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. Which of the following represents the arrangement of alleles on the F1's chromosome?

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Quizplus · Accepted Answer

The F1 progeny exhibit a wild-type phenotype (red eyes and normal wings), indicating they received a dominant allele for each trait from one parent. Since the parents were pure-breeding for opposite traits (one had red eyes and vestigial wings, the other had purple eyes and normal wings), the F1 must have inherited linked alleles from each parent, resulting in a heterozygous combination (pr+vg/prvg+).

In Fruit Flies, Red Eyes (Pr+_) Are Dominant to Purple