Early humans lived in a world that one evolutionary geneticist compared to the fantasy world of Lord of the Rings. Not only were there many hominid populations, but these populations interbred, contributing to the genetic diversity of modern humans.

The first genomes sequences of Neanderthals and Denisovans revealed that these groups interbred with anatomically modern humans more than 30,000 years ago. But now more complete versions of the Denisovan and Neanderthal genomes reveal another notch in the belt of our ancient ancestors. The Denisovan interbred with an unknown 'archaic ancestor' in Asia.

What's the Big Idea?

While we don't have the faintest idea of who this new population of humans is, a more complete picture of the ancient genomes of these groups reveals that there was more interbreeding going on than previously thought. These revelations not only help explain the genetic diversity of humans, but also shed light on the interconnectedness between populations. 

This has implications for the way we view genetic diversity today. 

For instance, consider the case of a notorious white supremacist named Craig Cobb who recently learned that his genetic heritage is 14 percent Sub-Saharan African. While Cobb dismissed the results of his DNA test as "statistical noise," the test reveals how close we are actually all connected to one another, and also how dependent we are on each other, through our shared DNA. 

"I’ve always wished I had the opportunity to test somebody from the Ku Klux Klan or a white supremacist," the geneticist Bryan Sykes told Big Think. "I would have asked them would they rather do without the African DNA, and if they had said, 'Well, yes, I really deny it’s there,' and I said, 'Well, actually, it’s running your kidneys or your heart muscles.  Would you rather do without your kidneys or your heart?'  Then, of course, I think the answer would change."

That helps explain why, as Peter Diamandis says, knowledge of our interconnectedness has led to "the most peaceful time of human history ever."

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