Round seeds (R)is dominant to wrinkled seeds (r), and yellow seeds (Y)is dominant to green seeds (y).A true-breeding pea plant with round and yellow seeds is crossed to a true-breeding plant with wrinkled and green seeds.The F₁ progeny are allowed to self-fertilize.What is the probability of obtaining a round, yellow seed in the F₂? A)3/4 B)1/16 C)9/16 D)3/16 E)1/2

Question

Quizplus · Accepted Answer

The parental genotypes can be represented as RRYY x rryy.
The F1 generation will all be RrYy (round and yellow).
When the F1 plants self-fertilize, the possible gametes they can produce are RY, Ry, rY, and ry in equal proportions. 
Thus, the Punnett square for the F2 generation will have the genotypes: 
RRYY, RRYy, RRyy, RrYY, RrYy, Rryy, rrYY, rrYy, rryy. 
Of these genotypes, 9/16 have at least one dominant allele for both traits (they have either R or Y or both). 
The probability of obtaining a round, yellow seed is only possible with the genotype RrYy, which is 1/16. 
Thus, the overall probability is (9/16) x (1/16) = 9/256, which is approximately 0.035 or 3.5%. 
Therefore, the most appropriate choice is C.

Round Seeds (R)is Dominant to Wrinkled Seeds (R), and Yellow