Presenter: This is such an interesting question [Refers to viewer’s question]. Even when I was young I wondered why there seemed so many older women than men.

COMM

There are several theories for this – testosterone may lead to men living riskier lives – more men go to war than women. Men might have more dangerous jobs and may live a less healthy lifestyle.

But this doesn’t explain why men’s life expectancy is shorter than women’s – at the moment it stands at nearly five years shorter in the UK.

Other theories suggest that it was an evolutionary advantage for women to live longer than men. They were of more use to hunter gatherer tribes as they were able to help feed the young and care for them.

Presenter: But there’s a new theory, known rather darkly as the Mother’s Curse, and part of the research was undertaken in here in Lancaster.

Dr David Clancy worked on the project.

Sync

David: Across the animal kingdom male animals often die before females we wanted to look in to the reasons for this.

COMM

The team looked at mitochondrial DNA. Mitochondria are essential components of cells and they convert food molecules into energy. They looked at the mitochondrial DNA in fruit flies – not humans – which despite the very obvious differences as a whole are actually very similar at this level.

Sync

David: What’s interesting is that mitochondrial DNA, unlike other cell DNA, is passed directly from the mother to her child, via the egg. The father has no part in the process.

So if mitochondrial DNA mutates in ways which are damaging to females then natural selection will ensure that over time these mutations are eliminated. However as men are simply passed the DNA any damage it does to them will go unnoticed by evolution.

COMM

So men are left with DNA that may well be damaging to them. Any negative aspects are not weeded out by evolution. Mitochondria are thought to have an impact on how we age so faulty mitochondria in men may go to explain why men die younger.

Sync:

David: Our research was done on fruit flies which in terms of the ways in which the mitochondria are made up and passed on is very similar to those of human beings. More research is needed before we can make the full link to humans in terms of mechanisms. One observation that interests me currently is that lots more men die of heart attack in middle age, and mitochondria are critical for heart muscle function.