A study led by University of Utah scientists is the first to find a genetic cause for the adaptation, a single DNA base pair change that dates back 8,000 years and demonstrate how it contributes to the Tibetans' ability to live in low oxygen conditions.
Josef Prchal, MD, said that the findings helped them to understand the unique aspects of Tibetan adaptation to high altitudes, and to better understand human evolution.
About 8,000 years ago, the gene EGLN1 changed by a single DNA base pair. Today, a relatively short time later on the scale of human history, 88 percent of Tibetans have the genetic variation, and it was virtually absent from closely related lowland Asians. The findings indicate the genetic variation endows its carriers with an advantage.
In those without the adaptation, low oxygen caused their blood to become thick with oxygen-carrying red blood cells, an attempt to feed starved tissues, which could cause long-term complications such as heart failure. The researchers found that the newly identified genetic variation protected Tibetans by decreasing the over-response to low oxygen.
Prchal further said that the implications of the research extend beyond human evolution. Because oxygen plays a central role in human physiology and disease, a deep understanding of how high altitude adaptations work might lead to novel treatments for various diseases, including cancer.
The study is published online in the journal Nature Genetics.