Researchers have identified alterations in Arctic bear DNA that could help the animals adjust to warmer climates. This study is believed to be the primary instance where a notable connection has been found between increasing heat and evolving DNA in a wild animal species.
Global warming is imperiling the future of polar bears. Estimates show that two-thirds of them might vanish by 2050 as their snowy habitat disappears and the weather becomes hotter.
“DNA is the instruction book inside every cell, guiding how an organism grows and functions,” stated the principal investigator, Dr. Alice Godden. “Through analyzing these animals’ expressed genes to area temperature records, we discovered that rising temperatures seem to be causing a significant increase in the activity of mobile genetic elements within the specific area bears’ DNA.”
Scientists examined tissue samples taken from Arctic bears in two regions of Greenland and contrasted “mobile genetic elements”: compact, mobile sections of the DNA sequence that can influence how various genes operate. The analysis examined these genes in connection to climate conditions and the associated shifts in genetic activity.
With environmental conditions and nutrition evolve due to changes in environment and food supply driven by warming, the genetics of the animals appear to be adjusting. The group of polar bears in the warmest part of the area exhibited more modifications than the populations farther north.
“This result is crucial because it demonstrates, for the first time, that a unique group of polar bears in the hottest part of Greenland are using ‘mobile genetic elements’ to quickly alter their own DNA, which might be a critical adaptive strategy against melting Arctic ice,” added Godden.
Temperatures in north-east Greenland are less variable and less variable, while in the south-east there is a more temperate and less icy habitat, with significant temperature fluctuations.
DNA sequences in animals change over time, but this process can be hastened by climate pressure such as a rapidly heating environment.
The study noted some interesting DNA changes, such as in areas associated to lipid metabolism, that may assist polar bears cope when resources are limited. Bears in hotter areas had more terrestrial diets versus the lipid-rich, marine nutrition of northern bears, and the DNA of these specific animals seemed to be evolving to this new reality.
Godden stated: “The research pinpointed several active DNA areas where these mobile elements were particularly busy, with some situated in the functional gene sections of the genome, indicating that the bears are experiencing swift, significant genetic changes as they adapt to their disappearing icy environment.”
The subsequent phase will be to examine other subspecies, of which there are numerous globally, to determine if similar modifications are occurring to their DNA.
This study could help conserve the animals from extinction. However, the experts emphasized that it was vital to slow temperature rises from accelerating by reducing the use of fossil fuels.
“Caution is still required, this presents some hope but does not imply that polar bears are at any reduced danger of extinction. We still need to be doing every action we can to lower pollution and mitigate temperature increases,” summarized Godden.
