Nashville (LabNews Media LLC) – A medical professional from Tennessee Oncology has participated in a new study examining the genetic and epigenetic characteristics of Jonathan, a 194-year-old giant tortoise considered the world's oldest known living land animal. As announced by the company on Wednesday, 287 unique genetic variants were identified that are associated with biological processes and could explain Jonathan's remarkable longevity and resilience to age-related diseases. The study was published in Science Advances.
The identified variants include, according to the researchers, pathways involved in DNA damage repair, inflammatory processes, insulin regulation, and cancer suppression. Dr. Yanjun Ma, a medical oncologist and researcher at Tennessee Oncology with a practice in Murfreesboro, contributed to the analysis of Jonathan's epigenome – the entirety of chemical modifications that regulate how genes are expressed without altering the underlying DNA sequence.
“Jonathan offers scientists an extraordinary opportunity to study the biological mechanisms associated with extreme longevity and cancer resistance,” Ma said. “Understanding how these mechanisms function at the genetic and epigenetic level could ultimately provide insights for new approaches to cancer prevention and the development of therapies.”
Background
Giant tortoises are of particular interest to longevity researchers because, despite their large size, they can live for more than a century. Jonathan, a Seychelles giant tortoise, was estimated to have been born around 1832 and arrived on the island of St. Helena in 1882. At approximately 194 years old, he is considered the oldest known living land animal. His exceptional lifespan spans nearly two centuries of human history – he lived during the time of presidents like Andrew Jackson and Abraham Lincoln, and was a contemporary of Charles Darwin, Queen Victoria, and Gustave Eiffel.
According to those involved, the study represents the first examination of a giant tortoise's epigenome and opens a new window for researchers into the biological mechanisms that may contribute to extreme longevity.
"Since advanced age is one of the biggest risk factors for developing most cancers, understanding how humans, or in this case turtles, age should benefit cancer treatment. Dr. Mas's oncological knowledge was particularly helpful for us to understand how some of Jonathan's gene variants kept him cancer-free," said Dr. Stephen Clark, Chief Scientist at Kallel and senior and corresponding author of the paper.
Classification
For Tennessee Oncology, the research reportedly reflects the practice's commitment to advancing cancer science beyond the traditional boundaries of clinical oncology. Tennessee Oncology is a founding practice of OneOncology, a physician-led national partnership for independent medical practices.
"Cancer research often focuses on understanding why cells get sick," said Dr. Natalie Dickson, CEO of Tennessee Oncology. "Studies like this allow us to approach the question from a different direction: What enables an organism to live for almost two centuries while maintaining mechanisms that protect against cancer? Nature has already developed some remarkable solutions. Our job as scientists is to understand them."
The research was led by scientists at Kallel, a non-profit organization focused on longevity research, and included staff from multiple institutions, according to Tennessee Oncology.
Original publication: Science Advances, October 7, 2026.
About Tennessee Oncology
Tennessee Oncology describes itself as one of the largest community-based cancer care practices in the U.S. and is home to one of the leading clinical trials networks in the country. Founded in Nashville in 1976, the practice aims to provide all patients with access to high-quality cancer care and clinical research expertise in convenient locations within their community and close to home.
