Fig. 8. four-jointed influences the initiation of WG expression in the proximal wing. fj^d1 mutant clones, made using the Minute technique and marked by absence of ß-galactosidase (green). (A) Early third instar disc. WG expression is reduced within large fj mutant clones (arrows). The requirement for fj is non-autonomous, as fj mutant cells in the proximal wing express WG normally (asterisk). Arrowhead identifies elevated WG expression in cells immediately adjacent to wild-type cells. (B) Mid-third instar disc, arrows point to reduced expression. (C) Mid-late third instar disc, with most tissue mutant. WG expression is no longer noticeably reduced by absence of fj (asterisk).