Figure 3

Robust transcriptome signatures of cellular senescence and aging. (a) Fifty-five pair wise comparisons of eleven aging and senescence datasets are divided into groups on the basis of the nature of the comparison: aging versus aging (n = 21), aging versus senescence (n = 28), and senescence versus senescence (n = 6). The aging versus aging group is further divided into within species, within tissue, and across species and tissue groups (the highly correlating aging mouse cerebellum to cortex comparison can not be allocated to any of these groups, as it is 'within species and tissue'). Bars represent the correlation in each comparison. The continuous line represents a threshold for significance corresponding to a Bonferroni corrected P value < 0.005, as determined by the random distributions of correlations. The dotted line represents the maximum correlation in that distribution (10,000 iterations). (b) Analysis of the average Z-score (displacement from the random distribution of correlations in numbers of standard deviations) for the aging versus aging, aging versus senescence, and senescence versus senescence groups. Only the aging versus aging and the senescence versus senescence groups have a mean that passes a t test for being different from zero. (c) Identical analysis of the within species, within tissue, and across species and tissue groups. Only the within species group has a mean that passes a t test for being different from zero. In (b,c), P values and tails represent the P value for having a mean different from zero, and the 95% confidence interval for the mean, respectively.