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Some afterthoughts: In seeking abiogenesis what we're really looking for is the first replicators. Certainly RNA strands can self replicate, but how is a parti

Some afterthoughts: In seeking abiogenesis what we're really looking for is the first replicators. Certainly RNA strands can self replicate, but how is a particular sequence alive? About as alive as a virus, perhaps. Ok, posit a whole world of naked RNA, with multitudes of different sequences. Has life arrived on such a world? I'd say the interesting event would still be downstream from there, when by chance some of those different sequences happened to cooperate to mutual advantage. But that's like viruses inventing the cell. Whereas, if you allow for the spontaneous collaboration of mere enzymes to create self sustaining metabolism, you can get a system that should exhibit natural selection, even without genes. I guess what I'm railing on about is this notion that we have one class of molecules that do the work, and another that merely describes other molecules. We create categories and labels for what we see, and then get stuck within those constructs. Truth is often more subtle.

Ultimatt 4y ago
RNA does all of those functions, thats why people think it was prevalent before DNA. There are very few DNA enzymes compared to RNA. RNA provides structure in complex with other molecules which is indirectly catalytic to their activity, as well as being catalytic directly from its own folded structure, then you also have coded information representing its own structure but later those of proteins with the establishment of the genetic code. But you have to remember ribosomes have to exist for the genetic code to mean anything, or at least whatever ribosomes looked like at the start, which is very likely just RNA and a couple of peptides.
- ianai 4y ago
  Saw a video on YT that I think was saying what you just described might eventually build up a living cell. That would be pretty huge.
lupire 4y ago
Life is not a binary. Life is a gradient of complexity.
robbiep 4y ago
You know RNA can work as enzymes right? You’re basically saying ‘let’s create some other form that was doing the work’ - which could be true - weird small crevices with certain molecular properties and different metals exposed to heat gradients where ‘the soup’ tidally comes and goes and catalyses reactions - and maybe that was an important step, but you’re also overly easily dismissing something that not only can act as that first step (maybe with some help from some unknown catalyst as a bootstrap) with the added benefit of actual inheritance
- passivate 4y ago
  >with the added benefit of actual inheritance Has this inheritance actually been experimentally demonstrated? Yes, random assembly of inherently unstable RNA molecules in a nucleotide soup is possible. And agreed, some of these randomly assembled RNA molecules might have limited catalytic properties (nothing like peptides). But - we need a mechanism of genetic continuity - before we get to inheritance.

Ultimatt 4y ago

RNA does all of those functions, thats why people think it was prevalent before DNA. There are very few DNA enzymes compared to RNA. RNA provides structure in complex with other molecules which is indirectly catalytic to their activity, as well as being catalytic directly from its own folded structure, then you also have coded information representing its own structure but later those of proteins with the establishment of the genetic code. But you have to remember ribosomes have to exist for the genetic code to mean anything, or at least whatever ribosomes looked like at the start, which is very likely just RNA and a couple of peptides.

ianai 4y ago
Saw a video on YT that I think was saying what you just described might eventually build up a living cell. That would be pretty huge.

lupire 4y ago

Life is not a binary. Life is a gradient of complexity.

robbiep 4y ago

You know RNA can work as enzymes right? You’re basically saying ‘let’s create some other form that was doing the work’ - which could be true - weird small crevices with certain molecular properties and different metals exposed to heat gradients where ‘the soup’ tidally comes and goes and catalyses reactions - and maybe that was an important step, but you’re also overly easily dismissing something that not only can act as that first step (maybe with some help from some unknown catalyst as a bootstrap) with the added benefit of actual inheritance

passivate 4y ago
>with the added benefit of actual inheritance Has this inheritance actually been experimentally demonstrated? Yes, random assembly of inherently unstable RNA molecules in a nucleotide soup is possible. And agreed, some of these randomly assembled RNA molecules might have limited catalytic properties (nothing like peptides). But - we need a mechanism of genetic continuity - before we get to inheritance.