Figure 2. Hatching of embryos from Blm mutant mothers.

Virgin females homozygous for the Blm alleles indicated on the X-axis were crossed to Oregon-RM males and allowed to lay overnight on grape-juice agar. Embryos were transferred to fresh grape-juice agar plates and scored for hatching 48 hours later. Each experiment was repeated three times, with 100–250 embryos transferred each time. Embryos from Blm^ΔCR2 (ΔCR2) or Blm^N1 (N1) females are rarely able to complete development. Embryos from Blm^ΔCR1 (ΔCR1) and Blm^N2 (N2) have a modest but significant reduction in hatch rates. We conclude that the CR2 region is more critical for embryonic development but the CR1 region contributes only to a small degree. n = wt: 598; ΔCR1: 1080; ΔCR2: 743; N1: 706; N2: 700. **** p < 0.0001 by Fisher’s exact test.