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Our closest worm kin regrow body parts, raising hopes of regeneration in humans

washington.edu

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Re: Our closest worm kin regrow body parts, raising hopes of regeneration in humans

#141

Post by Retric »

erelde wrote: post #114
dualogy wrote: post #109

Earlier quoted context omitted.

> This, to me, brings up the question of "where does myself ends and where does my environment begins?". Good question this! Until you find a conclusive answer, ie. until you clearly define/delineate "myself" & "env", you can ignore your follow-up question as irrelevant sophistry: > I could change parts of my brain like I'm changing the environment around me, what would I be changing, the environment around me or mys…

That question is exactly what I'm asking, what is "myself" and what is "the environment as defined around myself". And I'm pretty sure there's no clear answer, but the question and reasonings ensuing are interesting. By one definition, my possessions, my experiences, my social network would be part of myself. So changing my brain wouldn't be changing myself per se if those remained the same. Another definition would…

Self has no universal meaning robbing the question of any real value. You could include or exclude gut bacteria from you just as easily as you include or exclude identical clones, but that's just an outgrowth of your definition and says nothing about reality.

Re: Our closest worm kin regrow body parts, raising hopes of regeneration in humans

#143

Post by toasterlovin »

coldtea wrote: post #104
toasterlovin wrote: post #90

Earlier quoted context omitted.

Living for a long time after you have children is incredibly useful from the standpoint of genetic fitness. After all, grandparents play an important role in pretty much every human culture. And a grandparent with all their body parts is a whole lot more useful than one without.

> Living for a long time after you have children is incredibly useful from the standpoint of genetic fitness. After all, grandparents play an important role in pretty much every human culture. In the time scale that matters to evolution, grandparents played absolutely no role for the Homo Sapiens, and neither did culture.

Do you have children? Raising children is hard. And it's a lot less hard when you have other adults to help. Historically, those would be grandparents and aunts/uncles. But aunts/uncles would probably have children of their own.

Re: Our closest worm kin regrow body parts, raising hopes of regeneration in humans

#144

Post by logfromblammo »

sfink wrote: post #71

From what I've understood from things I've read on the past, we do have pretty much full regenerative ability already. It is blocked by various things, such as the epidermis. If you chop off a finger, a blastula of stem cells will develop on the tip, at least until the skin grows over and stops it. If you could hold back the skin, then... well, you'd die of an infection in very short order. Waiting for regeneration i…

As I understand it, scarring and regeneration are mutually exclusive. The advantage of regeneration is that you get the body part back. The advantage of scarring is that you don't bleed to death or get a fatal infection while waiting for the wound to close.

In larger animals, formation of scar tissue had a greater survival advantage. So humans scar instead of regenerating.

The regeneration capacity is probably all still there in humans, but it is never been observed in modern times, except after losing less than about 1 cm of fingertip. It may not be a matter of how to turn regeneration on, but how to turn scarring off.

Re: Our closest worm kin regrow body parts, raising hopes of regeneration in humans

#145

Post by toasterlovin »

derefr wrote: post #110
toasterlovin wrote: post #90

Earlier quoted context omitted.

Living for a long time after you have children is incredibly useful from the standpoint of genetic fitness. After all, grandparents play an important role in pretty much every human culture. And a grandparent with all their body parts is a whole lot more useful than one without.

The counterpoint being that in resource-scarce evolutionary environments, every grandparent (or even parent) that stays around is consuming resources that could instead go toward creating+maintaining an additional child.

That's assuming that they consume more resources than they extract from the environment. And then there's also that grandparents can use the power and influence they've accumulated to benefit their grandchildren.

Re: Our closest worm kin regrow body parts, raising hopes of regeneration in humans

#146

Post by ogrisel »

skriticos2 wrote: post #133
ogrisel wrote: post #122

Earlier quoted context omitted.

Indeed virii are part of the evolutionary process and can insert genes into hosts from various species. Such genes can be successful from an evolutionary standpoint even if some of the host species disappear.

Not contradicting your core argument (though I'm sceptical about the significance in impact of this process), but you are certainly apt at mutating grammar: the plural of virus is viruses - not virii. http://english.stackexchange.com/questions/3838/viruses-or-v... ps: this is like kerning, you can't unsee it.. http://xkcd.com/1015/

Thanks :)

Re: Our closest worm kin regrow body parts, raising hopes of regeneration in humans

#147

Post by Grishnakh »

avodonosov wrote: post #26
jonknee wrote: post #15

Earlier quoted context omitted.

