[1] Peking Univ, Minist Educ, Key Lab Cell Proliferat & Differentiat, Beijing 100871, Peoples R China
[2] Natl Res Inst Family Planning, Beijing, Peoples R China
[3] Peking Univ, Shenzhen Grad Sch, Shenzhen, Peoples R China
[4] Scripps Res Inst, Dept Chem, La Jolla, CA 92037 USA