If genes A and B are linked , which pair of gametes will be more frequent in the `F_(1)` (AaBb) derived from the cross AABB `xx` aabb ?

Options

A. AB and ab
B. Ab and ab
C. aB and ab
D. Ab and AB

Answer

To solve the problem of determining which pair of gametes will be more frequent in the F1 generation (AaBb) derived from the cross AABB x aabb, we need to consider the concept of gene linkage.

### Step-by-Step Solution:

1. **Understand the Cross**:
- We are crossing two purebred lines: AABB (homozygous dominant) and aabb (homozygous recessive).
- The F1 generation will be heterozygous for both traits, resulting in the genotype AaBb.

2. **Identify Gametes from Parents**:
- The AABB parent can only produce one type of gamete: AB.
- The aabb parent can only produce one type of gamete: ab.
- Therefore, the F1 generation (AaBb) will only receive the AB gamete from AABB and the ab gamete from aabb.

3. **Gametes from F1 Generation**:
- In the case of linked genes, the F1 generation (AaBb) will produce gametes that are combinations of the alleles it received from its parents.
- Since genes A and B are linked, the gametes produced will be predominantly parental types: AB and ab.

4. **Frequency of Gametes**:
- Because A and B are linked, the frequency of the parental gametes (AB and ab) will be higher than that of the recombinant gametes (Ab and aB).
- Therefore, the most frequent gametes in the F1 generation will be AB and ab.

5. **Conclusion**:
- The pair of gametes that will be more frequent in the F1 generation (AaBb) derived from the cross AABB x aabb are AB and ab.

### Final Answer:
The more frequent pair of gametes in the F1 generation will be **AB and ab**.