Scientists on an Arctic expedition have isolated polar bear DNA from frozen skin cells left behind in tracks in the snow—a breakthrough that could help protect vulnerable wildlife on every continent.
In rapidly changing environments like the Arctic, it’s particularly crucial for conservation efforts to stay up to date with information on wildlife health and population size. “At present, researchers use expensive, invasive techniques,” says Arnaud Lyet of WWF in a news release. “Using footprint DNA, we could dramatically cut the investment required, so monitoring populations could be done more easily.”
After collecting the snow around 10 giant pawprints, researchers melted it down and used filters to identify genetic material from the cells left in the meltwater. Then they amplified the DNA. “This is the first time we have been able to extract DNA from a track left by a polar bear,” says Eva Bellemain of French DNA-analysis firm SPYGEN. “We found not only the bear’s DNA, but also that of a seal and a seagull.”
Combined with observations by the WWF International team, the scientists puzzled together a likely scenario that took place on the Norwegian archipelago of Svalbard: A female polar bear had just killed a seal when a seagull arrived at the kill site (probably to get in on the meal). The bear left some blood from the butchery in her footprints, and the gull defecated at the site. “So this one footprint tells the whole story,” Bellemain adds.
The team is working on refining their analysis of the footprint DNA in order to extract more information about the animal, and they’re looking for molecular markers that will allow them to identify individual bears. “We will be able to see how they use their territories and how they are related to one another,” Bellemain tells The Guardian. Just a single cell would be enough.
They’re also hoping to see if the method can be extended to other rare or difficult to access wildlife—perhaps to include mud prints as well. After all, "animal tracks are what we find most often in the wild," Lyet tells Reuters. Although, DNA breaks down far more slowly in the cold than in the tropics.
Images: Tom Arnbom/WWF-Canon (top), Steve Morello/WWF-Canon (middle)
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