1. Department of Anatomy and Cell Biology, College of Veterinary Medicine, Seoul National University, Seoul 151-742, Korea.
2. BK21 PLUS Program for Creative Veterinary Science Research, and Research Institute for Veterinary Science, Seoul National University, Seoul 151-742, Korea.
3. Seocho High School, Seoul 137-952, Korea.
4. Department of Anatomy, College of Veterinary Medicine, Kangwon National University, Chuncheon 200-701, Korea.
5. Institute of Sports Science, Seoul National University, Seoul 151-742, Korea.