1. Department of Small Animal Clinical Sciences, Norwegian College of Veterinary Medicine, PO Box 8146 Dep., 0033 Oslo, Norway
2. *Department of Morphology, Genetics and Aquatic Biology, Norwegian College of Veterinary Medicine, PO Box 8146 Dep., 0033 Oslo, Norway
3. †Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Box 7037, 75007 Uppsala, Sweden