Fig. 3

Desired and undesired outcomes of the two-donor floxing method. a-f Wild-type locus showing exons 3, 4, and 5 of a hypothetical gene where exon 4 is chosen as a target exon for inserting LoxP sites. a Desired outcome showing a floxed allele. Overall occurrence was < 1%. b–f Various undesired outcomes including only one LoxP site insertion (b), only indels created at one or both sites (c), combination of LoxP insertion and indels (d), deletion between the two cleavage sites (e), and no indel or no insertion events (f)