Classical geneticists in the days before DNA analysis usually needed to work with traits showing complete penetrance. where the A-B genotypic class normally produces purple flowers and all other genotypic classes have white flowers. a. If the parental generation is AA bb * aa BB what phenotypic ration do you expect in the F2 generation assuming complete penetrance ?
b. Suppose now that only 75% of A-B individuals have purple flowers (that is, the penetrance of this trait is 75%). What phenotypic ratio do you now expect among the F2 plants?
c. In doing these types of crosses, what kinds of results (other than an unexpected F2 ratio) might suggest that penetrance of the purple phenotype is incomplete?