Metaphase spindles of mutant embryos show the same defects under anoxia as those of wild-type embryos.

Progression through mitosis takes place in ald^PL00781 embryos despite the presence of colcemid, a microtubule destabilizing drug.

Homozygous animals derived from heterozygous parents develop up to the pupal stages. Most homozygotes die as pharate adults, but a small fraction eclose with rough eyes and bent wings. 45% of homozygous animals derived from females carrying homozygous germline clones develop up to the pupal stages. Centrosome behaviour appears to be normal in embryos derived from females carrying homozygous germline clones. Inhibition of mitotic spindle formation by colcemid fails to induce a mitotic arrest in these embryos and the metaphase to anaphase transition occurs prematurely suring the syncytial cycles. Chromosome segregation during mitosis is normal in most cells, although there is an increased frequency of occasional division failures of individual nuclei in syncytial embryos. Some or even all the chromosomes fail to display poleward movements during anaphase in these abnormal mitoses. About 45% of fertilised embryos have a severely reduced number of nuclei with a highly irregular distribution and appearance (which prevents syncytial and cellular blastoderm formation) while another 45% of the fertilised embryos appear to progress successfully beyond cellularisation with no or few irregularities in the distribution and appearance of nuclei and mitotic figures. Embryos (derived from females carrying homozygous germline clones) that are subjected to hypoxic conditions are frequently observed to be in anaphase or telophase (in contrast to wild-type embryos subjected to hypoxic conditions). These mitotic figures are almost always highly aberrant, with frequent chromatin bridges and chromosome arms in hypoxic anaphase figures have a wavy appearances. The physiological arrest of mature oocytes during metaphase of meiosis I does not appear to be compromised in mutant oocytes and normal meiotic figures are seen after in vitro activation. Eggs derived from homozygous female germline clones show abnormal behaviour of the three haploid polar body nuclei; instead of forming the characteristic wild-type bouquet-like arrangement of polar body condensed chromosomes, one or two giant nuclei are seen in all of the progeny of females containing homozygous germline clones. These giant nuclei contain decondensed chromatin.