1. Nuclear Reprogramming Laboratory, Division of Gene Expression and Development, Roslin Institute, Edinburgh, EH25 9PS, UK
2. Laboratory of Developmental Genetics, National Institute for Medical Research, Mill Hill, London, NW7 1AA, UK
3. Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210, USA
4. Dipartimento di Agrobiologia e Agrochimica, Università della Tuscia, Via San C. De Lellis, Viterbo, 01100, Italy
5. Dipartimento di Genetica e Biologia molecolare, Università di Roma `La Sapienza', Piazzale Aldo Moro, Roma, 00185, Italy
6. Uppsala University, Department of Development and Genetics, Norbyvagen 18A, Uppsala, 75236, Sweden