Polar Bears Are Adapting Their Genetics to Thrive in a Warming Climate

As climate change continues to undermine the icy habitats crucial for polar bear survival, new studies indicate that these bears are swiftly altering their genetic makeup to adapt.

This species is being compelled to cope with the increasingly harsh conditions of a warming Arctic, marking what scientists believe to be the first documented instance of rising temperatures prompting genetic adaptations in a mammal.

Research conducted by the University of East Anglia in the UK revealed findings: published in Friday’s issue of the journal Mobile DNA, which offers a rare glimmer of hope for these animals.

“Polar bears are sadly projected to face extinction this century, with two-thirds of their population potentially gone by 2050,” Alice Godden, the study’s lead author, shared with NBC News.

“We believe our findings genuinely provide a flicker of hope: a chance to reduce carbon emissions, mitigate climate change, and allow bears more time to adapt to significant changes in their habitats.”

Building on previous research from the University of Washington, Godden’s team studied blood samples from polar bears in northeastern and southeastern Greenland. In the comparatively warmer southern region, genes associated with heat stress, aging, and metabolism showed different behavior compared to those in the north.

“Essentially, this indicates that various groups of bears are modifying different segments of their DNA at varying rates, with this activity seemingly linked to their specific environmental and climatic contexts,” Godden mentioned in a university press release.

He remarked that this is the first indication that a distinct population of a species has been driven to “rewrite its own DNA,” suggesting this process is a “desperate survival mechanism” against disappearing sea ice.

The Arctic Ocean has consistently recorded unusually high temperatures in recent years, as reported by the National Oceanic and Atmospheric Administration (NOAA). Monitoring data suggests.

Researchers assert that rising ocean temperatures are diminishing the vital sea ice foundation that bears rely on for hunting seals, leading to isolation and food shortages.

Godden explained to NBC News that the genetic changes emerged as the bears’ digestive systems adapted to food scarcity, including a lack of prey, plant life, and low-fat diets.

“Access to food poses a critical challenge for these bears everywhere, particularly in the South,” she notes. “This may indicate that their physical structure and composition are also evolving in response to warmer surroundings.”

The lead researcher stated that her team targeted the southern bear group as the region’s warmer climate provides insights into what other bear populations may experience later this century if current climate trends persist.

The International Union for Conservation of Nature estimates around 26,000 polar bears currently exist globally. Known scientifically as Ursus maritimus, or “sea bear,” these animals are classified as Vulnerable on the IUCN Red List of Threatened Species, believed to be at “high risk of extinction in the wild.”

The research “doesn’t imply that polar bears are at a reduced risk of extinction,” Godden stated. However, she added this finding “could provide a genetic framework for how polar bears may swiftly adapt to climate change.”

Godden further urged, “We all need to take action to reduce our carbon footprint and create opportunities to protect and expand this incredible and vital species.”

Source: www.nbcnews.com

Ash Trees Are Adapting Quickly and Showing Some Resistance to Ash Blight

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Certain ash trees exhibit genetic variations that offer partial resistance to ash dieback

FLPA/Alamy

British ash trees are evolving resistant traits to combat ash dieback, evident from DNA sequences found in numerous specimens.

This discovery is promising, according to Richard Buggs at the Royal Botanic Gardens in Kew, England, although complete resistance in ash trees is not anticipated soon. “A breeding program may be necessary to assist nature in this process,” he states.

Ash dieback, caused by the fungus Hymenoscyphus fraxineus, progressively impairs the tree’s capacity to transport water. It began its spread across Europe in the 1990s and made its way to the UK in 2012.

The demise of ash trees leads to increased carbon dioxide release and threatens various species that depend on these trees for their ecosystem. Additionally, fallen trees pose risks to people and property. “There are numerous ash trees close to footpaths and roads, creating significant hazards,” Buggs notes.

Buggs’ team compared genomes of 128 adult European ash trees. Since fungi take considerably longer to kill mature trees than younger ones (Fraxinus excelsior), this also included 458 seedlings at a location called Marden Park in Surrey. They discovered thousands of variations previously linked to resistance were more prevalent in younger trees, likely because those without such variations perished.

This study provides the most comprehensive genetic insight into evolutionary responses observed in nature. “The significance of this research is its ability to characterize the genetic foundation and demonstrate the changes occurring within a single generation,” Buggs explains.

However, each gene variant offers only a marginal effect, failing to provide complete resistance. As the older ash trees diminish and fungal spores decrease, the rate of evolutionary change may also slow in the future. This indicates that younger ash trees might have better survival prospects, Buggs suggests.

“It poses a major challenge, but these trees won’t vanish entirely,” he remarks. “Our findings inspire hope that some of these younger ash trees may mature and undergo natural selection for subsequent generations, if feasible.”

Ash dieback has yet to invade North America; however, the emerald ash borer (Agrilus planipennis) has been introduced, actively decimating ash tree populations there. The outcome of both ash dieback and the emerald ash borer coexisting in the same region remains uncertain but might exacerbate the issue.

“Globalization is mixing insects and pathogens across the globe, leading to increasing challenges for these trees, and it is becoming increasingly difficult for them to adapt,” Buggs states. “Trees now face threats they have never experienced before, and at unprecedented speeds.”

He believes interventions are essential to help trees withstand these pressures, such as creating resistant hybrids between resilient species and native trees.

“One potential solution is to enhance the genetic diversity of trees globally, keeping pace with the array of pests and pathogens we are spreading,” he concludes.

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Source: www.newscientist.com