Mendel’s purple flowers were purple or white, depending on whether they could make a purple pigment. The purple allele of the flower color gene made an enzyme that catalyzed a reaction turning a colorless molecule into a purple molecule, whereas the white allele of the flower color gene made an enzyme that couldn’t catalyze that reaction. Imagine that there is a different gene entirely. Allele B1 of this gene makes an enzyme that converts the purple pigment to a white pigment. Allele B2 of this gene makes an enzyme that couldn’t catalyze this reaction. What color would you expect in a plant that was homozygous for the purple allele (P,P) but heterozygous for the second gene (B1,B2)?