Live Science reports:

Dormant genes on the X chromosome may reawaken in old age, potentially giving the aging female brain a boost that the male brain doesn’t receive.

This phenomenon may help to explain why, on many measures, females show a higher level of cognitive resilience in old age than males do.

The findings come from a new study in lab mice, and the researchers also backed up the results with genetic data from humans. More research is still needed to confirm that the findings in mice translate to people, but overall, the work points to a potential difference in how female and male brains age.

Historically, “we simply haven’t looked at the X chrom[osome] very much,” said Rachel Buckley, an associate professor of neurology at Harvard Medical School who was not involved in the new study. “And now we’re starting to really shine a very, very big spotlight on it, and we’re starting to realize things that we had not fully appreciated” — namely, how sex chromosomes might influence how the brain ages.

“There are very important and potentially therapeutic targets that are coming out from these papers” that focus on the X chromosome, Buckley told Live Science. [Continue reading…]