The lethality of embryos from mothers with one copy of toc^{dsRNA.Scer\UAS} under the control of one copy of Scer\GAL4^{mat.αTub67C.T:Hsim\VP16} is increased when mothers are heterozygous for toc^P.

Embryos from toc^P mothers arrest their development prematurely, before nuclear migration. Typically after two or three nuclear divisions at the syncytial stage, the mutant embryos arrest in a metaphase-like state. The spindles of these mutants are nonfunctional and are characterized by broad poles. The pseudometaphase arrest begins with the detachment of centrosomes from the spindle poles. The spindle then stalls and does not increase in size. Pole-to-pole elongation does not occur. After around 15 minutes, the spindle progressively disassembles and finally disappears, leaving an unorganized mass of microtubules that eventually disperse in the cytoplasm.

None of the eggs laid by females develop. About 30% eggs are shorter than wild type, have strongly reduced or absent dorsal appendages and do not have a flattened dorsal side. Females transheterozygotes with toc^PR24 exhibit a compound egg chamber. Fertilised eggs laid by females carrying germline clones never develop and clearly show abnormal morphological structures. The eggs are round and smaller than wild type with reduced dorsal appendages.

Females lay eggs that do not develop.