Fig. 2

Diagram of genome editing in mammals. a Diagram summarizing the processes for gene editing of Astl in mice using the CRISPR/Cas9 system, including microinjection, embryo transfer, identification of founders, obtaining homozygous mutants through breeding, and performing phenotype examination and mechanism investigation. b Diagram summarizing the correction progression of a genetic defect in a cataract mouse model. The zygotes from wild-type mice crossed with Crygc^−/− mice were used. Some offspring embryos showed normal phenotypes following microinjection of Cas9 mRNA, sgRNA and exogenous DNA oligos into heterogeneous zygotes. c The processes to generate PERVKO·3KO·9TG pigs. In the first round of engineering, 3KO·9TG pigs were obtained by SCNT using CRISPR/Cas9-edited porcine fibroblasts. In the next round of engineering, the candidate fibroblasts from 3KO·9TG pigs were isolated and further edited by the CRISPR/Cas9 system, and PERVKO·3KO·9TG pigs were obtained using SCNT.