All female mammals have one active X chromosome per cell instead of two. What causes this?A) activation of the XIST gene on the X chromosome that will become the Barr bodyB) activation of the BARR gene on one X chromosome, which then becomes inactiveC) inactivation of the XIST gene on the X chromosome derived from the male parentD) attachment of methyl (CH3) groups to the X chromosome that will remain active

Respuesta :

The answer is; A


XIST RNA is a significant gene on the X chromosome (long (q) arm) that is involved in its inactivation in females, who have two X chromosomes. XIST RNA gene is activated in one of the X chromosomes, inactivating this chromosome and forming a Barr body.