The coding region from DroncC318S.GMR is driven by the βTub85D promoter.
In testes from mutant males cystic bulges and wastebags are largely absent. Defects are also seen in the movement of investment cones, which normally move tailwards in a co-ordinated fashion. Some spermatid individualisation failures are observed. In addition, many spermatids that have apparently undergone individualisation still contain large amounts of excess cytoplasm.