[Curiosities] This explains the longevity of giant tortoises

[Draeno]

 

With the death of the solitary George, who was over 100 years old and weighed 75 kilos, an entire species disappeared, Chelonoidis abingdonii, which lived on the island of Pinta in the Galapagos, in Ecuador. However, since a long time before its extinction, its DNA had been in the spotlight of the scientific community.

Now, according to the news agency SINC, an international team of scientists, led by the universities of Yale and Oviedo, has analyzed its genome, along with that of another giant tortoise, that of the Aldabra atoll -Aldabrachelys gigantea-, the only living species. giant tortoise in the Indian Ocean. Analyzes of these two species, which shared a common ancestor 40 million years ago, were compared with those of other species of these reptiles.

The results of the article titled Giant tortoise genomes provide insights into longevity and age-related disease and recently published in the journal Nature Ecology & Evolution , show that giant tortoises possess a series of genetic variants associated with the regulation of metabolism and the immune response, which could be related to the exceptionally large sizes and long lives of these turtles.

Before his death, the team led by Adalgisa 'Gisella' Caccone, a researcher in the Department of Ecology and Evolutionary Biology at Yale University and lead author of the study, began in 2010 to sequence George's entire genome to study po[CENSORED]tion evolution. of tortoises of the Galapagos Islands. Carlos López-Otín, from the University of Oviedo, was commissioned after analyzing this data and that of other species of turtles to look for genetic variants associated with longevity.

"We had previously described nine characteristics of aging, and after studying 500 genes based on this classification, we found interesting variants that could affect six of these characteristics in giant tortoises, opening new lines for aging research," explains López-Otín.

Why don't giant tortoises get cancer?
Genome sequencing has not only provided information about their size and longevity, but also great information about the prevalence of cancer in these reptiles. In general, long-lived organisms have a higher risk of cancer. However, the results confirm that, in the case of these giant tortoises, tumor suppressors were more widespread than in other smaller specimens.

In addition, the experts found giant tortoise-specific alterations in two genes whose overexpression is known to contribute to cancer. Although these findings could point to a cancer mechanism specific to giant tortoises, tumors are very rare in tortoises, so the scientists suggest further studies to determine if these genomic features are associated with tumor development.

On the other hand, this research will help, according to the experts, to improve the understanding of the biology of the giant tortoise, and may contribute to a better conservation of other giant tortoises in the Galapagos Islands.

 

https://www.nationalgeographic.com.es/medio-ambiente/esto-explica-la-longevidad-de-las-tortugas-gigantes_13605