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RNA World is really cooking: https://pubmed.ncbi.nlm.nih.gov/39358873/ https://pubmed.ncbi.nlm.nih.gov/39358873/ Ejection: https://link.springer.com/chapter/10

RNA World is really cooking: https://pubmed.ncbi.nlm.nih.gov/39358873/ https://pubmed.ncbi.nlm.nih.gov/39358873/ Ejection: https://link.springer.com/chapter/10.1007/3-540-25736-5_3 https://link.springer.com/chapter/10.1007/3-540-25736-5_3 Reentry: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0132611 https://journals.plos.org/plosone/article?id=10.1371/journal... Not to mention the constant trickle of "X survived in space" stories that we get every time someone bothers to collect and culture a sample. The amount of success at every stage with, frankly, very little effort spent tuning the conditions, multiplied by "bacteria are everywhere" makes hitchhiking less crazy than it sounds. Our intuition misleads us because bacteria are so much better at handling acceleration (easy if you're small) and dessiccation (everywhere is a desert if you're small) than anything we are used to thinking about.

Egret 11mo ago
https://pmc.ncbi.nlm.nih.gov/articles/PMC1892545/ https://pmc.ncbi.nlm.nih.gov/articles/PMC1892545/ An upper bound probability for the RNA world hypothesis is 10^-1018. A reasonable interpretation is that the RNA world hypothesis is impossible in the real world.
- avadodin 11mo ago
  A superficial reading doesn't inspire much confidence in this peer-reviewed article but I agree that RNA-world is a thought experiment at best. There is no evidence of these RNA structures in actual lifeforms. RNA encodes proteins. The most parsimonious explanation is that proteins(likely incapable of true replication by themselves) preceded RNA even if an RNA-based system can be designed in theory. I won't make claims of probability of unknown processes but proteins exist that can assemble spare nucleotides and proteins exist that can assemble proteins out of nucleotide chains. All you need is a pair of them to come in the vicinity of each other and wait until RNA comes along that encodes a similar-enough pair.
  - Egret 11mo ago
    The probability of assembling two proteins randomly close by in spatial and temporal terms runs into Chadwick's proximity problem.

Egret 11mo ago

https://pmc.ncbi.nlm.nih.gov/articles/PMC1892545/ https://pmc.ncbi.nlm.nih.gov/articles/PMC1892545/ An upper bound probability for the RNA world hypothesis is 10^-1018. A reasonable interpretation is that the RNA world hypothesis is impossible in the real world.

avadodin 11mo ago
A superficial reading doesn't inspire much confidence in this peer-reviewed article but I agree that RNA-world is a thought experiment at best. There is no evidence of these RNA structures in actual lifeforms. RNA encodes proteins. The most parsimonious explanation is that proteins(likely incapable of true replication by themselves) preceded RNA even if an RNA-based system can be designed in theory. I won't make claims of probability of unknown processes but proteins exist that can assemble spare nucleotides and proteins exist that can assemble proteins out of nucleotide chains. All you need is a pair of them to come in the vicinity of each other and wait until RNA comes along that encodes a similar-enough pair.
- Egret 11mo ago
  The probability of assembling two proteins randomly close by in spatial and temporal terms runs into Chadwick's proximity problem.