The anatomy of the reproductive system of ms(1)6S1 males is normal, however they have few or no motile sperm. Spermiogenesis is defective; some centrioles fail to form basal bodies, reducing the numbers of axonemes formed, the basal body fails to make a normal attachment to the nucleus, the mitochondria fuse irregularly but do elongate and elaborate paracrystalline material, large cytoplasmic units with multiple mitochondrial derivatives but few if any axonemes are seen in cross-sections and isolated cytoplasmic elements with or without single axonemes are also observed. Acrosome formation is abnormal. Chromatin condensation, nuclear elongation and formation of microtubules around the elongating nucleus is abnormal.
