Farming is thought to have originated from a single population in Southwest Asia, which includes parts of the present-day Middle East, and made its way to regions in Turkey, Greece, and eventually Western Europe. Scientists have long debated how these populations arose and spread in these regions, but now an international team of researchers has received new genetic information that may settle the debate. Their findings show that the world’s first farmers did not arise from a single group as previously thought, but from a mixture of two hunter-gatherer groups during a turbulent time when human settlements were nearly destroyed.
The genetic origins of the early Neolithic agriculturalists seemed to lie in the Near East for a long time. A new study shows that the first farmers actually represented a mix of Ice Age hunter-gatherer groups from the Near East that spread across southeastern Europe.
The first signs of agriculture and a sedentary lifestyle are found in the Fertile Crescent, a region in the Near East where humans began to settle and domesticate animals and plants about 11,000 years ago.
The question of the origin of agriculture and settlement has occupied researchers for more than 100 years: Did agriculture spread from the Near East through cultural diffusion or migration? Genetic analyzes of prehistoric skeletons so far have supported the idea that Europe’s first farmers came from hunter-gatherer populations in Anatolia.
Even so, this new study shows that Neolithic genetic origins cannot be clearly attributed to a single site. Unexpected and complex population dynamics occurred at the end of the Ice Age. It led to the ancestral genetic makeup of populations that spawned agriculture and a sedentary lifestyle, namely the first Neolithic farmers.
The first farmers and the mixing process
Previous analyzes had suggested that the first Neolithic humans were genetically different from other human groups since then. Little was known about their origins. Nina Marchi, one of the first authors of the study, from the University of Bern and the SIB Institute for Ecology and Evolution, says:
“We now see that the first farmers of Anatolia and Europe emerged from a mixed population of hunter-gatherers from Europe and the Near East.”
According to the authors, the process of mixing began about 14,000 years ago, followed by a period of extreme genetic differentiation that lasted several thousand years.
This research was made possible by combining two techniques: the production of high-quality ancient genomes from prehistoric skeletons and demographic modeling on the data obtained. The research team coined the term “demogenomic modeling” for this purpose.
Laurent Excoffier, one of the senior authors of the study, said, “For the latest statistical genomic methods to reconstruct the detailed demographic processes of the last 30,000 years in high resolution, it is necessary to have the best possible quality genome data.” says.
Nina Marchi adds: “Just comparing the similarities of different ancient genomes is not enough to understand how they evolved. We needed to reconstruct the actual histories of the populations studied as accurately as possible. This was only possible with complex population genetic statistics.”
Joachim Burger from the University of Mainz and the second senior author emphasize the need for interdisciplinarity:
“It took close to a decade to collect and analyze skeletons suitable for such a study. This has only been possible in collaboration with a large number of archaeologists and anthropologists who have helped us anchor our models historically.”
The historical contextualization was coordinated by Maxime Brami, who worked with Burger at Johannes Gutenberg University. The young prehistoric researcher was surprised by some of the research’s findings: “Europe’s first farmers are descendants of hunter-gatherer societies stretching from the Near East to the Balkans. This was not archaeologically predictable.”
Human population evolution
As Daniel Wegmann of the University of Friborg and the group leader at SIB explain, genetic data from fossils (skeletons) have been severely damaged and must accordingly be processed using bioinformatics: “To reconstruct the prehistory of Europeans in high resolution, but to analyze ancient fossil genomes It was made possible thanks to the methods we developed specifically for him.”
Joachim Burger adds: “With these approaches, we have not only elucidated the origins of the world’s first Neolithic populations, but also established a general model of the evolution of human populations in Southwest Asia and Europe.”
Laurent Excoffier said, “Of course, the spatial and temporal gaps remain, and this does not mean that the study of human evolution in this field is over.”
Therefore, the team’s research plan was predetermined; they want to supplement their demographic models with genomes from the later Neolithic and Bronze Ages to provide an increasingly detailed picture of human evolution.
Marchi, Winkelbach, Schulz, Brami et al. The genomic origins of the world’s first farmers. Cell, 2022 DOI: 10.1016/j.cell.2022.04.008