Epigenetics is a mechanism that changes the way genes are used, without changing the DNA sequence itself. The mechanism determines when and where genes are turned on or off by using DNA methylation to switch genes off, and also by finely controlling the switch by regulating the action of histones, the proteins around which DNA is wrapped. The crux of the matter is that even where genetic information is the same, gene function is influenced by environmental factors and life experiences. As such, epigenetics has become a major focus of research in many fields, including cancer, metabolic diseases, and other lifestyle diseases.