Jonathan, a giant Aldabra tortoise residing on the island of Saint Helena in the South Atlantic, is believed to be 194 years old, making him the oldest known living land animal. Born during the early 19th century, when figures like Charles Darwin were young and Queen Victoria was a teenager, Jonathan has lived through significant historical periods and offers researchers a unique opportunity to study longevity.
A recent international study, led by the American non-profit Kallel Foundation and published in the journal *Science Advances*, analyzed Jonathan’s genetic material to uncover the biological factors contributing to his remarkable lifespan. Scientists identified 287 genetic features associated with enhanced DNA repair, regulation of metabolism, inflammation control, and cancer resistance. These genetic variants are involved in multiple biological pathways known to influence ageing.
Beyond the genetic code itself, the researchers examined chemical modifications to Jonathan’s DNA known as methylation—the attachment of methyl groups that can silence gene activity and typically change with age. Remarkably, the patterns of these chemical tags, which shape the epigenome and influence gene expression, appeared notably stable in Jonathan, especially in genes related to mitochondrial function and energy production. Mitochondria, the cellular “powerhouses,” play a critical role in ageing and age-associated diseases, and maintaining their function is considered essential for longevity.
Dr. Stephen Clark, a senior researcher on the project, highlighted the importance of these findings, noting that Jonathan’s mitochondria seem especially well-preserved—a feature that may contribute to his lengthy lifespan. “His mitochondria must be especially stable, and that’s an insight into longevity in general,” Clark said. The research team is currently exploring ways to validate these observations and consider whether similar mechanisms might be harnessed to extend healthy life in humans.
Jonathan’s condition has not always been robust. In 2009, Joe Hollis, former senior veterinary officer of Saint Helena, took over his care when the tortoise was blind and struggling to eat. Through attentive care, Jonathan regained weight and vitality. More recently, in April, a false report circulated on social media claiming Jonathan had died; however, the governor of Saint Helena confirmed the tortoise was alive and well.
The study underscores the potential of leveraging evolutionary insights from long-lived species to better understand ageing and develop medical interventions. Researchers note that ageing remains the leading risk factor for most chronic diseases. Dr. Justin Gerlach, a zoologist affiliated with Peterhouse, Cambridge, commented on the findings, stating that gene regulators involved in energy production and DNA repair have remained remarkably stable in Jonathan over nearly two centuries.
While the precise influence of these genetic and epigenetic factors on Jonathan’s extraordinary lifespan is still being investigated, the research offers promising avenues for future studies aimed at promoting longevity and combating age-related diseases in humans.