Choose the incorrect statement related to Barr body

Options

A. Found attached to nuclear envelope in buccal mucosa cells
B. Barr body is the heterochromatinised X-chromosome
C. Occurs as drumstick body in the neutrophils
D. Of the two chromosomes in a female, only maternal chromosome becomes the Barr body

Answer

To determine the incorrect statement related to Barr bodies, we will analyze each of the provided statements one by one.

### Step 1: Analyze Statement A
**Statement A:** "Found attached to the nuclear envelope in buccal mucosa cells."
- **Explanation:** Barr bodies can indeed be found in buccal mucosa cells. They are visible when the cells are stained and observed under a microscope. This statement is **true**.

### Step 2: Analyze Statement B
**Statement B:** "Barr body is a heterochromatized X chromosome."
- **Explanation:** A Barr body is indeed an inactivated X chromosome that has undergone heterochromatinization. This means it is condensed and not actively expressed. This statement is **true**.

### Step 3: Analyze Statement C
**Statement C:** "Occurs as a drumstick body in the neutrophils."
- **Explanation:** Barr bodies can appear as drumstick-like structures in neutrophils, which is a characteristic feature observed in these white blood cells. This statement is **true**.

### Step 4: Analyze Statement D
**Statement D:** "Of the two chromosomes in female only maternal chromosome becomes the Barr body."
- **Explanation:** This statement is incorrect. In females, one of the two X chromosomes (either maternal or paternal) is randomly inactivated to form a Barr body. It is not exclusively the maternal chromosome that becomes the Barr body; it can be either one. Therefore, this statement is **false**.

### Conclusion
Based on the analysis, the incorrect statement related to Barr bodies is **Statement D**.

### Final Answer
The incorrect statement related to Barr body is: **D. Of the two chromosomes in female only maternal chromosome becomes the Barr body.**

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