Your genome is like a recipe book with all the recipes that a cell in your body needs to make the proteins it needs to function. Each of your 10 trillion cells has a full copy of the full recipe book. But that’s a problem — how does each cell know which recipes to use and which to ignore? For example, only skin cells need the recipe to make pigment, and they don’t need the recipe for insulin. That’s where epigenomics comes in, providing “post-it notes” in the recipe book, so each cell only uses the recipes it needs. In this episode we talk to Dave Gorkin, associate director of the new Center for Epigenomics at UC San Diego School of Medicine, about all this. He also tells us how our epigenetics can change over time, influenced by environmental factors and in turn affecting our susceptibility to disease.