Sperm chromatin remains condensed after sperm chromatin fragmentation in mice. Transmission electron microscope images showed no differences in sperm chromatin condensation between (A, B) 0.25% Triton-X100 for 60 min, (C, D) 0.25% Triton-X100 for 30 min + 100 mM EDTA for 30 min and (E, F) 10 mM Mn²⁺ in 0.25% Triton-X100 for 30 min + 100 mM EDTA for 30 min. A, C and E correspond to cauda epididymis sperm and B, D and F are vas deferens sperm. Bars indicate 800 nm.