In contrast, mice suffer from 796 mutations a year and live only 3.7 years. The average life expectancy in the study was 83.6 years, but the mutation rate was far lower at about 47.
Genetic changes, known as somatic mutations, occur in all cells and are largely harmless, but some can start a cell on the path to cancer or disrupt normal functioning.
Dr Alex Kagan, the study’s first author, said: “It was surprising to find a similar pattern of genetic change in animals as different as a mouse and a tiger.
“But the most exciting aspect of the study should be finding that life expectancy is inversely proportional to the rate of somatic mutation. This suggests that somatic mutations may play a role in aging. “
The team analyzed genetic defects in the stem cells of the intestines of 16 mammalian species and found that the longer the life of a species, the slower the rate of mutations.
The average number of mutations at the end of life of different species is about 3200, which suggests that there is a critical mass of errors, after which the body is unable to function properly.
“Aging is a complex process”
Although the figure varies about three times for different species, the variation is much smaller than the variation in body size, which varies up to 40,000 times.
Researchers believe the study opens the door to understanding the aging process and the inevitability and timing of death.
Dr Inigo Martincorena, senior author of the study, said: “Aging is a complex process, the result of many forms of molecular damage in our cells and tissues.
“Somatic mutations are thought to have contributed to aging since the 1950s, but they remain difficult to study.
“With the latest advances in DNA sequencing technology, we can finally explore the roles that somatic mutations play in aging and many diseases.
The study was published in the journal Nature.
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