October 11, 2013
Human Fossils Reveal Europe’s Prehistoric Hunter-Gatherers And Farmers Intermingled For Two Millenia
A pair of new DNA-related studies, each appearing this week in the journal Science, shed new light on the history and evolution of European populations – including the revelation that hunter-gatherers and immigrant farmers lived together in the central part of the continent for more than 2,000 years.
That discovery, reported in the paper “2000 Years of Parallel Societies in Stone Age Central Europe” by anthropologist Joachim Burger of the Johannes Gutenberg University and his colleagues, comes following an extensive analysis of genetic material and isotopes from human bones uncovered in Blätterhöhle cave near Hagen in Germany.
Blätterhöhle cave was known to be a burial ground for both hunter-gatherers and farmers, and Burger’s team used stable isotopes to determine what the deceased individuals had eaten which, in turn, is indicative of their lifestyles. They then used DNA to discover how they might have been related to one another, and radiocarbon dating to establish the age of the remains.
“It is commonly assumed that the European hunter-gatherers disappeared soon after the arrival of farmers,” lead author Dr. Ruth Bollongino said in a statement. “But our study shows that the descendants of the first European humans maintained their hunter-gatherer way of life, and lived in parallel with the immigrant farmers, for at least 2,000 years. The hunter-gathering way of life only died out in Central Europe around 5,000 years ago, much later than previously thought.”
“Until around 7,500 years ago all central Europeans were hunter-gatherers,” added co-author and University College London evolutionary genetics professor Mark Thomas. “They were the descendants of the first wave of our species to arrive in Europe, around 45,000 years ago. They survived the last Ice Age and the warming that started around 10,000 years ago. And now it seems they also survived the initial wave of farmers spreading across Europe from the southeast of the continent.”
The relationship between native hunter-gatherers and immigrant farm workers has been poorly analyzed historically, the researchers said. This new study reveals that the foragers remained in close proximity to their more agriculturally-minded counterparts, keeping in contact with them for thousands of years and even sharing burial grounds with them. The intermingling of the two groups also apparently led some hunter-gatherer women to marry farmers, though there is no genetic evidence that farmer women had ever married into the forager line.
In related research, a team of experts from several different institutions analyzed DNA from skeletons representing roughly 4,000 years of prehistory in order to create a genetic history of modern Europeans, while also determining the time and origin of those who helped settle the continent.
The paper, titled “Ancient DNA Reveals Key Stages in the Formation of Central European Mitochondrial Genetic Diversity,” found at least four different periods of significant migration and settlement in Central Europe. Those stages were highlighted by noticeable shifts in the genetic composition of the people living in that region, the investigators concluded following an extensive analysis of bone and tooth samples from 364 prehistoric human skeletons – 10 times more samples than any previous DNA study of this type.
The research was a collaborative effort involving scientists from the National Geographic Society’s Genographic Project, the Australian Centre for Ancient DNA (ACAD), and both the University of Mainz and the State Heritage Museum in Halle (Germany). Their work definitively demonstrates that people living in the region spent much of the time from 5500 BC to 1500 BC moving from one place to another.
“This is the largest and most detailed genetic time series of Europe yet created, allowing us to establish a complete genetic chronology,” ACAD scientist and co-lead author Wolfgang Haak said. “Focusing on this small but highly important geographic region meant we could generate a gapless record and directly observe genetic changes in ‘real time’ from 7,500 to 3,500 years ago, from the earliest farmers to the early Bronze Age.”
“This is perhaps the most important study to date of genetic patterns in Europe during a critical period in the formation of modern Europe,” added Genographic Project Director Spencer Wells. “Painstakingly collected data from well-dated archaeological remains spanning a period from the dawn of farming during the Neolithic period to the Bronze Age reveal successive waves of migration and population replacement genetic ‘revolutions’ that combined to create the genetic patterns we see today.”