spermatid & nucleus | supernumerary
A significant proportion of sgoZ0742 mutant spermatids have one large nebenkern with two nuclei of normal size, indicating failure of cytokinesis in one of the meiotic divisions. Further, many spermatids have four nuclei and a large nebenkern, indicating a cytokinetic failure in both meiotic divisions. A very small amount of spermatids have three nuclei, a defect which may be due to failure of cytokinesis in the first meiotic division, followed by budding off of only one daughter cell in the second meiotic division. Further, a tiny proportion have more than four nuclei, which may result from defects in the mitotic divisions preceding mitosis.