Spaniards live an average of 82.9 years, which places us in a privileged position among humans, who reach an average of 79. Only citizens of Japan, Switzerland and Singapore have longer lives than we do.
Let’s change species. Common mice live for about two years. Los dolphins, 17. A griffon vulture in the wild can reach 35 years. And an elephant will exceed 60. To explain these great differences, traditionally, body size – larger animals tend to live longer -, metabolism, heart rate and other physiological factors have been used.
Now, a team of scientists from the National Cancer Research Center (CNIO) has added a factor that they consider the key to the longevity of species: this would depend on the speed at which their telomeres shorten, the structures that protect the ends of chromosomes. Every time a cell divides, the telomeres lose some DNA and get shorter. Over time, the process repeats itself, chromosomes (the containers for genes) become unprotected and damaged, and cells deteriorate.
A mathematical pattern
The finding has just been published in the journal Proceedings of the National Academy of Sciences of the United States. The team that has done it, led by María Blasco, head of the Telomeres and Telomerase Group at the CNIO, has compared the telomeres of nine species of mammals and birds: humans, dolphins, seagulls, goats, mice, flamingos, reindeer, vultures and elephants. And he has observed that species whose telomeres shorten the fastest live fewer years. As Blasco explains on the website of the Scientific News and Information Service (SINC), “we have found a universal pattern, a phenomenon of biology that explains the life span of species, and that deserves further investigation.”
CNIO researchers, who have worked in collaboration with the University of Barcelona and the Madrid Zoo Aquarium, have expressed this relationship between longevity and the speed of telomere shortening with a formula that allows predicting how long a specimen can live healthy of each one of the studied species.
The relationship between aging and telomeres was known, but a link between telomere length and longevity of a species had not been discovered. In fact, there are species with short telomeres and long lives, and vice versa. The researchers ignored this parameter, preferring to compare the speed of telomere shortening, which differs greatly between species: ours measure an average of 70 genetic base pairs, and those of mice 7,000.
To do so, they extracted blood samples from specimens of the nine species studied, most of them from the Madrid Zoo Aquarium, except Audouin’s gulls, from a wild colony in the Ebro Delta and analyzed in collaboration with the University of Barcelona. In each species, the telomeres of the white blood cells of specimens of different ages were measured. The results showed that the speed of telomere shortening predicts the longevity of a species much more accurately than other physiological indicators.
