Cellular age dynamics predict the increase in transcriptome variability in aging mice. (A) The average log10 coefficient of variation (CV) of each cell type at each of three organismal ages (in months) is plotted over their respective mean cell ages (in days). The colored lines show ordinary least square regressions, with shading indicating 95% confidence intervals, each corresponding to one age group. (B) The mean change in transcriptome variability (βage; Methods) observed in cells over a 21-mo period, from 24-mo-old mice compared with cells from 3-mo-old mice, is correlated with the change in estimated mean cell age for 22 cell types (Pearson's r = 0.702, P = 2.7 × 10−4). The black line shows an ordinary least square regression, with shading indicating 95% confidence intervals. Filled circles indicate the 15 cell types with cell- and tissue-specific life span data; open circles, the seven cell types without tissue-specific life span estimates, and so their βage is the mean from all tissues in which they are detected (see Methods).
