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Axolotl Genome Slowly Yields Secrets of Limb Regrowth
- deleted 8y ago[deleted]
- reasonattlm 8y agoIn terms of gaining knowledge about the most relevant mechanisms in proficient regeneration, ARF seems important, and human ARF can shut down zebrafish regeneration [1]. That implicates the evolution of cancer suppression mechanisms as the reason why most higher species are not all that great at regeneration. Further, the dance between macrophages and senescent cells during regeneration seems highly influential in the quality of regeneration, whether the path to scarring versus the path to regrowth is chosen. This is found in the few examples of proficient mammalian regeneration such as the spiny mouse [2], as well as in salamanders and zebrafish. Salamanders exhibit much more efficient creation and clearance of senescent cells in regenerating tissue, for example. [3] [1]: https://www.ucsf.edu/news/2015/11/251746/human-gene-prevents-regeneration-zebrafish https://www.ucsf.edu/news/2015/11/251746/human-gene-prevents... [2]: https://uknow.uky.edu/research/uk-researchers-identify-macrophages-key-factor-regeneration-mammals https://uknow.uky.edu/research/uk-researchers-identify-macro... [3]: http://dx.doi.org/10.7554/eLife.05505 http://dx.doi.org/10.7554/eLife.05505
- toomuchtodo 8y agoBased on your post and profile, mind if I ask a question? How much further does this move us along on human regeneration as it relates to aging?
- reasonattlm 8y agoOne would have to speculate; it is very unclear. Proficient regeneration seems like it would be a good thing to pair with restoration of stem cell function, but without the restoration of stem cell function it might not be too helpful. As a general rule building a new human biology is hard. Even making tiny tweaks to our existing biochemistry, such as calorie restriction mimetics, is proving to be very challenging to do effectively and safely. Reverting to the known good youthful state on the other hand, is less complex. So I'd expect delivery of replacement stem cell populations to be a going concern long before adjustments that produce MRL-like or spiny-mouse-like regeneration in humans. The feature of aging that proficient regeneration seems most likely to help with is the business of fibrosis (liver, kidney, heart, lungs), where regeneration runs awry into excessive scarring, and damage to organs like the heart that do not repair themselves. Equally, it might have to be controlled very carefully in organs where structure is important, which would limit any early application. Recent experiments with cell therapy in the heart in monkeys produced disruption of heartbeat because of the formation of biological pacemarkers outside the normal parameters, for example.
- toomuchtodo 8y agoThank you for taking the time to reply.
- fratlas 8y ago"replacement stem cell populations" You expect us to be able to revert the ageing process through stem cells? Any stem cells or specifically those of the host? How far off do you estimate (order of magnitude - 10/100/500 years?)
- mkempe 8y agoRed/Green/Blue Mars implies that it's within the lifespan of the current generation between 30 and 50.
- matte_black 8y agoIs there a catch to regenerated limbs? Maybe weaker, more cancer prone, or faster aging?
- DennisP 8y agoWhat I read once: when you're a wild animal in the wilderness, just scarring over the wound sometimes gets you back in action faster than regrowing the limb, and that's a survival advantage. If that's the main reason evolution usually went this direction, then maybe there's not much downside for modern folks.
- abledon 8y agoNo? Fun fact: young children who have finger tips cut off sometimes can regrow them https://www.npr.org/sections/health-shots/2013/06/10/190385484/chopped-how-amputated-fingertips-sometimes-grow-back https://www.npr.org/sections/health-shots/2013/06/10/1903854...
- sxdx 8y agoIf the cut is clean, i.e. amputated by a scientist or vet there are no drawbacks to the regenerated limbs, but if they get into fights with other axolotls and the limbs are "half-off" they sometimes regrow deformed.
- daemonk 8y agoI'd never thought they would actually assemble this genome. But put together the father of string-graph assembly (Eugene Myers) and a shitload of money (PacBio reads), and you get an assembly of a 32gb genome.
- bumblebritches5 8y agoI just looked up how large the human genome is in bits (when the 4 bases are packed into 2 bits per base) the size of our genome is about 770MB. Is the Axolotl's genome really 42.5 times larger than ours?
