FlyBase curator comment: this entry is used to capture phenotypic information when the particular allele (or allele combination) used by the author could not be determined but the context of the experiment suggests that the phenotype being described is some kind of loss of function.
Neuroblast cells in homozygous larvae show a high frequency of metaphases with contracted and scattered chromosomes, and anaphases are not seen. Approximately 30% of the metaphase figures are polyploid. Spindle morphology and chromosome segregation during the first meiotic division is normal in males. The second meiotic prophase is also normal and two regular asters are formed. However, chromosome segregation is severely impaired in the second meiotic division; in most cells the chromosomes do not disjoin properly, and in many cases the entire chromosome complement migrates to one pole. This leads to abnormal spermatids, in which many of the nuclei are hypoploid or hyperploid and are associated with larger than normal nebenkern.
