Chapter 2, Problem 34P

The gene that likely controlled flower color (purple or white) in Mendel’s pea plants has also been identified. The flower color gene specifies a protein called bHLH required by cells to make three different enzymes (DFR, ANS, and 3GT) that function in the pathway shown in the accompanying figure, leading to synthesis of the purple pigment anthocyanin.

 

a.	What is the most likely explanation for the difference between the dominant allele (P) and the recessive allele (p) of the gene responsible for these flower colors?
b.	Given the biochemical pathway shown, could a different gene have been the one governing Mendel’s flower colors?