ballE107/Df(3R)ro80b third instar larvae display chromosome condensation defects in the mitotic cells in the central nervous system, the frequency of mitotic cells (phospho-histone H3-positive) is significantly increased compared to wild-type..
Brain-squashes of ballE60 mutants reveal a higher mitotic index and frequent overcondensation of chromosomes. The frequency of anaphase is also decreased. Some anaphase cells exhibit lagging chromosomes. Except for overcondensation, which is associated with mitotic arrest, the morphology of mitotic chromosomes is generally unaffected.
In ballE60 mutants, about one third of the spindles exhibit defects in bipolarity. The defects include monopolar spindles, multipolar spindles, and formation of ectopic microtubule foci that lack Cp190.