Recently, I delivered a lecture to the American Society for Human Genetics, focusing on the African record of human origins. It was a great privilege to speak to more than 5000 members of this professional organization, together with other distinguished experts on African genetic variation and health.
I wrote up and edited the text of my remarks to share more broadly. I focused the talk on “Three big insights into our African origins”.
Here are my three insights in brief:
First, modern humans did not originate in a bottleneck after 200,000 years ago. Our origin was much deeper in time than this.
Second, our species originated in Africa from deeply structured ancestral populations. These were much more different from each other than any human populations are today. We do not know how they interacted or which gave rise to living peoples.
Third, some of these deeply divergent populations survived in Africa until recent times. During the time of human origins, “modern” humans were not alone.
I discuss the Neanderthal and Denisovan contibutions, and include a good amount of context for the overall human evolutionary record, from Sahelanthropus on forward through deep time.
But my focus throughout is Africa, and I argue strongly for a reorientation of archaeology and genetics to recognize the continued centrality of Africa in our evolutionary history.
The “out of Africa” slogan came from well-intentioned scientists. They thought that by emphasizing the idea of an African origin, they would send a clear message that Africa had an important place in evolutionary narratives. That much is true. Africa was the center of human origins. But “out of Africa” stories focused almost exclusively on dispersal, as if it were an exodus. Africa’s place in these stories was the place that people left.
We must recenter Africa in this story of humanity’s common origin.
Africa was going strong before the bottleneck that affected non-African peoples. Most African populations didn’t experience this bottleneck, and they continued going strong afterward. Discoveries of the last few years sketch a picture of great diversity and surprising survivals, of deep histories and interactions. Today’s Africans share a rich heritage that reflects their position at the center of the action.