Question

n corn, three gene loci control color of the aleurone layer ofthe kernel (which gives the kernel its color). Each locus has twoalleles; C is dominant to c, R isdominant to r, and P is dominant to p.The presence of at least one dominant allele at each of the threeloci produces a purple aleurone. If the kernel is homozygousrecessive at the “P” locus, but each of “C” and “R” possess onedominant allele, the aleurone is red. If either the “C” locus or“R” locus is homozygous recessive, the aleurone is white,regardless of the state of the “P” locus.

a. What sort of genetic phenomenon does this relationshipdemonstrate?

b. Briefly explain what it is about this situation thatdemonstrates the phenomenon (relationship) you named in the blankabove.

c. What color aleurone do you expect in kernels of the followinggenotypes? CC rr PP ______________________.

CC Rr Pp ______________________.

CC rr Pp ______________________.

CC Rr Pp ______________________.

Cc RR pp ______________________.

cc Rr Pp ______________________.

d. Describe (or diagram) a simple, but sufficient, biochemicalpathway model that would explain this relationship. (The model maybe hypothetical)