Information capacity of genetic regulatory elements

TL;DR

This paper applies information theory to quantify the maximum reliable information transfer in genetic regulatory elements, revealing that such systems can theoretically transmit more than one bit of information despite biological noise.

Contribution

It introduces a formal information-theoretic framework for genetic regulation, analyzing how noise, cooperativity, and molecular costs influence channel capacity.

Findings

Capacities exceeding one bit are theoretically achievable.

Genetic regulation is not limited to binary on-off states.

Noise and molecular costs significantly impact information transmission.

Abstract

Changes in a cell's external or internal conditions are usually reflected in the concentrations of the relevant transcription factors. These proteins in turn modulate the expression levels of the genes under their control and sometimes need to perform non-trivial computations that integrate several inputs and affect multiple genes. At the same time, the activities of the regulated genes would fluctuate even if the inputs were held fixed, as a consequence of the intrinsic noise in the system, and such noise must fundamentally limit the reliability of any genetic computation. Here we use information theory to formalize the notion of information transmission in simple genetic regulatory elements in the presence of physically realistic noise sources. The dependence of this "channel capacity" on noise parameters, cooperativity and cost of making signaling molecules is explored systematically. We find that, at least in principle, capacities higher than one bit should be achievable and that consequently genetic regulation is not limited the use of binary, or "on-off", components.