Chapter 4, Problem 5EQ

In the clover butterfly, males are always yellow, but females can be yellow or white. In females, white is a dominant allele. Two yellow butterflies were crossed to yield an ${\text{F}}_{\text{1}}$ generation consisting of 50% yellow males, 25% yellow females, and 25% white females. Describe how this trait is inherited and specify the genotypes of the yellow parents.