1. Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences, and University Medical Centre, 3584 CT Utrecht, Netherlands
2. Centre for Biomedical Genetics, 3584 CT Utrecht, Netherlands
3. Experimental Zoology Group, Department of Animal Sciences, Wageningen University, 6709 PG Wageningen, Netherlands
4. Division of Experimental Oncology, Multidisciplinary Oncology Center, Central University Hospital, and Department of Biochemistry, University of Lausanne, CH-1066 Epalinges, Switzerland