A framework for parsing heritable information.

Living systems transmit heritable information using the replicating gene sequences and the cycling regulators assembled around gene sequences. Here, I develop a framework for heredity and development that includes the cycling regulators parsed in terms of what an organism can sense about itself and its environment by defining entities, their sensors and the sensed properties. Entities include small molecules (ATP, ions, metabolites, etc.), macromolecules (individual proteins, RNAs, polysaccharides, etc.) and assemblies of molecules. While concentration may be the only relevant property measured by sensors for small molecules, multiple properties that include concentration, sequence, conformation and modification may all be measured for macromolecules and assemblies. Each configuration of these entities and sensors that is recreated in successive generations in a given environment thus specifies a potentially vast amount of information driving complex development in each generation. This entity-sensor-property framework explains how sensors limit the number of distinguishable states, how distinct molecular configurations can be functionally equivalent and how regulation of sensors prevents detection of some perturbations. Overall, this framework is a useful guide for understanding how life evolves and how the storage of information has itself evolved with complexity since before the origin of life.