In the dark, freezing depths of the North Atlantic, a creature glides through the water at barely a meter per hour—a Greenland shark that could still be alive when your great-great-grandchildren are born. Scientists have now mapped 96.7% of this remarkable animal's genome, revealing the genetic secrets behind what may be nature's most extreme feat of longevity: a lifespan approaching 400 years.
Greenland sharks, known scientifically as Somniosus microcephalus, are native to the icy waters around Greenland, Canada, and Iceland. They grow at a glacial pace of just one centimeter per year and take around 150 years to reach sexual maturity. Until now, little has been known about how these deep-sea predators manage to live so extraordinarily long. But research published in the Proceedings of the National Academy of Sciences by Shigeharu Kinoshita at the University of Tokyo and an international team is beginning to change that.
The researchers successfully assembled around 5.9 billion DNA base pairs—nearly the entire shark's genetic blueprint. In doing so, they uncovered several striking genetic features that appear to shield the shark from the cellular damage that drives aging in most animals. One of the most significant is a series of amino acid substitutions in the histone H1.0 protein, which organizes DNA into a structured package called chromatin. The shark's version of this protein has changes predicted to affect chromatin stability in ways that help prevent the genetic wear and tear that normally contributes to aging.
Even more intriguing is an enormous expansion of the FTH1b gene on pseudochromosome 33. The Greenland shark carries 59 copies of this gene—far more than other sharks and related fish species. These genes control iron storage and ferroptosis, a form of programmed cell death that manages cellular stress. With so many copies, the shark appears to have an enhanced capacity to protect its tissues from oxidative damage, one of the primary drivers of aging.
The genome also reveals expansions in gene families linked to immune function, cancer resistance, and DNA repair—a genetic toolkit that seems to help the shark resist the diseases and deterioration that plague other animals over time. "Our analyses reveal potential mechanisms that may enable this species to exceed conventional lifespan limits," the study authors wrote.
The implications extend far beyond understanding one unusual shark. These genetic insights could eventually help scientists develop new treatments for cancer and age-related diseases in humans. Though this study examined the genome of a single shark rather than a broader population, the researchers emphasize that it opens significant possibilities. "This genomic resource provides a foundation for evolutionary studies of cartilaginous fish and advances our understanding of longevity and aging," they note.
The Greenland shark's genome is now a window into biological aging itself—a living record of how evolution can engineer a body to resist time in ways we are only beginning to understand. As researchers continue to study these genetic blueprints, they may unlock answers that could transform how we approach human health and lifespan.