Women often juggle motherhood with running a home and holding down a job – and now we know why they still manage to live longer than men.
And now we know why – they have better genes. Mutations in the ‘power packs’ of cells cause men to die early, it would seem.
The secret of long life was discovered after scientists studied the humble fruit fly. Just like humans, the flies inherit mitochondrial genes only from their mothers.
‘This means that evolution’s quality control process, known as natural selection, only screens the quality of mitochondrial genes in mothers,’ said Dr Damian Dowling from Monash University in Australia.
‘If a mitochondrial mutation occurs that harms fathers but has no effect on mothers, that mutation will slip through natural selection, unnoticed.’
It means that over thousands of generations, many such mutations have accumulated that harm only males, while leaving females unscathed.
Many theories have arisen to explain the disparity between men and women. The hormone oestrogen was thought to play a major role while some experts placed the blame on the inability of men to handle stress.
Figures from 2009 show that life expectancy in Britain is 82.6 years for women and 78.4 years for men.
If you are male and the findings make you miserable, don’t be.
Only about 30 per cent of life expectancy is due to genetics.
Most of us should be able to get into our late 80s, provided we don’t smoke, keep our weight down and eat properly. The study appears in the journal Current Biology.
In earlier research, Dr Dowling’s team linked the maternal inheritance of mitochondria to male infertility.