X chromosome

noun

: a sex chromosome that usually occurs paired in each female cell and single in each male cell in species in which the male typically has two unlike sex chromosomes compare y chromosome

Examples of X chromosome in a Sentence

Recent Examples on the Web

These new roles came to light from efforts to understand the process of X-inactivation, wherein one of the two X chromosomes carried by females is silenced, all 1,000 or so of its genes (in humans) being turned off. —Philip Ball, Scientific American, 14 May 2024

The X chromosome contains approximately 900 genes with multiple functions, whereas the Y has approximately 55 genes with only 27 of them being male-specific. —Devika Rao, theweek, 14 Mar. 2024

This is because almost all cases of Rett syndrome are caused by mutations found on an X chromosome gene called methyl CpG binding protein, or MECP2. —William A. Haseltine, Forbes, 27 Feb. 2024

Xist molecules work with those proteins to shut down gene expression in the second X chromosome. —Katie Hunt, CNN, 9 Feb. 2024

Word History

First Known Use

1911, in the meaning defined above

Kids Definition

X chromosome

noun

: a sex chromosome that is associated with femaleness and usually occurs paired in each female cell and single in each male cell in organisms (as human beings) in which the male normally has two unlike sex chromosomes compare y chromosome

Medical Definition

X chromosome

noun

: a sex chromosome that usually occurs paired in each female cell and single in each male cell in species in which the male typically has two unlike sex chromosomes compare y chromosome