pAbp5-SZ-4029/pAbpSH1908 cysts in the testis contain only 32 onion-stage spermatids, instead of the normal number of 64, which indicates that only one meiotic division has occurred in the mutants. In addition 7% of these onion stage spermatids have a ratio of two nuclei to one Nebenkern, revealing a failure of cytokinesis.