1. Animal Sciences Department; College of ACES; University of Illinois at Urbana-Champaign; Urbana IL 61801 USA
2. Institute of Cytology and Genetics of the Russian Academy of Sciences; Novosibirsk 630090 Russia
3. Institute of Molecular and Cellular Biology of the Russian Academy of Sciences; Novosibirsk 630090 Russia
4. Novosibirsk State University; Novosibirsk 630090 Russia