Final answer:
The Xist gene is only transcribed from the inactive X chromosome in females during a process called X inactivation, where one of the two X chromosomes is inactivated in each cell.
Step-by-step explanation:
Xist is only transcribed from the inactive X chromosome in females.
During embryonic development, females undergo a process called X inactivation where one of the two X chromosomes is randomly inactivated in each cell. The inactivated X chromosome condenses into a structure called a Barr body and its genes are not expressed. The Xist gene, located on the inactive X chromosome, is responsible for initiating and maintaining the inactivation by producing a long noncoding RNA called Xist. This inactivation helps females compensate for the double genetic dose of the X chromosome.