Thursday, May 5, 2016
Evolutionary change in humans?
The Tibetans live at altitudes of about 13,000 feet. The higher the altitude, the harder it is to breathe. This is because at an elevation of 13,000 feet, the air has 40% less oxygen compared to what is available at sea level. However, the Tibetans suffer from very little sickness.
To figure this problem out, researchers compared the genomes of the Tibetans and the Han chinese, which happen to be the two majority ethnic groups in China. The biologist found 40 genes that had undergone mutation or evolutionary change that allowed the Tibetans to adapt to the high altitude. The two groups split apart about 3,000 years ago.
If this holds true, this would be the most recently known example of evolutionary change in humans. When lowlanders try to adjust to the high altitudes, their blood thickens which causes the body to overproduce red blood cells. As a result, this causes mountain sickness which leads to lesser fertility.
I personally find this stuff fascinating. Later in the article it mentions that they think that natural selection played a role as more and more offspring were thrown into the population. However, I am in awe of what the human body is capable of. The way that it can heal itself and change in order to survive is taken for granted, I think.