Dr. Mark Groudine studies how cells turn genes on and off, and how changes to these processes can lead to cancer. He has shown that the packaging and 3D organization of DNA changes by type of tissue, and that this influences gene expression. Dr. Groudine’s work led to the discovery of a region of DNA that helps to control the expression of hemoglobin, the oxygen-transporting protein in red blood cells. A specific type of anemia, called thalassemia, occurs when this region of DNA is missing. Similar DNA regions have been discovered for other genes and have been implicated in other diseases, including a type of lymphoma.