12.6% of homozygotes survive, but no vnd⁴/Df(1)74 flies survive. Transheterozygotes with vnd¹, vnd² or vnd³ survive at a low frequency (3.3-6%) at 19^oC, at 29^oC no transheterozygous escapers are seen (with the exception of 1% of vnd¹/vnd⁴ flies). Hemizygous male embryos hatch and there is no specific stage of embryonic lethality, with some flies eclosing to give fertile adults with a normal appearance.