FIG. 8.

Cell fate transformation in the external sensory organs on the nota. (A) From a wild-type fly; (B) from a Nak overexpression fly; (E) from a Numb overexpression fly; (G) from a fly with both Nak and Numb overexpression; (C and F) from the inlets of panels B and E, respectively. In panel C, the arrowhead indicates a 2-hair–2-socket bristle and the arrow indicates a 1-hair–3-socket bristle. In panel D, the filled arrowhead indicates a 2-socket phenotype and the empty arrowhead indicates a 4-socket phenotype due to overexpression of Nak. In panel F, the 2-hair–no-socket phenotype caused by Numb overexpression is marked with two arrows. (H) Schematic drawing of an adult external sensory organ; (I) external sensory organ lineage, with the solid arrow indicating the direction of cell fate transformation due to overexpression of Nak and the lower, empty arrow indicating the direction caused by overexpression of Numb. n, neuron; sh, sheath cell; h, hair cell, so, socket cell.