1. The Roslin Institute and R(D)SVS; University of Edinburgh; Easter Bush, Midlothian, EH25 9RG UK
2. NordGen Farm Animals; Postboks 115, N-1431 Ås Norway
3. Institutt for Husdyr- og Akvakulturvitenskap; Norwegian University of Life Sciences; P.O. Box 5003, N-1432 Ås Norway