sub1/sub131 oocytes exhibit frequent monopolar and tripolar spindles as well as mono-orientation of homologous centromeres while they do not exhibit any failure to separate chromosomes or a defect in the movement of centromeres toward a pole present in the spindle as compared to controls.
The percentage of cells in mitosis in sub1/sub131 mutant larval brains is approximately double that of wild-type.
sub1/sub131 larval brains show an increased frequency of spindle assembly defects. These include frayed microtubules, unequal distribution of microtubules in the two half spindles, and disorganised or absent interpolar microtubules. 70% of mutant brains show disorganised metaphase, and 46% show lagging chromosomes at anaphase compared to 11% and 9% respectively in wild-type brains.
sub131 mutant larval brains show a higher percentage of cells in mitosis (2.66) compared to wild-type brains (1.32).
43% of sub131 mutant brains show disorganised metaphase spindles (including frayed microtubules, unequal distribution of microtubules in the two half spindles, and disorganised or absent interpolar microtubules) compared to 11% of metaphase spindles in wild-type brains. 52% show lagging chromosomes at anaphase compared to 9% in wild-type brains.
14/17 sub1/sub131 oocytes have abnormal spindle organisation. Among the abnormal spindles, 3 are monopolar, 9 are tripolar and 2 have other defects such as fraying of microtubules.
Most mutant oocyte spindles are not bipolar. All mutant spindles, even those that are bipolar, lack the prominent bundles of central spindle microtubules that are seen in wild-type oocytes.
Sterile females show rough eyes and clipped wings. Mutant males show elevated levels of X-Y chromosome non-disjunction in male meiosis. Embryos derived from mutant mothers show early mitotic abnormalities including arrest before embryonic mitoses begin, a polar body near one end and the development of one or two spindles in the middle. Structure of spindles in the embryos is abnormal, and their size variable.