R and y genes of Maize lie very close to each other . When RRYY and rryy gneotypes are hybridised , `F_(2)` genertion will show

Options

A. Higher number of the parental types.
B. Higher number of the recombinant types.
C. Segregation in the expected `9 : 3 : 3 : 1` ratio.
D. Segregation in `3:1` ratio

Answer

To solve the question regarding the R and Y genes of maize that lie close to each other and the expected outcomes in the F2 generation when hybridized, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Gene Linkage**:
- The R and Y genes are located very close to each other on the same chromosome. This proximity means they are likely to be inherited together, a phenomenon known as gene linkage.

**Hint**: Remember that genes located close to each other on a chromosome tend to be inherited together rather than assorting independently.

2. **Identifying the Parental Genotypes**:
- The parental genotypes given are RRYY (homozygous dominant) and rryy (homozygous recessive). When these are crossed, the F1 generation will all be RrYy (heterozygous for both traits).

**Hint**: When two homozygous individuals are crossed, the F1 generation will show the dominant traits.

3. **F1 Generation**:
- The F1 generation (RrYy) will be produced from the cross of RRYY and rryy. Since R and Y are linked, they will not assort independently during gamete formation.

**Hint**: Focus on how the F1 generation inherits traits from both parents.

4. **Gamete Formation in F1**:
- The gametes produced by the F1 (RrYy) will primarily be RY and ry due to linkage. The recombinant gametes (Ry and rY) will be produced but in smaller quantities.

**Hint**: Linked genes produce fewer recombinant gametes compared to parental gametes.

5. **F2 Generation**:
- When the F1 generation (RrYy) is self-fertilized, the F2 generation will show a higher number of parental types (RY and ry) compared to recombinant types (Ry and rY).

**Hint**: In linked genes, expect more offspring resembling the parental types than those showing recombination.

6. **Expected Ratios**:
- The expected phenotypic ratio in the F2 generation will not follow the typical 9:3:3:1 ratio seen in independent assortment. Instead, it will show a higher frequency of parental phenotypes.

**Hint**: Remember that the classic dihybrid ratio applies only when genes assort independently.

7. **Conclusion**:
- Therefore, the F2 generation will show a high number of parental types and a low number of recombinant types.

**Final Answer**: The F2 generation will show a high number of parental types.

### Summary of the Answer:
The correct answer is that the F2 generation will show a high number of parental types due to the linkage of the R and Y genes.