Polar bears can live in cold Arctic regions. Because they mainly eat seals. In humans, such a fat diet can cause heart attacks sooner or later, but due to appropriate mutations, it can tolerate heart attacks perfectly.
One of the authors of the study, Rasmus of the University of California, Berkeley, USA).
One of the adaptations to this environment is based on the diet of oily seals. Fat can account for up to half of polar bears’ body weight, and their cholesterol levels are so high that similar amounts in humans can cause cardiovascular disease.
Scientists do not yet know how bear creatures deal with the risk of heart disease. In order to better understand the evolutionary process of this adaptation in cold and desolate environments, scientists first wanted to determine when the polar bear might appear as a separate species.
To answer this question, Nielsen collaborated with Eske Willerslev from the University of Copenhagen (Denmark) and Jun Jun from Shenzhen BGI Institute of Genetics (China). Together, they checked the genetic sequence and analyzed the complete genomes of 79 Greenland polar bears and 10 brown bears from different parts of the earth. As they said, the separation time of the two species does not exceed 500,000. Years ago. Early data from other sources pointed out the upper limit of the event (which should have occurred earlier than five million years ago).
Since then, polar bears have evolved very rapidly due to mutations related to the work of the circulatory system and fatty acid metabolism accumulated in their genes. Both aspects of humans are closely related to heart disease. It is also known that one of these genes (called APOB) plays a role in the transfer of cholesterol from the circulatory system to human cells, thereby reducing the risk of heart disease.
These changes are a strong genetic response of the body to rising fat and dietary cholesterol levels. Thanks to them, bears can now eat a lot of fat instead of in a way that is more prone to cardiovascular disease. (PAP)