Transcription and morphogenesis factors with significantly variable expression across the proximal-distal axis. Gene names and relevant known functions are largely based on information and gene ontology categorization available in FlyBase. “Pattern” defines whether expression is highest apically or basally or whether variation separates the medial from peripheral regions. The heat map shows the mean intensity of expression across the conditions of the forewing arrays, with darker shading indicating more intense expression and levels relative to all gene intensities. Stages of differential expression are abbreviations of stages presented in Figure 1. pet: petiverana; B: basal; M: medial; A: apical.