Heritable, BOC-induced editing of native genomic alleles by Cas9K510B expressed from cRNA. (A) BOC-induced editing of the sex-determining gene, Sry following injection of wt C57BL/6 (B6) mII oocytes with B6 sperm and a mixture of PylRS cRNA (600 ng/μl), Cas9K510B cRNA (3,300 ng/μl), Pyl tRNA (1,200 ng/μl) and three gRNAs (800 ng/μl) (Supplementary Table S1). Results of ear-punch genomic PCR for Sry are presented (upper) for offspring generated when BOC had been included (+) or omitted (-). Internal reproductive organs are shown for wild type (wt) and sex-reversed adults. Scale bar, 5 mm. (B) Developmental efficiency and phenotypes of offspring produced by ICSI with wt B6 sperm and oocytes as per (A), except that the mixture of three gRNAs targeted Tyr (Supplementary Table S1). The total number of offspring (total) is given with numbers exhibiting different coat-color phenotypes. Data reflect at least two experiments per target. (C) Offspring of (B) at 7 d.