IMED2004 Study Guide - Final Guide: X-Inactivation, Long Non-Coding Rna, Xist (Gene)
Document Summary
Xist coats the x chr leading to heterochromatin spreading (silencing) & methylation. Happens at an early stage in embryonic development. Cell have to decide which one to activate/turn on via long non coding. This lncrna involved in x inactivation attaches to x chr via x inactivating centre. Which recruits other molecules involved in silencing gene expression. Coating of x chr with lncrna leads to silencing cascade occurring across x chr. Does this through methylation and histone modification. How much do individuals differ from each other in their actual characteristics. Proposed that the abnormal or mutation-carrying x chromosome: So cells in which it is active are fewer in number in adult females. Can provide evidence that an x-linked disorder. Can happen when abnormal mutant x chr. Someone with that: mutant x preferentially inactivated rather than random. With mutant x hence body compensates by inactivating mutant. End up where mutant x chr active.
