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LESSON 2 · How Humans Evolved

DNA Fills the Gaps

Denisovans were first identified through DNA pulled from a single finger bone in a Siberian cave — an entire species named from a fragment smaller than a coin. Ancient DNA revealed that modern humans interbred with both Neanderthals and Denisovans, and we still carry their genes.

Most non-African humans carry 1-4% Neanderthal DNA. Some Melanesians carry up to 6% Denisovan DNA, including genes that help them resist tropical diseases. The missing links are not missing. They are inside you, woven into your genome and shaping your health right now.