From: rokimoto557@gmail.com   
      
   On 1/28/2026 5:15 PM, MarkE wrote:   
   > A particularly good assessment of Lee Cronin's Assembly Theory:   
   >   
   > https://youtu.be/nMJ-_pTykog?si=fO1eCFGG3hd-41h1&t=693   
   >   
   https://pmc.ncbi.nlm.nih.gov/articles/PMC10978598/   
      
   This is a paper that discusses what Assembly theory is "What it does and   
   does not do."   
      
   It really is impractical to apply it to current biomes and evolution of   
   existing lifeforms.  It isn't even applicable past evolution of life.   
   It requires that you be able to determine what existed at the time and   
   then determine the possible historical assembly path.  Since the   
   possible materials available for assembly is changing over time you   
   can't determine the assembly path except over very short periods of time   
   for which you have some idea of what existed at that time.  This just   
   means that you can't use it to determine the probability of the assembly   
   path for something like a polypeptide enzyme (simple chain of amino   
   acids) and you definitely can't use it to assess something like the F0   
   ATPase complex of multiple polypeptide proteins.  You have no idea of   
   what the original polypeptide sequence was that evolved to have that   
   enzyme activity.  It isn't as simple as trying to figure out what the   
   sequence is and what the concentrations of each amino acid might have   
   been in order to create that particular sequence of amino acids.  For   
   extant proteins you have the genetic code to consider, but it isn't just   
   that.  The vast majority of existing proteins have evolved from   
   preexisting proteins by gene duplication.  So you have to figure out   
   what the original protein sequences were that eventually evolved to have   
   that enzymatic activity.  No one can do this at this time except for   
   closely related protein families, but these identifiable protein   
   families likely started from some other protein sequence.   
      
   What it seems to be useful for is to determine if some complex molecules   
   like amino acids and the purines and pyrimidines involved in nucleic   
   acid are found in higher amounts than expected by random chance.  You   
   may expect these molecules to be present at some low level in a cosmic   
   dust cloud or planetary atmosphere, but lifeforms assemble these   
   molecules, so they can be present in the mix of possible molecules at   
   higher concentrations than the existing concentration of carbon, oxygen,   
   nitrogen and hydrogen might be responsible for.  The assembly paths for   
   amino acids from the constituent atoms can be determined and the   
   probability of random chemical activity can be determined if you know   
   the concentration of component parts, so you may be able to tell if the   
   concentration of these complex molecules are in a higher abundance than   
   expected.   
      
   It works for simple molecules too.  If you found an 20% molecular oxygen   
   atmosphere around some exoplanet you might conclude that it had aerobic   
   photosynthetic life.  That seems to be the only means to maintain such a   
   high concentration of molecular oxygen in an atmosphere.   
      
   It doesn't seem to be very useful to use to evaluate the evolution of   
   life on earth.  It might be useful to assess the evolution of the first   
   self replicating molecules if we ever figure out what they were.   
      
   Ron Okimoto   
      
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