1. INRA, AgroParisTech, UMR1313, Animal Genetics and Integrative Biology, 78350 Jouy-en-Josas, France
2. Wageningen UR Livestock Research, POB 65, 8200 AB, Lelystad, The Netherlands
3. Lohmann Tierzucht GmbH, 27454 Cuxhaven, Germany
4. The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, Scotland
5. Institute of Farm Animal Genetics, Friedrich-Loeffler-Institut, 31535 Neustadt, Germany