January 16th, 2010, 03:10 AM
Passing by with some questions out of curiosity..
Are we(with our intelligence) ever going to be able to conquer aging, and defeat the processes of nature?
If we ever do discover/invent this "thing" that can conquer aging, or incredibly slow down aging, what could it possibly be?
Or maybe, we are still evolving..? in a million year maybe humans will be able to live 200,300+ years? Is this possible? or are we already living at our maximum lifespan?
Comments?
January 16th, 2010, 10:01 PM
"Life Ascending" actually discusses this in Nick Lane's chapter on death. However before we can do this we must understand what causes aging, and there are still quite a few candidates (and they may all be causes). For example the radicals spewed out by our mitochondria have toxic effects that may be to blame. Also the telomeres on the end of our chromosomes are constantly shrinking, but this also prevents cancer, so immortal maybe but at an increased risk of cancer.Originally Posted by kzhan90n
This is unlikely, natural selection only works before our reproductive age (and while we are raising children). Since this allows our offspring (with our genes to take over the population), however if we live to 100,000 it has little effect on our offspring, not enough for evolution to act upon. The only way evolution would favor increased lifespan is if our reproductive age also increased, which, thanks to medicine, is already well behind our average lifespan.
Until we understand ageing, we will not know what we can do about it. My own feeling is that it is just a matter of time, but only time will tell.
If it helps, it may be worth remembering that the bowhead whale lives to beyond 200 years. The genetic adaptations that it uses for this may be applicable to humans.
http://en.wikipedia.org/wiki/Maximum_life_span
January 17th, 2010, 07:21 AM
Not strictly true- kin selection is an element of natural selection! Humans may well have a longer life span than many animals as a result of the time it takes to raise a human child. Evolution favours those who live long enough to protect and train their young (who possess 50% of our genes) to breeding age. Similarly it will also favour our survival into old age as we can then act as another layer of protection and training for our grandchildren who will possess some 25% of our genes. This will tend to be most important in social species with long gestation and maturation times. Of course, with each generation we survive, our genetic "investment" decreases and the pool of individuals we would feel compelled to protect increases, so it makes sense that there would be an evolutionarily determined upper limit where our continued survival is not profitable.
Mind you, in a hyper-social species like ours where altruism now tends to cross genetic boundaries more freely, there may be even broader kinds of natural selection at work.
We don't always have to look at it from a biological perspective. I'm pretty sure that before any biological evolution or mutation increases our life span further, we would have developed technology capable of further stretching lifespan or even preventing death. If people are ever going to conquer aging, it would be by our own hands before nature has a chance.
Our maximum lifespan hasn't changed at all over time.
We managed to change life expectancy or average lifespan quite dramatically in some societies.
So I would say, No, I don't see anything happening any time soon regarding our maximum lifespan.
Well, the stem cell tharapy by IPS cells seems very promising to increase our lifespan. I think a revolution will occur in the next 50 years.
50 years sounds more like evolution.
How does stem cell therapy increase our maximum lifespan?
January 22nd, 2010, 05:22 AM
Not necessarily so for species that improve offspring beyond basic reproduction. For example mammals must survive beyond the birth of their children, to nurse those children. With social animals, and extended families assigning roles, it becomes more interesting. A culture where grandma's survival means she directly helps raise her own grandchildren or even shoulders the responsibility (i.e. Chinese), lends selective advantage to able-bodied grandmothers. I find this really hopeful, because we simultaneously get to live longer and improve rather than stifle future generations.
There is no reason in theory why humans cannot increase our own lifespan. There appear to be genes which lead to early death. Since genetic engineering capabilities are growing rapidly, there is no reason why a future generation cannot have genes for ageing and early death knocked out. Perhaps we could harvest genes from other animals that relate to longer life, and introduce them into that future generation?
The bowhead whale lives over 200 years. There is no reason in theory why a little genetic manipulation cannot lead to a future humanity doing the same.
The real question is how long will it take for our technology to reach that point. I suspect it will not be before the days of our great grandchildren, but that is purely a guess.
