Extended Data Figure 4: The scale is maintained by a single population during homeostasis.

a, Evolution of mean surviving basal (top) and suprabasal (bottom) clone size in the scale for K14-CreER/Rosa-YFP (red) and Inv-CreER/Rosa-YFP (blue). In contrast to the interscale, in the scale K14-CreER and Inv-CreER clones behave identically, indicative of a single progenitor pool. The lines are the fit from the model from which we extract the fate choices of progenitors displayed in b. b, Fate choices of the equipotent progenitor pool in the scale, as extracted from the fits. c, Clonal persistence (top) and labelled cell fraction (bottom) in the scale for K14-CreER/Rosa-YFP (red) and Inv-CreER/Rosa-YFP (blue). The blue and red lines are the predictions of the model (see Supplementary Notes for details) using only the parameters extracted in b. K14- and Inv-CreER clones behave similarly and display near-perfect long-term balance. For the clonal persistence data, we examined in each mouse a randomly chosen area shown in Extended Data Fig. 2b. Error bars represent the s.e.m. d, Cumulative basal clone size distribution of K14-CreER/Rosa-YFP clones at homeostasis in the scale upon Tamoxifen administration. One should note that there were too few Involucrin clones in the scale to plot meaningful distributions. Clonal distributions are plotted in log-plot, error bars indicate s.d., thick lines are the model prediction and shaded area indicate 95% confidence intervals in the model prediction.