In a cross, offsprings were 25% yellow round, 25% yellow wrinkled, 25% green round, 25% green wrinkled. Of which cross these results were obtained?

Options

A. YYRRx yyrr
B. Yy Rrx YyRr
C. YyRR x yyrr
D. YyRr x yyrr

Answer

To determine the cross that resulted in the offspring phenotypic ratio of 25% yellow round, 25% yellow wrinkled, 25% green round, and 25% green wrinkled, we can analyze the given options step by step.

### Step 1: Understand the Phenotypes
The phenotypes given are:
- 25% Yellow Round
- 25% Yellow Wrinkled
- 25% Green Round
- 25% Green Wrinkled

This indicates that we have two traits being analyzed: seed color (Yellow or Green) and seed shape (Round or Wrinkled).

### Step 2: Identify the Alleles
Let’s denote:
- Yellow (Y) is dominant over Green (y)
- Round (R) is dominant over Wrinkled (r)

### Step 3: Analyze the Given Crosses
1. **First Option**: \( YYRR \times yyrr \)
- Gametes: \( YYRR \) can only produce \( YR \), and \( yyrr \) can only produce \( yr \).
- Offspring: All will be \( YyRr \) (only one phenotype).
- **Conclusion**: Incorrect.

2. **Second Option**: \( YyRr \times YyRr \)
- Gametes: Each parent can produce \( YR, Yr, yR, yr \).
- Offspring ratio: 9:3:3:1 (not 25% each).
- **Conclusion**: Incorrect.

3. **Third Option**: \( YyRR \times yyrr \)
- Gametes: \( YyRR \) can produce \( YR, Yr \) and \( yyrr \) can only produce \( yr \).
- Offspring: Only two types of offspring (not all four phenotypes).
- **Conclusion**: Incorrect.

4. **Fourth Option**: \( YyRr \times yyrr \)
- Gametes: \( YyRr \) can produce \( YR, Yr, yR, yr \) and \( yyrr \) can only produce \( yr \).
- Offspring: This will produce four phenotypes:
- \( YyRr \) (Yellow Round)
- \( Yyrr \) (Yellow Wrinkled)
- \( yyRr \) (Green Round)
- \( yyrr \) (Green Wrinkled)
- Each phenotype will be 25% of the total.
- **Conclusion**: Correct.

### Final Answer
The correct cross that resulted in the given offspring ratio is the **fourth option**: \( YyRr \times yyrr \).

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