Final answer:
X-inactivation is the process where one of the X chromosomes in females is inactivated during development. This process forms Barr bodies, which are condensed structures where the genes on the inactive X chromosome are not expressed. XistAR is a lncRNA that plays a crucial role in X-inactivation by assisting in the formation of Barr bodies and silencing gene expression on the inactive X chromosome.
Step-by-step explanation:
In females, one of the two X chromosomes is inactivated during embryonic development because of epigenetic changes to the chromatin. This process is known as X-inactivation or Lyonization. X-inactivation occurs to compensate for the double genetic dose of X chromosome in females. The inactivated X chromosome condenses into a structure called a Barr body, where the genes on the inactive X chromosome are not expressed.
The relationship between long noncoding RNA (lncRNA) and X-inactivation is that certain lncRNAs, such as XistAR, play a crucial role in the process of X-inactivation. XistAR, along with the Xist gene, is required to form Barr bodies and initiate X-inactivation. XistAR is a recently discovered lncRNA that acts in coordination with Xist to silence gene expression on the inactive X chromosome. It helps recruit proteins and chromatin modifiers that lead to chromatin condensation and gene silencing.