Question

Genes R and Y follow independent assortment. If RRYY produce round yellow seeds and rryy produce wrinkled green seeds, what will be the phenotypic ratio of the F2 generation?

• A. Phenotypic ratio – 3:1
• B. Phenotypic ratio – 9:3:3:1
• C. Phenotypic ratio – 9:7
• D. Phenotypic ratio – 1:2:1

Hint:

Dihybrid cross = 9:3:3:1.

Answer 1

The Correct Option is B

This is a classic dihybrid cross. Independent assortment of two genes with dominant/recessive alleles (R/r and Y/y) results in a 9:3:3:1 phenotypic ratio in the F2 generation: 9: Round, Yellow (R\_Y\_)
3: Round, Green (R\_yy)
3: Wrinkled, Yellow (rrY\_)
1: Wrinkled, Green (rryy)