'Female' X Chromosome May Play Part in Sperm Production 07/22/13
SUNDAY, July 21 (HealthDay News) -- Researchers have made the
surprising finding that the "female" X chromosome may have an
important function in sperm production.
Women have two X chromosomes and men have an X and Y chromosome.
This study found that large portions of the X chromosome have
evolved to play a specialized role in producing sperm.
And despite its reputation as the most stable chromosome of the
genome, the X chromosome has actually been undergoing relatively
rapid changes, according to the study published online July 21 in
Taken together, these two findings suggest that it's time to
reexamine the biological and medical importance of the X
chromosome, said the researchers at the Whitehead Institute for
Biomedical Research in Cambridge, Mass.
"We view this as the double life of the X chromosome," Whitehead director David Page said in an institute news release.
"The X is the most famous, most intensely studied chromosome in all of human genetics. And the story of the X has been the story of X-linked recessive diseases, such as color blindness, hemophilia, and Duchenne's muscular dystrophy," Page noted. "But there's another side to the X, a side that is rapidly evolving and seems to be attuned to the reproductive needs of males."
In the study, the researchers compared mouse and human X
chromosomes and found that they had nearly 95 percent of their
X-linked, single-copy genes in common. Nearly all these genes are
expressed in both sexes.
But the study also identified about 340 genes that are not
shared between mice and humans. Most of these genes are active
almost exclusively in testicular germ cells where they likely
contribute to sperm production.
"These genes are more likely to have roles in diseases that are related to reproduction, infertility, perhaps even testis cancer. There's a whole other book to be written about this aspect of the X," Page noted in the news release.
The U.S. National Library of Medicine has more about
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