4 ms·

Adding to my previous comment: If a student asked "how did life originate?" a response about about nucleic acid synthesis would be a bit disingenuous, because

Adding to my previous comment: If a student asked "how did life originate?" a response about about nucleic acid synthesis would be a bit disingenuous, because that covers only very, very tiny fraction of the surface area of the problem. The more honest answer would be that there are so many large gaps in our knowledge that we truly don't know. To be clear, I'm not trying to cast skepticism on the whole of biology. There are other questions that we have much better answers to, like the evolutionary pathway from single cellular life to multicellular life. Or the evolutionary link between humans and great apes. But abiogenesis is not one of those questions.

marcosdumay 4y ago
> The more honest answer would be that there are so many large gaps in our knowledge that we truly don't know. Are the gaps really that large? We know that some configurations of nucleotids are enough to create a full metabolism, we know that they arrange at random, and we know how most of them appeared. Except for the few nucleotides that we don't know how they existed, we do know that if you have enough of them on enough places, some kind of life will appear. So looks like the open question here is how those molecules appeared.
- dathanb82 4y ago
  But RNA / DNA isn't sufficient for life, right? How are proteins synthesized from that string of nucleotides without ribosomes? And nucelotides randomly reshuffling certainly doesn't explain how ribosomes would be created. It's theorized that under the right conditions amino acids will bond to become proteins without needing the mediation of a ribosome. So it's certainly possible that with enough primordial soup you could get proteins. But that doesn't explain how the nucleotide string ends up getting treated as a reusable blueprint for proteins. That seems like a pretty big gap.
  - bobthechef 4y ago
  - marcosdumay 4y ago
    Ribosomes are mostly RNA, and there is good evidence that they evolved from something that was purely RNA. The aminoacid transport and encoding mechanism is also basically composed of RNA, with some evidence that something like them would work without any of the protein parts. Also, people have created RNA-only self replicating mechanisms that could quite well appear at random, with extremely low odds. Life probably comes from some structure with higher odds that we don't know about, but that's not a huge gap.
  - sterlind 4y ago
    I wish I recalled better, but I saw a hypothesis that centered around tRNA rather than the ribosome as the origin of replication. after all, the ribosome simply catalyzes the binding of tRNA to mRNA, and amino acid linkage. iirc the idea centered around the tRNA "code" having a pattern to it - one shaped by its binding affinity to part of the sequence that codes for the tRNA-aminoacyltransferase enzyme itself. I wish I remembered enough to find the reference. edit: ah! think I remembered. the hypothesis was that the codon sequence had some sort of binding affinity to the amino acid it codes for. that there's a relationship between them, suggesting a world where codons attracted amino acids to bind to them without an enzyme linking them. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7924937/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7924937/
mannykannot 4y ago
> If a student asked "how did life originate?" a response about about nucleic acid synthesis would be a bit disingenuous... As the article title does not say or imply that the answer to this question has been found, let alone that it will be revealed in the article, this is at least beside the point. In attempting to brush aside gliptic's pertinent question, you have switched to a general (and somewhat subjective) claim that does not seem to hold up in this specific case.
RosanaAnaDana 4y ago
Also, and imo fundamentally, it doesn't define a natural process of system where this reaction is thermodynamiccally favorable. That, imo, is far more important.

marcosdumay 4y ago

> The more honest answer would be that there are so many large gaps in our knowledge that we truly don't know. Are the gaps really that large? We know that some configurations of nucleotids are enough to create a full metabolism, we know that they arrange at random, and we know how most of them appeared. Except for the few nucleotides that we don't know how they existed, we do know that if you have enough of them on enough places, some kind of life will appear. So looks like the open question here is how those molecules appeared.

dathanb82 4y ago
But RNA / DNA isn't sufficient for life, right? How are proteins synthesized from that string of nucleotides without ribosomes? And nucelotides randomly reshuffling certainly doesn't explain how ribosomes would be created. It's theorized that under the right conditions amino acids will bond to become proteins without needing the mediation of a ribosome. So it's certainly possible that with enough primordial soup you could get proteins. But that doesn't explain how the nucleotide string ends up getting treated as a reusable blueprint for proteins. That seems like a pretty big gap.
- bobthechef 4y ago
- marcosdumay 4y ago
  Ribosomes are mostly RNA, and there is good evidence that they evolved from something that was purely RNA. The aminoacid transport and encoding mechanism is also basically composed of RNA, with some evidence that something like them would work without any of the protein parts. Also, people have created RNA-only self replicating mechanisms that could quite well appear at random, with extremely low odds. Life probably comes from some structure with higher odds that we don't know about, but that's not a huge gap.
- sterlind 4y ago
  I wish I recalled better, but I saw a hypothesis that centered around tRNA rather than the ribosome as the origin of replication. after all, the ribosome simply catalyzes the binding of tRNA to mRNA, and amino acid linkage. iirc the idea centered around the tRNA "code" having a pattern to it - one shaped by its binding affinity to part of the sequence that codes for the tRNA-aminoacyltransferase enzyme itself. I wish I remembered enough to find the reference. edit: ah! think I remembered. the hypothesis was that the codon sequence had some sort of binding affinity to the amino acid it codes for. that there's a relationship between them, suggesting a world where codons attracted amino acids to bind to them without an enzyme linking them. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7924937/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7924937/

mannykannot 4y ago

> If a student asked "how did life originate?" a response about about nucleic acid synthesis would be a bit disingenuous... As the article title does not say or imply that the answer to this question has been found, let alone that it will be revealed in the article, this is at least beside the point. In attempting to brush aside gliptic's pertinent question, you have switched to a general (and somewhat subjective) claim that does not seem to hold up in this specific case.

RosanaAnaDana 4y ago

Also, and imo fundamentally, it doesn't define a natural process of system where this reaction is thermodynamiccally favorable. That, imo, is far more important.