Potential energy landscapes reveal the information-theoretic nature of the epigenome

Abstract

Epigenetics is defined as genomic modifications carrying information independent of DNA sequence heritable through cell division. In 1940, Waddington coined the term \"epigenetic landscape\" as a metaphor for pluripotency and differentiation, but epigenetic potential energy landscapes have not yet been rigorously defined. Using well-grounded biological assumptions and principles of statistical physics and information theory, we derive potential energy landscapes from whole genome bisulfite sequencing data that allow us to quantify methylation stochasticity genome-wide and discern epigenetic differences using Shannons entropy and the Jensen-Shannon distance. We discover a \"developmental wheel\" of germ cell lineages and an association between entropy and chromatin structure. Viewing methylation maintenance as a communications system, we introduce methylation channels and show that higher-order chromatin organization can be predicted from their informational properties. Our results provide a fundamental understanding of the information-theoretic nature of the epigenome and a powerful methodology for studying its role in disease and aging.