He has outlived nearly every human who has ever lived. He was already middle-aged when Queen Victoria took the throne. And now, for the first time, scientists have read his DNA—and found something that could change how we think about ageing itself.
Jonathan is an Aldabra giant tortoise living on the remote South Atlantic island of Saint Helena. He is estimated to be 194 years old—the oldest known living land animal on Earth. His species typically lives to about 93 years. Jonathan has doubled that. He is roughly a century past his species’ usual upper limit.
On October 7, 2026, researchers published the first full genetic analysis of Jonathan in the journal Science Advances. What they found was not a single “longevity gene” or a miraculous mutation. It was something more subtle, and more profound: the biological machinery inside his cells has barely aged at all.
The Discovery: 287 Genetic Variants—and a Lot of Stability
The study, led by researchers at the University of Cambridge and other institutions, sequenced Jonathan’s genome and epigenome—the complete set of his DNA and the chemical switches that control which genes are active.
They identified 287 unique gene variants in Jonathan that appear to reduce the usual effects of ageing. Compared to other Aldabra tortoises, Jonathan’s genome contains distinctive variations that set him apart.
But the real surprise wasn’t the variants themselves. It was what they did.
What’s Actually Keeping Jonathan Alive
The researchers found that gene regulators involved in energy production and DNA repair have remained incredibly stable in Jonathan over almost two centuries.
In most animals—humans included—these systems degrade with age. Mitochondria, the powerhouses of the cell, become less efficient. DNA accumulates damage. The chemical switches that control gene expression become dysregulated. That’s what ageing looks like at a cellular level.
In Jonathan, that process appears to have been dramatically slowed or even halted.
The study identified 770 positively selected genes in his genome, with roles in DNA repair, telomere maintenance, and methylation stability. Telomeres are the protective caps on the ends of chromosomes that shorten with age—Jonathan’s appear to be protected. DNA methylation is a key epigenetic mechanism that goes haywire in ageing cells—Jonathan’s is stable.
And crucially, the researchers found chemical patterns on Jonathan’s genes that appear to protect the healthy functioning of his mitochondria. His cells are still producing energy efficiently at 194 years old.
“It’s not just good genes,” the researchers concluded. “It’s lack of genetic wear and tear”.
What This Means for Ageing Research
Jonathan’s genome isn’t just a curiosity. It’s a blueprint.
The study of exceptionally long-lived animals—tortoises, whales, naked mole rats—has become one of the most promising frontiers in ageing research. These creatures have evolved natural mechanisms to delay or avoid the diseases and degeneration that afflict most species, including humans.
If scientists can understand how Jonathan’s DNA repair and mitochondrial protection systems work, it could inform research into therapies that mimic those mechanisms in humans.
The study’s senior author and corresponding author, Clark, and lead author Vaisvil, published their findings in Science Advances on October 7, 2026. It’s the first genome sequence of a 194-year-old Aldabra giant tortoise, and it’s already reshaping how researchers think about the biology of extreme longevity.
A Life That Spans Centuries
To put Jonathan’s lifespan in perspective: he was born sometime before 1832. He was already about 50 years old when he was brought to Saint Helena in 1882. He has lived through the reigns of seven British monarchs. He was alive when Charles Darwin was still voyaging on the Beagle. He has seen the invention of the telephone, the automobile, the airplane, the computer, and the internet.
He is, in every sense, a living relic.
And he’s still going. In April 2026, a viral death hoax briefly claimed Jonathan had passed away. Officials confirmed he was alive and well. He is expected to celebrate his 195th birthday later this year.
The Lesson in a Tortoise’s DNA
Jonathan’s story is a reminder that ageing is not a fixed, inevitable process. It is a biological program—one that evolution can tune, slow, or, in rare cases, nearly pause.
The secret to Jonathan’s longevity isn’t a single miracle gene. It’s the quiet, relentless stability of systems that, in most animals, fall apart over time. His mitochondria keep working. His DNA keeps repairing itself. His epigenetic switches stay in place.
That’s not just good luck. That’s a blueprint.
And for the first time, scientists are reading it.
Jonathan has outlived every human who was alive when he was born. He has seen the world transform beyond recognition. And now, at 194, he may end up teaching us something about how to live longer ourselves.
Not bad for a tortoise from a remote island in the South Atlantic.
