X Chromosome Inactivation Results in the _______________________

Question

X chromosome inactivation results in the _______________________.  
A) total inactivation of both X chromosomes
B) inactivation of only the paternal X chromosome
C) inactivation of only the maternal X chromosome
D) inactivation of either the paternal X chromosome or the maternal X chromosome
E) nonrandom inactivation of X chromosomes in the initial cells of tissues

Accepted Answer

X chromosome inactivation results in the inactivation of either the paternal X chromosome or the maternal X chromosome, but not both, in female somatic cells. This process ensures a balance of X-linked gene expression between males and females. However, which X chromosome is inactivated is random and can vary between cells, resulting in mosaic patterns of X-linked gene expression in female tissues.