Europe鈥檚 first farmers lived alongside a ghost people. Even some 2000 years after farming began to spread through the continent, some people were still clinging to the hunter-gatherer lifestyles that had been practiced formerly. The first farmers and last of Europe鈥檚 hunter-gatherers lived alongside each other for millennia and even shared burial sites.
鈥淎fter 2000 years of agriculture in Europe, we still find hunter-gatherers,鈥� says of Johannes Gutenberg University in Mainz, Germany. 鈥淲e never expected anything like this.鈥�
Farming was invented in the Middle East about 10,500 years ago, and spread rapidly. It reached Europe about 7500 years ago, and continued to expand westwards 鈥� apparently because the incoming migrating farmers thrived and outcompeted the native hunter-gatherers. From this time forward, there are no archaeological records of hunter-gatherers in Europe, suggesting that the lifestyle had effectively died out. 鈥淲e had no archaeological hints of their existence,鈥� says Bollongino.
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But the genetic evidence tells a different story. Analysis of modern and ancient DNA shows that modern Europeans carry genetic elements from those early farmers 鈥� but many also carry DNA from early hunter-gatherers, says Bollongino. Apparently, Europe鈥檚 original hunter-gatherers did not simply disappear, but instead mixed, and seemingly interbred, with the incoming farmers.
Side by side
Attempting to figure out when this admixture happened, Bollongino and colleagues obtained DNA from the bones and teeth of 29 bodies found in Bl盲tterh枚hle cave in Germany. The cave seems to have been a burial site.
The team sequenced mitochondrial DNA from 25 of the bodies, and used carbon dating to work out how old they were. The oldest samples are 10,300 to 11,200 years old 鈥� and so date from before European farming. Unsurprisingly, the genetic signatures were typical of hunter-gatherers. Some of the bodies were much more recent, dating from between about 6000 and 5000 years ago, and at first glance, they appeared to carry genetic signatures typical of Europe鈥檚 incoming farmers.
But then the team examined the samples鈥� isotope content, revealing these ancient people鈥檚 diets. This analysis revealed that, as expected, the ancient hunter-gatherers mostly ate wild animals. But the more recent group, initially thought to be exclusively farmers, actually divided into two populations with different diets.
One of these populations clearly practiced farming, and ate mostly domestic animals. But the other population, living alongside them, mostly ate freshwater fish. This is a typical hunter-gatherer diet and indicates that the lifestyle persisted in the area until 5000 to 6000 years ago, perhaps 2000 years after farmers entered the region.
Not just farmers
The migrant farmers, and the local hunter-gatherers, must have lived as neighbours for many years. 鈥淭hey shared the [Bl盲tterh枚hle] burial place for 400 to 800 years,鈥� says Bollongino. 鈥淲e are pretty sure they were in contact.鈥�
The two cultures may even have traded with each other, or exchanged information. 鈥淲e know from examples from Africa and Indonesia that they can live side by side for centuries,鈥� say Bollongino. 鈥淭hey profit from each other.鈥� They may also have interbred: Bollongino鈥檚 team found three chunks of DNA, normally found in hunter-gatherers, in the farmers鈥� genes.
Clearly, farming did not outcompete the hunter-gatherer lifestyle immediately. 鈥淗unter-gatherers don鈥檛 need to work that hard,鈥� says Bollongino. 鈥淏eing a farmer is a full-time job.鈥� But in the long run, farming populations grow much bigger than those of hunter-gatherers due to the sheer quantities of food produced.
It is not clear why the hunter-gatherers have left little trace in the archaeological record. It may be that the record itself is poor. 鈥淲e don鈥檛 find many farming settlements either,鈥� says Bollongino. There is some evidence that . 鈥淢aybe we do not find a lot because there were not many people.鈥�
Multiple moves
The migration of early farmers was far from the only major population movement that shaped Europe鈥檚 genetic diversity, says , also at Johannes Gutenberg University, who was not involved in Bollongino鈥檚 study.
Brandt and his colleagues have chronicled how the genetic makeup of Europeans changed between 5500 and 1550 years ago, using genetic samples from the Mittelelbe-Saale region of Germany. This was after the first influx of farmers, but Brandt鈥檚 team could identify three important shifts in the population during this time period.
Soon after the rise of farming, a group of hunter-gatherers moved south into Germany from Scandinavia. This migration may have given rise to the hunter-gatherer culture that Bollongino found. Soon afterwards, there were two successive waves of migration of farmers and pastoralists into central Europe, first from the east and then from the south-west. Together, they show that by 4500 years ago, the genetic diversity of modern Europe was largely in place.
Journal references: : Bollongino et al, DOI: 10.1126/science.1245049; Brandt et al, DOI: 10.1126/science.1241844
