EPITHELIAL PLANAR POLARITY IN THE DEVELOPING DROSOPHILA EYE

Experiments with the insect ectoderm have suggested that planar polari ty in epithelia results from the local orientation of cells to the slo pe of a gradient of positional information. Here we show that planar p olarity in the Drosophila eye is inverted when the morphogenetic wave that sweeps through the presumptive retinal epithelium is induced to m ove in the reverse direction. We suggest that the movement of the morp hogenetic wave may be causal in establishing the planar polarity of th is epithelium.