Polar bears are 'rewriting their DNA' to survive warming Arctic, study suggests
The world’s polar bear population is projected to decline by two-thirds by 2050.
A new study from the University of East Anglia suggests that polar bears are undergoing rapid genetic changes, and scientists believe it's due to the impacts of climate change.
“It’s kind of the first time that we believe we’ve seen a mammal system such as the polar bear, where temperature has been the lead cause, and environmental stress at increased temperature, is impacting their DNA, their genome in real time,” Alice Godden, the lead author of the study, told ABC News.
Researchers say the discovery of these genetic changes offers a glimmer of hope for the bears' survival, as two-thirds of the world’s population could perish by 2050.
“This unique group of polar bears is essentially rewriting parts of its own genome to survive,” Godden said in a press release. She calls the breakthrough “a desperate survival mechanism against melting sea ice.”
The researchers found that polar bears in southeastern Greenland, the warmest part of their range, are showing rapid genetic changes linked to rising temperatures.
The scientists analyzed data from an earlier University of Washington study that collected blood samples from polar bears across northern and southern Greenland. The experiment found that the southeastern polar bears of Greenland have diverged genetically from their northeastern counterparts, who live in a colder part of the region and were separated from each other roughly 200 years ago.
Godden and her team took this previous discovery a step further by analyzing data collected from 17 polar bears to investigate how those genetic changes could be linked to the warming temperature and environmental changes.
“That’s what was really novel about our work,” Godden said. “We factored in the temperature and climate in our analysis to then give us a broad answer to how temperature might be driving changes in the genome.”
By studying “jumping genes,” DNA sequences that can move to different locations within a genome, potentially altering gene function, scientists found that the bears in southeastern Greenland are responding to their changing environment by incorporating more plants into their historically fatty diet.
“Normally, a polar bear would hunt seals and have quite a high fat diet, but there’s a huge change in that they’re eating more plant-based diets,” Godden said. “We’re seeing those changes in the genome that are signifying potentially that they’re adapting to that.”
The U.S. Fish and Wildlife Service currently lists polar bears as endangered, with approximately 26,000 remaining on the planet. Given their endangered status, Godden says the key message she hopes to send is that this "positive adaptation" can only go so far.
“This is a hopeful study, but it offers a small window of opportunity for us to understand the genomes of these polar bears in more detail,” Godden said. “We all need to continue to reduce our carbon emissions as well to help support, potentially, the survival of this species.”