1. Department of Fisheries and Marine Biology, University of Bergen, Norway2
2. Intervet Norbio, Thormøhlensgate 58, N-5008 Bergen, Norway1
3. Intervet International BV, Wim de Körverstraat 35, 5831 Boxmeer, The Netherlands3
4. Department of Medical Genetics, Haukeland Hospital, Bergen, Norway4
5. National Veterinary Institute, Oslo, Norway5