[Campbell Biology P.349] What is the primary reason for X chromosome inactivation in female ... | Practice Question

What is the primary reason for X chromosome inactivation in female mammals?

  • A: To prevent the expression of harmful Y-linked genes.
  • B: To ensure that females and males have the same effective dose of most X-linked genes.
  • C: To allow for the expression of different alleles in different cells, creating mosaicism.
  • D: To create a Barr body, which is necessary for meiosis in females.

Explanation

This concept is known as dose compensation. The text explains that since females XX have twice the number of X chromosomes as males XY , almost all of one X chromosome is inactivated so that 'the cells of females and males have the same effective dose one active copy of most X-linked genes.'