Though overall life expectancy varies around the globe, it is true for pretty much any country you look at that females live longer than males. There are many factors assumed to play into this, such as a later onset of cardiovascular disease for females compared to males, but a new study from a team of researchers led by Jan Dumanski of Uppsala University has found a correlation between loss of the Y chromosome and early death, in addition to an increased risk of cancer. Their findings were published in Nature Genetics.
As a person ages, the genome alters slightly through random mutations over a lifetime of DNA replication for cell division. This natural process has been attributed to an increase in risk for diseases like cancer or diabetes later in life, but not much was known about the causal mechanism. Dumanski’s team sought to find if there were any common trends about which parts of the genome were changing. Blood samples were taken from over 1,600 elderly men and their health was tracked until their deaths.
The most common place to identify the age-related loss of the Y chromosome (LOY) was in the white blood cells, which play a role in tumor suppression. One cohort found that about 8.2% of the men with non-hematological cancer had LOY, and those individuals lived an average of 5.5 shorter than those with the Y chromosome in tact. An independent cohort found that about one in five men had LOY and died earlier, regardless of the cause.
"Men who had lost the Y chromosome in a large proportion of their blood cells had a lower survival, irrespective of cause of death,” said Lars Forsberg, lead author on the study, in a press release. “We could also detect a correlation between loss of the Y chromosome and risk of cancer mortality."
The researchers note that this indicator could be used as a biomarker for physicians to use in explaining the risk carcinogenesis to their patients. This may also indicate that the Y chromosome, which contains the SRY gene responsible for sex determination, may also have other functions that are not currently well-understood.
“You have probably heard before that the Y chromosome is small, insignificant and contains very little genetic information. This is not true,” Dumanski explained in the press release. “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.”
[Hat tip: Anneli Waara, Uppsala University News]
[Image by Theis Kofoed Hjorth used via CC BY-SA 4.0]