1. Institute of Swine Science Nanjing Agricultural University Nanjing 210095 China
2. Department of Molecular Biology and Genetics Center for Quantitative Genetics and Genomics Aarhus University Tjele 8830 Denmark
3. Changzhou Jiaoxi Cooperatives of Erhualian Pigs Changzhou 213116 China
4. Changshu Animal Husbandry and Veterinary Station Suzhou 215500 China
5. Changshu Agriculture Committee Suzhou 215500 China