The lifespan of mammals, which includes humans, is much shorter than that of reptiles and amphibians. Microbiologist Juan Pedro de Magallais from the University of Birmingham in Great Britain suggested that the reason for this is the dinosaurs, which dominated millions of years ago – during a critical period for the development of mammals.
This is reported by Science Alert with reference to a study published in the scientific journal BioEssays.
The scientist put forward his hypothesis called the “longevity bottleneck”, which refers to the length of life.
When dinosaurs ruled the Earth, much smaller mammals had to reproduce quickly to survive. According to the microbiologist, because of this, the genes that ensure a longer lifespan could have been “rejected” in the process of evolution.
|Dinosaurs may have influenced the lifespan of humans. Photo: orlaimagen/Depositphotos
“Some of the earliest mammals were forced to live at the bottom of the food chain and probably took 100 million years during the age of the dinosaurs to survive through rapid reproduction.
I hypothesize that this long period of evolutionary pressure has influenced how we humans age.” – explains de Magallias.
The scientist notes that the very ancient ancestors of humans seem to have lost photolyases, enzymes that repair DNA damage caused by ultraviolet light, during the reign of the dinosaurs.
Even marsupials and monogamous mammals lack at least one of the three photolyases. However, it is not known for certain whether this is due to their relatively short life span.
One of the reasons why this might have happened is the nocturnal way of life of mammals, which helped her to stay in relative safety. After millions of years, people compensate for the loss of photolyases with the help of sunscreen.
However, there is another difference. In some reptiles, including alligators, teeth can grow throughout life. Humans do not have this ability. It can also be the result of genetic selection.
“In the animal world, we see examples of truly amazing recovery and regeneration. At the same time, this genetic information would have been unnecessary for early mammals that were lucky enough not to become food for a tyrannosaurus.” – says the scientist.
Some mammals, including humans and whales, can live into the triple digits. However, the question is whether the influence of the restrictions imposed by the ancestors really exists now.
Understanding the processes of aging is useful in combating age-related diseases, against which people are currently powerless.
“Although this is currently only a hypothesis, there are many interesting angles to this problem, including the prospect that cancer is more common in mammals than in other species precisely because of the rapid aging process.” – says de Magalyaish.
It will be recalled that scientists assumed that the secret of longevity may be hidden in the blood biomarkers of people who have crossed the 100-year mark.
Read also: Scientists have found a protein that can affect aging – research