The genetic origins of the early Neolithic farmers seemed to lie in the Near East. A new study published in the journal prison cell He shows that the early farmers were actually a mixture of Ice Age hunter-gatherer groups, scattered from the Near East all the way to Southeast Europe. Researchers from the University of Bern and the Swiss SIB Institute for Bioinformatics, as well as from Johannes Gutenberg University Mainz and the University of Friborg, participated in the study. The method they developed could help reveal other patterns of human evolution with unparalleled accuracy.
The first signs of agriculture and a sedentary lifestyle It is found in the so-called “Fertile Crescent”, a region in the Near East where people began to settle and domesticate animals and plants about 11,000 years ago. The question of the origin of agriculture and stability has preoccupied researchers for more than 100 years: did agriculture spread from the Near East through cultural diffusion or through migration? Genetic analyzes of prehistoric skeletons have so far supported the idea that the first farmers in Europe descended from hunter-gatherer groups in Anatolia. While this may be the case, this new study shows that Neolithic genetic origins cannot be clearly attributed to a single region. Unexpected and complicated Population The dynamics occurred at the end of the Ice Age, and led to the ancestral genetic formation of the population who invented agriculture and a sedentary lifestyle, that is, the first farmers of the Neolithic period.
The first farmers emerged from a mixing process that began 14,000 years ago
Previous analyzes indicated that the early Neolithic people were genetically different from other human groups at the time. Not much is known about their origins. “We now find that the first farmers in Anatolia and Europe originated from a mixed population of hunter-gatherers from Europe and the Near East,” says Nina Marchi, one of the study’s first authors from the Institute of Ecology and Evolution at the University of Bern and SIB. According to the authors, the mixing process began about 14,000 years ago, followed by a period of intense genetic differentiation lasting several thousand years.
A new approach to modeling population history from prehistoric skeletons
This research is made possible by a combination of two technologies: the production of high-quality ancient genomes from prehistoric skeletons, along with demographic modeling on the resulting data. The research team coined the term “demographic modeling” for this purpose.
“It is essential to obtain genome data of the best possible quality so that the latest statistical genomic methods can reconstruct accurate demographic processes over the past 30,000 years with high accuracy,” says Laurent Excoffier, one of the study’s senior authors. Excoffier is Professor at the Institute for Ecology and Evolution at the University of Bern and Group Leader at SIB. The project started with Joachim Burger of Johannes Gutenberg University in Mainz and Daniel Wegmann of the University of Friborg. Marchi adds that “just comparing the similarities between different ancient genomes is not enough to understand how they evolved. We had to reconstruct the actual dates of the groups studied as accurately as possible. This is only possible with complex population genetics statistics.”
Multidisciplinarity is key to solving such ancient mysteries
Joachim Berger of the University of Mainz and a second author stresses the need for interdisciplinarity: “It took nearly ten years to collect and analyze skeletons suitable for such a study. This was only possible through collaboration with several archaeologists and anthropologists, who helped us to solidify Our models are historical.
The historical context was coordinated by Maxime Bramy, who works with Berger at the Johannes Gutenberg University. The young prehistoric scientist was surprised by some of the study’s findings: “Europe’s first farmers seem to descend from hunter-gatherer societies that lived all the way from the Near East to the Balkans. This was not archaeologically expected.”
Towards a general model of human population evolution
Genetic data from fossils (skeletons) have been severely damaged and must be processed accordingly using bioinformatics, explains Daniel Wegmann of the University of Friborg and head of the group at SIB: “High-resolution reconstruction of prehistoric Europeans was only possible thanks to the methods we specially developed to analyze the genomes of ancient fossils”. Berger adds, “Through these methods, we have not only elucidated the origins of the world’s first Neolithic groups, but established a general model of population evolution in Southwest Asia and Europe.”
Excoffier concludes, “Of course, there are still spatial and temporal gaps, and this does not mean the end of studies on human evolution in this area.” Thus, the team’s research plan is already in place; They want to supplement their demographic model with genomes from the later Neolithic and Bronze Age stages to provide an increasingly detailed picture of human evolution.
Joachim Burger et al, The Genetic Origins of the World’s First Farmers, prison cell (2022). DOI: 10.1016 / j.cell.2022.04.00
University of Bern
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