AsianScientist (May 19, 2014) – Armed with the first sequence of the polar bear genome, scientists have a better understanding of the adaptations that made polar bears successful in the high Arctic; including their high fat diet. This research has been published as the cover story of the journal Cell.
The study compared blood and tissue samples from 79 Greenlandic polar bears and 10 brown bears from Sweden, Finland and Alaska.
“For polar bears, profound obesity is a benign state,” said Dr. Eline Lorenzen, one of the lead authors of the study from the University of California, Berkeley. “We wanted to understand how they are able to cope with that.”
The genomic comparison revealed that natural selection drove major changes in genes related to fat transport in the blood and fatty acid metabolism. One of the most strongly selected genes is APOB, which in mammals encodes the main protein in LDL (low density lipoprotein), known widely as “bad” cholesterol.
The increase of APOB and other genes may explain the polar bear’s ability to cope with a high-fat diet while avoiding cardiovascular diseases and fatty plaques in their arteries. These genes may provide insight into how to protect humans from the ill effects of a high-fat diet.
“The evolutionary history of the polar bear demonstrates how quickly an organism can adapt to the evolutionary challenges”, said Wang Jun, executive director of the Beijing Genomics Institute. “With genomic data released for more species, we hope to reveal a more complete picture of how animals adapt to environment and how biodiversity forms”.
The article can be found at: Liu et al. (2014) Population Genomics Reveal Recent Speciation and Rapid Evolutionary Adaptation in Polar Bears.
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Source: Beijing Genomics Institute; Photo: Emran Kassim/Flickr/CC.
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