An analysis of the genetic material of Jonathan, the giant tortoise regarded as the world’s oldest living land animal, identified 287 genetic variants linked to protecting cells from damage accumulated with age. Researchers also detected signs of efficient genes responsible for repairing DNA and reducing inflammation.
High genetic activity despite exceptional ageing
The study, published in the scientific journal Science Advances, found that Jonathan had maintained an appropriate level of genetic activity despite his exceptional age. This ability is one of the mechanisms that usually decline in many living organisms over time, affecting cell functions and their ability to resist damage.
Researchers believe that the slow metabolism of giant tortoises may be one of the factors contributing to their long lifespans. A lower metabolic rate can reduce the chemical reactions taking place inside cells and consequently limit damage to cells and DNA over time. Scientists compared Jonathan with younger tortoises from the same family, and the results revealed similarities in some genetic traits.
Mitochondria emerge as a new focus of longevity research
The mitochondria, the structures responsible for producing energy inside cells, were also found to be in notably good condition despite the tortoise’s advanced age. The study’s lead researcher, Stephen Clarke, said the findings were increasing scientific interest in the role mitochondria may play in longevity.
He added that his team was working to identify drugs that could help improve their performance, ahead of testing them in clinical trials on humans within the next year or two. Jonathan lives on the island of Saint Helena, a British territory in the South Atlantic, and belongs to the giant Aldabra tortoise species, native to the Seychelles.
His age estimate is based on a photograph taken in 1882 that showed him fully grown and having reached adulthood. On the basis of this photograph, 4 December 1832 was adopted as Jonathan’s official date of birth. Researchers nevertheless do not rule out the possibility that his true age is more than 200 years.
The tortoise weighs about 180 kilograms and remains active despite losing his sight as a result of cataracts. Scientists stressed that the findings alone were not enough to provide a complete explanation for Jonathan’s longevity.
Verifying them will require studying other tortoises, as well as different species known for their long lifespans, to determine whether these genetic traits are a general characteristic linked to longevity or an exceptional condition specific to Jonathan.
