(A, D, G, J) Negative control DapB RNAscope in situ staining shows no positive brown signal appearing around the face (A and D), the plates (G), or the pelvic junction (J). The slight brown color in the pelvic spine is due to natural pigmentation at this site. (B, E, H, K) Endogenous EDA expression is localized to the premaxilla, lips, lower jaw, cranial ganglia, gill and pectoral fin base (B and E); armor plates (H); and the junction between the pelvic spine and the pelvic girdle (K). (C, F, I, L) The p3.2mar-GFP construct drives reporter expression at several corresponding sites, including the lips, premaxilla, lower jaw and cranial ganglia surrounding the eyes (C and F); in the armor plates; (I) and at the pelvic junction (L). Anatomical abbreviations as in other figures, including: lips (L), premaxilla (PM), lower jaw (J), cranial ganglia (CG), gills (G), pectoral fin base (PF), anterior plates (AP), and pelvic spine junction (PSJ). Scale bars are 1 mm long.