But now, a growing body of researchers has challenged that narrative. Working in Senegal, Cameroon, Malawi and elsewhere, they uncover evidence that early humans spread across much of Africa before venturing elsewhere. This work has moved the field beyond the old out-of-Africa narrative and is transforming our understanding of how multiple groups of early modern humans mixed and spread across the continent, providing a more nuanced picture of the complex origins of our species.
“It’s becoming increasingly clear that humans did not come from one population in one region of Africa,” says Eleanor Scerri, an archaeologist at the Max Planck Institute for Geoanthropology in Jena, Germany. “If we really want to understand human evolution, we need to look at the entire African continent.”
Most researchers agree that the first modern humans appeared in Africa between 200,000 and 300,000 years ago. About 60,000 years ago, they spread to other parts of the world. Until recently, however, most experts believed that these people inhabited West and Central Africa, especially the rainforests there, only for the last 20,000 years or so.
For some researchers, this narrative made no sense. “People like to move around a lot,” says University of Pennsylvania geneticist Sarah Tishkoff, who has been working to unravel Africa’s deep genetic lineage for more than two decades. “They had this beautiful continent, they could move everywhere, go to different places, with different resources.”
The reason no one found evidence of early human settlement in West and Central Africa, Scerri and others say, is that few people had looked there. For many decades, most researchers tended to focus on low-hanging fruit—areas of the continent where fieldwork was less difficult. Because the climate is drier and cooler in East and Southern Africa and the terrain is more open, fossils are easier to find and date. Most of West and Central Africa is hot and humid, so bones and DNA degrade faster. Additionally, this area can be a difficult place to work, not only because much of it is densely forested, but also because some areas are involved in long-running and chaotic conflicts.
Some research suggests that cultural bias may also have played a role. “Most research has been done by people from the global North,” says paleoanthropologist Jessica Thompson of Yale University. “And their view is, ‘Well, we want to know how people got out of Africa, where we come from.’
As a result of all these factors, most scholars have focused heavily on sites in Southern and Eastern Africa. This contributed to the idea that early modern humans mainly inhabited these areas. Frustrated that the academic establishment was not taking their ideas seriously, some researchers began trying to uncover evidence that supported their views. In the last decade or so, they found it.
Last year, a team that included scientists from Senegal, Europe and the United States mentionted that modern humans had lived at a site on the coast of Senegal by 150,000 years ago. Previous estimates put the first human habitation in West Africa 30,000 years ago.
Furthermore, the site was in a mangrove forest, rather than the typical grassland or sparse savannah usually associated with early human habitation. Scerri says her latest research in Senegal, which has yet to be published, may push that date back even further. “It’s clear that there were different people in different places doing different things,” he says. “And it was there for a long time. Much more than we realized.”
Other study, from 2022, analyzed DNA from the bones of 34 people who lived in sub-Saharan Africa between 5,000 and 18,000 years ago. Examining this ancient DNA is important because it offers a much clearer window into the structure of the most ancient African populations. The research showed that from 80,000 to 20,000 years ago, populations that were quite isolated from each other began to interact over large areas of the continent. These connections stretched thousands of miles, from Ethiopia, through the forests of Central Africa, and into South Africa.
“People were clearly moving widely across Africa,” says Thompson, one of the study’s co-authors. “They didn’t live in these small isolated populations.”
And one paper published four years ago in Nature examined the remains of two children found in a rock shelter in Cameroon, in the western part of Central Africa. One of the children lived 3,000 years ago, while the other lived 8,000 years ago. The researchers, from Harvard and other institutions, managed to collect DNA from the two – the first ancient human DNA ever analyzed from Central Africa. They identified four distinct human lineages between 60,000 and 80,000 years ago, including a previously unknown lineage—what they called a “ghost population”—that probably lived in West Africa. The results further support the idea that humans have been in West Africa for much longer than previously realized and add to the evidence that humanity’s roots exist in more than one region of Africa.
Experts say it’s important to note that close relatives of modern humans — Neanderthals, Homo erectus and many other species — had already spread beyond Africa into Europe and Asia, in some cases millions of years ago. But these groups contributed relatively small amounts of DNA to modern human ancestry.
Because it can be so difficult to find fossils and recover ancient DNA in many parts of Africa, scientists have had to develop innovative approaches to establish early human habitation. For example, Thompson and her colleagues studied sediments around Lake Malawi in the north of the country. Over thousands of years, the lake shrank and grew, depending on the amount of rainfall. During wetter periods, the number of trees around the lake will expand significantly.
But Thompson found that during a wetter period that began 80,000 years ago (and continues today), the number of trees did not increase nearly as much as expected. Instead, scientists found plenty of coal. Thompson says this shows that people lived in the area, perhaps in fairly large numbers, and burned wood on a significant scale, either to modify the environment for hunting or for cooking or warmth – or all three.
A key aspect of this new understanding is the Pan-African hypothesis: Scerri and others argue that modern humans probably evolved from the mixing of different groups from a number of regions of the continent. “There were a number of modern human populations living in different regions of Africa, and we emerged over time from the complex interactions between them,” says Scerri. “Basically, we’re a mix of a mix of a mix.”
In research published last year, University of California, Davis population geneticist Brenna Henn and her colleagues examined the genomes of nearly 300 Africans from across the continent. By analyzing and comparing the genetic data, they were able to construct a model of how people came to the continent over the past hundreds of thousands of years. They found that modern humans are descended from at least two different populations that lived in different parts of the continent. She and her colleagues are now analyzing the genomes of 3,000 people, mostly Africans but also people of African descent living elsewhere, as well as Native Americans and others.
Scerri also found evidence to support the pan-African idea. It has shown that Middle Stone Age civilization remained in West Africa until very recently, less than about 11,000 years ago. This culture, a particular way of making stone tools, disappeared much earlier in other parts of the continent, 30,000 to 50,000 years ago. This is important, he says, because it is exactly what the Pan-African theory predicts: “In this model, one would expect each region to have its own distinct cultural trajectory, due to periods of isolation. This research shows how this was possible.”
Not everyone is convinced. Richard Klein, a paleoanthropologist at Stanford University who has spent decades studying early modern human origins and migration into Africa, says, “I don’t understand the evolutionary mechanism behind” the pan-African origin theory.
Pontus Skoglund, a population geneticist at the Francis Crick Institute in London who has worked with Scerri, says the pan-African idea is plausible, but he is not fully convinced. “To me, it’s also possible that a large part of the ancestry of today’s humans can be found in a single region,” he says. “But we don’t know.” He says there is still “a lot of uncertainty” about who was where and when.
Scerri agrees that more research is needed. But after years of battling skepticism, she says she feels vindicated that the new perspective has caught on. “Right now, this is such an exciting area to work in,” he says. “It really is an incredible story, a story unfolding before our eyes.”
