1. Department of Pig Breeding and Production Technology, University of Life Sciences in Lublin, Akademicka 13, 20-950 Lublin, Poland
2. Department of Pig Breeding, Poznań University of Life Sciences, Wołyńska 33, 60-637 Poznań, Poland
3. Department of Animal Cytogenetics and Molecular Genetics, National Research Institute of Animal Production, 32-083 Balice n. Kraków, Poland