Why do tortoises live so long?
In life, Lonesome George was arguably the most famous tortoise in the world for being the last of his species. Now, over half a decade after he died, he’s still making headlines by helping geneticists understand why giant tortoises have such long lifespans.
Scientists believe the lifespans of giant tortoises like George are so long because they have gene variants that tweak how their DNA is repaired and their bodies respond to inflammation and the development of cancer.
Prior to the study, little was known about the genes of these invertebrates. An international team of researchers at Yale University, the University of Oviedo in Spain, the Galapagos Conservancy, and the Galapagos National Park Service worked together on the paper, published in the journal Nature Ecology & Evolution.
The process started in 2010 when Dr. Adalgisa Caccone, co-senior author of the study and senior researcher in the Department of Ecology and Evolutionary Biology at Yale University, sequenced George’s genome.
Then, Professor Carlos Lopez-Otin of the University of Oviedo, Spain, studied the resulting data, and that of the Aldabra giant tortoise, and noted gene variants which were linked to a long lifespan. The data was also compared to that from the P. sinensis, or Chinese soft shelled turtle, and humans.
Lopez-Otin explained: “We had previously described nine hallmarks of aging, and after studying 500 genes on the basis of this classification, we found interesting variants potentially affecting six of those hallmarks in giant tortoises, opening new lines for aging research.”
The research “expands our understanding of the genomic determinants of aging” and could help restore giant tortoise populations, the authors wrote.