News in Science

Secret to a long life is still a genetic mystery

Longevity gene If the secrets of longevity are written in our genes then we are yet to discover them, say scientists.

Genetic experts searching for longevity genes in the genomes of people who live over 110 years of age report that they have drawn a blank, but there are hints such genes do exist.

The scientists sequenced the whole genomes of 17 supercentenarians. The results of their research is published today in PLOS One.

There is something quite remarkable about this group of individuals that sets them apart from the rest of us, explains study co-author Professor Stuart Kim from the department of developmental biology and genetics at Stanford University in California.

One supercentenarian involved in the study Leila Denmark worked as a paediatrician until 106 years old before dying at the age of 116.

"She was alert and able to work independently so I think of her as having a slower clock than the rest of us," says Kim.

"If we could capture the idea of staying middle-aged for 50 years and then have a more compressed old age that would be a really important and useful way to reduce health costs".

However the researchers, including leading longevity expert Stephen Coles from the Gerontology Research Group in Los Angeles, found no significant evidence of a single rare gene or gene variant in supercentenarians compared to control genomes.

Nevertheless the researchers still believe there is a strong genetic component to longevity, it's just not going to be simple to find it.

"Twin studies have shown that 40 per cent of longevity is genetic. For people with an extremely long life I think it could be more than this but there are not enough supercentenarians to know," says Kim.

Longevity gene remains elusive

The strongest candidate they found for a longevity gene was the transcription-factor gene TSHZ3, which showed the most enrichment for protein-altering variants in supercentenarians compared to controls.

But when they looked at the gene in a further study of genomes from people aged between 98 and 105 the difference was not significant.

"In order for it to count as a longevity gene we are going to need to study the genes of more people," says Kim.

And with people living longer and more genetic data sets on centenarians it is plausible to sequence the genomes of thousands of centenarians allowing an analysis with more statistical power, he says.

"One of the nice things about our paper is that we made the data public," he says

"We wanted that data to be used worldwide because if it can be combined with other people's studies then we may be able to find out what's different between supercentenarians and ourselves".

Interestingly the authors discovered that one of the supercentenarians carried a known genetic mutation that can cause individuals to die of sudden cardiac death.

However the mutation did not cause a fatal cardiomyopathy during the individual's 110 years of life.