1. Animal Breeding and Genetics Program, IRTA, Torre Marimon, 08140 Caldes de Montbui, Spain.
2. INRAE GABI, Domaine de Vilvert, 78350 Jouy-en-Josas, France.
3. IFIP-Institut du porc and Alliance R&D, La Motte au Vicomte, 35651 Le Rheu, France.
4. Hendrix Genetics, P.O. Box 114, 5830 AC Boxmeer, the Netherlands.