A new study may explain why women live longer and why their brains are less prone to cognitive decline.
The study explored the untapped potential of women’s extra X chromosome.
Researchers are hopeful that interventions can be made to take maximum advantage of the x chromosome’s power for both sexes.
Females, on average, live nearly five years longer than males. They also tend to experience age-related cognitive decline at slower rates. Scientists have many theories as to why this may be. Now, a new study takes a deeper look, aiming to explain why women tend to live longer and age smarter.
The study, conducted on mice, was recently published in Science Advances. As you might know, people born as females carry two X chromosomes, and people born as males carry an X and Y. The study helped researchers develop a theory that females’ extra X chromosome—which is located in the corner of the cell and thought to be inactive—is activated later in life. Researchers at the University of California San Francisco found that it expressed over 20 genes in aged female mice, most of which aid brain development.
“In typical aging, women have a brain that looks younger, with fewer cognitive deficits compared to men,” said Dena Dubal, M.D., Ph.D., a professor of neurology and the David A. Coulter Endowed Chair in Aging and Neurodegenerative Disease at UCSF in a statement regarding the study. “These results show that the silent X in females actually reawakens late in life, probably helping to slow cognitive decline.”
The experiments were done on 20-month-old female mice, an age likened to 65-year-old humans. In one group, the researchers engineered the extra X chromosome to remain silent, and yet, found it to express over 20 genes. Many of those expressions lit up in the hippocampus, a region of the brain that deals with learning and memory that typically takes a hit throughout the aging process.
“Aging had awakened the sleeping X,” Dubal said.
And so, this research may help explain why women, and their brains, tend to lead longer lives. With this discovery, the hope is that researchers may be able to find interventions that may amplify the helpful, “sleeping” expressions in both men and women, now that they are known to exist.
“Cognition is one of our biggest biomedical problems, but things are changeable in the aging brain, and the X chromosome clearly can teach us what’s possible,” Dubal said. Obviously, much more research needs to be done, but the findings are certainly promising.
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