Genes R and Y follow independent assortment. IfRRYY produce round yellow seeds and rryyproduce wrinkled green seeds, what will be thephenotypic ratio of the F2 generation?
Answer
🧬 Dihybrid Cross & Independent Assortment Explanation
Given:
- RRYY = Round Yellow (dominant)
- rryy = Wrinkled Green (recessive)
- R = Round, r = Wrinkled
- Y = Yellow, y = Green
🔄 Step 1: F₁ Generation
Cross: RRYY × rryy → All RrYy (Round Yellow)
🌱 Step 2: F₂ Generation (RrYy × RrYy)
This is a dihybrid cross following Mendel’s Law of Independent Assortment.
🧪 Phenotypic Combinations in F₂:
| Seed Shape | Seed Color | Genotype | Phenotype |
|---|---|---|---|
| R_ | Y_ | 9 combinations | Round Yellow |
| R_ | yy | 3 combinations | Round Green |
| rr | Y_ | 3 combinations | Wrinkled Yellow |
| rr | yy | 1 combination | Wrinkled Green |
✅ F₂ Phenotypic Ratio: 9 : 3 : 3 : 1
- 9 Round Yellow
- 3 Round Green
- 3 Wrinkled Yellow
- 1 Wrinkled Green