Information Processing at the Cellular Level: Beyond the Dogma

Abstract

The classical view of information flow within a cell, encoded by the famous central dogma of molecular biology, states that the instructions for producing amino acid chains are read from specific segments of DNA, just as computer instructions are read from a tape, transcribed to informationally equivalent RNA molecules, and finally executed by the cellular machinery responsible for synthesizing proteins. While this has always been an oversimplified model that did not account for a multitude of other processes occurring inside the cell, its limitations are today more dramatically apparent than ever. Ironically, in the same years in which researchers accomplished the unprecedented feat of decoding the complete genomes of higher-level organisms, it has become clear that the information stored in DNA is only a small portion of the total, and that the overall picture is much more complex than the one outlined by the dogma.

The cell is, at its core, an information processing machine based on molecular technology, but the variety of types of information it handles, the ways in which they are represented, and the mechanisms that operate on them go far beyond the simple model provided by the dogma. In this

chapter we provide an overview of the most important aspects of information processing that can be found in a cell, describing their specific characteristics, their role, and their interconnections. Our goal is to outline, in an intuitive and nontechnical way, several different views of the cell using the language of information theory.