There are striking differences between the rate at which mammals (including us) age and the rate at which many species of reptiles and amphibians age.
One scientist argues that this discrepancy may be due to the dominance of dinosaurs during a critical period in mammal history millions of years ago.
João Pedro de Magalhães, a microbiologist at the University of Birmingham in the UK, describes the ‘longevity bottleneck’ hypothesis in a newly published paper. paper.
Possible options include: When dinosaurs ruled the earth, much smaller mammals needed to be able to reproduce quickly to survive. This means that genes for longevity may have been discarded during evolution.
“Some early mammals were forced to live at the bottom of the food chain and likely spent 100 million years during the dinosaur era evolving to survive through rapid reproduction.” To tell De Magalhães.
“I think that long-term evolutionary pressure is influencing the way we age.”
Published research shows that our very ancient ancestors Eutherian mammal lineage It seems that certain enzymes are missing Dinosaur days – Enzymes that repair damage caused by UV rays.
Interestingly, even marsupials and monotremes lack at least one of the three UV repair enzymes known as photolyases. Whether this is somehow related to their own relatively short lifespan is difficult to determine.
One possibility is that mammals lost money by becoming nocturnal to stay safer, and millions of years later we’re compensating for it with sunscreen. This is an example of a repair and restoration mechanism that we would otherwise have in place.
There are other signs as well. To take teeth as an example, certain reptiles, including crocodiles, keep teeth growing All through their lives. Obviously humans can’t do that. This too is probably the result of genetic selection dating back hundreds of thousands of years.
“We see some truly amazing examples of repair and regeneration in the animal world.” To tell De Magalhães. “That genetic information would have been unnecessary for early mammals that were lucky not to go extinct.” tyrannosaurus food. “
Of course, many mammals celebrate triple-digit birthdays, including whales and us humans. Whether we do so under constraints imposed by our short-lived ancestors, or whether we have somehow evolved to be immune to them, may be the subject of future research.
A deeper understanding of the factors behind aging will always help in the fight against age-related diseases such as dementia and stroke. Also, the genetics behind the “longevity bottleneck” may tell us more here.
“Although it’s just a hypothesis at this point, there are many interesting angles to look at this, including the prospect that cancer occurs more frequently in mammals than in other species due to the rapid aging process.” To tell De Magalhães.
This research bio essay.