0-2 hours eggs derived from cortQW55/cortRH65 females contain two spindles near the anterior cortex of the egg. Both of the spindles contain a single X-chromosome signal, indicating arrest in metaphase II.
Transmission rate of Dp(1;f)J21A through females to progeny is 28%, cort mutation has no effect on transmission.
cort embryos do not develop to the cellular blastoderm stage. Embryos exhibit a complete absence of microtubule containing spindles, embryos do not initiate mitotic divisions. Oocyte meiosis is initiated but is arrested before completion. Sperm tails are present in embryos indicating a defect in oocyte fertilisation. Df(2L)cact-255rv64/cortQW55 embryos develop at 18oC but fail to develop at 29oC. A shift to the restrictive temperature during any stage of embryogenesis arrests embryonic development.
Females lay eggs that arrest in meiosis II, the earliest defect is in anaphase I. Premature sister chromatid separation does not rescue the meiotic defects, as shown in mei-S3321 double mutants. Male meiosis and mitosis are normal.
Eggs derived from homozygous females initiate development and cytoplasmic clearing occurs in a narrow zone around the egg periphery (in wild-type embryos this process is coupled to the arrival of the nuclei at the periphery). The eggs do not seem to develop beyond this stage; pole cells are not formed and cellularisation does not occur. However, about two hours after cytoplasmic clearing, the egg periphery starts to show local contractions, in what might be an attempt at gastrulation. These contractions eventually lead to eggs which typically have one or two condensed yolk balls surrounded by more transparent cytoplasm.