In two genes inheritance, number of the offspring in F2 generation matched with parental phenotype is/are

Options

A. 10
B. 9
C. 3
D. 1

Answer

To solve the question regarding the number of offspring in the F2 generation that match the parental phenotype in a dihybrid cross, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Dihybrid Cross**:
- A dihybrid cross involves two traits, each represented by two alleles. For example, consider seed shape (round vs. wrinkled) and seed color (yellow vs. green).
- Round shape (R) and yellow color (Y) are dominant traits, while wrinkled shape (r) and green color (y) are recessive traits.

2. **F1 Generation**:
- When we cross a homozygous round yellow plant (RRYY) with a homozygous wrinkled green plant (rryy), all F1 offspring will be heterozygous (RrYy) and exhibit the dominant phenotype (round yellow seeds).

3. **Selfing F1 Generation**:
- To obtain the F2 generation, we self-cross the F1 individuals (RrYy x RrYy).

4. **Punnett Square for F2 Generation**:
- Construct a Punnett square for the dihybrid cross. The combinations of alleles will yield 16 different genotypes in the F2 generation.

5. **Phenotypic Ratio**:
- The phenotypic ratio for a dihybrid cross is typically 9:3:3:1.
- This means:
- 9 offspring will show the dominant phenotype (round yellow),
- 3 offspring will show one dominant and one recessive phenotype (round green),
- 3 offspring will show the other dominant and recessive phenotype (wrinkled yellow),
- 1 offspring will show the recessive phenotype (wrinkled green).

6. **Identifying Parental Phenotypes**:
- The parental phenotypes are those that match the original parents: round yellow (dominant) and wrinkled green (recessive).
- From the phenotypic ratio, we see that:
- Round yellow (9) + Wrinkled green (1) = 10 offspring that match the parental phenotypes.

7. **Final Count**:
- Therefore, in the F2 generation, out of 16 total offspring, 10 will exhibit the parental phenotype.

### Conclusion:
The number of offspring in the F2 generation that match the parental phenotype is **10 out of 16**.

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