Here’s what you’ll learn when you read this story:

• Polar bears are particularly vulnerable to climate change, as they rely on sea ice to hunt seals.
• A new study analyzed a small subpopulation of polar bears in southeastern Greenland and found small genetic changes, likely in response to environmental stressors.
• This DNA blueprint could help scientists save polar bear populations in other parts of the world.

Around 500,000 years ago (at least, by recent estimates), a subpopulation of the brown bear migrated northward, adapting to the frigid Arctic. At the time, this looked like a good bet—the Earth was experiencing a glacial period, so developing strategies and defenses for hunting in such an environment made a lot of sense. Fast-forward half a million years, and that long-ago bet is looking a bit risky, as the polar regions of the world warm four times faster than other parts of the world due in large part to the albedo effect.

Because today’s polar bears rely on sea ice for hunting, the alarmingly quick disappearance of that ice has scientists worried that the bears may be unable to adapt to climate change and drastic changes in the environment. However, it appears that a small subpopulation of polar bears in southeastern Greenland may have a 200-year start on developing advantageous genetic changes for survival in this shifting landscape.

According to a new study published in the journal Mobile DNA, scientists from the University of East Anglia in the U.K. expanded on previous research (from the University of Washington in 2022) that focused on this unique polar bear population, which separated from northern polar bears some 200 years ago. By comparing blood samples from polar bears in the southeast and northeast of Greenland (where it’s much colder), and comparing that data with climate analyses of the two regions, scientists discerned that the more southerly polar bears’ genes relating to heat-stress, aging, and metabolism behaved differently. This suggested that these bears are adapting to their warmer climate.

“Additionally, we found active jumping genes in parts of the genome that are involved in areas tied to fat processing—important when food is scarce,” Alice Godden, a co-author of the paper from University of East Anglia, wrote in an article for The Conversation. “This could mean that polar bears in the south-east are slowly adapting to eating the rougher plant-based diets that can be found in the warmer regions.”

The analysis revealed that these changes occurred via transposons (TE), also known as “jumping genes,” which are mobile pieces of a gene that can move around to influence how other genes work. According to Gooden, 38.1 percent of a polar bear’s genome is made up of these TEs (compared to a human genome’s 45 percent). Typically, protective molecules known as piwi-interacting RNAs (piRNAs) can silence the activity of TEs, but under situations of immense environmental stress—such as climate change—“piRNAs cannot keep up with the invasive actions of TEs,” Gooden said.

Although they occupy the same landmass, the polar bear populations in the northeast and southeast Greenland exist in two very different ecosystems. While the former is a flat arctic tundra where polar bears rely on the fatty tissue of seals to survive, the latter ecosystem is a forest tundra, representing the transitional zone between coniferous forests and tundra. Because this population initially separated two centuries ago—decades before the first oil well was ever drilled—they currently serve as a genetic blueprint for how the rest of the polar bear species could be conserved.

“As the rest of the species faces extinction, these specific bears provide a genetic blueprint for how polar bears might be able to adapt quickly to climate change, making their unique genetic code a vital focus for conservation efforts,” Gooden said in a press statement. “However, we cannot be complacent, this offers some hope but does not mean that polar bears are at any less risk of extinction. We still need to be doing everything we can to reduce global carbon emissions and slow temperature increases.”

Darren lives in Portland, has a cat, and writes/edits about sci-fi and how our world works. You can find his previous stuff at Gizmodo and Paste if you look hard enough.