Incomplete sister chromatid separation during mitosis. Transmission rate of Dp(1;f)J21A through females to progeny is 28%, rod mutations cause a mild increase in transmission. mei-S3321 ord1 double mutant has no effect Dp(1;f)J21A transmission in males.
Strong allele. Lagging chromatids are often observed during anaphase in larval brain cells. Nuclear bridging by strands of chromatin during anaphase/telophase is also common.
% abnormal anaphases: 20.2 % homozygous viable: 25 Mutants show mitotic abnormalities in larval neuroblasts; there is a high frequency of both aneuploid cells and abnormal anaphase figures, with lagging chromatids, anaphase bridges and stretched chromatid arms. Abnormal chromosome behavior also occurs in the second meiotic anaphase in male meiosis, although motile sperm are produced. All surviving homozygous females and 90% of surviving homozygous males are sterile and have roughened eyes, sparse abdominal bristles and notched wings.