Researchers at the University of East Anglia report genetic changes in polar bears that suggest the animals may be responding, in near real time, to a warming Arctic. The study focuses on small, mobile DNA elements often called “jumping genes” (transposable elements) that can modify how other genes are expressed.
Study Overview
Polar bears depend on sea ice to hunt seals, and the rapid decline of that ice due to climate change threatens the species’ survival. Scientists have warned that up to two-thirds of the global polar bear population could be lost by 2050 if warming continues.
To better understand whether bears are genetically responding to changing conditions, researchers analyzed blood samples from animals in two distinct regions of Greenland. They compared patterns of jumping genes and measured gene expression, then related those genomic patterns to regional temperature differences.
Key Findings
The team found a statistically significant association between rising temperatures and shifts in the bears’ genomes — the first such link reported for wild mammals. Bears from the warmer, more temperature-variable southern region of Greenland showed more genomic changes than bears from the colder, more stable northern region.
Some of the DNA changes were located near genes involved in fat processing and metabolism, which could help animals cope when high-fat prey is less available. The authors suggest these shifts may reflect dietary differences: bears in warmer areas appear to consume a tougher, more plant-rich diet compared with northern bears that rely more heavily on fatty seal meat.
What It Means — And What It Doesn’t
The findings offer cautious hope that polar bears may be exhibiting rapid genetic responses to environmental stressors. However, the researchers and independent experts note important caveats: natural genetic change does not guarantee long-term survival, and evolutionary responses may not keep pace with the speed and scale of climate-driven habitat loss.
Next steps include examining other polar bear populations worldwide to see whether similar DNA changes are occurring elsewhere and to better understand the functional effects of the detected shifts.
Conservation Context
While the study could inform conservation strategies, scientists emphasize that reducing greenhouse gas emissions and protecting critical sea ice habitat remain essential to prevent wide-scale population declines.
"Genomic shifts are a sign of biological response, not a substitute for policy action to halt warming and preserve habitat," researchers caution.