One of the theories of aging says that aging occurs due to cellular loss of organs or stem cell pools. These cells stop to replicate after a certain amount of divisions (<100 see Hayflick limit). This is called cellular senescence. As time goes by, these cells die and cannot be replaced. With stem cells these lacking cells could be replaced. The stem cells (that have your genome) are transformed into the desired cell type and can be injected into the organ/tissue. In particular IPS cells are suited for this. IPS cells are stem cells that are generated from a normal differentiated cell. That was done 3 years ago and was a scientific breakthrough. By reversing that differentiation the cellular senescence limit is reversed. This is a process known from cancer. That similarity to cancer cells is one of the big problems of IPS cells. They can easiliy transform...yet...
well, it doesn't work like that.
Why not? That should be just a vague explanation how it could maybe work.
January 24th, 2010, 06:54 PM
I think its an evil circle. Scientists that work on this need a way longer lifespan to reach a breakthrough to discover it.
Also...
Lets say we take a time machine and kidnap a zebra from africa and send it to the exact same place 1000 years into the future. This zebra wouldnt be able to survive in the changed enviroment, Due to anything from weather changes to bacteria or other stuff am i right?
Reproduction and evolution is the process of change, and immortality would stop this process rendering us unable to survive in a changing world, thats my guess anyway.
Im not an expert just my thoughts on this :P
January 24th, 2010, 08:12 PM
Reproduction is a neat trick.
From a "selfish gene" aspect, why should we age? It would seem that bodies not deteriorating, staying fruitful into old age and continuing to pass on more and more genes would be fulfilling the gene's evolutionary "purpose". Dawkins wrote about this. Can't remember what he wrote.
Well for one thing, those gametes between your legs contain all of us, mostly (uh, hi there). So how does one gene, duplicated ad nauseum, make the most of its multiple selves?
For another, it will always be to the advantage of any one gene, if some other gene schmuck gets mutated for (heh heh) "the greater good". I guess you could say the "selfish" idea is to win the fruits of evolution vicariously. And it usually does work that way: some other gene gets sacrificed, and the remainder reap the rewards.
And another, given that a gene lives through multiples, a gene is rather in the position of skin cells - where the clan of skin cells fairs better when its identical members are continually shed off and rejuvenated.
For example: Your nose Bunbury. It's a selfish nose. It desires to grace the faces of the future. But how? Consider that it must endure catastrophe, and ice ages, and travelling to Mars and colonizing Mars, the destruction of Earth, and someday Martian alligators, and diving deep beneath the Martian seas. Obviously this expendable body your selfish nose is attached to must evolve, if the nose is to survive. Your prideful selfish nose would gamble on other features changing. The odds are actually pretty good.
No, my nose isn't selfish even in a metaphorical way. It's the genes, dude, if Dawkins is right.
Reverse that, if the trend continues, imo in 300 years we'll probably have an life span that exceed a million years.Are we(with our intelligence) ever going to be able to conquer aging, and defeat the processes of nature?
If we ever do discover/invent this "thing" that can conquer aging, or incredibly slow down aging, what could it possibly be?
Or maybe, we are still evolving..? in a million year maybe humans will be able to live 200,300+ years? Is this possible? or are we already living at our maximum lifespan?
The "you" you perceive to be is the interaction between cells that need not be yours. If you have a heart transplant that heart is part of you, if you change each part you would still consider yourself "you". If stem cells that become neurons are injected in your brain and take their place in a harmoneous way with the rest they become you except they could be much younger. These young cells could be negatively impacted by the old environment they are part of, but if you rejuvenate enough of this environment you would become less old from one perspective. Eventually most of the cells you would be composed of would no longer be directly coming from the originals but you would have the vitality of a younger person and would still perceive that you are yourself.
In addition, when you look at fields like genetic engineering, computer-robotics-etc and nanotechnology its reasonable to imagine that some of the beings we now call humans, will change in the next 200 years more than we have in the past million years, some humans will probably be cyborgs that is nanotechnology will be fused in our bodies. Right now our bodies are a host for billions of baterias that help a bit, dont pull their weight or are more or less detrimental, and we have access to various devices we prefer operating with (watch, ipod, computer, glasses/lenses, etc) but that arent integrated. In the future we will probably be hosts for millions of nanites programmed to scan our blood, monitor life signs, boost are immune system like nothing we can imagine, counteract aging/help renew cells, and provide various usefull computerized aid, instead of having a watch/ipod/computer we will have integrated circuitry that provides us with processing and memory, like a laptop in our brain(network, utilities, games, etc). With genetic engineering the shape of our bodies will eventually no longer matter, as we would have the option of changing it behond what we consider to be human, and eventually when the nanotech goes to a level where both it and genetic engineering are in fact advanced molecular programming, then there the difference between artificial beings and our lifeforms will gradually dissipate (and our consciousness can probably travel between bodies by then).
