Figure 2.
Mean frequencies of no-change mutants and size-change mutants in mouse heart and small intestine of 3.3- and 32-month-old animals (n = 7). Error bars indicate standard deviations of the means. Significant age-related changes for no-change mutants were found in both heart (P = 0.0049) and small intestine (P = 0.0022). Age-related changes for size-change mutants were significant for heart (P = 0.0073), but not for small intestine (P = 0.61; Wilcoxon Rank-Sum test). The shaded area indicates the fraction of size-change mutants with one break point in the mouse genome (genome rearrangements). The mutation load per cell, determined on the basis of a 3,000-bp lacZ target locus and a 6 × 109-bp diploid genome, is given in parentheses above each bar.