Sequence selection by dynamical symmetry breaking in an autocatalytic binary polymer model

TL;DR

This paper introduces a model of prebiotic binary polymer replication showing how autocatalysis leads to intrinsic selection of highly ordered, repetitive sequences through symmetry breaking, revealing new insights into early molecular evolution.

Contribution

The study presents an idealized autocatalytic binary polymer model demonstrating how symmetry breaking causes selection of ordered sequences, a novel mechanism in prebiotic chemistry modeling.

Findings

Autocatalysis induces strong selection for ordered sequences.

Symmetry breaking amplifies random fluctuations leading to population-level patterns.

Model reveals a 'dullest' sequence selection mechanism in prebiotic systems.

Abstract

Template directed replication of nucleic acids is at the essence of all living beings and a major milestone for any origin of life scenario. We here present an idealized model of prebiotic sequence replication, where binary polymers act as templates for their autocatalytic replication, thereby serving as each others reactants and products in an intertwined molecular ecology. Our model demonstrates how autocatalysis alters the qualitative and quantitative system dynamics in counter-intuitive ways. Most notably, numerical simulations reveal a very strong intrinsic selection mechanism that favours the appearance of a few population structures with highly ordered and repetitive sequence patterns when starting from a pool of monomers. We demonstrate both analytically and through simulation how this "selection of the dullest" is caused by continued symmetry breaking through random fluctuations in the transient dynamics that are amplified by autocatalysis and eventually propagate to the population level. The impact of these observations on related prebiotic mathematical models is discussed.