Microarray differential expression profiles of selected developmental gene families. A), protocadherins (Pcdh); B), cadherins (Cdh); C), bone morphogenetic proteins and bone morphogenetic protein receptors (Bmp and Bmpr); D), growth differentiation factors (Gdf); E), Wnt family, (Wnt); F), fibroblast growth factors and fibroblast growth factor receptors (Fgf and Fgfr); G), homeobox transcription factors (Hox); H), T-box transcription factors (Tbx); I), Sry-like homeobox transcription factors (Sox); J), forkhead/winged helix box transcription factors (Fox); K), selected non-collagenous extracellular matrix molecules. Yellow bars indicate relative expression at 11.5 dpc. Blue bars indicate relative expression at 12.5 dpc. Orange bars indicate relative expression at 13.5 dpc. For each gene, the time point at which the relative expression was lowest was defined as one, and this was used to calculate the relative expression at the remaining time points. Numbers above each gene denote average Log2 intensity (A) for that gene.