Expression of Axs^{D.Scer\UAS.P\T} in the germline under the control of Scer\GAL4^{nos.UTR.T:Hsim\VP16} results in high levels of achiasmate-specific chromosome non-disjunction. Defects in meiotic chromosome positioning and meiotic spindle structure are also seen. The spindles are shorter than normal and have a barrel-shaped structure. Comparison of the ratio of spindle length and spindle width suggests that the spindle mid-zone in the mutant spindles does not unergo the tightening normally associated with late stages of spindle morphogenesis. The chromosome complement is only rarely arranged in a completely symmetrical manner during meiosis I metaphase (in contrast to 79% of wild-type metaphase figures). The chiasmate chromosomal mass is often symmetrically stretched across the metaphase plate, while the achiasmate chromosomes fail to be positioned properly. The incidence of anaphase is increased in the mutant oocytes compared to wild type. These anaphase figures often contain 16 distinct chromosomal masses, each with a centromere.