What determines longevity?
A team of researchers has found that there is a very clear relationship between what being lives and the speed at which their telomeres – the structures that protect the genes in the chromosomes – shorten.
This is the main conclusion of a study published in the journal PNAS, in which researchers also show that this relationship can be expressed with a mathematical equation, a formula capable of accurately predicting the longevity of the species.
With this equation it is possible to determine that a flamenco lives 40 years, a mouse two years, an elephant 60 and a person more than 80.
The reason is what scientists at the National Center for Oncological Research (CNIO) have been trying to answer after analyzing nine species of mammals and birds.
The work has been done in collaboration with the Zoo Aquarium of Madrid and the University of Barcelona, reports the CNIO in a press release.
Telomeres from mice, goats, dolphins, gulls, reindeer, vultures, flamingos, elephants and humans have been compared to see if it is true that species whose telomeres shorten faster actually live less.
Scientists point out that the existence of such a clear relationship between the speed of telomere shortening and longevity suggests that “we have found a universal pattern, a phenomenon of biology that explains the life span of the species, and that deserves more research.
Why does aging happen?
It has long been known that telomeres are at the origin of the aging of an organism.
Telomeres integrate the ends of the chromosomes, inside the nucleus of the cell, and their function is to protect the genes.
Each time the cells multiply to repair damage, their telomeres become a little shorter; Throughout life it can happen that the telomeres shorten too much and cannot regenerate anymore. When that happens the cell stops working normally.
Until now, however, no relationship had been found between the telomeres of each species and their longevity as there are species with very long telomeres that live little, and vice versa.
That’s why CNIO researchers decided not to compare their absolute length but the speed of shortening: human telomeres lose on average about 70 base pairs a year, while those of mice, about 7,000 base pairs, scientists detail in their new research.
“We showed that the important thing is not the initial size but the rate of shortening, a parameter that predicts the longevity of the species with a high degree of precision”, underlines Kurt Whittemore, first author of the article.
This factor could predict the longevity of species much better than other parameters considered until now, such as body weight or heart rate.
“These results support the idea that the critical shortening of telomeres and the consequent appearance of telomeric DNA damage and cellular senescence is a determining factor in the lifespan of the species,” the authors write.
With this point of the discussion clarified, the next step of the investigation will be to study very long-lived species for their size, such as the naked mole-rat or the bat.
Further steps include determining how to help telomeres shorten less or repair themselves so that cells can continue to operate properly and extend life even more than today.