3 hours ago
Men lose their Y chromosome as they age. Scientists thought it didn’t matter – but now we’re learning more
https://theconversation.com/men-lose-the...ore-275823
EXCERPTS: Men tend to lose the Y chromosome from their cells as they age. But because the Y bears few genes other than for male determination, it was thought this loss would not affect health. But evidence has mounted over the past few years that when people who have a Y chromosome lose it, the loss is associated with serious diseases throughout the body, contributing to a shorter lifespan.
Loss of the Y in older men
New techniques to detect Y chromosome genes show frequent loss of the Y in tissues of older men. The increase with age is clear: 40% of 60-year-old men show loss of Y, but 57% of 90-year-olds. Environmental factors such as smoking and exposure to carcinogens also play a role.
Loss of Y occurs only in some cells, and their descendants never get it back. This creates a mosaic of cells with and without a Y in the body. Y-less cells grow faster than normal cells in culture, suggesting they may have an advantage in the body – and in tumours.
The Y chromosome is particularly prone to mistakes during cell division – it can be left behind in a little bag of membrane that gets lost. So we would expect that tissues with rapidly dividing cells would suffer more from loss of Y.
The human Y is an odd little chromosome, bearing only 51 protein-coding genes (not counting multiple copies), compared with the thousands on other chromosomes. It plays crucial roles in sex determination and sperm function, but was not thought to do much else.
[...] Despite its apparent uselessness to most cells in the body, evidence is accumulating that loss of Y is associated with severe health conditions, including cardiovascular and neurodegenerative diseases and cancer. Loss of Y frequency in kidney cells is associated with kidney disease... (MORE - missing details)
https://theconversation.com/men-lose-the...ore-275823
EXCERPTS: Men tend to lose the Y chromosome from their cells as they age. But because the Y bears few genes other than for male determination, it was thought this loss would not affect health. But evidence has mounted over the past few years that when people who have a Y chromosome lose it, the loss is associated with serious diseases throughout the body, contributing to a shorter lifespan.
Loss of the Y in older men
New techniques to detect Y chromosome genes show frequent loss of the Y in tissues of older men. The increase with age is clear: 40% of 60-year-old men show loss of Y, but 57% of 90-year-olds. Environmental factors such as smoking and exposure to carcinogens also play a role.
Loss of Y occurs only in some cells, and their descendants never get it back. This creates a mosaic of cells with and without a Y in the body. Y-less cells grow faster than normal cells in culture, suggesting they may have an advantage in the body – and in tumours.
The Y chromosome is particularly prone to mistakes during cell division – it can be left behind in a little bag of membrane that gets lost. So we would expect that tissues with rapidly dividing cells would suffer more from loss of Y.
The human Y is an odd little chromosome, bearing only 51 protein-coding genes (not counting multiple copies), compared with the thousands on other chromosomes. It plays crucial roles in sex determination and sperm function, but was not thought to do much else.
[...] Despite its apparent uselessness to most cells in the body, evidence is accumulating that loss of Y is associated with severe health conditions, including cardiovascular and neurodegenerative diseases and cancer. Loss of Y frequency in kidney cells is associated with kidney disease... (MORE - missing details)