Scientists Test DNA of 194-Year-Old Tortoise and Discover Clues to His Extraordinary Long Life!

 For nearly two centuries, Jonathan has lived through world wars, pandemics, and generations of human history. While the world around him changed, this giant tortoise continued his quiet life on Saint Helena, a British island territory about 1,200 miles off Africa’s western coast. But scientists have now discovered something remarkable in his DNA that could help explain his extraordinary lifespan.

Jonathan, an Aldabra giant tortoise, is the oldest living land animal and the oldest turtle in recorded history. His exact age remains uncertain, but an 1882 photograph shows him already fully grown. Since his species takes at least 50 years to reach maturity, researchers estimate he is about 194 years old.

His veterinarian, Joe Hollins, suspects Jonathan might be even older, although there is no way to confirm it.

What makes Jonathan particularly fascinating is that he has survived more than a century beyond his species’ average lifespan of 80 years. His protected environment, diet, and medical care may have helped, but scientists believe there could be another explanation.

In a study published in Science Advances, researchers examined Jonathan’s DNA, hoping to uncover the genetic secrets behind his remarkable longevity.

To collect the DNA sample, veterinarian Joe Hollins gently held Jonathan’s mouth open with a gloved finger and swabbed his cheek cells and saliva.

Steve Horvath, a biologist at the University of California, Los Angeles, explained that scientists rarely have the opportunity to study an animal this old while it is still alive.

After sequencing Jonathan’s DNA, researchers identified 287 genetic variants unique to him. Many were connected to repairing damaged DNA, reducing inflammation, and regulating insulin. They also discovered similarities between Jonathan’s aging-related genes and those of naked mole-rats, animals that almost never develop cancer.

The scientists then examined Jonathan’s epigenome, chemical markers that control whether certain genes are switched on or off. As animals age, these markers become less predictable, sometimes causing irregular gene activity.

Researchers compared Jonathan’s epigenome with those of four younger tortoises. Although his overall epigenome showed signs of aging, something unexpected appeared in specific areas.

The chemical markers associated with DNA repair and mitochondria, the structures responsible for producing energy inside cells, looked remarkably youthful.

In fact, these parts of Jonathan’s epigenome closely resembled those of a five-year-old juvenile tortoise.

This discovery raised an important question: Could these unusually youthful genetic markers help explain Jonathan’s extraordinary lifespan?

Although the findings were remarkable, researchers cautioned that they did not prove these genetic markers caused Jonathan’s extraordinary longevity. However, they offered valuable clues about how DNA might remain protected over long periods.

The results also showed similarities to findings from human supercentenarians, people who have lived beyond 110 years.

Study co-author Stephen Clark, founder and chief scientist of the Kallel Foundation, explained that aging is the greatest risk factor for nearly every chronic disease. His team hopes these discoveries could eventually lead to affordable treatments that improve human health.

But significant challenges remain before the findings can be applied to medicine.

Jonathan’s cheek swab provided incomplete DNA, forcing researchers to combine his genetic information with that of a younger tortoise. As a result, the reconstructed genome was only about 95 percent Jonathan’s.

A blood sample could have provided more complete information, but Saint Helena officials refused permission because of the potential infection risk.

Another limitation was that Jonathan was only one animal, and researchers compared his genome with relatively few other tortoises.

Bioinformatics researcher Kousuke Hashimoto acknowledged these limitations but still described the study as fascinating.

Despite the uncertainties, scientists believe Jonathan’s genetics offer important insights into the mysteries of aging.

Björn Schumacher, an aging researcher at the University of Cologne who was not involved in the study, explained that the findings fit into the broader scientific understanding of longevity.

Jonathan’s remarkable journey began in the Seychelles, an island nation in the western Indian Ocean. In 1882, he was brought to Saint Helena as a gift to the governor. Already an adult when photographed that year, he has since lived at Plantation House, the governor’s residence, alongside other giant tortoises.

In 2009, veterinarian Joe Hollins took responsibility for Jonathan’s care. At approximately 180 years old, the tortoise was struggling with several age-related problems.

Cataracts had affected his eyesight, while his declining sense of smell made finding food difficult. His beak had also become soft, preventing him from grazing properly.

Hollins began feeding Jonathan by hand, ensuring he received the nutrition he needed. Over the following years, Jonathan recovered, and his beak developed a sharp edge again.

Today, Jonathan remains an extraordinary symbol of resilience, longevity, and endurance.

Having survived countless historical events and nearly two centuries of change, he continues his peaceful life on Saint Helena.

And while scientists investigate the genetic secrets behind his exceptional age, Jonathan remains a living reminder of how much there is still to discover about longevity.