4 ms·

How about prions[0] or something similar? They replicate, and are much simpler and smaller than RNA or DNA based replicators. [0] https://en.m.wikipedia.org/wi

by axytol 4y ago

How about prions[0] or something similar? They replicate, and are much simpler and smaller than RNA or DNA based replicators. [0] https://en.m.wikipedia.org/wiki/Prion https://en.m.wikipedia.org/wiki/Prion

COGlory 4y ago
They don't replicate, they take other proteins and refold them. They need existing protein to do that.
- gus_massa 4y ago
  I agree, but I want to add two bad metaphors. (I'd like to have a good one, but I only have bad ones.) * Prions are like falling domino pieces. If you have a lot of standing domino pieces, and one of them falls, it may cause other domino pieces to fall. But they don't create more domino pieces, or standing pieces. They just pull down the pieces that are around. Also, they store no information, they just flip a bit from 0 to 1. * RNA is like a small pile of glued magnets glued on their side. If you put some glued magnets in a box full of magnets and shake them, they will pick other magnets and create a inverse copy. If the side of the magnets is (magically) sticky, the copy may get glued permanently. After some more shaking, you have two piles of glued magnets moving around and collecting more magnets and making copies. They store information, because the initial pile may be NNSNSNS and the new piles will have the same pattern until there is an error in the copy.
  - COGlory 4y ago
    Those are interesting analogies, particularly for the RNA. Thanks for sharing them.
    - gus_massa 4y ago
      Thanks. I agree that they are interesting. (I wrote them :) .) But I can think a few reasons why they are wrong. Anyway, I think they are useful to understand the difference between prions and rna, and why prions are not a good proposal for the origin of life.
      - axytol 4y ago
        Good points, I like the analogies. I would also not classify prions as life originators, but rather thinking if a similar model would have been employed by an intermmediate non-nucleotide based replicator. So basically chemical folders that would gradually evolve the replicator molecular complexity.
        gus_massa 4y ago
        Nobody is sure, and I'm not an expert in this field, but looking at https://en.wikipedia.org/wiki/RNA_world#Alternative_hypotheses https://en.wikipedia.org/wiki/RNA_world#Alternative_hypothes... there are a few ideas. I think the https://en.wikipedia.org/wiki/PAH_world_hypothesis https://en.wikipedia.org/wiki/PAH_world_hypothesis is somewhat similar to your idea. IIUC they don't self reproduce, they just grow in a random order in a pattern. And the proposal is that it 's good to support the RNA bases for a small time to make it easy to build small chains. [I remember to have read something like that about clay or crystals, but I can't find it now in the article in Wikipedia. Perhaps the idea was abandoned a long time ago.]

by axytol 4y ago

COGlory 4y ago

They don't replicate, they take other proteins and refold them. They need existing protein to do that.

gus_massa 4y ago
I agree, but I want to add two bad metaphors. (I'd like to have a good one, but I only have bad ones.) * Prions are like falling domino pieces. If you have a lot of standing domino pieces, and one of them falls, it may cause other domino pieces to fall. But they don't create more domino pieces, or standing pieces. They just pull down the pieces that are around. Also, they store no information, they just flip a bit from 0 to 1. * RNA is like a small pile of glued magnets glued on their side. If you put some glued magnets in a box full of magnets and shake them, they will pick other magnets and create a inverse copy. If the side of the magnets is (magically) sticky, the copy may get glued permanently. After some more shaking, you have two piles of glued magnets moving around and collecting more magnets and making copies. They store information, because the initial pile may be NNSNSNS and the new piles will have the same pattern until there is an error in the copy.
- COGlory 4y ago
  Those are interesting analogies, particularly for the RNA. Thanks for sharing them.
  - gus_massa 4y ago
    Thanks. I agree that they are interesting. (I wrote them :) .) But I can think a few reasons why they are wrong. Anyway, I think they are useful to understand the difference between prions and rna, and why prions are not a good proposal for the origin of life.
    - axytol 4y ago
      Good points, I like the analogies. I would also not classify prions as life originators, but rather thinking if a similar model would have been employed by an intermmediate non-nucleotide based replicator. So basically chemical folders that would gradually evolve the replicator molecular complexity.
      - gus_massa 4y ago
        Nobody is sure, and I'm not an expert in this field, but looking at https://en.wikipedia.org/wiki/RNA_world#Alternative_hypotheses https://en.wikipedia.org/wiki/RNA_world#Alternative_hypothes... there are a few ideas. I think the https://en.wikipedia.org/wiki/PAH_world_hypothesis https://en.wikipedia.org/wiki/PAH_world_hypothesis is somewhat similar to your idea. IIUC they don't self reproduce, they just grow in a random order in a pattern. And the proposal is that it 's good to support the RNA bases for a small time to make it easy to build small chains. [I remember to have read something like that about clay or crystals, but I can't find it now in the article in Wikipedia. Perhaps the idea was abandoned a long time ago.]