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 The inactivated X chromosome makes Xist, which establishes an X-inactivation center on that chromosome. Diana Gitig, Ars Technica, 6 Feb. 2024 To prevent the body from making too many of these proteins, one of the two X chromosomes in females is silenced in a process called X-chromosome inactivation. Will Sullivan, Smithsonian Magazine, 5 Feb. 2024 The research states that a type of RNA produced by a woman’s X chromosomes creates proteins that could make the immune system attack itself if genetic predisposition or other factors are present. Emma Hinchliffe, Fortune, 2 Feb. 2024 Chang’s team decided to engineer male lab mice to artificially make Xist — without silencing their only X chromosome — and see what happened. TIME, 2 Feb. 2024

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'X chromosome.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1911, in the meaning defined above

Time Traveler
The first known use of X chromosome was in 1911

Dictionary Entries Near X chromosome

Cite this Entry

“X chromosome.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/X%20chromosome. Accessed 2 Jul. 2024.

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

More from Merriam-Webster on X chromosome

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