Scientists studying Jonathan, a giant tortoise estimated to be 194 years old, have found genetic clues to his exceptional longevity. The study, published on October 7 in Science Advances, links his remarkable age to unusually stable regulation of some genes, according to Vanderbilt Health and the University of Cambridge.
Jonathan lives at Plantation House on Saint Helena in the South Atlantic. Cambridge says the Aldabra giant tortoise arrived from the Seychelles in 1882, already fully grown. His estimated birth year is 1832; the researchers describe him as the world's oldest known living land animal.
The team identified 287 distinctive genetic variants associated with processes including DNA repair, inflammation, insulin regulation and cancer suppression, Cambridge reported. They also compared his epigenome, the chemical markings that regulate gene activity without changing the DNA sequence, with those of younger tortoises of the same species.
Some regulatory patterns looked strikingly youthful. Vanderbilt said promoters controlling genes involved in mitochondrial function and RNA processing showed low methylation entropy, meaning relatively little disorder in their chemical markings. Mitochondria supply cellular energy, making their maintenance a possible lead for understanding how organisms resist age-related decline.
The analysis used tissue collected from inside Jonathan's cheek after a request for a blood sample was refused over concerns for his health, Vanderbilt reported. The findings offer an association rather than proof that these patterns caused his long life. They do not demonstrate that changing similar patterns in humans would safely extend lifespan.
Senior author Stephen Clark of the nonprofit Kallel Foundation said further studies using blood would be needed to validate the findings, according to Vanderbilt. The foundation also plans to study other long-lived species and aging pathways. For now, Jonathan offers a starting point for research into cellular resilience, rather than an established treatment for human aging.
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