Extended Data Fig. 1: Transformed age in universal clocks.

The plot displays transformed age in universal Clock 2 (a–c) and universal Clock 3 (d–f). (a, b) Loglog transformation of Relative Age (y-axis) versus age in universal Clock 2 and (d, e) log-linear age (y-axis) versus age in our universal Clock 3. Of the 969 mammalian species with available gestation time, age at sexual maturity and maximum lifespan in AnAge database, 339 species are available in our collection. We multiplied the reported maximum lifespan of non-human or non-mouse species by 1.3. Transformed ages were calculated for all the 969 species with simulated age ranging from gestation time through the modified maximum lifespan. The columns (a, d) display all the 969 species with the simulated ages. In panel d, we proposed the log-linear age with the parameter \({\boldsymbol{m}}\) formulated with maximum lifespan as the information is available for all species (\({{\boldsymbol{m}}}^{{\boldsymbol{* }}}{\boldsymbol{=}}{{\boldsymbol{c}}}_{{\boldsymbol{1}}}{\boldsymbol{* }}\frac{{\boldsymbol{MaxLifespan}}{\boldsymbol{+}}{\boldsymbol{GestationT}}}{{\boldsymbol{ASM}}{\boldsymbol{+}}{\boldsymbol{GestationT}}}\) in Methods). Of the 339 species, 185 species with age information of high confidence and known tissue types were used in training universal clocks. The columns (b, e) empirically display these 185 species with the age variable (x-axis) based on the observed ages from all the samples in our collection (N = 11,754). In panel e, we applied the log-linear age formulated without knowing maximum lifespan to train Clock 3 (formula (5) in Methods). Each line represents a species marked by gray for non-profiled and marked by black or pink for profiled species in our collection, as listed in the legend. Some species such as lemurs with relatively short gestation time in regressing \({{\boldsymbol{m}}}^{{\boldsymbol{* }}}\) (formula (7) in Methods) exhibiting high log-linear ages in (e) are marked in pink. Each panel reports the Pearson correlation coefficient. (c, f) display the histograms of transformed ages based on all samples from the 185 species with vertical lines presenting at means.