1. Department of Molecular Biotechnology, Biotechnology Research Institute, Inst. of Ag. Sci. and Tech., Chonnam National University, Gwangju 500-757, Republic of Korea
2. National Institute of Animal Science, RDA, Suwon 441-706, Republic of Korea
3. Department of Animal Science and Technology, Sunchon National University, Suncheon 540-742, Republic of Korea