X-Chromosome Inactivation Spreads Itself: Effects in Autosomes

Abstract

Despite recent major advances, the mechanism of X-chromosome inactivation remains largely a mystery. X;autosome translocations have been a source of insight into this mechanism since the original discovery of the phenomenon. The first evidence for the existence of an X-inactivation center came from the spread of X inactivation from the X chromosome into the attached autosome—but from only one of the two segments into which the X chromosome was broken, putatively that bearing the X-inactivation center (Russell 1963).