During development, the differentiation of cells to different lineages is closely associated with the establishment of specific epigenetic marks along the sequence of the DNA. During ageing, temporal changes in these patterns have been found to be tightly correlated to biological age and predictive of the time of death. The mechanistic basis underlying these processes is, however, poorly understood. The recent advent of single-cell sequencing technologies for the first time give the opportunity to probe these processes with unprecedented molecular resolution in vivo. Biological function, however, relies on collective processes on the cellular scale which emerge from many interactions on the microscopic scale. But what can we learn about such collective processes from detailed empirical information on the molecular scale?
Concepts from non-equilibrium statistical physics provide a powerful framework to understand collective epigenetic processes. We combine data obtained from novel single-cell technologies with methods from non-equilibrium statistical physics to understand collective epigenetic processes regulating cellular behaviour during development and ageing.