1. Laboratory of Animal Genetics and Reproduction, Department of Animal Science, Research Faculty of Agriculture, Hokkaido University, Hokkaido 060-8589, Japan
2. Laboratory of Animal Reproductive Physiology, Graduate School of Environmental and Life Science, Okayama University, Okayama 700-8530, Japan
3. Present: Institute for Reproductive Health and Regenerative Medicine, Departments of Pathology and Laboratory Medicine and Pediatrics, University of Kansas Medical Center, Kansas City, KS, USA
4. Livestock and Grassland Research Division, Kyushu Okinawa Agricultural Research Center, NARO, Kumamoto 861-1192, Japan
5. Obihiro University of Agriculture and Veterinary Medicine, Hokkaido 080-8555, Japan