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> Carell, an organic chemist, and his collaborators have now demonstrated a chemical pathway that — in principle — could have made A, U, C and G (adenine, uraci
by aazaa 7y ago
> Carell, an organic chemist, and his collaborators have now demonstrated a chemical pathway that — in principle — could have made A, U, C and G (adenine, uracil, cytosine and guanine, respectively) from basic ingredients such as water and nitrogen under conditions that would have been plausible on the early Earth. The reactions produce so much of these nucleobases that, millennium after millennium, they could have accumulated in thick crusts, Carell says. His team describes the results in Science on 3 October.
> The results add credence to the ‘RNA world’ hypothesis, says Carell, who is at the Ludwig Maximilian University of Munich in Germany. ...
It's worth noting that what was made were nucleobases - flat very low molecular weight molecules - that when attached to ribose yield nucleotides.
It is nucleotides, not nucleobases, that form RNA.
The "RNA world hypothesis" still needs to explain where the ribose came from, how it was joined with the bases that were supposedly littering the Earth's surface, and how the resulting nucleotides started spontaneously assembling themselves through combination with phosphate into polymers.
That's a very, very tall order in chemistry.
- hinkley 7y agoThere's a multiverse theory that there are many possible or existing universes with different physical constants, affecting everything from chemistry to orbital mechanics, and the reason we are having this conversation is because this universe was conducive to the formation of highly organized lifeforms capable of abstract thought. In this line of reasoning "Why this set of constants" doesn't matter, because only the universes that could have observers would be observed.
- builderburg 7y agoThe anthropic principle doesn't depend on a multiverse.
- chrisshroba 7y agoNot on a multiverse directly, but I think there is merit to @hinkley's claim. Say there's a one trillionth chance that life forms on an earth-like planet. There are likely trillions of earth-like planets, so chances are good (given the assumptions) that life forms on (at least) one of those planets. People on that planet (Earth) will marvel that life was created and search for reasons that seem plausible and likely for life to have been created given the initial conditions, but the initial assumption that the chances were minuscule still remains. That is to say, we may not be able to easily predict and rationalize the beginning of life based on the initial conditions of the earth, because it is likely that it was an improbable fluke. It feels like a lottery winner trying to explain how they won the lottery.
- ramshorns 7y agoOne of the things we're trying to figure out is how likely life is to form on an Earth-like planet. Of course it happened here, but we have no idea how common it is. If we do the chemistry and figure out the mechanism and it looks like it happens all the time, then that tells us one more term in the Drake equation and gives us a reason to go check out the exoplanets.
- hinkley 7y agoI don’t disagree that having tighter bounds for the Drake equation is worth investing time and energy into. I think we are going to find that the preconditions for life are quite common. The way solar fusion and supernovas work, what atoms are produced, The distribution of material and of those atoms within an accretion ring... if a planet forms at the right distance, then it will have the mix of chemical precursors. Honestly I suspect the only thing that makes Earth rare is our freakishly large moon. If we can ever prove that life is viable on a timescale of eons on a planet without such huge tidal forces pumping the biosphere, that will be a revelation.
- goldenkey 7y agoSo the moon stirred the biosoup in a way only an earthmoon sized moon could? And then life formed?
- tapland 7y agoWow. You just found a reason for you not to get into science. Now most of the rest of us are still curious to find out how stuff works around here.
- hinkley 7y agoAnd I just found a reason you should adjust your chemical intakes. Too much caffeine or not enough? You don’t know me, or how I work.
- JohnJamesRambo 7y agoNone of what you said remotely answers their question.
- bduerst 7y agoI agree, but keep in mind abiogenesis is probably one of the tallest orders for chemistry. I'm glad scientists are at least exploring possible explanations, even if it means possibly disproving the mechanisms.
- CobrastanJorji 7y agoOf course! Disproving known stuff is the best thing about science.
- SomeOldThrow 7y agoWhat are the alternatives? Even with panspermia life would have had to begin elsewhere. The universe would have been too hot at the Big Bang to support organic molecules if that theory is true. Even with “intelligent design” the intelligence would have its own heritage and origin. The implications of an alternative to abiogenesis seem outside the realm of scientific inquiry entirely. Is the desire here a coherent, detailed narrative for how we went from hot plasma to RNA?
- novalis78 7y agoIf nothing else Panspermia allows for more time assuming a similar chemical process but over a much longer time horizon than ancient Earth.
- Smithalicious 7y ago>Even with “intelligent design” the intelligence would have its own heritage and origin Is this really a given? Certainly there must be something in the universe that "started it all" and has no origin of itself. Or, alternatively, everything in the universe has a history stretching back infinitely far, but that's equally incomprehensible and still allows you to perform the same "trick" (in this case: life has always existed). Not saying that I believe in intelligent design, but in this case it seems to me that it does answer a question without creating any new ones.
- qubex 7y ago
- Fjolsvith 7y agoAnother way that nucleobases could have formed were in ice [1]. 1. http://discovermagazine.com/2008/feb/did-life-evolve-in-ice http://discovermagazine.com/2008/feb/did-life-evolve-in-ice
- jeffdavis 7y agoWhat are the alternative theories that are more plausible, in your opinion?
- mrwhizzer 7y agoDNA teleportation.., the recent discussion on HN about the hydrophobic effect of DNA basically proves it is true... naysayers be damned! https://en.m.wikipedia.org/wiki/DNA_teleportation https://en.m.wikipedia.org/wiki/DNA_teleportation https://news.ycombinator.com/item?id=21051949 https://news.ycombinator.com/item?id=21051949 https://en.m.wikipedia.org/wiki/Water_cluster https://en.m.wikipedia.org/wiki/Water_cluster http://www1.lsbu.ac.uk/water/magnetic_electric_effects.html http://www1.lsbu.ac.uk/water/magnetic_electric_effects.html
- deleted 7y ago[deleted]
- rygh 7y agoFirst you have some shell script, then you have static code (dna)?
- kremi 7y agoIndeed, the author does recognize it: > The next major problem Carell wants to tackle is what reactions could have formed the sugar ribose, which needs to link to nucleobases before RNA can form. Possibly something resembling the Calvin cycle could be the start you talk of. [1] [1] https://link.springer.com/article/10.1007/s00239-018-9840-1 https://link.springer.com/article/10.1007/s00239-018-9840-1