So yes, its only a matter of time and development before we are immortal from our present day perspective and "live" millions of years and that will probably be within a few hundred years, but while it might take a few hundred years to become virtually immortal I think with a combination of techniques including stem cell reintroduction we can reach 200 years life span within a 100 years.
Note that under our current monetary based socio-economic system where you can die of starvation as a 4 years old toddler if you dont have money to eat, its quite probable that a limited portion of the population will have access to life extending tech. If our economic system can change to take all people into consideration then most or all people would have access.
http://en.wikipedia.org/wiki/Evolution_of_ageing
Aging obviously emerged in the shadow of evolution. Reproduction occurs in the early life. So, selection acts only up to the the age of first reproduction. If a gene would cause a adverse affect in later age it would not be selected. Aging genes could be such adverse genes. That is also why degenarative diseases like Alzheimer's disease are so widespred. The theroy of antagonistic pleiotropy is correlated to this. It says that a specific gene can have multiple effects. If the gene has advantagous effects in the young life and adverse effects in the later life Selection will be boosted anyway, as reproduction has already occured.
Too many comments about evolution.
Humans are still evolving, of course, but very slowly. Our future involves massively rapid evolution by gene manipulation. We are already doing it with crops and with micro-organisms. It is only a matter of time before we modify our own genome. And when that happens - forget natural evolution. It will be the ultimately slow snail to the enormously fast hare of designer evolution.
Within a few hundred years, we can expect everyone to be born with a very long lifespan built into our genes, and with good health, athleticism, and good looks for everyone. Natural evolution won't get a look in!
Sadly none of us will be around to see it.
The selfish gene does better when distributed amongst a range of genetic milieus, such that it can survive in one of those combinations when confronted with a changing environment.
Hey there, there's an idea for a novel. A world in which there is no environmental change, and therefore no reproduction and no aging.
interesting to consider a software package the aging could order that allows them to experience millions of years in the span of a few minutes, as a way to welcome death!
Should'a made clear it's an analogous nose.
Now I wonder: If a person can be selfish, and a gene can be selfish, why can't a nose be selfish?
I don't actually subscribe to the selfishness theory. It's not "what will work" or even "what works", it's just "what did work".
My wife doesn't agree with this.The selfish gene does better when distributed amongst a range of genetic milieus, such that it can survive in one of those combinations when confronted with a changing environment.
Can there still be sex?Hey there, there's an idea for a novel. A world in which there is no environmental change, and therefore no reproduction and no aging.
Well, I think I've figured out why we get old. If there's a gene for, say, heart failure, if it were to be expressed at a young age it wouldn't get passed on at a high rate. It would die out. If that gene was only expressed in older people, the genes they've already contributed to the gene pool would include that one so the gene for heart disease in old age would multiply. I suppose it's obvious but I had to think it through.
Bunbury
That is one of the reasons for ageing.
There are many.
For example : mutations in mitochondria increase over time, till more and more of our little cyto-power cells are deactivated.
For example : telomeres shorten, reducing the ability of cells to divide and repair damage.
For example : oxygen damage inside cells accumulate over time
etc.
I would assume that genes need to make copies continuously and discard older versions because the original (well... original to your body) genetic material would deteriorate eventually, as it does in the fossilized remains.
Death is essential in the evolutionary sense, because the environment changes. The genome needs to be upgraded in a process called adaptation, to enable fitness for the new set of conditions. Death is nature's way of getting rid of the maladapted genes, rather than see them preserved by continuing reproduction with the old model.
Right. Next the uncomfortable question: when should we die?
She is not a gene.My wife doesn't agree with this.The selfish gene does better when distributed amongst a range of genetic milieus, such that it can survive in one of those combinations when confronted with a changing environment.
Can there still be sex?Hey there, there's an idea for a novel. A world in which there is no environmental change, and therefore no reproduction and no aging.Centuries of it.
