In fruit flies, red eyes (pr _) are dominant to purple eyes (prpr) and normal wings (vg _) are dominant to vestigial wings (vgvg). The genes are located on the same chromosome. A pure breeding red-eyed fly with vestigial wings was crossed with a pure-breeding purple-eyed fly with normal wings. All of the F1 progeny had a WT phenotype. What represents the arrangement of alleles on the F1's chromosome?