This animation explains epigenetics, the study of changes in the pattern of gene expression that is regulated independently of the DNA sequence itself, and depends on modifications and conformational changes of the chromatin, the basic unit of our chromosomes. Epigenetics is central to our understanding of the role the environment plays and how the choices we make alter our health and that of our children. This video was produced for the Simpson Querrey Center for Epigenetic Medicine by Nicole Ethen, Biomedical Visualization Program, University of Illinois at Chicago.