Gene expression noise accelerates the evolution of a biological oscillator

TL;DR

Gene expression noise unexpectedly speeds up the evolution of biological oscillators by inducing oscillatory dynamics and guiding evolution towards stable, self-sustaining oscillations, revealing a beneficial role of stochastic fluctuations.

Contribution

This study demonstrates that gene expression noise can accelerate the evolution of oscillatory behavior in biological systems through noise-induced dynamics and fitness landscape shaping.

Findings

Noise induces oscillations in non-oscillatory regions.

Noise-driven oscillations guide evolution efficiently.

Gene expression noise can have beneficial evolutionary effects.

Abstract

Gene expression is a biochemical process, where stochastic binding and un-binding events naturally generate fluctuations and cell-to-cell variability in gene dynamics. These fluctuations typically have destructive consequences for proper biological dynamics and function (e.g., loss of timing and synchrony in biological oscillators). Here, we show that gene expression noise counter-intuitively accelerates the evolution of a biological oscillator and, thus, can impart a benefit to living organisms. We used computer simulations to evolve two mechanistic models of a biological oscillator at different levels of gene expression noise. We first show that gene expression noise induces oscillatory-like dynamics in regions of parameter space that cannot oscillate in the absence of noise. We then demonstrate that these noise-induced oscillations generate a fitness landscape whose gradient robustly and quickly guides evolution by mutation towards robust and self-sustaining oscillation. These results suggest that noise can help dynamical systems evolve or learn new behavior by revealing cryptic dynamic phenotypes outside the bifurcation point.