Activity of Cdc20 contributes to the ability of Δrad4 strains to carry out double strand break repair. Plasmid DNA (pYES.2/URA3 ⁺) was linearized with PvuII, and aliquots from the same pool of digested DNA were used to transform Δrad4, Δrad4/cdc20-1, cdc20-1, or a wild-type strain (Y2454). Following incubation at 22°C for 4 days, colonies were counted, and transformation efficiencies were calculated. The fold changes (linearized/uncut) are represented.