1. Department of Genetics and Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH;
2. Dana Farber Cancer Institute, Department of Medical Oncology, Harvard Medical School, Department of Pathology, Boston, MA; and
3. Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Headington, Oxford, United Kingdom