DmBlm impacts DSB repair pathway usage. (A) I-SceI heat shock-induced DSB repair events in a DmBlmN1/D2 null mutant background (red; n = 94) compared to DmBlmN1 heterozygote controls (blue; n = 125). Results shown are averages and SEM of individual male germline events compiled from five independent experiments. * P < 0.05 and **** P < 0.0001 by unpaired Student’s t-test. (B) I-SceI heat shock-induced DSB repair events in a DmBlmD3/D2 helicase-dead mutant background (red; n =52) compared to DmBlmD3 heterozygote controls (blue; n = 59). Results shown are averages and SEM of individual male germline events compiled from three independent experiments. ** P < 0.01 and **** P < 0.0001 by unpaired Student’s t-test. CO, crossover; DSB, double-strand break; HR, homologous recombination; NHEJ, nonhomologous end-joining; SSA, single-strand annealing.