Life expectancy: Experts think they’ve solved mystery of why humans live to around 80 – Express

Experts previously suggested that size was the key to longevity as smaller animals burn up energy quicker than their larger counterparts. This means they require a faster cell turnover, which causes them to decline faster. But new research from the Wellcome Sanger Institute in Cambridge suggests that the speed of genetic damage could be the key to survival.

They believe that long-living animals are able to successfully slow down their rate of DNA mutations regardless of their size.

It could explain how a five-inch long naked mole rat can outlive a giraffe.

That's because the team found that naked mole rats suffer 93 mutations a year and giraffes 99.

Meanwhile, mice experience up to 796 mutations a year which may explain why they live on average for 3.7 years.

Genetic changes, known as somatic mutations, occur naturally in cells.

Dr Alex Cagan, the first author of the study, said: To find a similar pattern of genetic changes in animals as different from one another as a mouse and a tiger was surprising.

But the most exciting aspect of the study has to be finding that lifespan is inversely proportional to the somatic mutation rate. This suggests that somatic mutations may play a role in ageing.

The team found, overall, that the longer the lifespan of a mammal, the slower the rate at which mutations occur.

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Dr Inigo Martincorena, the senior author of the study, said: Ageing is a complex process, the result of multiple forms of molecular damage in our cells and tissues.

Somatic mutations have been speculated to contribute to ageing since the 1950s, but studying them has remained difficult.

With the recent advances in DNA sequencing technologies, we can finally investigate the roles that somatic mutations play in ageing and in multiple diseases.

The research was published in the journal Nature.

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Life expectancy: Experts think they've solved mystery of why humans live to around 80 - Express