(A–D) Representative images of juvenile animals of the indicated genotypes expressing an MC reporter and stained with Alizarin Red S (ARS) to visualize scales (A and B) or co-expressing MC and keratinocyte (Tg(krt4:DsRed)) reporters (C and D). Dotted lines indicate scale boundaries. nm, neuromasts of the posterior lateral line. (E–H) Tracings of scale outlines (E and F) and density plots of MC position (G and H) from juvenile animals (n=43–49 scales/genotype from N=10–13 fish/genotype; 11.6–14.7 mm standard length [SL]) of the indicated genotypes. Scale tracings were aligned at the dorsal-ventral midpoint of the posterior scale margin. Note the variability in scale shape and size and corresponding increased spread of MC position in fgf8adhiD1Tg/+ juveniles compared to sibling controls. Scale bars: 100 μm (A–D) and 200 μm (E–H).
