NCIt synonyms : X Inactivation; X Chromosome Inactivation; X-Inactivation; Lyonization;
NCIt definition : A human early embryonic event in which in any given cell one of a female's two X chromosomes
becomes inactivated and converted into a Barr body. After inactivation has occurred,
all descendants of that cell have the same inactivated X chromosome. Thus, X-inactivation
creates cell clones with differing effective gene content. An organism whose cells
vary in effective gene content and hence in the expression of a trait, is called a
genetic mosaic.;