Polar bear genome reveals rapid adaptation to fatty diet
"In this limited amount of time, polar bears became uniquely adapted to the extremities of life out on
Up to half of the body weight of polar bears consists of fat, and their blood cholesterol levels are high enough to cause cardiovascular disease in humans. But it has been a mystery how polar bears are able to cope with these major risk factors for heart disease. To understand the evolutionary processes driving such adaptations to extreme environments, it's essential to first establish a reliable time frame for when polar bears emerged as a species.
To address these questions, Nielsen teamed up with Eske Willerslev of the
Since then, polar bears evolved rapidly by accumulating mutations in genes that are involved in cardiovascular function and fatty acid metabolism and have been linked to heart disease in humans. One such gene, called APOB, is known to play a role in moving cholesterol from the bloodstream into cells, thus reducing the risk of heart disease. "Such a drastic genetic response to chronically elevated levels of fat and cholesterol in the diet has not previously been reported," Willerslev says. "It certainly encourages a move beyond the standard model organisms in our search for the underlying genetic causes of human cardiovascular diseases."
Keywords for this news article include: Cardiology,
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