Heterozygous females deposit normal numbers of normal looking eggs. The eggs are normally fertilised as revealed by the presence of a sperm tail in the egg cytoplasm. As in wild type, the nuclei are well contoured in newly deposited eggs, suggesting compact nuclei. The four haploid nuclei appear compact in unfertilised eggs laid by virgin heterozygous females. A bundle of microtubules is seen between the two inner haploid nuclei and is most likely the central spindle pole body that persists following the second meiotic division (this phenotype is never seen in wild-type eggs). Severe defects appear 6-7 minutes after fertilisation when the female and male pronuclei become juxtaposed; the male and female pronuclei are poorly contoured suggesting nuclear envelope defects. Generally, disorganised masses of microtubules (MTs) form instead of the gonomeric spindle. The MT mass appears as a prominent sperm aster and persists for several minutes. The centrosome replicates, however, the daughter centrosomes cannot separate. The chromosomes fail to segregate and disintegrate in minutes. The centrosomes may replicate 2 or 3 times but instead of separating they organise rudimentary asters of MTs along with a general decay of the egg cytoplasm. Egg cytoplasm from eggs laid by heterozygous females injected into the presumptive head region of wild-type cleavage embryos causes the corresponding head structures to be missing. Dp(2;Y)G does not reduce the sterility of Fs(2)Ket¹/+ females. Females containing Fs(2)Ket¹/Df(2L)Fs(2)Ket-RX32 germline clones deposit normal looking eggs. Embryogenesis does not occur due to the lack of cleavage nuclei formation.

Heterozygous females are fully viable and fertile. Injection of cytoplasm from eggs of heterozygotes into wild type eggs causes fail of head development at the site of injection. Mutant phenotype may be 'cured' by increasing the normal gene product ratio.

Eggs laid by heterozygous females show meiotic defects; the polar body and oocyte nuclei are missing or abnormal.

dominant female-sterile. Heterozygous females show meiotic defects.