Loss of Y chromosomes in elderly men is not harmless, say experts

Newer studies are finding the absence of Y chromosomes is harmful to human males.

The gradual disappearance of the Y chromosome with age poses detrimental effects on male health, research has found out.

While most chromosomes (genetic material) are found in pairs, the sex determining chromosomes XY are unusual, with Y being smaller than X and also it having no duplicate copy.

Y chromosomes have a peculiar history with them having only 49 genes, however, they stand out for determining the sex of a male child and also making sperm.

With the Y chromosome not having much to offer other than maleness to the sex, scientists initially thought its loss won’t drastically affect humans as other genes would evolve to do the same function.

However, newer studies are finding their absence is harmful to human males.

Problems with a Y chromosome

The Y chromosome is prone to make errors in cell division cycles because of its small, structurally weak composition, a media report has said.

Reportedly, it can be left behind in a membrane that eventually gets lost. So, certain cells which divide rapidly are likely to suffer its loss. 

Some experts have said their connection with sperm production can enable their disappearance as it requires fast cell division for the formation of sperms. The more the number of cell divisions, the higher the risk of mutations.

Also, most chromosomes come in pairs, with even the female sex determining pair XX being homologous (similar). When there is a genetic dysfunction in one chromosome, the other compensates for the loss. However, the Y chromosome is a loner, with no self corrective abilities. 

While the estimated time for the shrinking chromosome to completely disappear is still far off, their gradual loss in elderly males has become a cause of concern.

More prone to diseases

While the genes on Y chromosomes are not associated with cellular growth, their absence is now being linked to increased risk of metabolic and degenerative diseases.

The gradual loss of Y chromosomes in older men is connected to heart diseases, kidney disease and some kinds of cancers, reducing life expectancy.

If the loss occurs in younger men, it can cause fertility problems and developmental diseases.

Studies have shown that cells with Y chromosomes are likely to multiply faster, facilitating the formation of tumours. Y chromosomes are known to inhibit aggressive cell growth, protecting against unusual cell growth. For those who have cancer, the absence of Y chromosomes can accelerate the multiplication of malignant cells.

A German study found that blood cells without Y chromosomes were more likely to contribute to inflammation and heart disease.

The Y chromosome has been shrinking for 150 million years now.