194-Year-Old Tortoise Could Reveal Secrets to Human Longevity
Could a 194-year-old tortoise reveal clues about how humans can live longer? Read on for how scientists are studying this giant tortoise and what they hope to learn from their research.
A Nearly 200-Year-Old Tortoise Could Hold the Key to Human Longevity
Researchers have been monitoring the life of a 194-year-old tortoise named Jonathan. The Aldabra giant tortoise is believed to be the world's oldest land animal as he approaches his 200th birthday.
Jonathan lives on the remote South Atlantic island of St. Helena. As Jonathan continues to age, scientists have taken a special interest in studying his specific DNA to understand his secret to longevity.
A new study published recently in the journal Science Advances offers potential explanations for Jonathan's extended lifespan. “The assumption has always been that their metabolic rate is very low compared to us,” said study coauthor Justin Gerlach, a fellow in biology at the University of Cambridge in the United Kingdom. Gerlach explained, “That means that the processes that are going on inside the cells are slower, so there are fewer chemical reactions and therefore less damage to the cells and to the DNA.”
Gerlach and his team of researchers identified 287 gene variants linked to protecting the tortoise from the natural cellular damage that happens during the aging process. According to Gerlach, “He does have some genes that are particularly good for DNA repair and reducing inflammation."
Diving deeper into the analysis of Jonathan's genome found the reptile can continue to produce the right genes even as he ages, a process that typically falls apart earlier for most other types of animals. Gerlach explains that “Our cells start doing the wrong things and we get cancers, for example. But Jonathan has still got the genetic controls of a much younger animal." In short, this means that tortoises are much fitter than what their age on paper would indicate, particularly when compared to humans.
Why does this research matter? Scientists hope that understanding why some species are able to live longer could provide breakthroughs about aging and longevity across the animal kingdom. These findings could potentially apply to human health.
About Jonathan the Tortoise
Scientists have not been able to confirm Jonathan's exact age. Researchers estimate his age from a photograph taken in 1882. Because Jonathan was already fully grown, and at least 50 years old, when the photo was taken, he likely hatched around 1832.
St. Helena’s governor gave Jonathan an official birthday in 2022, putting the date at December 4, 1832. Gerlach said that it is possible that Jonathan could be over 200 years old.
Historians believe that Jonathan could have arrived in St. Helena as a gift when the region was being colonized. This was common practice during a time when people regarded these giant reptiles as "curiosities."
Jonathan weighs roughly 400 pounds and is still active even though he is blind. Today, tourists flock to St. Helena to view the massive tortoise.
Scientists note that there are some limitations in their studies due to Jonathan's age. Because they do not want to risk infection, the researchers collect DNA from mouth swabs rather than blood draws. Mouth swabs are not as accurate as blood DNA sequencing techniques.
Why Scientists Are So Interested in Jonathan's DNA
The study's researchers were able to compare Jonathan's DNA with the epigenome of younger tortoises that live on the Aldabra Atoll of Seychelles. The research revealed several similarities, indicating that mitochondrial health is key for long-lived species. Jonathan's specific genome has provided scientists with a map to study cellular resilience that could apply to humans.
It is important to remember that Jonathan is just one animal. Everything learned about him may not transfer to other applications; however, the data may give scientists a clearer picture of what genetic factors influence longevity. According to Handan Melike Dönertaş, an assistant professor and genomics researcher at the Middle East Technical University in Turkey, “By comparing such extreme individuals with others, not only among humans such as centenarians, but also in other species, we can start to learn what makes them special, and with advances in medical technology we may find ways to apply what we learn."
The goal of this study, and other similar bodies of research looking at long-lived animals, is to glean information that could be transferred to the human aging process. Notably, scientists are hopeful that these findings may be instrumental in the field of cancer research.
While the goal is not necessarily to figure out how to live forever, researchers want to unravel how some organisms are better equipped to achieve greater levels of longevity. The latest study signals that Jonathan could provide clues that will lead scientists down a more complex path of understanding.
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