(a), Schematic of clonal growth in epidermis started from a single cell with rate of renewal = 0.5, division interval = 1 day, and tissue turnover rate = 10 days. (b), Theoretical growth pattern of epidermal clones started from a single basal cell, and with a constant division interval and tissue turnover rate = 10 days (based on long term EdU chase and previous publication41). Rate of progenitor renewal is in the physiological range of 0.4-0.6. (c), Theoretical growth pattern of wild type and Pik3ca 2X clones started as a single cell at P20. Rates of differentiation, proliferation and tissue turnover are as observed in 3 independent differentiation and tissue turnover assays.