X chromosome


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Related to X chromosome: Y chromosome

X chromosome

[′eks ′krō·mə‚sōm]
(genetics)
The sex chromosome occurring in double dose in the homogametic female sex and in single dose in the heterogametic male sex in mammals, Diosophila, and many other organisms.
References in periodicals archive ?
If this holds true, they could be under the influence of the same mysterious X chromosome factor as the mice.
Since women have two X chromosomes, the mothers had a backup copy of a normal neuroligin gene that presumably protected them from developing autism.
They found that, unlike in mouse placental cells, Tsix is expressed only on the inactive X chromosome and is thus unlikely to be stopping Xist.
(In contrast, male fruit flies double the activity of their single X chromosome.)
It then directed most of those bearing X chromosomes to swim down one collection tube, and most of the Y-bearing sperm went down another tube.
The researchers divided their volun-teers into two groups: 55 with a complete X chromosome inherited from their mother and 25 with an undamaged X chromosome from their father.
Two new reports add to a growing body of evidence that an unusual gene called Xist may hold the key to X chromosome inactivation.
Page and his colleagues suggest that this finding is at odds with theories that the Y chromosome, once it started evolving separately from the X chromosome, only degenerated.
Two years ago, Hamer reported that men might inherit a predisposition to homosexuality through the X chromosome, whose genes are passed on by mothers (SN: 7/17/93, p.37).
Because if you're female, no matter what you do to your limbs and outward flourishes, you'll still have two X chromosomes. If male, an X and a Y.
Unfertilized fish eggs normally carry one of the mother's two X chromosomes. Sperm can carry either the father's X or his Y chromosome.
In at least eight species of the mouse genus Akodon, from 10 percent to 60 percent of the females carry a Y chromosome in place of one of the two X chromosomes usually found in the cells of female mammals, report Hopi E.