Downregulation of cadm3 in p15 ⁺ retinae is required for clonal expansion of WT donor RPCs. (A) Representative clones derived from single 12-hpf WT donor RPCs in WT (n = 34), p15⁺ (n = 32), p15⁺/cadm3⁺ (n = 21), or p15⁺/cadm3-ect⁺ (n = 28) host retinae. (B) Quantification of the size of 72-hpf clones in A. (C) Representative clones derived from single 12-hpf WT donor RPCs in scramble-sg (n = 25) or cadm3-disrupted (n = 29) host retinae. Inserts (top) in A and C describe the patterns of Cadm3-mediated cell–cell interaction in different conditions. (D) Quantification of the size of 72-hpf clones in C. (E and F) Representative cases (E) and quantification of cell-cycle length (F) of single 12-hpf WT donor RPCs in scramble-sg (top, n = 17) and cadm3-disrupted (bottom, n = 12) host retinae. The area of dashed white circles is the optic vesicle, and the area between two dashed white lines is the retina. Yellow arrowheads show RPCs at the M phase. OPL, the outer plexiform layer; IPL, the inner plexiform layer. Data in B, D, and F represent mean ± SEM. Scale bars, 10 µm.