Fig. 3. Kinetics of pachytene/spermatid stages of spermatogenesis and spermiogenesis in homozygotes (all-telocentrics, C3H standard karyotype shown by O; all-Rb metacentrics, CR mice shown by 
) and heterozygotes (seven trivalents in diakinesis, C3H x CR shown by 
). The pachytene/spermatid ratios reach the expected 1:4 value only for the homozygous mice, whereas the C3H x CR heterozygotes show a decreased value because of germ-cell losses. On the right, the inserts show seminiferous tubules of a fully fertile (tubules with normal histoarchitectural germ cell arrangement) C3H (top) and a subfertile (tubules with different degrees of cell depletion) C3H x CR (bottom) mouse from histological sections of testes. The testicular picture of the fertile Rb homozygous CR mice is not reported as it looks like that of the C3H mice. The bar represents 100 µm.
