The Wnt planar polarity signaling pathway normally ensures that each wing cell in Drosophila has a single hair. Overexpression of the Frizzled gene from a heatshock promoter (hs-Fz) causes multiple hairs to grow from many cells (Figure Q15–5A). This phenotype is suppressed if hs-Fz is combined with a heterozygous deletion (DshΔ) of the Dishevelled gene (Figure Q15–5B). Do these results allow you to order the action of Frizzled and Dishevelled in the signaling pathway? If so, what is the order? Explain your reasoning.

Figure Q15-5A

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(A) (B) hs-Fzl+ hs-Fzl+ +/+ Dsh Al+