This explains why bad genes are passed, but not why we get old.Well, I think I've figured out why we get old. If there's a gene for, say, heart failure, if it were to be expressed at a young age it wouldn't get passed on at a high rate. It would die out. If that gene was only expressed in older people, the genes they've already contributed to the gene pool would include that one so the gene for heart disease in old age would multiply. I suppose it's obvious but I had to think it through.
fr
An explanation for why bad genes lead to ageing.
There are already a large number of mutations to genes that have effects that are age dependent. Note that I am talking of a situation such as throughout most of human history and prehistory, where there are no effective medical treatments. It was under these conditions that the human species evolved.
Progeria is a mutation that kills, after a rather nasty illness, before the victim reaches puberty.
Hemophilia is a mutation that normally kills a little later on (depending on how bad it is), and the victims often do have the chance to reproduce.
Huntingtons is a disease that affects people in their late 40's and older.
Researchers have discovered that the progeria mutation dies out within a generation. Hemophilia can take up to 10 generations before natural selection removes it from the gene pool. Huntingtons can take 100 generations before natural selection removes it.
These genes all cause serious illness before death. Now think of the thousands of useless genes in our genome. If they are harmful, they are removed by natural selection. However, if they cause relatively minor harm at a later age, they are not removed. Over millions of years, these genes accumulate, till we get a species that increasingly gets more and more feeble and ill with increasing age, till it finally kills them.
That seems to be a very reasonable explanation for specific illnesses. Does the same sort of process apply to the effects of ageing that are not looked upon as diseases: gray hair; loss of skin flexibility; balding; general decrepitude? Some people die of "old age" rather than any identifiable disease.
Bunbury
As I pointed out before, there appear to be a number of mechanisms leading to ageing. The idea you proposed and which I expanded is probably one of them. However, I suspect that the complete story will involve a number of ways we age, and will not be simple.
Cheers for that, but none of that gets at the question as to why we age in the first place.
free radical
The reason for ageing.
As I said, there are a number of reasons.
The business of harmful mutations not being removed by natural selection is just one reason.
The way it works is that harmful mutations reduce the fitness to survive and reproduce. Some are lethal, but let's think just about those that reduce fitness. If these genes act on the individual at an early age, they get weeded out of the population by natural selection, because those people who possess those harmful genetic mutations are less likely to be reproductively successful.
However, if the gene kicks in only on older people (say, over 40), then there is a damn good chance that they have already successfully reproduced. Thus, the power of natural selection to eliminate those harmful genes is much reduced. The later the age at which the harmful mutation kicks in, the less the power of natural selection to remove those genes. Over millions of years, lots of harmful mutations enter the population and fail to be eliminated, because they have their impact only at a greater age.
If a gene is seriously harmful, like the Huntingtons Chorea gene, even though it acts only after 40, it will still eventually be eliminated. Thus, harmful genes that kick in relatively young (say 40) are retained only if the harm is not too great. However, those that kick in at greater age, can be more harmful without being eliminated.
Thus we end up with a whole bunch of nasty mutations that cause minor harm at 40, greater harm at 50, even more at 60 etc. It is called ageing.
I am 61, and I am pretty fit, but beginning to get aches in my knee joints. Assuming this trait is a genetic mutation, it would have been a bar to my fitness if it struck at age 20. However, striking at age 60 plus, it has no evolutionary impact, and is not eliminated.
We're like fingernails discussing if we're ever going to be able to conquer clippers.
You have my sympathy about the knees - same thing happening here.
This is not a subject I know much about and I appreciate your input. I have to rely on sources like wikipedia with its attendant problems; having said that, wikipedia tells me that accumulation of mutations seems to be questionable as a mechanism for ageing:
Theories involving some overall controlling mechanism, mediated by hormones, seem to be in vogue. I can't judge. I will continue reading however and see if I can make sense of it all.Theories to the effect that ageing results by default (mutation accumulation) or is an adverse side-effect of some other function are logically much more limited and suffer when compared to empirical evidence of complex mechanisms.
@Aching joints: I'd like to recommend tai chi (the way of the bent knee). I had osteoarthritis in both knees in my 20's - noisy joints climbing stairs - and was told it would worsen. This worked for me: Tai chi helps cut pain of knee arthritis: study . Plus how cool is it to nonchalantly stand up fishing in a rocking canoe?
