A comparison of the genomes of polar bears and brown bears reveals that the polar bear is a much younger species than previously believed, having diverged from brown bears less than 500,000 years ago. The analysis also uncovered several genes that may be involved in the polar bears’ extreme adaptations to life in the high Arctic. The species lives much of its life on sea ice, where it subsists on a blubber-rich diet of primarily marine mammals.

Polar bears occassionally have to go without food for a long time. But when they do, they will feed until they are exhausted.
Polar bears occassionally have to go without food for a long time. But when they do, they will feed until they are exhausted.

The genes pinpointed by the study are related to fatty acid metabolism and cardiovascular function, and may explain the bear’s ability to cope with a high-fat diet while avoiding fatty plaques in their arteries and the cardiovascular diseases that afflict humans with diets rich in fat. These genes may provide insight into how to protect humans from the ill effects of a high-fat diet. The study was a collaboration between Danish researchers, led by Eske Willerslev and including Rune Dietz, Christian Sonne and Erik W. Born, who provided polar bear blood and tissue samples; and researchers at BGI in China, including Shiping Liu, Guojie Zhang and Jun Wang, who sequenced the genomes and analyzed the data together with a team of UC Berkeley researchers, including Eline Lorenzen, Matteo Fumagalli and Rasmus Nielsen. Nielsen is a UC Berkeley professor of integrative biology and of statistics.

While the older, bigger bear is resting, the younger one gets the opportunity to feed on the remains of the hunted seal.
While the older, bigger bear is resting, the younger one gets the opportunity to feed on the remains of the hunted seal.

Quelle: The Arctic Journal,  http://arcticjournal.com