Fig. 1. Formation of a partial contractile ring during the first meiotic division of a D. melanogaster spermatocyte carrying a mutation in the chickadee (profilin) gene. A wild-type spermatocyte is shown in A and the chickadee mutant spermatocyte shown in B. Microtubules are stained green, DNA blue and F-actin red. Reproduced, with permission, from Giansanti et al. (Giansanti et al., 1998).