The epigenetic evolution models include the idea of “programming’’, a process by which a stimulus or insult applied at a critical period of development results in long-term effects on the structure or the function of the cell. Hypomethylation of genes is a crucial epigenetic mechanism for the silencing of genes and it is related to the development of cancer and other diseases. Cumulative errors in maintenance of genetic and epigenetic information contribute to interindividual epigenetic variation with age. When disruptive, they increase the risk of disease.