Figure 1.

Hypothetical gene models illustrating deletion strategy for producing null alleles using paired CRISPR guides flanking the region of interest. (a) Two examples of internal exon deletions are shown to indicate removal of large portion of coding sequence for single exon gene. The other example shows an internal deletion within an exon for a multi-exon gene that has all exons in the same phase. (b). Paired guides flank a critical exon within a multi-exon gene that when deleted will result in a frameshift mutation. Exon phases (0,1,2) are indicated above the gene model for multi-exon genes and guide cut sites are shown as arrows.