This article appears in the Witness section of the spring 2020 issue of the New Humanist. Subscribe today.
The first major study of a whole human ancient genome was carried out in 2009. It produced the discovery that Homo sapiens in Europe and Asia had interbred with Neanderthals. That study – which sequenced DNA from the bones of the Stone Age hominims who populated Europe until around 40,000 years ago – found that modern Europeans, Asians and Americans, but not Africans, inherited about two per cent of their genes from Neanderthals.
However, researchers at Princeton University have questioned this finding. Their research, based on a new computational method, suggests that Africans also have Neanderthal DNA, and that that very early human history was more complex than previously thought. The paper said that technical constraints and the assumption that Neanderthals and ancient African populations were geographically isolated from each other had led to a blind spot in the field. The new data indicates that a wave of modern humans left Africa approximately 200,000 years ago and this group interbred with Neanderthals. This ancient group of Europeans then migrated back into Africa, introducing Neanderthal ancestry to African populations.
All of this shows how much is still unfolding in the study of ancient DNA. In our summer 2018 issue, Peter Forbes interviewed David Reich, a Harvard geneticist and pioneer in the field, who was involved in the 2009 study. Reich said: “We’ll be able to understand at each place in time the grid samples of all the places people lived, and find what their ancestry was like, their material culture and how those people are related to people nearby. We have to learn to think on a different scale temporally.”
With each new piece of research, perhaps we are coming closer to establishing the detail of this grand, sweeping human story.
