1. Institute of Reproductive Sciences; College of Animal Science and Technology; Qingdao Agricultural University; Qingdao, China
2. State Key Laboratory of Reproductive Biology; Institute of Zoology; Chinese Academy of Sciences; Beijing, China
3. Department of Reproductive Medicine; Peking University Shenzhen Hospital; Medical Center of Peking University; Shenzhen, Guangdong, China
4. Department of Veterinary Pathobiology; University of Missouri; Columbia, MO USA