From Recursion to Functionality: Exploring the Origins of Life-Like Chemistry in Oligomer Systems

Abstract

Understanding how the first functional polymers of life emerged has drawn considerable focus in origins of life studies. Theoretical models have demonstrated the ability of peptides to interact in dynamic ways, widely relying on chemical autocatalysis and selection for self- propagation. Since it is highly unlikely that complex replicators emerged spontaneously on a prebiotic Earth, it is important to investigate how catalytic peptides might have been generated via non-enzymatic peptide synthesis, and whether further proliferation and an emergence in functionality could be possible in plausible prebiotic settings. One approach to studying the emergence of such autocatalytic regimes in the laboratory involves multiple recursive dehydration cycles, which promotes amino acid condensation while imposing a selective pressure on the system through the continuous dilution of products and partial replenishment of fresh feedstock. This work tests the potential of this recursive framework to enrich for effective catalytic sequences in an equimolar mixture of ten prebiotically plausible amino acids and montmorillonite, a clay mineral that has been extensively studied for its ability to catalyze, aggregate and stabilize peptide motifs in solution. We observe differences in relative amino acid abundances over analyzed generations that likely reflects changes in montmorillonite-associated absorbance properties over time, either through constraints posed by dehydration on system behavior, or possibly through competition with species that build over time. An analysis of global system behavior reveals a potential role for autocatalytic feedback in driving some of these trends, through the emergence of undetectable catalytic sets in the compositional space. Additional experiments will be required to robustly investigate this experimental system, as well as corroborate some of our findings.