New study finds temperature stress may be causing genetic mutations in polar bears(Sea bear)living in southern Greenland. Global climate change is especially noticeable there, writes Live science.

Salvation in jumping genes

The effects of climate change, such as record low sea ice and rising sea levels, threaten polar bears. These animals depend on ice sheets.

However, a group of polar bears in southern Greenland may have begun to evolve to adapt to these changes. Researchers have established a link between changes in the bears’ DNA and rising temperatures.

Research published in the journal Mobile DNAhas shown for the first time that polar bears in the warmest part of Greenland use “jumping genes” to rewrite their DNA. This may be a survival mechanism in the face of melting sea ice.

Jumping genes, or transposons, are pieces of DNA that can move around the genome. Depending on their position, transposons can affect the functioning of other genes.

In polar bears, than a third of the genome consists of such elements. For comparison, in humans this figure is about 45%, and in plants – up to 70%.

The study authors argue that transposons may help bears adapt to climate change. A previous study published in the journal Science in 2022 described an isolated population of polar bears in southern Greenland that split from the northern population about 200 years ago as being less dependent on sea ice.

Initial adaptation

The researchers analyzed the DNA of 17 bears from Greenland: 12 from the northeastern region and 5 from the southeastern region. They compared transposon activity in these populations with climate data.

Bears from southeast Greenland were found to have changes in genes associated with heat stress, aging and metabolism, as well as fat processing, an important process when food is scarce. This confirms that bears may be slow to adapt to warmer conditions.

“We found that rising temperatures increase the activity of jumping genes in the DNA of bears in southeast Greenland. This means that different groups of bears undergo genetic changes at different rates depending on their habitat and climate,” said lead author Alice Godden, a senior research fellow at the University of England in the UK.

Despite the bears’ ability to adapt to warmer conditions, Godden stressed that climate change remains a real threat to polar bears – the climate is changing very quickly, and the genetic evolution of bears is very slow.