First-wave spermatocytes have persistent autosome-localized γH2AX, but no change in RAD51 foci.

A) Meiotic chromosome spreads were prepared from PND14, PND21, and adult mice, and stained for SYCP3 (red) and RAD51 (green). RAD51 foci were quantified per zygotene-staged cell (n = 2 mice per age, with greater than 30 cells quantified). RAD51 foci are not significantly different at any of the profiled ages (Kruskal-Wallis test). B) Meiotic chromosome spreads were prepared from PND14, PND21, and adult mice, and stained for SYCP3 (red) and γH2AX (green). Persistent γH2AX on autosomes was quantified per pachytene-staged cell (n = 2 mice per age, with greater than 30 cells quantified). The average percentage of cells with at least one persistent γH2AX flare on autosomes is significantly higher in first-wave PND14 spermatocytes than in adult spermatocytes (* = p<0.05, One-Way Anova). C) Representative images of pachytene spermatocytes used to produce the quantification in (B).