DNA changes in polar bears linked to warming temperatures

This story, originally published by the Guardian and reproduced here as part of the Climate Desk collaboration, reports on a study showing a statistically significant link between rising temperatures and changes in polar bear DNA. Researchers found that in southeast Greenland, where temperatures are warmer and more variable, polar bears exhibit unusually high activity of 'jumping genes'—mobile DNA sequences that can influence how other genes work.

Researchers from the University of East Anglia analyzed blood samples from polar bears in two Greenland regions and compared the activity of jumping genes to local climate data. Lead researcher Alice Godden said, "DNA is the instruction book inside every cell, guiding how an organism grows and develops," and noted that rising temperatures appear to drive a dramatic increase in the activity of jumping genes in the southeast Greenland bears.

DNA sequences in animals change over time, but environmental stress such as rapid climate warming can accelerate the process. In this study, the team found that southeast bears—which experience warmer, less icy conditions and greater temperature swings—show more of these genetic changes than their northern counterparts. They identified several genetic hotspots where jumping genes were highly active, including regions that code for proteins involved in metabolism and fat processing.

The researchers also observed dietary differences that may be linked to genetic shifts. Bears in the warmer region rely more on plant-based foods, while northern bears maintain a traditionally fatty, seal-based diet. The data suggest the southeast population is adapting to a changing habitat and prey base through rapid genetic changes that affect how they process energy and respond to heat stress.

Co-author Godden said the findings could help explain how polar bears might survive in a warming world, identify populations at greatest risk, and guide future conservation efforts. "We identified several genetic hotspots where these jumping genes were highly active, with some located in the protein-coding regions of the genome, suggesting that the bears are undergoing rapid, fundamental genetic changes as they adapt to their disappearing sea ice habitat," she said.

Scientists stress that the work does not imply polar bears are safe. The study represents an initial step in understanding adaptation, and researchers plan to study the other approximately 20 populations around the world to see if similar changes are occurring. The researchers emphasized that reducing global carbon emissions remains essential to slowing temperature rise and protecting polar bear habitat.

Two-thirds of polar bears are expected to disappear by 2050 as sea ice continues to melt, underscoring the urgency of conservation. The new genetic findings offer a possible glimpse of resilience but do not alter the looming threat posed by climate change.

Further work will examine whether these jumping-gene changes translate into survival advantages in the wild, and how quickly such genetic shifts can occur across populations. The team says the evidence so far points to rapid rewriting of DNA in response to environmental stress, a potential mechanism for short-term adaptation in a species already stressed by habitat loss.