1. Wellcome Trust – Medical Research Council Stem Cell Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QR, UK
2. Department of Physiology, Development and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 3EG, UK
3. Epigenetics Programme, Babraham Institute, Cambridge CB22 3AT, UK
4. Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA, UK
5. Central Institute for Experimental Animals, Department of Applied Developmental Biology, 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki 210-0821, Japan