Improve it or lose it: evolvability costs of competition for expression

TL;DR

This paper explores how feedback between protein expression levels and evolutionary dynamics can create a loop that influences adaptation speed, showing that gradual environmental change can sometimes accelerate reaching higher fitness.

Contribution

It introduces a minimal model demonstrating the impact of expression-evolution feedback loops on adaptation, revealing counterintuitive effects of slow environmental shifts.

Findings

Feedback loops can accelerate adaptation in changing environments.

Gradual environmental change can lead to higher fitness faster than direct exposure.

Evolutionary dynamics can influence expression levels, creating a feedback mechanism.

Abstract

Expression level is known to be a strong determinant of a protein's rate of evolution. But the converse can also be true: evolutionary dynamics can affect expression levels of proteins. Having implications in both directions fosters the possibility of a feedback loop, where higher expressed systems are more likely to improve and be expressed even higher, while those that are expressed less are eventually lost to drift. Using a minimal model to study this in the context of a changing environment, we demonstrate that one unexpected consequence of such a feedback loop is that a slow switch to a new environment can allow genotypes to reach higher fitness sooner than a direct exposure to it.