1. Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G61 1QH
2. MRC Human Reproductive Sciences Unit, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, EH16 4TJ, UK
3. INRA, UMR 1198, Biologie du Développement et Reproduction F-78350, Jouy-en-Josas, France
4. The James Hutton Institute, Craigiebuckler, Aberdeen, AB15 8QH, UK
5. INRA, UMR791 MoSAR/AgroParis Tech, UMR MoSAR, F-75005 Paris, France
6. Dept Human Anatomy and Cell Science, University of Manitoba, Winnipeg, Canada
7. Dept Medical Sciences, Occupational and Environmental medicine, Uppsala University, 751 85 Uppsala, Sweden
8. Institute of Medical Sciences, Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK