Why Women Outlive Men

Mitochondria mutations that affect male, but not female, aging could explain why women tend to live longer than men.

Aug 3, 2012
Jef Akst

Researchers have discovered several mutations in the mitochondrial DNA of Drosophila that affect male lifespan and rate of aging, but have no effect on aging in females, according to a study published this week (August 2) in Current Biology.

According to BBC News, there are about 50 percent more women in the UK population by the age of 85, and twice as many more women by the age of 100. And this pattern is not just limited to humans.

Analyzing the mitochondria of male and female Drosophila melanogaster, Damian Dowling of Monash University in Australia and colleagues found that the mitochondria harbor numerous mutations that affect male, but not female, aging. Because mitochondria are passed down from the mother, evolutionary theory predicts that male-harming mutations can accumulate in its DNA.

“If a mitochondrial mutation occurs that harms fathers, but has no effect on mothers, this mutation will slip through the gaze of natural selection, unnoticed,” Dowling told the BBC. “Over thousands of generations, many such mutations have accumulated that harm only males, while leaving females unscathed.”

Of course, there are likely other factors at play as well, such as lifestyle, social and behavioral traits, and of course, hormones, ageing expert Tom Kirkwood of Newcastle University added. “It may be it does tell us something rather important about mitochondria and the difference between male and female fruit flies,” he told the BBC. “But I certainly don't think this is a discovery that explains why women live 5–6 years longer than men.”