A new study found that the loss of the Y chromosome in blood cells may explain why men have a shorter life expectancy and higher cancer risk than women.
Many studies have highlighted that women have a longer life expectancy than men. They also seem to be less susceptible to many types of cancer. Unfortunately, possible risk factors behind this disparity are largely unknown.
In a new study conducted by Uppsala University researchers, it was discovered that the loss of the Y chromosome in blood cells may have a major role to play in this. For the study, researchers examined the DNA in blood samples from more than 1,600 elderly men. It was found that the loss of Y chromosome in the blood cells of some men was accompanied by a loss of 5 years in their life span and more cancer affliction was noticed
Previous studies have also established that DNA alternations in normal cells that accumulate over time up the risk of diseases like diabetes and cancer. Uppsala University researchers found that the most common type of DNA alteration in men was a loss of the Y chromosome in a portion of the white blood cells. The participants of the study were followed for many years and researchers were able to determine an evident association between loss of Y chromosomes and shorter survival rates.
"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", said lead author, Lars Forsberg, in a press statement.
Y chromosomes are present only in men and are commonly referred to as the sex-determining gene. A long time ago, Y and X chromosomes were the same until suddenly the Y chromosome started differentiating itself from the X chromosomes. During this transition period, it progressively shrank to such an extent that now it contains only about 20 genes while the X chromosome contains more than a thousand genes.
"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 tumor 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", said co-author Jan Dumanski.
A recently conducted study found that these sex-determining genes originated about 180 million years ago, much earlier than previously believed.
The current study was published online in the journal Nature Genetics.