1. Department of Zoology, University of Cambridge, UK
2. School of Natural Sciences, Bangor University, Gwynedd LL57 2TH, UK
3. Department of Biological and Marine Sciences, University of Hull, UK
4. Department of Genetics, University of Cambridge, UK
5. Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, UK
6. Wellcome Sanger Institute, Wellcome Trust Genome Campus, Cambridge, UK
7. University of Maryland, USA