1. Department of Animal Molecular Biology , National Research Institute of Animal Production , 32-083 Balice n. Kraków , Poland
2. Faculty of Biotechnology and Horticulture , University of Agriculture , Al. 29 Listopada 54, 31-425 Kraków , Poland
3. Department of Pig Breeding , National Research Institute of Animal Production , 32-083 Balice n. Kraków , Poland