1. Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
2. Key Laboratory of Agricultural Animal Genetics, Breeding, and Reproduction, Ministry of Education College of Animal Science and Technology, Huazhong Agricultural University, China
3. Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA