1. Laboratory of Reproductive Engineering The Institute of Experimental Animal Sciences Osaka University Medical School Suita Osaka Japan
2. Division of Stem Cell Regulation Research Osaka University Graduate School of Medicine Suita Osaka Japan
3. Yale Stem Cell Center Yale University School of Medicine New Haven CT USA
4. Department of Cell Biology Yale University School of Medicine New Haven CT USA
5. Central Institute for Experimental Animals Kawasaki‐ku, Kawasaki Kanagawa Japan
6. Department of Pathology Graduate School of Medicine and Frontier Biosciences Osaka University Suita Osaka Japan
7. Department of Anatomy Kyorin University School of Medicine Shinkawa Mitaka Tokyo Japan
8. Center for Experimental Animal Tokyo Medical and Dental University Bunkyo‐ku Tokyo Japan
9. Institute for Frontier Medical Sciences Kyoto University Kyoto Japan