Title: “Schroedinger’s Cell:  Gene Expression Noise Accelerates the Evolution of a Biological Oscillator”

Authors:  Yen Tin Lin, Nicolas Buchler

Abstract: Gene expression is a biochemical process, where stochastic binding and unbinding 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 how gene expression noise counter-intuitively accelerates the evolution of a biological oscillator and, thus, could impart a benefit to living organisms. We used simulations to evolve a mechanistic, biophysical model of a circadian clock at different levels of gene expression noise. Our work shows that gene expression noise induces oscillations in regions of parameter space that cannot oscillate autonomously in the absence of noise. We describe two types of mechanisms of noise-induced oscillation that reveal cryptic phenotypes and show how they guide evolution towards robust oscillation.