Question

Which of the following statement is true for Barr body?

• A. It is a highly condensed chromosome.
• B. It is an active X chromosome.
• C. It is equivalent to the single Y chromosome of the male.
• D. It is equivalent to the two X chromosomes of the female.

Hint:

Consider the role of X chromosome inactivation in females and its cytological appearance.

Answer 1

The Correct Option is A

The Barr body, a dense nuclear structure in females, is the inactivated X chromosome. Its condensation provides dosage compensation, balancing X-linked gene expression between males (one active X chromosome) and females (two X chromosomes). Unlike the active X, the inactive X chromosome is highly condensed and transcriptionally silent.