- stochastic_monk 8y ago3 billion bp in a haploid human genome, 6 billion in a full diploid one. If you store the masked/unknown/variable ranges as annotations on the side, you can get away with close to 2 bits per base, as you suggested. The axolotl haploid genome is 32 Gbp, which, in 2-bit encoding and ignoring masked bases, takes 8GB to store. Axolotl, like humans, is diploid, meaning it has 2 copies of each chromosome. That’s only about 10 times the size of the human genome. That being said, the complexity of a genome doesn’t scale with size. Many plant genomes are gargantuan but highly repetitive. The Kolmogorov complexity of a genome would better predict the complexity of the organism than a genome’s length would.
- raverbashing 8y agoI wonder how that competes with the latest generation of Flash memory in terms of (physical) storage size and mass. Though storage capacity is growing, it seems DNA still wins by some margin though
- Thiez 8y agoFlash memory has considerably better read/write speeds. It can also be read electronically instead of chemically. I don't think it makes sense to compare them.
- mr_spothawk 8y ago""" In 1952, a scientist named Charles Breedis injected coal tar and other known carcinogens into the arms of more than 500 newts — amphibians related to salamanders that can also regenerate. Only two animals grew tumors. Much more often, the newts responded by sprouting an extra arm. If scientists can crack how a carcinogen triggers that kind of regenerative growth, it would be “some kind of holy grail” for this area of research, Whited said. """ the article has an editorial tone around the distinction of lab vs. natural populations. it starts with an acknowledgement of the consequences of the lab on the animals (losing limbs). hard to argue with the holy grail, tho.
- ekianjo 8y ago> they hardly get cancer this is based on what, a few thousands individuals from that specie? on that kind of sample size humans also hardly get cancer, unless humans get really old. Not sure that statement can be substantiated.
- onychomys 8y agoThe singular of species is species. The only person allowed to say "specie" is Vincent Price at the beginning of Alice Cooper's song "Black Widow", because he's a badass like that.
- stevesimmons 8y ago"specie" is money in the form of coins. Nothing badass about it!
- smt88 8y agoAccording to American Cancer Society[1], 40% of humans get cancer. Of those, more than half are killed by it. Further, half of all cancer cases are seen in people under 50[2]. Axolotls are amazing and unusual in many ways, and their cancer rates are one of those ways. 1. https://www.cancer.org/cancer/cancer-basics/lifetime-probability-of-developing-or-dying-from-cancer.html https://www.cancer.org/cancer/cancer-basics/lifetime-probabi... 2. https://www.cancerresearchuk.org/health-professional/cancer-statistics/incidence/age#heading-Zero https://www.cancerresearchuk.org/health-professional/cancer-...
- manmal 8y agoAn N of a few thousand should be high enough to have a fairly high confidence for the more common cancers.
- brian-armstrong 8y agoI can’t help but feel a little bad about the mass amputation happening in these labs. Of course these are lower animals, but don’t we lose a little of our humanity doing this?
- andai 8y agoI am roughly equal parts excited and sad.
- yani 8y agoIf they regrow it and it is painless... it is like removing the wool from a sheep.
- callesgg 8y agoWhy would it be painless?
- jhoh 8y agoIf the chances of dying after loosing a limb aren't very high it just doesn't make sense to develop (extreme) pain from an evolutionary perspective.
- jazoom 8y agoThe chance of me dying from placing my finger on the stove is 0%, but I assure you the pain is severe.
- smt88 8y agoYou can't regrow your finger, and having working fingers would've been useful for survival for nearly 100% of your ancestors (the ones that had digits, that is). There are lizards who lose their tails painlessly as a way to escape predators. If they felt pain in that situation, they might die, so it would've been selected out over time.
- 8y ago
- sxdx 8y agoFascinating animals, I keep several of them as pets. Sadly they are basically extinct.
- deleted 8y ago[deleted]
- userbinator 8y agoThe wild ones, yes. But the ones used in research and kept as pets are essentially domesticated and breed readily.
- louithethrid 8y agoWhat if i steal somebodys finger, and keep it alive and it regrows into a whole new person? Is involuntarily cloning evil?