A noise-induced mechanism for biological homochirality of early life self-replicators

TL;DR

This paper proposes a stochastic noise-driven mechanism for the emergence of biological homochirality in early life self-replicators, challenging the necessity of autocatalytic cross inhibition.

Contribution

It introduces a stochastic model showing noise can stabilize homochiral states without chiral inhibition, providing a new explanation for biological homochirality.

Findings

Intrinsic noise stabilizes homochiral states in autocatalytic systems.

Homochirality can arise without chiral inhibition mechanisms.

The theory applies to both well-mixed and spatially-extended systems.

Abstract

The observed single-handedness of biological amino acids and sugars has long been attributed to autocatalysis. However, the stability of homochiral states in deterministic autocatalytic systems relies on cross inhibition of the two chiral states, an unlikely scenario for early life self-replicators. Here, we present a theory for a stochastic individual-level model of autocatalysis due to early life self-replicators. Without chiral inhibition, the racemic state is the global attractor of the deterministic dynamics, but intrinsic multiplicative noise stabilizes the homochiral states, in both well-mixed and spatially-extended systems. We conclude that autocatalysis is a viable mechanism for homochirality, without imposing additional nonlinearities such as chiral inhibition.