1. 1Beijing Key Laboratory for Animal Genetic Improvement, National Engineering Laboratory for Animal Breeding, Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing, China
2. 2Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
3. 3Department of Surgery and Cancer, Institute of Reproductive and Developmental Biology, Imperial College London, London, UK
4. 4Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing, China