RNA gets made from pure, energy-rich molecules that themselves are quite complex. This soup of pure monomers isn't something that just arises naturally in the absence of life. Prebiotic chemistry produces a random soup of a wide variety of chemical species, with the abundance of each declining exponentially in its size and complexity.
You see this issue all the time in origin of life claims. For example, that recent result of "all the bases of RNA and DNA were found on this asteroid by the Japanese" tended to slide over the fact that they were there at extremely low levels, mixed with huge numbers of other non-biological organic molecules.
Trying to replicate RNA in a mix of random crap will just give you polymers of crap, if it gave you anything at all.
OoL needs an idea that will work in a soup of junk, not in massively artificial pure soup on a lab bench.
The research does something like this. You run an experiment and show some chemicals are present in low concentration. You say "ah ha, we've shown one step". Those chemicals are now taken off the shelf in high concentration and used in the next experiment, which makes slightly more complex chemicals in low concentration. Repeat this multiple times until done.
Lampooning this, the fictional OoL researcher in the book also demonstrates that monkeys can type out "To be or not to be, that is the question" on a typewriter. He arranges the typewriter with an automatic right margin and lets them type away until he gets a line starting with "T". First letter demonstrated! Now he rereun the experiment, but now with paper the "T" in the first column and margins set to the second column. Repeat this with subsequent letters until the entire sentence is produced. Of course, the monkeys didn't type the sentence, the researcher did.
Getting around the exponential complexity barrier is the whole goddamn point, it's not something to just wave away with a "we don't know" comment.
IMO some fundamentally new idea is needed for OoL.
About that, not that long ago I was entertaining the idea of what environments can be completely devoid of life. I was thinking about examples like a volcano Cauldron, a nuclear reactor or the insides of a particle accelerator.
Ever since I first learned about it, it seems to me a much more likely origin of life hypothesis, as it doesn't require something to catalyze itself, which causes inevitable problems with mutation causing loss of catalytic efficiency.
Also, it is not incompatible with RNA being one of the early building blocks. It just doesn't require RNA to be where everything started.
I don't think you can say this with certainty. It is assumed that life and evolution go hand-in-hand from the beginning but it is not proven to be the case.
Of course, the are too many limitations for evolving into some more complex, but they can self-replicate and they can infect other organisms. If we could give them an oceanic soup of PrPC and enough time, who knows?
Isn't the building block that a prion requires to create a copy of itself essentially a chemically almost-identical protein that is just folded differently?
How about an alternative analogy of the prion folding pattern spreading through chemically-similar molecules like a meme through a population of similarly conditioned brains?
This is where the hard part of the field is currently: finding chemistry that can support accurate RNA copying that is also both sufficiently high yielding and also compatible with these reactions being inside protocells (fatty acids for example). An RNA genome only really has value when it can be selfish and keep any innovations it makes to itself inside a protocell!
I work in Origins Research - if you have questions please ask and ill try to answer with the current opinions of the field!
†one note about my em dashes: I am a real person who thinks evolution AND em dashes are cool and for a total aside: it’s such a bummer people think I’m a bot just because I like tinkering w/ f* punctuation marks.
Good source that develops on this?
https://en.wikipedia.org/wiki/Ribosomal_RNA#Sequence_conserv...
Most mutations are negative dead-ends, not unlikely DNA now where most pregnancies spontaneously abort due to errors. But life has many, many chances — especially at the molecular scale. So what’s the actual problem?
Similarly, if you have a soup of 10-15 nucleotide sequences, what are the odds actually that they’d link into larger segments?
Let’s suppose that density is a million times lower than blood, so you have one picogram per gram of water. There are 10^24 grams of water on Earth’s surface and 10 base pairs weighs 10^-20 grams, giving us approximately 10^32 segments of that length.
Feel free to play with my numbers, but I’m supposed to believe that with ~10^30 pieces, we can’t have ten of them form the right sequence?
A combinatorial explosion. To have mutations you need to have replication first. If a smallest viable self-replicator is, say, 100 nucleotides long, and there's not many other such replicators of the same length, the improbability of its spontaneous formation (~4^-100) dwarfs any amount of material available on Earth.
The researchers have found QT45 replicator. But it replicates other RNA strands, that is it needs another replicator nearby to replicate itself, which brings the probability down to 4^-90 range.
And it's not clear from the article whether QT45 is a viable replicator. That is whether it is stable enough and replicates other RNA strands correctly enough to sustain exponential growth instead of petering out due to filling its surroundings with broken copies that don't perform replication before decaying itself.
Imagine you have molecules that can form spontaneously, like gliders in Conway's Game of Life. You may have several different molecules that are capable of helping to create one another -- an autocatalytic set.
Eventually this could result in more complex chains, and eventually a self replicating molecule can arise.
Imagine slamming a bunch of gliders together to make a machine that replicates more gliders. It's possible! Not likely, but there are so many variables that can influence the environment substantially. It's not like there was a giant homogeneous soup. Parts from over here and over there would form differently and when they meet, amazing things can happen.
In the Game of Life, this spontaneous event is extremely unlikely, astronomically unlikely.
Unlike Game of Life, the real world has a few advantages that improve performance. For one, it's less fragile. Bonds are much stronger and collisions don't cause everything to break. Another advantage is that bonds are attractive: molecules can rotate and turn to snap together strongly. Gliders just explode violently. And finally, the real world is very dense. We're talking trillions of molecules mixing around millions of times per second per microdroplet. Compound that with a few hundred million years... it certainly doesn't feel as surprising as you might expect.
If there were a highly advanced alien race watching earth over a long period of time, it might be interesting, but not unexpected, that suddenly an Eiffel tower springs forth from the surface of the planet, erected by intelligent organisms.
Let's say that you have some RNA soup with some ribozymes some of which weakly encourage some reaction involving other RNA molecules. The occurrence of a cycle of reinforcing reactions might be sufficient to build a crude evolutionary ratchet.
In fact the "cycle of reactions" perspective feels a bit more robust to me since it allows for the proto-replication process to take place over a longer period of time and over larger areas.
Core wars (1984) strongly favored short replicators, so at least in some possible universes complexity growth is not a given.
What's the probability of spontaneous formation across an infinite universe?
Interestingly we now are thinking about ways to use mutations in other ways, youve spent a lot of energy making these polymers, so it would be a shame to waste that right? We think that they can be used to assemble larger functional pieces as mutations are mostly deterministic meaning you'll get the same kinds of errors - so why not put them to use!
Early on that may have been a feature though, isn't it?
What strikes me as the most interesting thing about life is that almost immediately (on geological time scales) after Earth had developed an environment where life in theory could exist it came to be. That suggests strongly that the mechanism to do so was relatively simple. Then again, the Earth was a vast laboratory and it only has to happen once.
aside: you have the most interesting job!
"Life's first molecule." Take your favorite quantum field theory and consider how it draws a line between a molecule and not a molecule. Consider how it draws a line between life or not. That'd be cool. Consider that it doesn't give a shit who did what first.
"given any word, there's no such thing"