Bunbury
As I said before, there are a number of ideas on why ageing occurs. The theory we discussed is but one. Add in mitochondrial theories, telomere theories, oxidant theories, and programmed senescence theories, and we may accidentally touch on the real reason.
Currently we do not know, and any idea is as likely as any other.
Because that would mean you could just inject ips cells.Why not? That should be just a vague explanation how it could maybe work.
If it was that easy why don't we do it?
Because the IPS technology is not far enough. IPS cells tend to become cancer cells. But this is only a matter of time until that problem is mastered. Besides, IPS cell have benn generated from normal cells, so far. But the reverse, generating certain cells from IPS cells, has not been done, yet. There are still a lot of problems. Here is a link, that discusses the IPS technology:Because that would mean you could just inject ips cells.Why not? That should be just a vague explanation how it could maybe work.
If it was that easy why don't we do it?
http://www.sens.org/index.php?pagename=replenisens
the main page gives also other suggestions for solving the aging problem:
http://www.sens.org/index.php?pagename=mj_index
Greenland sharks are also believed to live up to 200 years, but I have also read that some scientist estimate they live up to 400 years
http://en.wikipedia.org/wiki/Greenland_shark
No, we will never 'beat' aging. To 'beat' aging, one would need to become immortalised. It may be possible to substantially extend life-span from its current limits, but so long as there is an upper limit (be that what it may), 'aging' as a phenomenon will always exist... so it is 'unbeatable'
tridimity
There is no scientific reason to suggest we cannot 'beat' ageing. Nor would that make anyone immortal. Beating ageing just means they do not grow physically older. That does not make people immune to death. There will still be accidents, natural disasters, violence, suicide, disease, poisons etc.
It will definetely be possible, in the far future. The biggest problem of the aging problem is its extreme complexity. It is considered as one of the most complex topics in biology. Propably because it partly devoloped in the absence of natural selection. Therefore a lot of aging machanisms could arise.
Maybe the problem will not be solved in the biological way, but but transferring the consciousness to a simulated brain or similar.
I tried glucosamine tablets for about a year. The arthritis in my thumb disappeared but the knees still hurt after sitting with bent knees (e.g. driving or at a desk) for a while. Haven't tried tai chi but will look into it. This is O.T. so must stop.@Aching joints: I'd like to recommend tai chi (the way of the bent knee
Bunbury
I don't think being off topic for a short while is too bad, as long as it is friendly and constructive.
You might like to read the following on glucosamine.
http://www.quackwatch.com/01Quackery...ucosamine.html
I find myself a bit skeptical about Tai Chi as a means of fixing bad knees. It is, doubtless, a good exercise regimen, but bad knees seem to be degenerative, and I do not know of any clear means of reversing the damage.
I think Tai Chi is less about reversing degeneration and more about slowing it... all while growing new muscle fibers and neural connections in the process. I have no data to support my thinking on this, it just seems right from personal experience and understanding. Tai chi involves small movements... slow movements... directed movements. Those movements engage an incredible amount of muscle fibers which are otherwise mostly dormant. I am thinking mostly of the balance muscles, and all of those tiny little twitchy muscles that nobody seems to think or know about. Further, movements during Tai Chi (practiced appropriately) will encourage synaptic growth and blood flow, and those things tend to be overall positive, and will also help with immune response and healing.
You probably feel the same way, so please consider this a supplement to your post, not an argument against it.
You have successfully explained why deleterious alleles do not express themselves prohibitively before reproductive age. This is different than explaining why we age.
free radical
By this mechanism, it is the expression of deleterious alleles that causes the ageing. If you think of the ageing process as a series of minor deteriorations of the body, then think of each deterioration as a mutant gene expressing itself. There may be a thousand such genes, which kick in as we grow older.
Of course, this is an over-simplification. There are almost certainly other mechanisms behind ageing also, which affect the process.
"Deleterious" because making way for subsequent (evolving) generations is ...disadvantageous? Ageing and death is adaptive, isn't it? I mean in terms of propagating genes, all genes. I'm suggesting that if we didn't age, we should evolve to; and it wouldn't be deleterious or loophole mutation - ageing would be a positive adaptive trait.
