Fig. 8.

In ds^– stan^– mutant flies, muscle orientation is not affected. The bristles and hairs are oriented by the Stan and Ds systems, the twin mechanisms of planar cell polarity (PCP) (Casal et al., 2006; Lawrence et al., 2007). (A-C) Wild-type dorsal epidermis and the underlying muscles. (D-F) ds^– stan^– flies have disoriented hairs and bristles but the identity of the epidermal cells is not changed. Muscle orientation is not affected by lack of organised polarity in the cuticle. Muscles are stained with phalloidin.