Fresh DNA data challenge the established theory of a single source of Homo sapiens in Africa, pointing to a more complex and multifaceted origin from several interacting populations.
Scientists have questioned one of the most well-known theories about human origin. A new genetic study suggests that Homo sapiens may not have emerged from a single population in Africa, as previously thought, but from several interconnected groups. This was reported by the Daily Mail.
The traditional "Out of Africa" concept posited that modern humans descended from a single isolated community. However, fresh data reveals a more complex picture: ancient human populations were dispersed across the continent, maintained contacts, and interbred over hundreds of thousands of years.
These conclusions were reached by a team of researchers led by scientists from the University of California, Davis. They analyzed the DNA of modern African populations, including 44 new genomes from the Nama people of southern Africa, who exhibit a high level of genetic diversity.
Using computer modeling, the researchers compared various scenarios of human origin. They considered both a single-source model and a scenario with multiple interacting groups. The results convincingly showed that the latter version best explains the current genetic data.
According to the study, the first significant split between ancient human populations occurred approximately 120-135 thousand years ago. Even after this event, they continued to actively exchange genes for many generations.
Anthropologist Brenna Henn, one of the authors of the study, noted that previous understandings were limited by a lack of fossil remains and ancient DNA. She emphasized, "This uncertainty is related to limited data, as well as the fact that fossil finds do not always align with models built on modern DNA. The new research changes our understanding of the species' origin."
A New Vision of Homo sapiens Evolution
The researchers describe the new model as a "loosely structured root." In this model, early human populations were not completely isolated but existed as a constantly interacting network.
According to the scientists, this concept better explains the genetic diversity of modern humans. It does not require assumptions about a significant contribution from unknown archaic human species.
Co-author of the study Tim Weaver added that these results change the approach to interpreting both genetic and paleontological data. He explained, "Previously, more complex models assumed the involvement of archaic hominins, but our results suggest otherwise."
The scientists also note that due to constant mixing, early populations were similar in appearance. Therefore, some fossil species that differ significantly in structure likely did not play a direct role in the evolution of Homo sapiens.
