Fig. 1.

Summary of the axes and morphogens of the eye, wing and abdomen of Drosophila, the main organs used to study PCP. The colours indicate the zones of expression of genes encoding the three morphogens, showing their radically different dispositions. Note the structures that indicate PCP: ommatidia in the eye, hairs of the wing and hairs and bristles of the abdomen. Note that while the wing hairs are aligned parallel to the A/P axis, the abdominal hairs and bristles are orthogonal to the same axis. The ommatidia are aligned along the A/P axis but have two chiral forms depending if they are dorsal or ventral in the disc. Do=dorsal, Di=distal, Pr=proximal, Ve=ventral.