Heterozygous males have significantly reduced fertility, although they do produce progeny. Chromosome segregation and cytokinesis during meiosis are abnormal in homozygous males. Chromosomes fail to move to the poles and remain scattered during meiosis I and II, although some separation of the chromosomes does occur. Early spermatids typically have multiple nuclei of various sizes, often associated with large mitochondrial derivatives. Nuclear shaping during spermatogenesis does not occur and nuclear alignment is defective. Clusters of abnormal microtubules are present in place of axonemes. In late spermatids these structures fill with the dense core material characteristic of wild-type central pair and accessory microtubules. Spermatid cyst elongation is very poor. Mitotic division before meiosis appears normal.
Flagellar elongation is extremely defective in homozygous males. The developing spermatids contain a variety of aberrant microtubule structures, the most common of which are S-shaped microtubules. Closed microtubules and outer doublet-type structures are rarely seen. S-shaped microtubules are seen in both the astral and central spindle region of the meiotic spindle, in the place of axonemes in developing spermatid bundles and next to the nucleus during nuclear shaping. Meiosis is defective. Nuclear shaping is defective; although a few nuclei begin to flatten, most remain large and round.