Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

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

washington.edu

Post reply on HN
Print view View original

111–120 of 167 posts

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

#111

Post by devoply »

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.

Often grandparents will starve to keep grandkids alive. Grandkids eat first.

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

#112

Post by tachyonbeam »

devoply wrote: post #82
xux wrote: post #74

A lot of people are focusing on the mechanics, but it seems like humans don't generate body parts just like cells don't generate organelles. The entity is not _meant_ to exist by itself, but form a cohesive living group. A cell doesn't need to repair itself, it can simply clone itself and then die. A human being doesn't need to regenerate itself because it can reproduce and be cleared away. Evolution evolved to ensur…

> Evolution evolved to ensure the survival of the species, not the individual. At some point in our evolutionary history the cells in our body made this choice. Evolution favors survival and potentially reproduction, because otherwise you are no longer in the game. So there was some evolutionary constraint that caused those genes not to regenerate parts. It's possible we can change things so that those genes are acti…

It doesn't have to be all about the evolutionary fitness of regenerating limbs. I think it might just be that losing a limb (and having the opportunity/time to regrow it) may have been a fairly unlikely event. Possibly, those genes mutated and were broken, right around the same time that some other genetic advantage evolved that caused a huge gain in evolutionary fitness.

The ability to regenerate limbs could have been lost in mammals simply because some old pre-mammal who happened to have broken regeneration genes was smarter and much better at finding food than the rest, and went on to pass his/her genes to all of us.

Furthermore, the evolutionary advantage of regenerating limbs may not be much in most animals. It's something we really would like to have, But imagine that some ancient primate species was able to regenerate limbs. Under what scenario do primate lose limbs? When some tiger chews them off? If that was ever to happen to a primate, it was basically fucked. Even if the tiger didn't eat it, it didn't fare very well lacking an arm for several months. The primate that is better at spotting tigers and avoiding them has much higher evolutionary fitness.

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

#113

Post by devoply »

vacri wrote: post #108
arcticfox wrote: post #96

Earlier quoted context omitted.

> Evolution only requires that you get to reproduction, however that happens. It doesn't require that you're happy, sad, whatever, just that you reproduce. It requires that your offspring actually survive as well. Humans are, at least historically, exceptionally well-equipped to influence the survival of their offspring.

Humans also take figuratively forever to be self-sufficient. Herd animals are born with the ability to walk, for example. Humans take about 10 years before they can be taught to be even somewhat self-sufficient, which is a ridiculously long time in comparison to others. So, given that humans are sexually mature before they're fully self-sufficient, that enhanced ability to support their offspring is not all advantage…

A 7 or 8 year old can hunt if you were to teach them to do so. An 8 year olds has conceived. So it's possible to do it at a much younger age if you have no choice.

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

#114

Post by erelde »

dualogy wrote: post #109
erelde wrote: post #107

Earlier quoted context omitted.

This, to me, brings up the question of "where does myself ends and where does my environment begins?". 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 myself directly? Both? Classic greek Boaty McBoatface question I know. (cf Ship of Theseus )

> 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 be the strictly biological body, and of course changing the body would be changing the self.

But there's a fuzzier definition where something in the brain brings up "consciousness" and a sense of self, if I change something in the brain that isn't that particular part, the sense of self, have I changed the self or not?

(I can see my French high school teaching re-surging here...)

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

#115

Post by avodonosov »

Jtsummers wrote: post #52
avodonosov wrote: post #26

Earlier quoted context omitted.

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).

May want to read "2 B R 0 2 B" by Vonnegut.

thanks for the reference

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

#116

Post by namaemuta »

If this were possible, I wonder how our new limb would grow. Would it be a reconstruction of the structure of the old limb or would it grow like a child limb and take the same amount of years (18-20) to reach the adult stage of the limb?

Edit: replaced limb instead of member.

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

#117

Post by fourstar »

avodonosov wrote: post #35

It would be good to regenerate at least teeth.

http://www.dailymail.co.uk/sciencetech/article-3676060/The-e...

http://www.cda.org/news-events/learn-about-stem-cell-tooth-r...

I've spoken to Dr. Vining and it's probably about 50-60 years out in practice.

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

#118

Post by Terr_ »

namaemuta wrote: post #116

If this were possible, I wonder how our new limb would grow. Would it be a reconstruction of the structure of the old limb or would it grow like a child limb and take the same amount of years (18-20) to reach the adult stage of the limb? Edit: replaced limb instead of member.

FYI, referring to a body-part like "his member" is often a euphemism for penis, so your post is (unintentionally?) amusing to read.

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

#119

Post by simonh »

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.

I don't think that's at all likely. We've had fire and had the physiological adaptations enabling speech for well over a million years. We've been manufacturing complex tools such as spears with stone tips for about half a million years, to Homo heidelbergensis. Even Ergaster had lifespans allowing survival to an age where grandchildren could reach adulthood, allowing for skills transfer.

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

#120

Post by namaemuta »

Terr_ wrote: post #118
namaemuta wrote: post #116

If this were possible, I wonder how our new limb would grow. Would it be a reconstruction of the structure of the old limb or would it grow like a child limb and take the same amount of years (18-20) to reach the adult stage of the limb? Edit: replaced limb instead of member.

FYI, referring to a body-part like "his member" is often a euphemism for penis, so your post is (unintentionally?) amusing to read.

Unintentionally. In my defence I have to say that the term is correct but I get your point. I've replaced it for limb hoping the question will be taken more seriously.
Post reply on HN