Figure 1. Obtaining F0 heterozygous pigs through SCNT by knocking out GHR gene with ZFNs.

(a) Schematic representation of ZFNs targeting exon 6 of the pig GHR gene. E1–E10 represent the ten exons of the pig GHR gene, the lower-case characters and the upper-case characters are the spacers and the DNA binding sequences, respectively. (b) Identification of the cell clones for SCNT. The mutation types of GHR in different cell clones were small indels. (c) Identification of F0 heterozygous pigs by Sanger sequencing of PCR products. The results of 2 bp (TG) and 4 bp (TGGA) inserts are double peaks; WT indicates the result obtained from the wild-type pigs.