Barr body is found in following phase of cell cycle?
**Core Concept**
The **Barr body** is a compact, inactivated **X chromosome** found in female mammals, which helps maintain **dosage compensation** between males (XY) and females (XX) for genes located on the X chromosome. This concept is crucial in understanding **genetic** and **cellular biology**. The Barr body is typically visible during interphase.
**Why the Correct Answer is Right**
The Barr body is most easily visible during **interphase**, particularly when the cell is not dividing and the chromatin is less condensed. This allows for the identification of the inactivated X chromosome. The process of X chromosome inactivation is mediated by the **Xist gene** and involves the silencing of one of the two X chromosomes in female mammals to avoid a doubling of gene expression.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because **prophase** is a stage of mitosis where chromosomes condense and become visible, but the Barr body, being an inactivated X chromosome, is not specifically identified by this stage.
**Option B:** Incorrect because **metaphase** is the stage where chromosomes line up at the metaphase plate, and while chromosomes are visible, the specific identification of a Barr body as an inactivated X is not the focus.
**Option D:** Incorrect because **telophase** is the stage where nuclear envelopes reform around each set of chromosomes, and while it's a part of the cell cycle, it's not where the Barr body is typically identified.
**Clinical Pearl / High-Yield Fact**
Remember, the Barr body is a key concept in understanding **sex chromosome abnormalities** and **genetic disorders**, such as Turner syndrome (45,X) where the presence or absence of a Barr body can help in diagnosis.
**Correct Answer:** C. Interphase.