***
OT: The most common & remarkable experience when beginning tai chi is a burning ache in the anterior thigh muscles. Supporting one's own weight muscularly takes serious energy! Many people adopt the lazy posture of using their legs like columns, with all the body's weight running straight down the bones. If you straighten your legs the instructor will come behind and nudge the knees forward. You are supposed to develop the habit of walking and standing comfortably throughout an uninterrupted range of flexion.
I speculate tai chi helps arthritis by varying how a knee is loaded, and by promoting a springier step.
Maybe tai chi is actually bad though? It could be that elderly Chinese do this for short-term reduction in pain, though it eventually makes them worse?
At the time I made a point of eating all the cartilage and tendons in my normal diet, plus some bone, and still do. That's just unscientific common sense.
I didn’t take biology, ever, so this is probably complete crap. I’m looking at it not from a biological mechanistical perspective (because I can’t) but from the basic idea of Dawkins’ selfish gene. Dawkins’ high-level argument is: The body is a survival machine for genes. Once a body has reproduced its usefulness is over as far as the gene is concerned so the genes don’t have any interest in the continued existence of its survival machine, so genes have not evolved to protect the body from deterioration and death. They don’t need to since they live on in other bodies.
The weakness I think exists in this argument is this: A body (human, mushroom, frog) is a cozy, protective environment for a gene. It could sit there in a thousand billion cells unthreatened and unchanging, and if the body continued to live forever the gene could live forever in its castle. Survival is a gene's only "purpose". On the other hand, if that gene ventures out into the wide world in an egg or a sperm it is at risk of being displaced by a competing allele in its new home, before it gets established. From the gene’s point of view it has gone from a safe environment to a dangerous one. So immortality of the host body is a better strategy than reproduction for a gene’s survival.
Going back to the primordial soup, where genes (perhaps) had to sink or swim without protection, the obvious step was to form protective bodies, which they did through the inevitability of evolution. Those bodies weren’t perfectly designed for the job (no designer implied, please) and evolution continued its relentless march towards perfection. Our bodies are just another step along the road to perfection, but since imperfect, our genes continue the process.
Now with our brains and opposable thumbs we have the ability do the gene’s work for it in improving and modifying their survival machine. (Memes doing the work of genes?) Ultimately this might result in a very long-lived machine to house the gene. This, with reproduction, will lead to untenable overpopulation, so reproduction will be controlled to maintain a sustainable level of population. The gene wins. It has a low-risk long-lived environment, with the possibility of reproduction when that environment eventually does break down. The survival machine is a thinking machine so a changing external environment can be accommodated by the thinking machine making appropriate adjustments.
Stream of consciousness rambling. But it touches on some themes already mentioned in this thread.
Bunbury
Just a couple of additions to your logic. First the 'survival machine' for genes cannot be immortal, even if ageing does not occur (and many primitive bodies do not age). Death strikes from a multitude of causes, from accident to predation and disease. In fact, in most cases over the past 4 billion years, death strikes while the 'survival machine' is quite young.
Thus, genes have a more important 'goal' than mere survival. That is to reproduce and increase their numbers.
Early evolution was probably not quite Darwinian as we know it. Horizontal gene transfer is so prevalent among prokaryotes that is may well have been the dominant driver of genetic change for the first couple of billion years of Earth life.
http://www.newscientist.com/article/...evolution.html
Good point. If eaten by a lion at twenty you need to have done your duty already. Explains much.
Then rephrase the question as to why we have deleterious genes (rather than why we don't express deleterious before reproductive age).
Put in other words, you are explaining why we have health. You are not explaining why we lose health.
Why do we age = why do we have deleterious genes.
How many homo sapiens were actually ever eaten by lions, yet this is what we seem to universally describe as the typical fate for our forbearers!Good point. If eaten by a lion at twenty you need to have done your duty already. Explains much.
I rather suspect dying from massive infection at age 20 killed off many more of our ancestors, but we never seem to use that description!
Free radical
Deleterious genes arise by random mutations. It is well known that most mutations are harmful. Natural selection removes most harmful genes within a few generations because, well, they are harmful.
By the same random process, these genes kick in at various ages. There is no process determining this. Just randomness. However, a harmful gene that has its effect early will be eliminated by natural selction quite rapidly.
A harmful gene that has its effect later in life will be slow to be eliminated, or possibly not eliminated at all. Note that most harmful genes are not actually lethal. Just harmful, leading to loss of strength or illness. For example, a harmful gene that has its impact at age 60 might lead to loss of cartilage in joints. That is : arthritis. Sound familiar?
