Mean mutation frequency in 10⁻⁶ compared between control (0 Gy) and irradiated (3 Gy) mice.

*Wilcoxon z-values: intestine, 3.35; liver, 2.43; pancreas, 0.45; spleen, 1.11. Means were compared with a Wilcoxon-Mann-Whitney test. Fold increase (irradiated vs. control), along with bootstrapped 95% CIs, are also presented; CIs not containing 1 indicate statistical significance at α = 0.05.