Which of the following is suitable for experiment on linkage ?

Options

A. aaBB `xx` aaBB
B. AABB `xx` aabb
C. AaBb `xx` AaBb
D. AAbb `xx` AaBB

Explanation

To determine which of the given options is suitable for an experiment on linkage, we need to understand the concept of linked genes and how they are inherited. Here’s a step-by-step solution to the question:

### Step-by-Step Solution:

1. **Understanding Linkage**:
- Linkage refers to genes that are located close to each other on the same chromosome and tend to be inherited together. This means that when one gene is passed on, the other gene linked to it is likely to be passed on as well.

2. **Analyzing the Options**:
- We have four options to consider, and we need to identify which one uses pure line parents (homozygous) for the genes involved.

3. **Option 1**:
- The first option involves a cross between small a small a and large b large b.
- This option mixes dominant and recessive traits, which does not provide a clear understanding of linkage since the genes are not pure.

4. **Option 2**:
- The second option involves a cross between AABB (dominant) and aabb (recessive).
- This option uses pure line parents, which is essential for studying linkage. The offspring will show the inheritance pattern of linked genes clearly.

5. **Option 3**:
- The third option also mixes dominant and recessive traits, similar to the first option. This does not provide a clear understanding of linkage.

6. **Option 4**:
- The fourth option is also a mix of dominant and recessive traits, which again does not clarify the linkage.

7. **Conclusion**:
- After analyzing all options, the second option (AABB x aabb) is the most suitable for studying linkage because it uses pure line parents, allowing for a clear observation of how linked genes are inherited together.

### Final Answer:
- The suitable option for an experiment on linkage is **Option 2** (AABB x aabb).