The survival of Lig4⁵⁷/Y males carrying a source of transposase (P\T^Δ2-3) and a P-element that can be mobilised (P{}w^hd80617) is reduced to 24% compared to controls lacking a source of transposase, indicating that Lig4 is required for the repair of P-element induced double-strand breaks in males. In contrast, the survival of Lig4⁵⁷ females carrying a source of transposase (P\T^Δ2-3) and a P-element that can be mobilised (P{}w^hd80617) is not reduced compared to controls lacking a source of transposase.

Lig4⁵⁷ hemizygous embryos are hypersensitive to X-rays: the ratio of hemizygous males to heterozygous female siblings from irradiated embryos is 0.24. Hypersensitivity to X-rays is most acute from 4-20 hours of embryogenesis when the ratio is 0.14, whereas for those irradiated between 0 and 4 hours of embryogenesis the ratio is 0.93. At later stages of development, the hypersensitivity of larvae to X rays gradually decreases: the ratio for larvae irradiated at 24-48 hours is 0.43 and at 48-72 hours old is 0.76. X-ray hypersensitivity of 0-8 or 8-24 hour old Lig4⁵⁷ hemizygous male embryos is increased 2-fold and 3.3 fold respectively if they have Lig4⁵⁷ homozygous mothers. This maternal effect is not seen when irradiation is done at 24-48 hours development (All X-ray treatments: 9 Gy at a dose rate of about 1 Gy/min).