Why is X-inactivation needed in humans?

1 Answer
May 31, 2018

X-inactivation is a process by which one of the X chromosomes present in the female mammals is inactivated.

Explanation:

The X chromosome contains over 1,000 genes essential for proper development and cell viability. Two copies of the X chromosome in females results in a potentially toxic double dose of X-linked genes. To correct this imbalance, female mammals transcriptionally silence one of them by the process of X chromosome inactivation.

This is achieved by it being packaged in such a way that it is transcriptionally inactive. This inactive structure is called as Barr body. This inactivation event is irreversible during the lifetime of the individual with the exception of the germline.