Dormant X chromosome genes may boost older females' cognition

A new study suggests that some dormant genes on the X chromosome may "reactivate" as females age, potentially improving cognitive function. This phenomenon appears to give older women a cognitive advantage over men. Researchers conducted experiments with lab mice, examining the impact of the X chromosome on brain aging. They found that, unlike men, women may benefit from this reawakening of X-linked genes, which could explain why women often display more cognitive resilience in old age. The study involved crossing two subspecies of lab mice to investigate changes in gene activity. Scientists discovered that around 22 genes, which were previously silenced, became active again in aging female mice. Some of these genes were related to the myelin sheath, which helps neurons send signals efficiently. In experiments with both male and female mice, scientists observed that enhancing the activity of one particular gene, PLP1, improved learning and memory in both sexes. There is also preliminary evidence suggesting that similar gene activity may occur in older women compared to older men. The findings indicate that understanding how sex chromosomes influence brain aging could lead to new treatments for cognitive decline. More research is needed to explore how these results may apply to humans and how changes in hormones during menopause might relate to this phenomenon.