Fig. 5. The distribution of clonal progeny from the central DM sheet. Transverse sections of segments transfected with a GFP-encoding DNA into single cells followed by double desmin (red) and GFP (green) immunolabelings. (A) Time zero control. Six hours after transfection, a single cell is apparent spanning the apico-basal thickness of the epithelium. (B-D) Twenty-four hours after transfection, labeled progeny is localized to the ID and myotome (B), to the myotome only (C) or to the ID only (D). Each panel represents the overlay of two to three serial sections. (E-G) Sequences of five serial sections, each showing the distribution of clonal progeny 48 hours after transfection. (E1-E5) Labeled cells in both myotome and dermis. (F1-F5) Progeny restricted to dermis. (G1-G5) GFP+ descendants localized to the myotome. In all cases, GFP+ cells in myotome are desmin-negative. GFP+ cells are marked by white arrowheads. Yellow labeling represents blood cell autofluorescence. D, dermis; DM, dermomyotome; ID, intermediate domain; M, myotome; NT, neural tube. Scale bar: 40 µm in A; 50 µm in B-D; 70 µm in E-F; 60 µm in G.