Such a gene would not be readily removed by natural selection, both because it has its impact after the individual has reporduced, and because it is not lethal.
An accumulation of genes like this over millions of years leads to an individual whose genes cause him/her to slowly become less and less healthy and strong as he/she gets older. It is called ageing.
There is a big reason why we cannot beat aging.
Aging is part of what we are. We are a developmental process going from fertilized egg, fetus, infant, child, adolescent, adult, to elderly.
Or body is designed to evolve during a life cycle. To stop aging would mean that you would mess with the underlying design.
And this is NOT a trivial matter.
Eaten by lions is a proxy for all the bad things that could happen, and that includes dying from infection and then being eaten by lions. Its modern equivalent might be "you could be run over by a bus tomorrow". Not many people actually get run over by a bus. But other than that, what do you think of my logic (in this particular case, no need to comment on my general logic or lack thereofHow many homo sapiens were actually ever eaten by lions, yet this is what we seem to universally describe as the typical fate for our forbearers!Good point. If eaten by a lion at twenty you need to have done your duty already. Explains much.
I rather suspect dying from massive infection at age 20 killed off many more of our ancestors, but we never seem to use that description!
spurious
You are not giving a reason why we cannot beat ageing.
You are giving your opinion on why we should not beat ageing, which is a totally different thing.
When you think about the current theories about ageing (cellular senescence, oxidative stress and gene expression) it all seems to come down to maintenance of DNA. This would suggest that any steps taken to artificially increase the human lifespan would come at a cost; if you were able to add telomerase to cells so that they can maintain telomere length and therefore don’t under go senescence, you’d get cancerous cells. Likewise for attempting to prevent apoptosis of certain cells, which is another theory I once heard someone put forward for preventing ageing.
A biologist I know once suggested that ageing is the body’s “anti-cancer mechanism”, by which I suppose he meant that it’s a way of stopping cell reproduction and starting to kill them off before our DNA gets too screwed up from oxidative damage. So if we do manage to find a way to keep our cells alive and dividing for longer, we might just be setting ourselves up for mutations and cancer (which might then be fatal, which would sort of defeat the purpose of the exercise
(Also, I apologise if this turns out not to make any sense. I’ve been awake for a long time and the caffeine is wearing off.)
itsapanda
Your logic is sound up to a point. However, ageing is just one of the body's many anti-cancer tactics. Halting ageing will not automatically cause cancer. In fact, cancer is far more common amongst older people than younger, who have more effective immune systems.
A 25 year old has only 1% of the chance of cancer compared to a 75 year old.
This implies that, if we could reverse ageing, and turn the 75 year old into the physical equivalent of a 25 year old, his chances of getting cancer would drop by 99%,
Well, there are many factors to consider as we ponder a "cure" for aging...(cure in italics because I don't consider aging a disease) including defects in functional genes of mitochondria and possibly telomerase lengthing or protection. We are far from a definitive "cure" the closest thing we'll ever have to eternal life is one lived as a human/machine hybrid..with metallic livers, hearts, lungs, limbs, etc...either that or stem cell research will progress to the point that we don't need those biomechanic parts.
P.S. Read Nick Lane's Power, Sex and Suicide: Mitochondria and the Meaning of Life if you want to know more about how mitochondria relate to aging. What you'll find is that there are few signs of aging in the mitochondria of older people because free radical leakage causes cardiolipin of the inner membrane to deteriorate and signals the death and recycling of either a single mitochondria or apoptosis if involving several mitochondria and if it's severe enough. In other words, natural selection takes place and the defective mitochondria and cells of which they are a part are eliminated, leaving only the ones that work properly. After a while though, the defective mitochondria can no longer be replaced and muscles and organ systems begin to waste away. The most metabolically active organs (heart and liver especially) will often be the first to fail in elderly people who die of "natural causes" because they are more prone to mutation.
