The 'Silent' X Chromosome Gives the Aging Female Brain a Boost

[WestMichRad]

UCSF (Univ of San Francisco) researchers may have discovered how the female brain remains resilient in aging, answering an age-old question of how most women outlive men and retain their cognitive abilities longer.

Females carry two X chromosomes. One of them is ensconced in a corner in the cell called the Barr body, where it can’t express many genes, and scientists thought it didn’t do much of anything.

But the UCSF team discovered that as female mice reached the equivalent of about 65 human years, their ‘silent’ second X started expressing genes that bolster the brain’s connections, increasing cognition.

“In typical aging, women have a brain that looks younger, with fewer cognitive deficits compared to men,” said Dena Dubal, MD, PhD, a professor of neurology and the David A. Coulter Endowed Chair in Aging and Neurodegenerative Disease at UCSF. She is the senior author of the new paper, which appears on March 5, in Science Advances. “These results show that the silent X in females actually reawakens late in life, probably helping to slow cognitive decline.”

https://www.ucsf.edu/news/2025/03/429571/silent-x-chromosome-gives-aging-female-brain-boost

Cool!!