New research published in the academic journal PLOS Genetics, shows how mice living at high altitudes have a high heart rate in order to help them thrive in areas of low oxygen.
Researchers have found that mice living at high altitudes in the American West carry a genetic variant that increases their heart rate. This mechanism allows the mice to cope at high elevations where there are low levels of oxygen.
Rena Schweizer and her colleagues from the University of Montana, investigated the genetic changes in the North America deer mouse to further understand this phenomenon.
The environments of mountains and plateaus make it difficult for mammals to survive due to the cold temperature and low concentrations of oxygen. Researchers have linked the deer mouse’s physiological changes to their ability to cope at such altitudes.
By sequencing samples from 100 mice from several different level of elevation, the researchers were able to identify the Epas1 gene variant. The genetic variant Epas1 is particularly common in deer mice that live at high altitudes rather than the lowland populations.
Deer mice that live higher up have a higher heart rate when exposed to air with a lower oxygen concentration. This high heart rate increases the amount of oxygen circulating in their bloodstream, subsequently allowing them to survive at higher altitudes.
This is the first study to highlight the relationship between naturally occurring variations of the Epas1 and changes to the heart rate. The study also suggests that Epas1 may aid long-term survival of high-altitude deer mice.
The Epas1 gene has also been implicated in respiratory and cardiovascular adaptations in Tibetan humans living on the Qinghai-Tibetan plateau. This becomes evident when their genetics are compared to lowland Han Chinese populations.
“Our study addresses a really important question about how adaptation occurs on complex physiology that is controlled by multiple interacting system,” said author Rena Schweizer.
Schweizer continued:”Epas1 may aid long-term survival of high-altitude deer mice, and is a case by which a relatively simple genetic change in a control gene may alter adaptive traits. Our future work on Epas1 is aimed at exploring the specific mechanisms by which the protein-altering mutation affects heart rate, and whether the mutation affects any other traits that we did not previously measure.”