While most people are familiar with the inheritance of genes from generation to generation via DNA, the activity of these genes is determined by epigenetics. Epigenetics refers to modifications to the DNA or the proteins associated with DNA, such as histones, which in turn determine whether a gene is on or off or whether its activity is high or low. Examples of these modifications include acetylation, methylation and phosphorylation. These modifications are added to histones by enzymes called “writers” and removed by enzymes called “erasers”. Other proteins, called “readers”, recognize a specific pattern of modifications by binding to them and recruiting additional proteins to regulate gene activity. Differences in the pattern of modifications occur between different cells and organs of the body or in response to different physiological stimuli. There is now substantial evidence that alterations in these patterns underlie multiple diseases. For these reasons, epigenetics has become an exciting forefront for the discovery of new medicines.