The east^hop-1 phenotype is not associated with a significant rate of nondisjunction of achiasmate X-chromosomes in female meiosis. Embryos derived from females carrying homozygous east^hop-1 germline clones have a higher rate of lethality than embryos derived from females carrying east^hop-1 heterozygous germline clones. Heterozygous east^hop-1 zygotic flies derived from female homozygous east^hop-1 germline clones show a range of phenotypes. Around 40% of resulting embryos have severe developmental defects that result in lethality. Flies that do survive to adulthood often lack body structures such as tergites on the abdominal cuticle or appendages such as legs. A small proportion of heterozygous zygotic east^hop-1 syncytial embryos derived from females carrying homozygous east^hop-1 germline clones have vast areas of the embryonic surface that are depleted of nuclei. The frequency of mitotic errors was up to four times higher in embryos derived from females carrying homozygous east^hop-1 germline clones than in embryos derived from wild-type germline clones. In embryos derived from females with wild-type east, on nuclear envelope breakdown, condensed chromosomes remain clustered in the centre of the cell and rapidly orient themselves perpendicular to the future axis of division. In embryos from east^hop-1 females, chromosomes sometimes break up into distinct clumps of DNA or stray to the periphery of the cell. The onset of anaphase following the beginning of prometaphase is much more variable (4-9.75 minutes) in embryos from east^hop-1 females than in embryos from wild-type females (3.5-6 minutes duration). However, all cells in embryos from east^hop-1 females eventually enter metaphase and complete mitosis.