Give on example of complete linkage.

Answer

### Step-by-Step Solution

1. **Understanding Complete Linkage**:
- Complete linkage occurs when two genes are located very close to each other on the same chromosome. This proximity means that during meiosis, the genes do not assort independently and are inherited together.

2. **Recombination and Crossing Over**:
- Normally, during meiosis, crossing over can occur between homologous chromosomes, leading to genetic recombination. However, in the case of complete linkage, the genes are so closely linked that crossing over does not occur between them, resulting in no recombination.

3. **Example of Complete Linkage**:
- A classic example of complete linkage is found in the X chromosome of Drosophila melanogaster (fruit fly). In male Drosophila, certain traits, such as eye color, are inherited together due to complete linkage.

4. **Specific Trait**:
- The red eye condition in Drosophila is a well-known trait that demonstrates complete linkage. In male fruit flies, the genes responsible for this trait are so closely linked that they are passed on together to the next generation without recombination.

5. **Conclusion**:
- Therefore, the example of complete linkage is the X chromosome of male Drosophila, specifically the inheritance of the red eye trait.