In a nutshell: > The new study suggests that life's dependence on these 20 [naturally-occurring] amino acids is no accident. The researchers show that the kind

In a nutshell: > The new study suggests that life's dependence on these 20 [naturally-occurring] amino acids is no accident. The researchers show that the kinds of amino acids used in proteins are more likely to link up together because they react together more efficiently and have few inefficient side reactions. This is an odd leap. Protein synthesis is an extremely complex process involving not just enzymes (amino acid chains), but other stuff like DNA, RNA, lipids, energy transduction, and sugars. Highly organized compartments are key - without them nothing remotely resembling life occurs. The lack of any convincing pathway from random amino acid chains to life is a big limitation here. For example, it's entirely possible that peptides occurred relatively late in the chemical evolution of self-replicating systems. Only after sufficient machinery had been built up could anything as complex as a well-defined peptide chain be produced. Along these lines, a different study looking at how chemical microenvironment could have developed abiotically might be of interest: https://news.ycombinator.com/item?id=20505689 https://news.ycombinator.com/item?id=20505689 On the other hand, if it turned out that certain chemically active amino acid chains tended to form more readily than others in a re-evaporator environment, that could offer an explanation: enzymes (amino acid chain catalysts) form naturally without any other intervention by virtue of the relative reactivity of the growing chain with the next amino acid. Maybe there's even some self-catalysis and/or other selection mechanism at some point. AFAICT, the paper doesn't deal with this possibility, though.