Which of the following is not applicable to sickle cell anaemia?

Options

A. Exhibits co dominance in heterozygous condition
B. Example for single gene mutation in cistron of haemoglobin
C. Emplifies pleiotropy as it affects different functions of body
D. Sickle cell anaemia is caused by autosomal dominant mutation in gene of hemoglobin

Answer

To determine which statement is not applicable to sickle cell anemia, we need to analyze each option provided in the question. Sickle cell anemia is a genetic disorder caused by a mutation in the hemoglobin gene, and it is characterized by the presence of abnormal hemoglobin, leading to distorted (sickle-shaped) red blood cells.

### Step-by-Step Solution:

1. **Understand the Nature of Sickle Cell Anemia**:
- Sickle cell anemia is a genetic disorder caused by a mutation in the hemoglobin gene.
- It is classified as a recessive disorder, meaning that the disease manifests only when an individual is homozygous for the recessive allele.

2. **Analyze Each Option**:
- **Option 1**: "Exhibits co-dominance in a heterozygous condition."
- This statement is true. In individuals who are heterozygous (carriers), both normal and abnormal hemoglobin are produced, demonstrating co-dominance.

- **Option 2**: "An example of single gene mutation in the gene of hemoglobin."
- This statement is true. Sickle cell anemia is indeed caused by a single point mutation in the hemoglobin gene (specifically, a substitution of adenine for thymine).

- **Option 3**: "Amplifies pleiotropy as it affects different functions of the body."
- This statement is true. Sickle cell anemia affects multiple body functions due to the altered shape of red blood cells, leading to various complications.

- **Option 4**: "Sickle cell anemia is caused by autosomal dominant mutation."
- This statement is false. Sickle cell anemia is caused by a recessive mutation, not a dominant one. Individuals must inherit two copies of the recessive allele to express the disease.

3. **Conclusion**:
- The statement that is not applicable to sickle cell anemia is **Option 4**: "Sickle cell anemia is caused by autosomal dominant mutation."

### Final Answer:
The statement that is not applicable to sickle cell anemia is: **"Sickle cell anemia is caused by autosomal dominant mutation."**