> If somehow we can stay alive as a species long enough we very well might be able to discover the secret to regeneration and immortality in some way. Hopefully we won't figure that out before we figure out how to not overcrowd Earth.

Forbid procreation for those who chosen immortality. If you decided to spawn children, then free space for them - die. (Or go cryopreservation and be kept in a small box occupying little space. In this case you and your decedents can live in turns: they live for one century while you sleep frozen; next century other way around).

That's really not necessary. "Immortal" people aren't going to live forever; something is eventually going to kill them, like a speeding bus, or a skydiving accident, etc.

Also, it's been proven over and over that when people have more education and resources, they breed a lot less, which is why all the developed nations are looking at zero or negative population growth if you ignore immigration. Make people biologically immortal and they'll end up not having many kids at all, on average.

I think you're worried about something that isn't going to be a problem.

Re: Our closest worm kin regrow body parts, raising hopes of regeneration in humans

#148

Post by BurningFrog »

ThrustVectoring wrote: post #100
BurningFrog wrote: post #39

Earlier quoted context omitted.

Another exception would be if a limb has fallen off or otherwise failed. Then it would be great to be able to turn regeneration on, for that limb only. Any added risk should be much smaller than the always-on version.

That's a bit much to expect out of evolution. First it needs a way to detect whether a limb has fallen off or otherwise failed. Then it needs to send a biochemical signal to the cells in the area iff the limb in the area failed. Then it needs to activate the regeneration iff the chemical signal is present. And each of these mutations has to be beneficial to the organism (or at least randomly there and costless). You…

I agree. What I was thinking (but didn't say) is that maybe we can make that happen with technology!

Re: Our closest worm kin regrow body parts, raising hopes of regeneration in humans

#149

Post by chei0iaV »

PeterisP wrote: post #18
SilasX wrote: post #7

Earlier quoted context omitted.

>Well, a plausible answer is that if we (or random mutations) re-enable those genes then the end result is simply a lot of cancer. Interesting idea, but does the risk of cancer have that much selective pressure? It tends to be the "last thing that kills you", after you live long enough to survive everything else. So it seems like any increased risk of cancer would have to be pretty high before it traded off against i…

For large animals, I'd believe that it's very rare to have non-fatal injuries that are large enough where regeneration would make a big difference to future life. According to evolution (which hasn't yet noticed medicine), if something rips off your foot, that's not an injury, you simply bleed to death or die of infection even if you win the fight - unlike, say, various small regenerating lizards. What selective pres…

> if something rips off your foot, that's not an injury, you simply bleed to death or die of infection

That's a false premise.

Plenty of (four-legged) animals can survive just fine without a leg - in fact, it's often said that animals have a spare leg. Some animals might even gnaw their own leg off it's stuck in something and they can't get it out.

Re: Our closest worm kin regrow body parts, raising hopes of regeneration in humans

#150

Post by SilasX »

PeterisP wrote: post #18
SilasX wrote: post #7

Earlier quoted context omitted.

>Well, a plausible answer is that if we (or random mutations) re-enable those genes then the end result is simply a lot of cancer. Interesting idea, but does the risk of cancer have that much selective pressure? It tends to be the "last thing that kills you", after you live long enough to survive everything else. So it seems like any increased risk of cancer would have to be pretty high before it traded off against i…

For large animals, I'd believe that it's very rare to have non-fatal injuries that are large enough where regeneration would make a big difference to future life. According to evolution (which hasn't yet noticed medicine), if something rips off your foot, that's not an injury, you simply bleed to death or die of infection even if you win the fight - unlike, say, various small regenerating lizards. What selective pres…

I see what you mean, but it still seems like cancer resistance is a bit "overengineered" relative to what you'd expect from selection pressures. If typical cancer onset were e.g. at age 50 rather than 70, I don't imagine that having much selective relevance in the human ancestral environment, as you'd have raised child-bearing children at that point (and you probably can barely carry your own weight at that point, metaphorically speaking).

OTOH, cancer rate is probably superlinear with respect to error rate, so a small loss of cell instruction robustness corresponds to a disproportionately shorter lifespan.

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