Find the odd one out about sickle - cell anemia

Options

A. It is an example of point mutation.
B. Glutamate is replaced by valine .
C. Change occurs in single base pair in gene for globulin chain.
D. It is an example of allosomal recessive mutation.

Answer

To solve the question "Find the odd one out about sickle-cell anemia," we need to analyze the statements provided in the options regarding sickle-cell anemia and identify which one is incorrect.

### Step-by-Step Solution:

1. **Understanding Sickle Cell Anemia**:
- Sickle cell anemia is a genetic disorder that affects the shape of red blood cells. Instead of being disc-shaped, the red blood cells become crescent-shaped (like a sickle).
- This abnormal shape causes the cells to become rigid and sticky, leading to blockages in small blood vessels, which can result in pain and tissue damage.

2. **Identifying the Genetic Basis**:
- Sickle cell anemia is caused by a mutation in the beta-globin gene, specifically a point mutation where a single base pair change occurs. This mutation changes the codon from GAG to GUG, resulting in the substitution of glutamic acid with valine.

3. **Inheritance Pattern**:
- Sickle cell anemia is inherited in an autosomal recessive pattern. This means that a person must inherit two copies of the mutated gene (one from each parent) to express the disease.

4. **Analyzing the Options**:
- **Option A**: "Sickle cell anemia is an example of point mutation."
- This statement is true because the disease is caused by a single point mutation in the beta-globin gene.
- **Option B**: "Glutamate is replaced by valine in the condition of sickle cell anemia."
- This statement is also true as the mutation leads to the replacement of glutamic acid (glutamate) with valine.
- **Option C**: "The change occurs in a single base pair in the gene for globulin chain."
- This statement is true because the mutation involves a change in a single base pair.
- **Option D**: "It is an example of allosomal recessive mutation."
- This statement is false because sickle cell anemia is an example of autosomal recessive mutation, not allosomal.

5. **Conclusion**:
- The odd one out is **Option D**, as it incorrectly categorizes sickle cell anemia as an allosomal recessive mutation instead of an autosomal recessive mutation.

### Final Answer:
**Option D is the odd one out.**