Question

What is a Barr body, and where is it found in a cell?

Short answer

Based on the solution above: A Barr body is an inactive X chromosome in the nucleus of a female cell, which ensures that females express a similar amount of X-linked genes compared to males. The process of inactivation is called X-chromosome inactivation or lyonization. The Barr body is located within the nucleus of a cell and is generally found at the periphery of the nucleus, near the nuclear envelope, as it remains condensed and is not involved in active transcription of genes.

Step-by-step solution

Define Barr body

A Barr body is an inactive X chromosome in the nucleus of a female cell. It was named after Murray Barr, a Canadian scientist who discovered it in 1949. Barr bodies are formed when one of the two X chromosomes in each female cell condenses and becomes inactive. This process of inactivation is called X-chromosome inactivation or lyonization, and it ensures that females express a similar amount of X-linked genes compared to males, who have only one X chromosome.

Location of Barr body in a cell

The Barr body is located within the nucleus of a cell. The nucleus is a double-membrane-bound organelle that contains the cell's genetic material (DNA). Since the Barr body is an inactive X chromosome, it is generally found at the periphery of the nucleus, near the nuclear envelope, as it remains condensed and is not involved in active transcription of genes.