Scientists say a giant tortoise called Jonathan could hold the key to living to 200 years of age. Researchers have been conducting genetic tests on Jonathan, who at an estimated 194 years old is believed to be the world’s oldest living land animal.
Their findings suggest that it is not just down to good genes, but a lack of genetic wear and tear that have kept him going for nearly two centuries.
287 gene variants linked to longevity
The study pinpointed 287 unique gene variants that reduce the usual effects of ageing in Jonathan, who was born five years before Queen Victoria succeeded to the throne. The researchers explained that those variants control “key” processes in the body including repair of DNA damage, reducing inflammation, regulating insulin, and suppressing cancer.
Jonathan, an Aldabra giant tortoise, is believed to have hatched in 1832, making him a contemporary of Charles Darwin and Charles Dickens as well as Queen Victoria. He has lived most of his life on the island of St Helena, a British Overseas Territory in the South Atlantic Ocean, in the grounds of Plantation House, the governor’s residence.
Epigenome comparison with younger tortoises
He arrived on St Helena, already fully grown, from the Seychelles 144 years ago as a gift to the governor. The giant tortoises of the Galapagos and Seychelles islands are the last survivors of animals that used to dominate the ecology of many of the world’s islands.
Researchers also compared Jonathan’s epigenome, the “on/off” switches on his genes, with those of younger giant tortoises of the same species. They found the switches controlling Jonathan’s DNA repair and metabolism genes were remarkably “very similar” to those in his younger relatives. Usually, the epigenome changes over time, contributing to the ageing process, a key reason why things start to go wrong in older bodies.
First epigenome study of a giant tortoise
The study, published in the journal Science Advances, marks the first time the epigenome of a giant tortoise has been investigated. It was led by scientists at longevity research non-profit organisation Kallel, who say that cracking the genetic code of a multi-century life offers “unprecedented” insights into extreme lifespan.
Cambridge University scientist Dr Justin Gerlach, who was involved in the study, said: “We found that the gene regulators involved in energy production and DNA repair have remained incredibly stable in Jonathan over almost two centuries.
“There are few creatures that could tell us more about ageing than the giant tortoises of the Galapagos and Seychelles islands.”
Dr Gerlach has studied the ecology and conservation of giant tortoises for several decades, but the new paper is the first time he has analysed their exceptionally long lives. He added: “Working with a really old giant tortoise is such a privilege: you get a sense of the tortoise being your collaborator, not your study subject.”
Study senior author Dr Stephen Clark, founder of Kallel, said: “Nature has already solved the puzzle of ageing in remarkable ways, and Jonathan’s genome provides a blueprint for cellular resilience.”
He added: “Our goal is to take these evolutionary insights and immediately translate them into practical, affordable treatments for everyday people.
“Ageing is the greatest risk factor for nearly every chronic disease we face, and through the generosity of philanthropic partners, we can democratise access to longevity medicine.”