Ordered :wink:
As I already pointed out, it is a matter of complexity. That topic still requires a lot of research. The more scientists are working on that issue, the faster we will achieve this goal. So, don't hesitate and begin to study biology :wink:
PS: One more good link about aging and stem cells:
http://websites.afar.org/site/PageSe...IA_b_stem_home
February 1st, 2010, 01:05 PM
Some theorists say we are purposely designed to age and that we therefore possess what amounts to a suicide mechanism. This is the "programmed aging" concept in which the destructive processes such as oxidation and telomere shortening that have already been mentioned are in turn "programmed" by a suicide mechanism. If this is true it should eventually be possible to find ways of defeating or "tricking" the suicide mechanism and thereby substantially extend life span and delay occurrence of age-related diseases.
The big scientific arguments are of course:
1) What would be the benefit that caused the evolution of a purposely shortened life span? Proposals are that aging benefits group survival or benefits the evolution process since a purposely limited life, of itself, obviously does not benefit individual organisms.
2) Could a design that was adverse to individual organisms evolve regardless of how beneficial it was for groups or evolution process? Traditional evolution theory says no. Newer alternative theories regarding the evolutionary mechanism say yes.
These arguments, pro and con are discussed at length on this web site:
http://www.programmed-aging.org/
February 25th, 2010, 05:28 AM
Interesting information about science in general and an interesting documentary about THE NEW BIOLOGY here: http://www.humanrestore.com/?p=1073
we could mess around with DNA to 'regenerate' skin and reverse aging
however aging is just oxidation on a slow scale, so all we need to do is find an oxygen substitute
February 26th, 2010, 02:10 PM
Hi. here are some info about anti-aging cream ingridients:
Ingredients to Avoid
* Dioxane: (a synthetic derivative of coconut). This substance is widely used in skincare products. It often contains high concentrations of 1,4-dioxane, which is readily absorbed through the skin. I know this sounds crazy, but 1,4-dioxane is considered a chemical "known to the State of California to cause cancer". To think people pay money to put this stuff on their skin unknowingly is downright scary.
* Fragrances.
* Parabens: methyl, propyl, butyl, and ethyl paraben.
* Alcohols: ethanol, ethyl alcohol, methanol, benzyl alcohol, isopropyl alcohol and SD alcohol.
Ingredients to Look For
* Collagen.
* Phytessence Wakame.
* Cynergy TK: This is a new exciting, cutting edge substance. Cynergy TK actually stimulates your own collagen to grow again. In fact, it is proven in clinical trials to stimulate not only the regrowth of collagen but also elastin, thereby promoting firmness and elasticity. In short, fewer wrinkles, and more youthful, healthier looking skin. It may help improve your skin's ability to retain its needed natural moisture.
Indeed, studies show a sustained 14% improvement in skin moisture retention over 18 days. Studies on Cynergy TK also show a sustained improvement in skin elasticity of 42% over 18 days.
* CoQ10: CoQ10 is a powerful antioxidant. A lot of skin damage and aging comes from free radicals wreaking havoc in our body's cells. CoQ10's antioxidant ability can counter these free radicals before damage occurs.
More detailed info you can see in LINK DELETED.
February 26th, 2010, 08:44 PM
You post reads like an advert... It's hard enough to get CoQ10 to cross mucosal surfaces, let alone the skin. Would love to see some research showing that this is effective as a topical cream. Generally speaking, the "active ingredient" in cosmetic products, be it CoQ10, "pentapeptides" or any other similarly sciencey-sounding compound, are not readily absorbed by the skin, are typically adsorbed instead and are present in concentrations too low to be effective either way. They're just a useless hook used to sell moisturisers which actually differ very little from brand to brand.
I'd also question whether you'd really want CoQ10 to work well in your skin. Sure, it'll stop those nasty free radicals. But since your skin leukocytes use free radicals to kill pathogens, that's a double edged sword.
Beautifully put. Belated response, I know.
there are many reasons why arresting the aging process would be a disaster. first, the life death cycle is necessary for evolution to continue in an ever changing environment. second, it would speed up immensely the already dangerous population explosion. this would lead to war, disiease, and famine...and people would die anyway. of course u can put limits on births...but that can be problematic for two reasons. first...see point number one on evolution. second...people are always going to die...so births will still be necessaary but highly regulated. this can get ugly. of course, u can limit aging for the privileged few...but this would no doubt lead to a revolt. not to mention that these people will eventually feel out of place as the rest of humanity evolves. and then u have to ask what happens when the brain eventually becomes saturated with memories...we're not equipped with an infinite hard drive.
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