About 100 million years ago, during the reign of the dinosaurs on the planet, then mammals lost genes responsible for cell regeneration and, as a consequence, for life extension. This is stated in a scientific article in the journal BioEssays.
It was the dinosaurs that drove the ancestors of modern mammals in such unbearable conditions of existence, in which longevity became impossible and unnecessary. Scientists note that humans, although they have a fairly long life span compared to other animals, they are still significantly inferior to many reptiles, which show minimal signs of aging during their lives.
Aging is thought to be caused by the gradual degradation of chromosomes and the depletion of stem cell reserves in the body responsible for tissue regeneration. But the causes and mechanisms of aging are still largely poorly understood. One of the mysteries here is why mammals generally age much faster than reptiles and amphibians.
The authors of a new study have proposed their own answer to this question. According to them, it is the result of evolutionary changes that mammals underwent during the age of the dinosaurs. Back then, mammals were at the bottom of the food chain, so the only option for their survival as a population was to reproduce as quickly as possible. That’s the direction evolution took, but along the way mammals lost the ability to regenerate, which prevents aging.
“In the animal kingdom we see examples of really amazing repair and regeneration. This genetic information would have been unnecessary for early mammals that were lucky enough not to become food for a tyrannosaur. Although we now have many mammals, including humans, whales and elephants, that grow and live long lives, we and these mammals live with the genetic constraints of the Mesozoic era, and we age surprisingly faster than many reptiles,” the researchers said.
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