X chromosome

noun

, Genetics.

1. a sex chromosome of humans and most mammals that determines femaleness when paired with another X chromosome and that occurs singly in males.

X-chromosome

noun

1. the sex chromosome that occurs in pairs in the diploid cells of the females of many animals, including humans, and as one of a pair with the Y-chromosome in those of males Compare Y-chromosome

X-chromosome

/ ĕks′krō′mə-sōm′ /

1. The sex chromosome that in female mammals is paired with another X-chromosome and in males is paired with a Y-chromosome. Very few genes on the X-chromosome have counterparts on the Y-chromosome, and since males have only one X-chromosome, any gene present on it (even if the gene is recessive in females) is expressed in males. In females, one of the two X-chromosomes in each cell is deactivated.
2. See more at sex chromosomeSee note at sex

Word History and Origins

Origin of X chromosome¹

First recorded in 1910–15

Example Sentences

Once it was shown that women can have a single X chromosome (just as men can have two of them) that was abandoned as well.

From The Daily Beast

The multitask gene is obviously linked to the X chromosome, because I know of no men who carry the trait.

From The Daily Beast

This X chromosome has also the factor for the development of red-eye pigment.

From Project Gutenberg

The chromosome situation in Protenor is a somewhat extreme case, inasmuch as one X chromosome is entirely lacking in the male.

From Project Gutenberg

The normal red-eyed Drosophila has one kind of eggs, each possessing one X chromosome.

From Project Gutenberg

In the latter case an egg without an X chromosome is produced.

From Project Gutenberg

We are justified, therefore, in speaking of the factors carried by the X chromosome as sex-linked.

From Project Gutenberg