Homozygous females produce embryos that arrest prior to cellularisation. Embryos derived from cnn^mfs2/Df(2R)cnn females have severe defects in nuclear division and distribution. The embryos never achieve cellularisation.

Cytokinesis and karyokinesis during meiotic divisions are disrupted in males. The percentage of aberrant spermatids varies from testis to testis (20-50%), and the cytokinetic defects are more severe than karyokinetic defects. Despite these defects, the spermatids elongate their mitochondrial derivatives and go through varying degrees of spermiogenesis in cnn^mfs2/Df(2R)cnn males. The spermatids degenerate before individualisation, and no motile sperm are seen in the seminal vesicles. The prominent asters seen in wild-type spermatocytes at the transition to meiotic division I do not form in cnn^mfs2/Df(2R)cnn spermatocytes. Some spermatocytes have regions of high microtubule density, and in many cases only one focus of higher microtubule density can be distinguished.