The Disappearing Y Chromosome
Not only do men have a shorter average life span than women but the incidence of cancer and the death rate from the disease is higher in men than in women. Yet the reason for these differences between the genders has long eluded researchers. Now a study led by scientists as Uppsala University in Sweden has shown a correlation between a loss of the Y chromosome in blood cells and both a shorter life span and higher mortality from cancer in other organs. As you probably know, women have two X chromosomes and men have one X chromosome and on Y chromosome. The study was published in April 2014 in the journal Nature Genetics.
The international team analyzed the DNA in blood samples from a group of more than 1,600 elderly men. The researchers found that the most common genetic alteration was a loss of the Y chromosome in a proportion of the white blood cells. The group of men was studied for many years and the researchers could detect a correlation between the loss of the Y chromosome and shorter survival.
A release from the university quotes lead researcher Lars Forsberg of the Department of Immunology, Genetics and Pathology, Uppsala University,as saying, "Men who had lost the Y chromosome in a large proportion of their blood cells had a lower survival, irrespective of cause of death. We could also detect a correlation between loss of the Y chromosome and risk of cancer mortality
The the genes contained on the Y chromosome have so far mostly been associated with sex determination and sperm production but this limited view is incorrect, according to the researchers.
"You have probably heard before that the Y chromosome is small, insignificant and contains very little genetic information. This is not true. Our results indicate that the Y chromosome has a role in tumour suppression and they might explain why men get cancer more often than women. We believe that analyses of the Y chromosome could in the future become a useful general marker to predict the risk for men to develop cancer", says Jan Dumanski, professor at the Department of Immunology, Genetics and Pathology, Uppsala University, and responsible for the study.
The researchers behind the study are from Uppsala University, Karolinska Institutet, University of Southampton, HudsonAlpha Institute for Biotechnology, University of Oxford, Broad Institute of MIT and Harvard University.