Fig. 5. The ORS follows a coherent regional mode of growth and shows apoptosis. (A-D) In toto views of ORS clones; ORS precursors are dispersed (brackets) along the proximodistal axis of the HF. Scale bar: 100 µm. (E-M) Anti-cleaved caspase 3 immunostaining on 20 µm anagen HF sections. Scale bar: 25 µm. (E,H,K) Bright field. (F,I,L) DAPI staining in blue. (G,J,M) Cleaved caspase 3 staining in green. Apoptotic cells are marked by red arrowheads. (N) Clonal complexity (y-axis) of the 100 subdivisions of equal length of the ORS proximodistal axis (x-axis). Clonal complexity is the number of times a subdivision is labeled (calculated from the 60 clones in O, Experiment 1). (O) Classification of the 60 ORS clones according to their proximodistal extension. Each horizontal line corresponds to a clone (the colored rectangles). The numbers indicate the position of the clone according to the subdivision of the proximodistal axis in 100 equal parts. Each color refers to the number of cells in the clone. See color code in P. (P) Number of clones in relation to the number of ß-galactosidase⁺ cells. The x-axis represents the number of ß-galactosidase⁺ cells for each class of clones. The y-axis represents the number of clones. ORS clones differ considerably in size. (Q) Percentage of ORS clones of the total number of HFs observed (labeled and unlabeled) (y-axis) calculated for D7, D9, D11 and D14 (experiment 3). Percentage decrease indicates the loss of ORS clones during anagen owing to apoptosis.