Amazing stuff! Older men now have another reason to blame their mothers now! Caution: satire!
"Men and women are known to age differently, with women showing better longevity and cognitive resilience. Yet the biological reasons behind this disparity are not well understood.
A study by scientists ... could shed light on why women’s brains age better than men’s. Researchers found that the X chromosome inherited from the mother can impede healthy aging by affecting certain cognition-related genes in the brain. For women, only one of their two X chromosomes is active in a given cell, meaning they may luck out and have their dad’s X chromosome take control. However, men only have one X chromosome: their mother’s. ...
Additionally, expressing only a maternal X was causing certain cognition-related genes to just shut off in neurons and brain cells, and at a much higher rate than expected. ...
The results also suggest a reason as to why men’s brains do not age as well as those of women. Men only have cells with maternal X chromosomes, as their fathers always provide a Y chromosome. In this way, the male brain may function similarly to that of an engineered mouse, impeded by the inability to express anything other than a maternal X. ..."
From the abstract:
"Female mammalian cells have two X chromosomes, one of maternal origin and one of paternal origin. During development, one X chromosome randomly becomes inactivated. This renders either the maternal X (Xm) chromosome or the paternal X (Xp) chromosome inactive, causing X mosaicism that varies between female individuals, with some showing considerable or complete skew of the X chromosome that remains active. Parent-of-X origin can modify epigenetics through DNA methylation and possibly gene expression; thus, mosaicism could buffer dysregulated processes in ageing and disease. However, whether X skew or its mosaicism alters functions in female individuals is largely unknown. Here we tested whether skew towards an active Xm chromosome influences the brain and body—and then delineated unique features of Xm neurons and Xp neurons.
An active Xm chromosome impaired cognition in female mice throughout the lifespan and led to worsened cognition with age. Cognitive deficits were accompanied by Xm-mediated acceleration of biological or epigenetic ageing of the hippocampus, a key centre for learning and memory, in female mice. Several genes were imprinted on the Xm chromosome of hippocampal neurons, suggesting silenced cognitive loci. CRISPR-mediated activation of Xm-imprinted genes improved cognition in ageing female mice.
Thus, the Xm chromosome impaired cognition, accelerated brain ageing and silenced genes that contribute to cognition in ageing. Understanding how Xm impairs brain function could lead to an improved understanding of heterogeneity in cognitive health in female individuals and to X-chromosome-derived pathways that protect against cognitive deficits and brain ageing."
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