When a child takes after her parents, it must be the genes, right? No, because the genetic information stored in deoxyribonucleic acid (DNA) is not the only thing humans pass on to their offspring. They can also pass on epigenetic changes in the structure of chromatin, which serves as the packaging of DNA, over the course of generations. Scientists at the Univer- sity of Freiburg and the Freiburg Max Planck Institute of Immunobiology and Epigenetics have been studying such changes since 2012 at collaborative research center (SFB) 992, “Medical Epigenetics.” Epigenetic modifications play a key role in diseases like prostate cancer, leukemia, and diabetes, as well as in the formation of fat and in other important processes in the body. “We want to understand the foundations as a basis for developing new therapeutic pro- cedures,” says Prof. Dr. Roland Schüle, director of the SFB. Every body cell in humans and other mammals contains a roughly two-meter long strand of DNA in which their genetic information is stored. In order to ensure that it fits inside the nuclei of these cells, nature did a good job of packaging this strand: It is coiled tightly around a kind of column – a nucleosome, which is a compound of so-called histone proteins. All of the DNA, the histones, and further proteins in the nucleus all combine to make up the chromatin. Chromatin can be present in open or condensed form. In its condensed form the chromatin is more tightly wound up into a ball, which makes it fit even better in the cell. However, the genes on this condensed part of the strand are more difficult to transcribe, because in order for this to happen so-called transcription factors have to be able to reach them. These proteins bind to the DNA to show another protein which gene it should transcribe and which product it should produce according to that blueprint. 8 The biologist Roland Schüle is studying epigenetic processes and searching for new therapies for cancer and other diseases Changing the Packaging of Genes by Katrin Albaum 8 The biologist Roland Schüle is studying epigenetic processes and