Centenarians (people who live to 100+ years of age) are fascinating to science. These people defy the average lifespan by well over 20 years – with one woman supposedly making it to a staggering 122 years old, although this claim has been disputed – and scientists have never quite understood why. Diet is important, avoiding carcinogens such as smoking is huge, and keeping fit extends lifespan by a significant margin. But sometimes, these incredible people just inexplicably live for over a century.
However, new research may begin to illuminate just how this can be possible, and the answer seems to lie in their genetic code. Researchers from the University of Bologna, Italy, have discovered five genetic mutations within the DNA of people that made it past 105 years old that may change how their cells repair broken DNA, hinting at their mysterious elixir of life.
“Previous studies showed that DNA repair is one of the mechanisms allowing an extended lifespan across species,” says Cristina Giuliani, Senior Assistant Professor at the Laboratory of Molecular Anthropology, Department of Biological, Geological and Environmental Sciences, University of Bologna, and a senior author of the study, in a statement.
“We showed that this is true also within humans, and data suggest that the natural diversity in people reaching the last decades of life are, in part, linked to genetic variability that gives semi-supercentenarians the peculiar capability of efficiently managing cellular damage during their life course.”
Their results were published in the journal eLife.
To unlock the super-centenarians' secrets, the researchers took a large sample (considering how many people aged 105+ there are) of 81 people aged 105 and over and compared their genomes to a healthy, geographically matched control group of 36 people around the age of 68. Each person was subject to high-coverage genome sequencing to identify any mutations that may separate the super-centenarians from the controls. Variants across the genomes were analyzed, and should associations be made, they were then validated in data from another larger cohort.
Once complete, five variants were discovered. The researchers delved into the genes that these variants called home, and found that the most common ones associated with advanced lifespan were linked to increased activity of the STK17A gene. This gene – and its resulting protein – is involved in the apoptosis pathway, in which damaged cells with faulty DNA are broken down to stop them increasing the chance of cancer and other diseases. There was also an association between the variants and increased COA1 activity, which facilitates an important part of cellular respiration and is implicated in aging.
Together, these variants appear to increase the bodies’ efficiency at repairing DNA and help prevent the onset of serious disease. It is an impressive start, and may finally aid our understanding of increasing human longevity, but more work will need to be done before a causal link can be developed. Genomic studies are looking for correlations, and it is important to understand that these variants could be part of a wider mechanism for aging – or just simply present in older people by coincidence. Larger cohorts and further understanding of the variants will aid researchers in discovering just how important these mutations are in increasing our lifespan.