In a species of tree, seed color is determined by four independently assorting genes: A, B, C, and D. The recessive alleles of each of these genes (a, b, c, and d) produce abnormal enzymes that cannot catalyze a reaction in the biosynthetic pathway for seed pigment. The pathway is diagrammed as follows:
White precursor (A) arrow Yellow (B) arrow Orange arrow red(c) and Blue (D)
When both red and blue pigments are present, the seeds are purple. Trees with the genotypes AaBbCcDd and AaBbCcdd were crossed. For each problem you must show your probability calculation as part of your answer. Show your answer in fraction and decimal form. If you have done it correctly, answers b-g will add up to 1.
a. What color are the seeds in these two parental genotypes?
b. What proportion of the offspring from the cross will have white seeds?
c. What proportion of the offspring from the cross will have red seeds?
d. What proportion of the offspring from the cross will have yellow seeds?
e. What proportion of the offspring from the cross will have blue seeds?
f. What proportion of the offspring from the cross will have orange seeds?
g. What proportion of the offspring from the cross will have purple seeds?