Scientists have detected changes in polar bear DNA that may help the mammals adapt to increasingly warm environments. This research is thought to be the primary instance where a notable connection has been established between rising heat and changing DNA in a wild mammal species.
Environmental degradation is threatening the future of Arctic bears. Estimates indicate that two-thirds of them may disappear by 2050 as their snowy environment melts and the climate becomes more extreme.
“Genetic material is the guidebook within every cell, instructing how an organism grows and functions,” stated the principal investigator, Dr. Alice Godden. “By comparing these animals’ active genes to local climate data, we discovered that escalating temperatures appear to be fueling a significant surge in the activity of jumping genes within the warmer Greenland region bears’ DNA.”
The team studied blood samples taken from Arctic bears in different areas of Greenland and compared “jumping genes”: small, roving segments of the genome that can affect how other genes operate. The study looked at these genes in relation to climate conditions and the associated shifts in genetic activity.
With environmental conditions and diets change due to changes in habitat and food supply forced by global heating, the DNA of the animals seem to be adapting. The population of bears in the hottest part of the area showed greater genetic shifts than the communities farther north.
“This finding is significant because it demonstrates, for the initial occasion, that a distinct group of polar bears in the hottest part of Greenland are employing ‘jumping genes’ to swiftly rewrite their own DNA, which could be a desperate survival mechanism against disappearing sea ice,” added Godden.
Temperatures in north-east Greenland are colder and more stable, while in the warmer region there is a more temperate and less icy environment, with steep weather swings.
Genetic code in organisms evolve over time, but this evolution can be accelerated by external pressure such as a quickly warming environment.
Scientists observed some interesting DNA changes, such as in sections associated to lipid metabolism, that might help polar bears persist when resources are limited. Animals in temperate zones had a greater proportion of terrestrial food intake compared with the fatty, seal-based nutrition of Arctic bears, and the DNA of these specific animals appeared to be adapting to this new reality.
Godden explained further: “Scientists found several active DNA areas where these mobile elements were very dynamic, with some found in the critical areas of the DNA, implying that the bears are undergoing fast, profound genetic changes as they respond to their disappearing icy environment.”
The next step will be to study other Arctic bear groups, of which there are 20 globally, to determine if similar genetic shifts are taking place to their DNA.
This investigation could assist protect the bears from dying out. However, the researchers noted that it was crucial to halt climate change from increasing by cutting the consumption of carbon-based fuels.
“We must not relax, this presents some hope but is not a sign that polar bears are at any diminished threat of disappearance. It remains crucial to be pursuing everything we can to reduce global carbon emissions and slow temperature increases,” summarized Godden.
