Jonathan the 194-year-old tortoise has unusually stable gene switches, researchers report

Jonathan, a giant tortoise estimated to be 194 years old on St Helena, is the subject of a study published on October 7 in Science Advances that reports distinctive genetic variants and unusually stable controls on some genes. The findings offer researchers clues about how giant tortoises age, but do not establish why Jonathan has lived so long or point to a proven treatment for people.

The researchers compared Jonathan’s epigenome — chemical controls that help regulate gene activity — with those of younger Aldabra giant tortoises of the same species. They reported that controls associated with DNA repair and metabolism remained similar to those in the younger animals, despite Jonathan’s estimated age. That comparison is the central new finding: it describes an observed pattern, not a demonstrated cause of his longevity.

What researchers found in Jonathan’s genes

According to the research account published by Phys.org and provided by the University of Cambridge, the team identified 287 distinctive gene variants in Jonathan. The researchers linked those variants to processes including DNA repair, inflammation, insulin regulation and cancer suppression. Genetic variants can suggest biological pathways worth examining, but their presence alone cannot show how much they contributed to one animal’s lifespan.

Study co-author Justin Gerlach of the University of Cambridge said the regulators involved in energy production and DNA repair had remained stable in Jonathan over almost two centuries. Vanderbilt Health scientists helped sequence DNA taken from inside Jonathan’s cheek, Axios reported. Its account described signs of unusually orderly controls on cellular energy production, adding a separately reported detail to the account of the new work.

How the study builds on earlier tortoise research

The search for explanations of giant tortoises’ long lives predates the work on Jonathan. A peer-reviewed study published in 2018 compared the genomes of Lonesome George, the last Pinta Island tortoise, and an Aldabra giant tortoise with those of related species. Its authors identified candidate variants in genes associated with DNA repair, inflammation and cancer-related processes. They described their analysis as a preliminary account of pathways that might help explain giant tortoise traits, including longevity.

That earlier study named changes in NEIL1, RMI2 and XRCC6 among candidates associated with maintaining the genome. Its authors called for further work to assess proposed cancer-related mechanisms. In laboratory cell experiments, increasing the expression of NEIL1 and RMI2 was associated with lower measures of DNA damage after oxidative stress or ultraviolet light exposure. Those cell results did not test whether either change extends a tortoise’s life, and they did not establish an effect on human aging.

The new study shifts attention from candidate variants alone to the state of gene controls in an exceptionally old living animal. Comparing Jonathan with younger tortoises can reveal a striking difference from the patterns researchers usually associate with aging. It still cannot, by itself, establish whether those controls helped keep him alive or reflect some other aspect of his biology. The earlier genome work and the new epigenetic comparison therefore identify related research questions, rather than a settled explanation.

What the findings mean for human longevity research

The study was led by researchers at Kallel, a nonprofit focused on longevity research, and its founder Stephen Clark is the senior author. Clark has said the group wants to translate insights from Jonathan into treatments for people. That is an ambition attached to the research, not a result of the tortoise study: the reported genetic patterns do not show that a drug can reproduce them or extend healthy human life.

Axios reported that Clark hopes to fund further research and may test generic drugs that have shown promise in animal studies. In a statement conveyed through Vanderbilt, he said clinical trials could start next year if sufficient funding became available. No trial launch or benefit for people is established by that conditional timetable. Axios also cautioned that determining whether this work could lead to interventions that extend healthy human life will take a long time.

For now, the established development is a comparison involving one famously old tortoise and younger members of his species, alongside a list of genetic candidates. Jonathan’s estimated age, the limits of association-based findings and the gap between animal biology and human treatment leave the practical implications open. Further research would need to test which mechanisms matter and whether any of them can be changed safely and usefully in people.