DNA Found in Paw Prints Can Now Be Used to Identify Polar Bears

Given dire forecasts suggesting the potential extinction of polar bears by the century’s close, it becomes imperative for scientists to establish a means of tracking their population to gauge the effectiveness of conservation endeavors in mitigating the impacts of rapidly disappearing habitats.

However, working safely with polar bears (Ursus maritimus) is notoriously challenging due to the harsh Arctic climate and their extensive range, spanning some of the world’s most isolated regions. To monitor them, researchers must sedate the bears and attach tracking devices, a process that is perilous, costly, and invasive. Some scientists have even attempted tracking them from satellites in orbit.

University of Idaho Scientists Introduce Environmental DNA Tracking

In a groundbreaking development in polar bear research, scientists from the University of Idaho (UI) have pioneered the use of environmental DNA, a cutting-edge approach that involves collecting genetic material left in the tracks of these animals. This innovative technique not only enables the researchers to confirm the species (given the unmistakable nature of polar bear footprints) but also provides insights into the animal’s gender. Moreover, if the individual bear is known to scientists, it can be specifically identified using this method.

Jennifer Adams, a researcher from UI, expressed, “To the best of our knowledge, this marks the inaugural instance in which polar bears, or any other species for that matter, have been individually recognized and their genders determined through the collection of environmental DNA from snow.”

As the polar bear moves across the snowy terrain, it leaves behind minuscule fragments of its skin, which get transferred from its paws to the ground. The research team employed trowels to delicately remove a thin layer of snow from these tracks. Subsequently, the collected samples were transported from Alaska to Moscow, Idaho, where the laboratory conducted PCR tests to extract the genetic information.

Shifting from Mitochondrial to Nuclear DNA Unlocks Valuable Data for Polar Bear Conservation

In contrast to mitochondrial DNA (mt-DNA), typically utilized in conservation for species identification, the researchers managed to obtain nuclear DNA (n-DNA). This allowed for the acquisition of more extensive data, including a genetic profile of the individual bear and its gender. Such information is particularly invaluable for researchers as it aids in making predictions related to reproduction and the revitalization of polar bear populations.

However, it’s important to note that this study had a relatively small sample size, consisting of 15 snow samples, including two negative controls and 11 positive samples containing DNA, which exhibited varying levels of quality. Additionally, environmental DNA (e-DNA) is known for its susceptibility to environmental degradation and disturbances.

A Dire Future as the Arctic Ice Continues to Vanish

The World Wide Fund for Nature (WWF) estimates that the Arctic has been losing approximately 13% of its ice cover every decade over the last three decades, with little likelihood of improvement. Given the polar bear’s specific dietary requirements and energy needs, it’s highly improbable that these animals can adapt to a different environment without rapidly succumbing to starvation.

Nevertheless, as long as polar bears continue to traverse snowy and icy landscapes, this paw-print monitoring technique offers scientists a novel, non-invasive, cost-effective, and reasonably safe method to gather information about polar bears without interfering with their natural behavior.

Read the original article on: New Atlas

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