see aging and death as an core mechanism, we're going to be looking in the wrong place.
A lot of fallacies and assumptions in this comment. First of all there is nothing in biology or evolution where the "good of the species" has any kind of bearing on natural selection. This is the group selection hypothesis that has numerous counterexamples. If anything selection happens at the gene level over the long run.
There is also no clear reason we know of yet as to why a human being couldn't simply reach sexual maturity and hunting age faster. In fact, there might be at least some evidence other hominids did reach sexual maturity faster. It is not fully understood why humans take so long, but in animal kingdom terms we take roughly as long as the Asian Elephant to reach reproductive maturity. Almost certainly a tradeoff for achieving greater brain development and intelligence, but this could also simply be the consequences of being intelligent (e.g. it's easier to evolve for bigger skulls once ape intelligence surpasses a threshold where the apes are capable of committing to greater early childcare such that natural selection in absence of intelligence is weakened).
If dogs were optimized to age and die more quickly for the betterment of the canine species, then you could make the same argument for humanity. That's simply not what's going on. Human ancestors in the past who traded generation time for greater intelligence, likely selfishly outcompeted those who did not, and those other hominids either died off or represent a much smaller allelic contribution to the extant human gene pool.
For evolutionary biologists, aging and death similarly likely represent evolutionary tradeoffs. After reaching sexual maturity, as the probability of producing more offspring declines, so too does natural selection as alluded to in the article. Women are born with their entire compliment of ova and the rate of errors increases dramatically as they get older. Men have similar but more subtle issues with sperm generation. These error rate absolutely can be driven by mechanical stresses over time, and I would imagine could be driving much of the selective pressure that puts a cap on human longevity in the long run.
So chronic stress is one of the main contributors to aging. I hope I make it to my 40s.
Do we currently have the ability to do targeted methylation or de methylation at sites in cells?
> Do we currently have the ability to do targeted methylation or de methylation at sites in cells?
No, and you probably wouldn’t want it if you could. You don’t know what mutations are lurking in the genes that have been switched off or the consequences of turning them back on.
I’ve thought about this a bit, and what resetting the methylation map really requires, in addition to actually resetting that map, is resetting your genome to a known good state.
That’s pretty radical, but to selectively switch methylation on and off with precision you’re already talking about science beyond anything we have, featuring custom engineered constellations of proteins that unwrap your chromatin from around histones and then walk along it changing methylation state, then pack everything back.
And doing it for each cell type, without applying the wrong map anywhere.
And knowing what all the cell types and their correct methylation maps actually are.
And assuming that methylation isn’t used anywhere, for example in the brain, in a way we don’t expect.
And methylation isn’t the only kind of epigenetic modification.
So, if we’ve solved all of those problems, rebuilding your DNA to a clean, mutation free state at the same time should be a breeze.
We really do need AI for this if any of it is going to be remotely feasible.
in my futile searches for meaning I’ve wondered whether cancers in humans are a failsafe to something else or preventing something worse
more specifically the lack of more failsafes seen in some other mammals are a reaction to something besides happenstance
Cancer is the price we pay for complex multicellular life. It’s not a failsafe, it’s the failure of all failsafes to regulate cellular growth within an organism.
> We really do need AI for this if any of it is going to be remotely feasible.
Would you give your life into the hands of AI skynet slop?
I understand your rationale, of course, but I for one don't want big fat mega-corporations dictate over our life here. Naturally, all of this hinges whether AI can even solve this problem. I assume it can, but I doubt it can do so initially - and the legal implications are still enormous. I really am not ready to turn my hands to claude's gene therapy slop.
Good news! Research shows that hope reduces stress! [0]
[0]: https://www.forbes.com/sites/tracybrower/2024/09/15/how-bein...
Sadly, AI just made many of us lose all hope.
It makes me concerned on many levels, but perhaps also more hopeful. It was inevitable that we would eventually develop AI if we didn't go extinct first, and while there are myriad risks and challenges, there is also massive potential, which seems like it could be a source of hope. As the earlier comment said, the only way that therapies like these could be remotely viable on any kind of near to medium timeframe would be with AI assistance, and this is just one example.
You spelled SI wrong.
Sometimes I like to close my eyes and dream of electric sheep.
Thanks, Obama
What about Xanax or medication. Hypothetically ignoring the ill effects of the drugs themselves will chemical stress relief have the same anti-aging benefits?
If you believe that HRV is inversely correlated with stress then Xanax has the opposite of your intended effect.
I just don't understand. Wouldn't we have evolved in an environment with constant stress? Constant fear of disease, starvation, predation, attacks by neighboring tribes? Why would our body's natural response to our environment be to immediately grenade itself.
