An Electron Microscopic Examination of Spermiogenesis in the Recessive Sex-Linked Male-Sterile Mutant, ms(1)10S of \u3cem\u3eDrosophila melanogaster\u3c/em\u3e
Electron microscopy of the testes of mutant ms(1)10S of Drosophila melanogaster is characterized by three major defects in the tail region of the developing spermatid. One is the apparent lack of paracrystalline body formation. The second is the loss of the primary derivative as development proceeds, and the third is the breakup and incorporation of the plasma membrane and periaxonemal sheath into membranous whorls. The mutant shows different patterns of axonemal breakup depending on the stage of differentiation in which degeneration begins. Degeneration continues until only cellular debris, scattered axonemal profiles and membranous whorls are all that are seen in the basal end of the testis. Randomly distributed, longitudinally oriented microtubules are also observed in the cyst cells surrounding spermatid bundles. The analysis of this mutant has elucidated the importance of the primary derivative to the developing spermatid and the requirement for a paracrystalline body for normal development. It further shows that the integrity of the axonemal components increases as spermatid development proceeds
