Editing porcine IGF2 regulatory element improved meat production in Chinese Bama pigs.

Insulin-like growth factor 2 (IGF2) is an important growth factor, which promotes growth and development in mammals during fetal and postnatal stages. Using CRISPR-Cas9 system, we generated multiple founder pigs containing 12 different mutant alleles around a regulatory element within the intron 3 of IGF2 gene. Crossing two male founders passed four mutant alleles onto F1 generation, and these mutations abolished repressor ZBED6 binding and rendered this regulatory element nonfunctional. Both founders and F1 animals showed significantly faster growth, without affecting meat quality. These results indicated that editing IGF2 intron 3-3072 site using CRISPR-Cas9 technology improved meat production in Bama pigs. This is the first demonstration that editing non-coding region can improve economic traits in livestock.