“Do the ages of animals differ according to their types and sizes?” Get to know about the latest scientific discoveries

While humans can live to about 80 years, giraffes tend to die at 24 and naked mole rats at 25, suggesting that something beyond their body size is to blame.

To help unravel this mystery, researchers from the Wellcome Sanger Institute compared the genomes of 16 species, including humans, mice, lions, giraffes and tigers.

The findings suggest that animals with a slower rate of genetic changes - known as somatic mutations - have a longer lifespan. Somatic mutations occur naturally in all cells throughout an animal's life, with humans acquiring about 20-50 mutations annually on average.

While most somatic mutations are harmless, some mutations can impair cell function or even start a cell on its way to cancer.

The role of these mutations in aging has been suggested since the 1950s, but until now, their observation has been difficult in practice.
One of the long-standing key questions has been the "Peto paradox", which questions why larger animals have no higher cancer risk, despite having more cells.

In the new study, the researchers used whole-genome sequencing of samples from 16 mammals with a wide range of ages and body sizes - colobus monkey, black and white, cat, cow, dog, ferret, giraffe, porpoise, horse, human, lion, mouse, naked rat, rabbit, rat, ring-tailed lemur and tiger.

Their analysis revealed that the somatic mutations were caused by similar mechanisms across all species, including humans.
They also accumulated linearly over time, with species with a higher mutation rate having a shorter lifespan. For example, giraffes, which can reach 18 feet in height, have been found to have boom rates of around 99 per year, and are about 24 years old.

Meanwhile, naked mole rats, which are only five inches in size, were found to have very similar mutation rates of 93 per year and a similar lifespan of about 25.

Finding a similar pattern of genetic changes, said Dr. Alex Kagan, who led the study. In animals differs from each other was surprising.

But the most exciting aspect of the study is finding that age is inversely proportional to the rate of somatic mutations.
This suggests that somatic mutations may play a role in aging, although alternative explanations may be possible. And over the next few years, it would be nice to extend these studies to more diverse species, such as insects or plants.

Unfortunately, the results did not provide an answer to Peto's paradox.

After calculating the life span, the team found no significant association between somatic mutation rate and body mass.

This suggests that other factors must be involved in the ability of larger animals to reduce cancer risk. The fact that differences in the rate of somatic mutations appear to be explained by differences in age, not body size, suggests that although modifying the rate of mutations appears to be an elegant way to control the incidence of cancer across species, evolution did not in fact choose this, said Dr. Adrian Báz Ortega, author of the study.

And it's entirely possible that every time a species evolves a size larger than its ancestors - as in giraffes, elephants, and whales - evolution may come up with a different solution to this problem. We will need to study these species in more detail to find out.
The researchers hope that the results will help unravel the mystery of the exact causes of aging.

The study was published in the journal Nature.