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'Inert' Female Chromosome May Be Active

One pair of chromosomes out of the 23 found in human cells determines sex. Women have two full-sized X chromosomes, while men have one X and a smaller Y, which holds the genes for masculine traits. To even things up, one of the two X chromosomes is inactivated in women, according to standard genetics textbooks.

Those textbooks may now need to be revised, according to a report in the March 17 issue of Nature. Studies have detected activity by some of the genes on the supposedly inert X chromosome, researchers conclude.

"Our study shows that the inactive X in women is not at silent as we thought," said co-researcher Laura Carrel, an assistant professor of biochemistry and molecular biology at Pennsylvania State University College of Medicine.Read entire article...