One of the panels I’ve given at several conventions this year has been “Where did the first Americans Come From?” In that panel, we discuss 6 different theories held by various scientists, from the one most of them agree is most likely to the one most people ridicule.
In doing my research for that panel-and just generally reading up on science subjects that spark my interest-I have arrived at one conclusion about humans and our ancestors... We have been nomads pretty much as long as we’ve been hominins. An article I read this past week has done much to confirm that, in my mind.
The article was actually about the Tibetan people and how they can thrive in the rarified atmosphere of the high altitudes where they live. Genetic studies have shown that most Tibetans (and a much lower percentage of the Han people in China) have an archaic gene. Not a mutant gene. An archaic gene inherited from a type of human that no longer exists.
This dead species of human is called the Denisovans. They are believed to have been related to-but distinct from-The Neanderthals (also extinct). And scientists probably would not know anything about the Denisovans at all, if someone had not found a single finger bone and 2 teeth in a Siberian cave. DNA study of those 41,000-year-old bones showed they belonged to people who were not Neanderthals, but definitely not modern human, either.
A genetic study of the Tibetan and Han people revealed they had inherited just enough Denisovan genetics to have the ability to up the production of hemoglobin in their blood. This increases their ability to get enough oxygen to their cells in an environment where most of us would have a tough time, due to lack of oxygen.
So, in order for the more modern humans to have bred with Denisovans (or the Neanderthals, for that matter) those earlier versions must have not just left Africa at some earlier time, but spread out across all of Eurasia. After all, Siberia is just about as far away from Africa as they could have gone. And later groups of hominins and humans would have exchanged DNA as they moved into the area, or passed through the area, or whatever.
If humans were not naturally nomads, they might never have left Africa, and then where would we be? Well, I guess we might all still be in Africa.