It would be good to regenerate at least teeth.
I believe the hairs within the ear also don't regenerate (leading to deafness when damaged through loud noises).
Our closest worm kin regrow body parts, raising hopes of regeneration in humans
121–130 of 167 posts
Re: Our closest worm kin regrow body parts, raising hopes of regeneration in humans
#122A 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. Depending on which view you take, evolution can be seen optimized for the survival of individual genes, not species[0]. In Dawkins' book, bodies are portrayed as mere useful survival vehicles for various genes. (I'm ignorant on this, would love to read counterarguments from someone better versed!) [0] https://en.wikipedia.org/wiki/Gene-cen…
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.
Re: Our closest worm kin regrow body parts, raising hopes of regeneration in humans
#123Re: Our closest worm kin regrow body parts, raising hopes of regeneration in humans
#124Earlier quoted context omitted.
Regenerating body parts doesn't happen because it is hugely expensive in terms of biochemical resources. Teeth are the most materially expensive parts of the human body. That is why teeth are often the most long lasting and best preserved human remains.
And yet, sharks do it. Also, the skeleton is similarly long lasting and that gets renewed. So why not? Say a finger, which isn't too "expensive in terms of biochemical resources", why not regrow that? Take the acorn worm mentioned, in proportion to the worm regrowing itself must be really expensive. I don't think this too expensive argument explains it.
Shark also have rows of them.
Re: Our closest worm kin regrow body parts, raising hopes of regeneration in humans
#125Earlier quoted context omitted.
The ability to regenerate body parts and cancer are not inextricably linked. Take the axolotl. It has the ability to regenerate entire limbs. It's also estimated to be a couple orders of magnitude more resistant to cancer than humans.
Maybe that's the ticket? The cancer resistance is something that allows the axolotl to also keep regrowing limbs around in the genome?
There are also many animals who are long living, and immune to cancer (to varying degrees). Naked mole rats live up to 30 years and almost never get cancer (only one case formally verified so far).
Elephants have many more cells than us, and live to almost the same age, but only have a 5% chance of getting cancer, vs 10%-25% in humans. Lions have a 2% chance of getting cancer.
Re: Our closest worm kin regrow body parts, raising hopes of regeneration in humans
#126I'm a huge believer that humans can cherry-pick the best traits of many different species and apply them to ourselves. It might sound like science fiction right now, bit give it time and we humans will have unlocked some crazy things that we claimed to be "impossible." It's always impossible until it's done. And to be honest, I think the second something is thought of, it becomes possible. I live for this shit.
I don't think you're wrong, but I think there can be a lot of unintended, bad consequences. Especially if we start doing germline editing, where results might manifest themselves generations later when it's far too late.
Re: Our closest worm kin regrow body parts, raising hopes of regeneration in humans
#127Well, a plausible answer is that if we (or random mutations) re-enable those genes then the end result is simply a lot of cancer. A reasonable default assumption is that each switch in our "genetic configuration" is set to a quite good value. The only exception is if we see a feature that is beneficial at a high calorie cost - those features have been (reasonably) optimized away during our evolution, but would be use…
>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…
Cancer tends to be "the last thing that kills you" in much the same way your keys are always in the last place you look. A significant amount of cellular regulation is devoted to preventing runaway cell division, and sometimes in long-lived and large-bodied organisms those defenses eventually give way.
Re: Our closest worm kin regrow body parts, raising hopes of regeneration in humans
#128A 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…
This idea can be applied to any species, and yet, there are animals who regrow body parts - octopus can regrow tentacles, crayfish and lobsters can regrow claws, salamander can regrow tail and limbs, etc.
Re: Our closest worm kin regrow body parts, raising hopes of regeneration in humans
#129seems to me that when the original generation of organs, bones, and other structure is occurring, there is a chemical soup of proteins/hormones/etc that provides the right environment for a whole host of gene expressions not seen after the generation is done and the organism is more or less fully formed. recreating that environment seems challenging. it's like getting back to bios after you already booted the OS.
Re: Our closest worm kin regrow body parts, raising hopes of regeneration in humans
#130But when then if you cut of an arm - do the body then regenerate a new arm and the cut off arm a new body ?