Epigenetics is the study of how genes are turned off and on during an animal's lifetime, including humans.
A Greek word meaning “above genetics”, epigenetics is the study of changes in gene function that occur without detectable changes to DNA sequence. What this means is that your gene expression (like what proteins your cells produce) changes but your gene sequences themselves do not change.
Epigenetics most often involves changes that affect gene activity and expression. These epigenetic changes can occur due to normal biological development but they can also result from external or environmental factors like food choices, stress levels or even injury.