The idea that pre-agricultural societies are subjected to constant stress reflects modern biases somewhat. I remember years ago I saw a talk from Spencer Wells where he described how pre-agricultural life might have been like in Anatolia. Fields and fields of wild wheat stretching across the horizon. Long periods of seasonal abundance. Occasional periods of hunger and privation where families would often have to rely on the help of friends and acquantainces, with the understanding that one day the debt would be repaid if similar ill circumstances befell your neighbors.
You can see some of how life might have been like in modern Papua New Guinea. War is nothing like modern warfare with artillery and guns. Its two groups of people firing arrows at each other from stand off distances while shouting at each other with minimal casualties. If you look at casualty rates from some of the early Greek warfare during the hoplite era, it's also surprisingly low.
Also note that in this post, and from research, caloric restriction counteracts some of these inflammatory effects. In many ways modern life can be stressful in its own ways, especially as we remove ourselves more and more from the active lifestyles that necessitated survival in previous eras.
I suppose the stress was running away from a lion, not having the all-eating thought of meeting deadlines, a bad boss, backstabbing coworkers and so on, i.e. intense, but short, not persistent and chronic.
I'm no biologist, but it's pretty easy to imagine a plausible mechanism.
Stress doesn't cause your body to "immediately grenade itself", it causes gradual problems over an extended period. But you can imagine that evolutionarily speaking, a stressful situation would frequently be a situation involving imminent danger. A response that prioritizes short-term survival (e.g. releasing adrenaline and cortisol) regardless of the long-term consequences could easily improve evolutionary fitness.
There always has been a lot of stress, but there used to be relaxed moments as well. The issue is that we don't calm down anymore.
Relevant video by Kurzgesagt – In a Nutshell: https://www.youtube.com/watch?v=Mo1A45ShcMo
Considering that aging only happens later in life, it wouldn't have much of an effect on how efficient humans produce offspring, so it wouldn't be selected against. It is the same explanation for why Huntington's and Alzheimer's are still around.
> Considering that aging only happens later in life,
In other news, widows outlive their husbands.
> Wouldn't we have evolved in an environment with constant stress?
Well, humans did not reach an old age if you look back to history. Only in recent times, say, 2000 years or so, or, if you want to be strict, the last 100 years, did humans reach very old ages. Back in older days, 30 years was considered old. Then 40 or so.
I heard that is mostly a myth due to misunderstanding what life expectancy means. It's an average over populations, pulled down mostly by enormous infant mortality. If you made it to 15 then there was a good chance you'll make it to 60.
No mention of new limit.
In fact there is very little talk about new limit. But what they are doing seems impressive and important.
I suspect that epigenetic aging is adaptive; a deliberately programmed sequence wherein genes more likely to contribute to age-related mortality are shut down progressively. This being in response to random genetic damage accumulating at a predictable rate.
What we think of as aging then becomes primarily the epigenetic response to the problem of DNA damage, much like the symptoms of a virus are mostly the result of the immune response rather than the virus’s direct effects.
There's a lot of indirect evidence for this from the fact that some naive attempts at stopping aging give you cancer, like turning telomerase on indiscriminately.
Almost everything in nature has multiple functions or causes, but one cause of aging is probably an evolutionary compromise between longevity and not getting cancer.
One option, I guess, would be turning the guard rails off and just getting incredibly good at treating cancer or inventing some extraneous cancer detection and killing mechanism.
It’s rarely such a simple tradeoff that only two things are being optimized. Modern humans live way longer than wolves for example despite being of similar body mass. However that’s fairly new in our evolutionary history as wild chimps for example cap our at ~63.
Cancer is extremely rare as a cause of death in wild animals. Again is more common but late enough that reproduction has produced multiple offspring.
Energy expenditure isn’t something we’re concerned with but drives a great deal of evolutionary optimization.
> one cause of aging is probably an evolutionary compromise between longevity and not getting cancer
Yes, and proteinopathies, and likely lots else besides. We probably don’t even understand the failure modes that aging protects against.
This assumes there are genes that:
a) contribute to age-related mortality, and
b) shutting down helps combat aging.
Can you state which genes these are that do that? Because I don't know of any.
Plus, many genes have pleiotropic effects. There is no specific aging gene.
On top of that, aging is a word that combines to many different factors. For instance, progeria was called accelerated aging. Well, turns out you have a mutation in lamin A. So, it is about cytoskeletal structure that is defect, rather than aging in itself. Of course the effects that this has, looks like an older person then, so it is related to aging. But one can not say it is "accelerated aging" as such. People having a normal lamin A allele still age nonetheless. So the whole term is problematic. And you can find many more such descriptions where xyz is about aging. Well, most of that it is about damage rather than aging. The Hayflick limit, though, is not about damage; that's just that cells fatigue for some reason when their telomeres shorten, but I have not yet read a sound explanations about why that is the case - after all there must be a mechanism in place.