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 each statement provided in the options carefully.

### Step-by-Step Solution:

1. **Understanding Sickle Cell Anemia**:
Sickle cell anemia is a genetic disorder caused by a mutation in the hemoglobin gene, specifically affecting the beta-globin chain of hemoglobin. This mutation leads to the production of abnormal hemoglobin, known as hemoglobin S (HbS), which causes red blood cells to deform into a sickle shape.

2. **Analyzing the Options**:
- **Option 1**: "It is an example of point mutation."
- This statement is **true**. Sickle cell anemia is indeed caused by a point mutation where a single nucleotide change results in the substitution of one amino acid for another in the hemoglobin protein.

- **Option 2**: "Glutamate is replaced by valine."
- This statement is **false**. In sickle cell anemia, glutamic acid (not glutamate) is replaced by valine at the sixth position of the beta-globin chain. Therefore, this statement is incorrect because it misidentifies the amino acid being replaced.

- **Option 3**: "Change occurs in a single base pair in the gene for globulin chain."
- This statement is **true**. The mutation that causes sickle cell anemia involves a change in a single base pair in the gene that encodes the beta-globin chain of hemoglobin.

- **Option 4**: "It is an example of allosomal recessive mutation."
- This statement is **false**. Sickle cell anemia is an example of an autosomal recessive mutation, not allosomal. Allosomal refers to sex chromosomes, while autosomal refers to non-sex chromosomes.

3. **Identifying the Odd One Out**:
- From the analysis, we find that **Option 2** ("Glutamate is replaced by valine") is the odd one out because it incorrectly states the amino acid being replaced. The correct statement should indicate that glutamic acid is replaced by valine.

### Conclusion:
The odd statement out about sickle cell anemia is **Option 2**: "Glutamate is replaced by valine."