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1 .This is Scientific American 60-Second Science. I'm Karen Hopkin. This'll just take a minute.
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2 .A triple bacon cheeseburger seems like a heart attack on a plate.
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3 .So how can polar bears thrive on their version, seal blubber?
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4 .Turns out they've stocked up on genes that let them clear fats from their blood.
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5 .That's according to a study in the journal Cell.
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6 .Polar bears are well adapted to life on the sea ice.
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7 .Up to half their body weight's fat, which gives them extra insulation and buoyancy, and provides them with a ready source of energy.
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8 .But how can an animal so fat also be so fit?
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9 .Researchers compared the genomes of polar bears with those of brown bears, and found that polar bears have accumulated genetic changes that boost their heart health and fat metabolism.
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10 .One gene in particular, called ApoB, helps move cholesterol out of the blood, where it causes problems in humans and into cells.
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11 .These genomic changes happened quickly, evolutionarily speaking.
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12 .Polar bears and brown bears diverged from a common ancestor less than half a million years ago.
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13 .But if that seems super speedy, the ability to digest lactose didn't spread through human populations until we domesticated cows, just 10,000 years ago.
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14 .A moving testament to the power of natural selection.
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15 .Thanks for the minute, for Scientific American 60-Second Science. I'm Karen Hopkin.
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