A study provides reasons why humans typically die around the age of 80, while other mammal species have significantly shorter or longer lifespans.
Scientists have discovered that both humans and animals die after accumulating a similar number of genetic mutations, indicating that the rate of DNA damage is crucial in determining the lifespan of a species.
There is a vast difference in the lifespans of mammal species, ranging from South Asian mice that live only 6 months to bowhead whales that can survive for 200 years.
Previously, experts believed that size was the key to longevity. According to this view, smaller animals burn energy faster, leading to quicker decline.
Illustrative image: Asianscientist
However, new research from the Wellcome Sanger Institute (UK) shows that the rate of gene damage may be the key to survival. Long-lived animals exhibit a slow rate of DNA mutations, regardless of species size.
This analysis helps explain why the naked mole rat, measuring 12 cm, lives for 25 years, which is comparable to a much larger giraffe that typically lives for 24 years. The number of mutations per year for the mole rat is 93, while for giraffes, it is 99.
In contrast, common mice have 796 mutations per year and only live for 3.7 years. The average lifespan of humans in the study was 83.6 years, with a mutation rate of 47.
Genetic changes, or somatic mutations, occur in all cells, most of which are harmless. However, some can lead to cancer or impair function. Somatic cells are responsible for forming tissues and organs in multicellular organisms.
Dr. Alex Cagan, the study’s author, stated: “Finding a similar pattern of gene variation in such diverse species as mice and tigers is truly surprising.”
“But the most interesting aspect of the research is discovering that lifespan is inversely proportional to the rate of somatic mutations. This suggests that somatic mutations play some role in the aging process.”
The team analyzed genetic errors in stem cells from the intestines of 16 mammal species. They noted that the higher the species’ lifespan, the slower the mutation rate.
The average number of mutations at the end of a species’ lifespan is about 3,200. This indicates that there are many severe errors that ultimately prevent the body from functioning normally.
Dr. Inigo Martincorena commented: “Aging is a complex process, resulting from many forms of molecular damage in our cells and tissues. Somatic mutations have been hypothesized to contribute to the aging process since the 1950s, but research has faced many challenges.”
“With recent advancements in DNA sequencing technology, we can finally investigate the role of somatic mutations in aging and the onset of many diseases.”
