Definition: A dosage compensation process occurring at an early embryonic stage in mammalian development whereby, at random, one X CHROMOSOME of the pair is repressed in the somatic cells of females.
Other names X Inactivations; Inactivation, X Chromosome; Inactivation, X; Hypothesis, Lyon; Chromosome Inactivation, X; X-Inactivation; Lyonization; Lyon Hypothesis; X Inactivation