Program for Evolutionary Dynamics, Harvard University, Cambridge, Massachusetts, United States of America.|Department of Radiation Oncology, University of Minnesota, Minneapolis, Minnesota, United States of America.|Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, Minnesota, United States of America.|Department of Radiotherapy, Universitair Ziekenhuis Brussel, Brussels, Belgium.|Department of Hematology and Beckman Research Institute, City of Hope National Medical Center, Duarte, California, United States of America.|Department of Radiation Oncology, University of Minnesota, Minneapolis, Minnesota, United States of America.|Department of Mathematics, University of Minnesota, Minneapolis, Minnesota, United States of America.|Department of Mathematics, University of Minnesota, Minneapolis, Minnesota, United States of America.|Industrial and Systems Engineering, University of Minnesota, Minneapolis, Minnesota, United States of America.|Department of Radiation Oncology, University of Minnesota, Minneapolis, Minnesota, United States of America.