Pleiotropic effect is found in

Options

A. Human skin colour
B. Night blindness
C. Haemophilia
D. Sickle cell anaemia

Answer

### Step-by-Step Solution:

1. **Understanding Pleiotropic Effects**:
- Pleiotropic effects occur when a single gene influences multiple phenotypic traits. This means that one gene can have various effects on different characteristics of an organism.

2. **Analyzing the Options**:
- **Option 1: Human Skin Color**:
- Human skin color is a polygenic trait, meaning it is controlled by multiple genes. Each gene contributes to the overall phenotype, but this does not exemplify pleiotropy.
- **Option 2: Night Blindness**:
- Night blindness is an autosomal disorder that primarily affects vision in low light. It is not a classic example of pleiotropy since it is mainly associated with a specific trait.
- **Option 3: Hemophilia**:
- Hemophilia is a genetic disorder affecting blood clotting. While it affects a specific function (clotting), it does not demonstrate pleiotropy as it does not influence multiple traits.
- **Option 4: Sickle Cell Anemia**:
- Sickle cell anemia is caused by a mutation in the gene that codes for the beta chain of hemoglobin. This single mutation leads to various effects, such as changes in red blood cell shape, increased risk of stroke, and pain crises. Therefore, it is a classic example of pleiotropy.

3. **Conclusion**:
- Based on the analysis, the correct answer to the question "Pleiotropic effect is found in" is **sickle cell anemia**.

### Final Answer:
Pleiotropic effect is found in **sickle cell anemia**.