Extended Data Fig. 1: Intravital microscopy set-up to follow the same clone over time in living mice.

a, Set-up of intravital microscope. b,c, Making tattoos in the mouse ear (b) and back skin (c). d, Method combining tattoo and the stable pattern of hair follicles to establish spatial coordinate to monitor and track the same clones in the skin by intravital microscopy over time. For the ear, we used a 30g needle to make three punctiform tattoos. The tattoos are visible at 10× magnification. At 10× magnification, we can select an easily identifiable area using the hair follicles (yellow dashed square). At 40× magnification, we can image an area at the single-cell resolution. This area will be revisited over time to monitor cell dynamics. e, The same strategy is used to follow the same clones over time in the back skin, with the difference that tattooing (white dashed line) is performed using a tattoo machine. For more details, see Methods. White dashed line: delimitation of the tattoo. Hair follicles are numbered.