A Quechua man looks out over the Andes mountains.
Galen Rowell / Getty Images
By Freda Kreer
Human evolution is at work in the Andes mountains. Indigenous peoples of Quechua, Peru, who have lived at altitudes above 2500 meters for at least the last 11,000 years, have developed genetic adaptations to sustain their harsh environment. New studies show that these extreme conditions can alter the chemical changes that control the activity of DNA. These “epigenetic” changes are the first evidence that not only the genes that grow in the mountains, but how the body can use them.
Scientists have long thought that environmental stress, like low stress oxygen concentrations, could shape gene activity in highland populations, says Cynthia Bell, an anthropologist at Case Western Reserve University who studies altitude adaptation in Tibet. This “pioneering” research shows that it is not only possible that M was not involved in the study, but may have involved ep epigenetic changes.
Your environment can cause chemical changes in your DNA that turn genes on or off or increase or decrease the activity of certain genes. The strategy allows people to adapt to the area around them faster than pure heredity. Yet, it is not clear what role epigenetics plays in adapting life to ep.
So in a new study, a team of international researchers from Peru, Germany and the United States focused on an epigenetic process called methylation, in which cells attach chemical TGs to DNA called methyl groups. The team studied three groups: Quechua born and raised above 3000 meters, Quechua born at an altitude, went to the bottom of the sea when they were young, and Quechua whose families went to sea before their birth.
Data revealed significant differences in methylation patterns across groups, the team reported last month. Genome Biology and Evolution. The genes involved in making red blood cells and building endurance muscle were more methylated in Quechua who spent more time at most altitudes, regardless of whether they went lower in later life. These epigenetic changes were probably cemented into Quechua DNA because they were exposed to low levels of oxygen before birth and during childhood.
But other methylated regions, including a gene involved in the breakdown of sugar, were specific to the group born and raised at elev altitude, the team found. This suggests that such changes occur only when the quetia is constantly exposed to high altitudes.
Scientists have not been able to determine whether any epigenetic changes they have observed have altered the activity of genes. But they found that many of the changes were reversible, meaning that DNA methylation in Quechua stabilized at lower altitudes, so adults continued to behave at higher altitudes.
“I think it’s so exciting that we didn’t find anything,” says Anash Childebayeva, a postdoctoral researcher at the Max Planck Institute for Human History. That said, the findings further support the idea that humans can evolve in challenging situations faster than previously thought.
Childabayeva hopes her work will inspire others in Highlanders around the world to investigate these questions. A scientist, at least, is considering that. “I want to talk to the person who is analyzing my DNA and see if we should pay attention to methylation,” says Bell.
