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

It may have some genetic material missing, damaged or swapped with the X chromosome, depending on the variation.

From BBC

The team identified over 140 new genetic risk loci, increasing the number known eight-fold to 164, including three on the X chromosome.

From Science Daily

The team found that, compared to the X chromosome, the Y chromosome varies greatly across ape species and harbors many species-specific sequences.

From Science Daily

They examined the X chromosome, which earlier studies did not do, and found five loci linked with PTSD.

From Science Daily

Unlike women, who have two X chromosomes, men have an X and a Y. For a long time, the genes found on the Y chromosome were not thought to play important roles in disease.

From Science Daily