Encyclopedia of Cancer (2015)
Heritable changes in genome function that occur without a change in DNA sequence. DNA methylation at CpG-islands and posttranslational histone modifications are the molecular basis for epigenetic information. Epigenetic changes of DNA influence the phenotype without altering the genotype.
They consist of changes in the properties of a cell that can be transmitted through cell cycle divisions but do not represent a change in genetic information. The main epigenetic changes that target gene regulatory regions and modulate gene expression are methylation and acetylation.