Figure 4

Similarity in the transcriptome signatures of senescence and mouse aging. (a) Two senescence datasets, where data derived from proliferating cells (denominator in ratio of differential expression with senescence) have been replaced by data derived from quiescent cells, are compared to seven aging datasets. Arrows represent the Pearson correlation in each comparison. Distributions of correlations produced by random pairing of genes are displayed as density curves. P values (calculated using the random correlation distributions as a reference) and numbers of gene or ortholog pairs (present in the individual comparison) are displayed in the top right part of each figure. (b) Left: analysis of the average Z-score for groups of comparisons. Only the six comparisons of senescence (mouse and human) and mouse aging (cerebellum, neocortex and heart) have a mean that passes a t test for being different from zero. Right: similar analysis of mean Pearson correlations for the same groups, producing the same result. In (b), P values and tails represent the P value for having a mean different from zero, and the 95% confidence interval for the mean, respectively.