Question

a dihybrid cross is created from plants that are heterozygous for both round seeds and yellow seed color. what is the ratio of offspring that have round seeds and yellow seed color? 1:16 3:16 9:16 16:16

Explanation:

Step1: Define alleles

Let R represent the allele for round seeds (dominant) and r for wrinkled seeds (recessive), Y for yellow seeds (dominant) and y for green seeds (recessive). The parents are RrYy.

Step2: Determine gametes

Using the law of independent assortment, each parent can produce 4 types of gametes: RY, Ry, rY, ry.

Step3: Set up Punnett - square

A 4x4 Punnett - square is set up with the 4 gametes from one parent along the top and the 4 gametes from the other parent along the side.

Step4: Count offspring phenotypes

When filling out the Punnett - square, we find that the number of offspring with round (R -) and yellow (Y -) seeds is 9 out of 16 possible combinations.

Answer:

C. 9:16