Studies have shown that DNA mutations can influence the aging process: each of them would shorten the life span by up to six months.
Scientists have found that rare mutations present in some people’s cells can shorten their lifespan. The study was the result of the efforts of scientists at Harvard University in the United States and the Russian company Gero LLC, and was published on Friday (24) on eLife.
A person’s genes are not solely responsible for determining life expectancy (diet and habits, for example, play a more important role in this). Still, the study shows that DNA variants can influence the aging process: each of these mutations can reduce life expectancy by up to six months, the researchers estimate.
According to the biologists who participated in the study, less than a third of this influence is the result of hereditary genes. This means that the other genetic mutations come from environmental factors, such as damage from the sun, exposure to chemicals and other damage that creates thousands of random mutations.
The search for these rare mutations, found in less than one in 10,000 people, was based on the UK Biobank, a public database that contains the genotypes of about 500,000 volunteers. Using more than 40,000 of these genetic codes, the team looked for correlations between minor DNA changes and people’s health conditions.
The researchers concluded that, on average, each person is born with six of these rare variants that can shorten their life span and their health span before developing serious illnesses. This means that the more mutations, the more likely a person is to develop an age-related condition or die earlier than expected. “The exact combination matters, but in general, each mutation decreases life span by 6 months and health span by 2 months,” Vadim Gladyshev, co-author of the study, told Science.
The results corroborate an old thesis that defends hereditary genes as an important factor when it comes to aging and life expectancy. Still, they believe the discovery could help researchers focus their studies on other variables, such as age and sex.
Gladyshev points out, however, that the results are potentially controversial, as they minimize the contribution of “somatic” mutations (caused by environmental factors) acquired throughout life. “They [all] contribute to the aging process, but on their own they do not cause it,” he noted.