Why Do Tortoises Live So Long?: Lonesome George Genome Study Offers New Answer

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.

George lived on the Galapagos islands, which inspired Charles Darwin's theory of natural selection.

He died in 2012, at the age of around 100 years old, according to scientists' estimates, the BBC reported. He was the last of the Chelonoidis abingdonii, or Pinta, tortoises who are said to live up to 200.

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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.

"Lonesome George is still teaching us lessons," commented Caccone.

The elderly creature earned his name after environmentalists repeatedly tried and failed to mate him with similar species of female tortoise, according to BBC News.

At one stage George did mate with another tortoise, but their eggs failed to produce hatchlings.

When he was first spotted by a scientist in 1972, it was feared that his species had been wiped out. At the time of his death in 2012, the Galapagos National Park said his passing meant the Pinta had gone extinct.