NEW YORK – An international team led by investigators in Germany has retraced prehistoric population migrations through present-day Bohemia by sequencing remains from hundreds of individuals who lived in the region as far back as 6,900 years ago.
"Our results reveal a complex and highly dynamic history of Neolithic to [Early Bronze Age] central Europe, during which migration and the movement of people facilitated abrupt genetic and social changes," senior and co-corresponding author Wolfgang Haak, an archaeogenetics researcher affiliated with the Max Planck Institute for the Science of Human History in Germany and the University of Adelaide in Australia, and his co-authors explained.
For a paper published in Science Advances on Wednesday, the researchers screened more than 260 human samples from more than three dozen archeological sites in northern Bohemia, ultimately generating data spanning some 1.2 million informative SNPs in 206 ancient individuals — primarily Neolithic, Late Neolithic, Eneolithic, and Early Bronze Age representatives — that they assessed by targeted in-solution capture panel sequencing.
By analyzing the sequences alongside those from 65 ancient individuals profiled in Bohemia in the past, and in relation to genetic data for more than 1,100 individuals from present-day Europe, the team unraveled relationships in the region between around 3,600 and more than 6,900 years ago, spanning a period before and after the arrival of an agricultural group with Yamnaya-related "steppe" ancestry from the Pontic-Caspian region.
With the new and previously reported sequence data, the team identified migrations that brought three populations with distinct genetic and cultural histories together in the area roughly 4,800 years ago: individuals from the Corded Ware, Bell Beaker, and Únětice cultures.
"The high-resolution genetic time transect in Bohemia, allowing early and late phases of cultural groups to be divided and studied separately … elucidates several major processes before and after the arrival of steppe ancestry," the authors wrote. "Our dense sampling allows detection of novel, important, and perhaps 'unexpected' changes within cultural groups."
The team estimated that genetically diverse individuals from a Corded Ware population in Eastern Europe turned up in Bohemia roughly 4,900 years ago, for example, including Corded Ware representatives that did not carry Yamnaya-like steppe ancestry.
The Corded Ware group appeared to "assimilate" women with Anatolian Neolithic and hunter-gatherer ancestry and other pre-Corded Ware ancestries into their culture, leading to Corded Ware burials for females from distinct genetic backgrounds.
"We were finally able to fill key temporal gaps, especially in the transition period around 5,000 years ago, when we see the genetic landscape changing drastically," Haak said in a statement. "Intriguingly, in this early horizon we find individuals with high amounts of 'steppe' ancestry next to others with little or none, all buried according to the same customs."
Over around 500 years, Y chromosomal diversity declined in members of the Corded Ware culture, the authors reported, perhaps due to shifting social structures that led to a few men fathering many children. That pattern continued and became more pronounced in individuals from the Bell Beaker culture in Bohemia between around 4,200 and 4,500 years ago, when a single Y lineage not detected at earlier time points took over.
Still other Y lineages appeared in many Únětice culture representatives during Early Bronze Age Bohemia, the investigators reported, as did nuclear genetic sequences that pointed to the arrival of new individuals from more northeasterly sites in Europe.
"This finding was very surprising to us archaeologists as we did not expect to see such clear patterns, even though the region has played a critical role, e.g. in the emerging trade of amber from the Baltic, and became an important trading hub during the Bronze and Iron Age," co-first author Michal Ernée, an archaeology researcher at the Czech Academy of Sciences in Prague, said in a statement.