(A, D, G, J) WISH images showing expression domains of planarian tissue markers for the eye spots (ovo), pharynx (foxA), epidermis (prog-2), and gut (hnf4). (B, E, H, K) Single confocal planes showing tissue specific progenitors after RNAi knockdown of hh or ptc. Region of interest is represented by the white boxes in (A, D, G, and J). Scale bars = 100 µm. (C, F, I, L) Quantification of tissue progenitors after hh or ptc RNAi knockdown. All graphs are dot plots, showing the value mean ± standard deviation. *p<0.05, **p<0.01.