aly2/aly5 adult heterozygote males show morphological defects of the nuclear lamina in stage S4-S6 spermatocytes (the lamina has distinctly more ballon-like shape, lacking the deformations that correlate with chromosome distribution seen in wild-type), while in stage S3 the lamina is of wild-type appearance.
aly2/aly5p mutant spermatocytes arrest at the G2/M transition of meiosis I, exhibit lobe-like extensions of the nucleolus, and the condensing autosomal bivalents largely remain as incompletely condensed crescents near the nuclear periphery.
Sister chromatid separation occurs normally in homozygous mutants.
Early stages of spermatogenesis up through mature primary spermatocytes are present and normal. Postmeiotic stages are completely absent. Mutant testes have an abundance of mature primary spermatocytes with large, round nuclei and prominent nucleoli. Spermatocytes arrest in the G2/M transition of meiosis I with partial chromosome condensation.