Question

D Question 22 Identify a FALSE statement about X chromosomes: a) X chromosome inactivation occurs in all somatic cells of females. b) Xist inactivates only the maternally inherited X chromosome. The inactiveX chromosome is coated with Xist transcripts. di X chromosome inactivation does not occur in males. In early cleavage stage embryos, both X chromosomes are active.

Answer 1

Option B -Xist inactivate only the maternally inherited X chromosome

Unlike the Y chromosome ,X chromosome have numerous gene.So some of the gene should be inactivated ,this is done by a process called X chromosome inactivation (XCI).

Xchromosome Inactivation occur in the females,it doesnot occur in males because there is only one X chromosome in male.

X chromosome inactivation occurs in all the somatic cells of females.

X chromosome inactivation js done with the help of Xist (X inactive specific transcript) .it is a non coding RNA that inhibit the transcription of X chromosome (it can be paternal X chromosome or maternal X chromosome ) and condense it into a inactive X chromosome coated with Xist.