An international team of researchers, including Devin Absher, PhD, of the HudsonAlpha Institute, have found a correlation between the age-related loss of the Y chromosome in blood cells and shorter life span in men. The findings were published this month in the journal Nature Genetics.

Led by Uppsala University in Sweden, the researchers analyzed the DNA in blood samples from more than 1,600 elderly men. They found that the most common genetic alteration was a loss of the Y chromosome in a portion of the white blood cells. Absher’s lab conducted a detailed molecular analysis of the patient samples to identify the somatic changes in chromosome number that lead to the discovery of the Y chromosome effect.

The Y chromosome is only present in men, and the genes contained on the Y chromosome have so far been associated with sex determination and sperm production. The Y chromosome was previously thought to carry very little genetic information. However, this study’s results indicate that the Y chromosome has a role in tumor suppression and might explain why men get cancer more often than women.

While the study has not revealed the exact reason for the loss of the Y chromosome in some cells, it does suggest a process that impacts aging, Absher said. Every time a cell divides it can give rise to mutations, but most of the time the mutations are in single bases in the genome, rather than complete chromosome loss. The loss of the Y chromosome has been detected in immune cells, but it’s not clear if the loss is occurring also in other tissues or if the loss is specific to the immune system.

The results of this study indicate that major somatic mutations, like losing part or all of a chromosome, certainly affect human health, and more studies need to be done to determine why certain somatic variants arise in the immune system and alter disease risk.

It’s possible that the loss of the Y chromosome could be used as a biomarker to predict future cancers or predict cancer risk. “The more we learn about somatic changes to the genome, the better we’ll be at making predictions about cancer risk,” Absher said.

Researchers collaborating on the study were HudsonAlpha, Uppsala University, Karolinska Institutet, the University of Southampton, the University of Oxford, and the Broad Institute.