FIG. 2.

Example targets and efficiencies of base editor. (A) The targeted genomic site of F₁ male flies containing the base editor and a gRNA were PCR amplified and sequenced. Targeted cytosine (C) residues are shown in blue on top of the chromatographs. The PAM sequence is underlined. (B) Fourteen different genomic loci were targeted by the base editor. Cytosine residues mutated by the base editor are shown in red. Cytosine residues not highlighted were not mutated. The PAM sequence is highlighted in blue. (C) Examining the location of base editing within the gRNA target. The bar graphs shows the frequency that a cytosine residue at a particular location in the 20 bp targeted site was mutated. The numbers in the bars indicate the number of times a cytosine was present in that position across all 14 targeted genes. For example, C > T mutations in positions 5–8 were found in all PCR-amplified targets examined from F₁ flies. (D) Estimating the efficiency of base edit targeting. The EditR program²⁴ was used with chromatographs to estimate the percentage of cytosine converted to thymine at each gRNA-targeted site. Points above the red-dashed line at 50% suggest that both alleles were targeted. The line indicates the average. PCR, polymerase chain reaction; PAM, protospacer-adjacent motif. Color images are available online.