Expression of FGF20 in developing feather placodes. (A,B) E8 (Hamburger-Hamilton stage 33) WT chicken embryos (dorsal view) hybridised with a digoxigenin-labelled riboprobe specific for FGF20 (antisense) (A) or a negative control FGF20 riboprobe (sense) (B). Punctate purple staining indicates specific expression of FGF20 in developing feather placodes (arrowhead). Scale bar = 500 μm. (C) Quantitative RT-PCR assessing FGF20 expression levels in separated dermis and epidermis from E8 WT chicken skin. Expression is specific to the epidermis. Error bars indicate SEM.