(A) Percentage of nuclei with different types of γ-H2AX staining patterns in the flight and ground samples with and without bleomycin treatment. All of the nuclei were Type III in placebo treated cells, whereas the percentages of Types and II nuclei after bleomycin treatment were similar between the flight and ground samples. For bleomycin treated samples, the percentage of type I, II, and II are 5.5, 14.5, and 80.1 for ground samples, and 6.5, 15.6, and 77.9 for flight samples, respectively. (B) γ-H2AX foci number distribution in Type III nuclei in ground and flight samples after bleomycin treatment showing differences mainly in the lower quantiles of the two count distributions.