1. The Francis Crick Institute 1 , 1 Midland Road, London NW1 1AT , UK
2. University of Cambridge 2 Department of Genetics , , Cambridge CB2 3EH , UK
3. Abcam 3 , Discovery Drive, Cambridge Biomedical Campus, Cambridge CB2 0AX , UK
4. Wellcome Trust – MRC Stem Cell Institute, University of Cambridge, Jeffrey Cheah Biomedical Centre 4 , Puddicombe Way, Cambridge CB2 0AW , UK
5. University of Cambridge 5 Department of Physiology, Development and Neuroscience , , Tennis Court Road, Cambridge CB2 3EG , UK
6. Centre for Trophoblast Research, University of Cambridge 6 , Cambridge , UK