Largest ever genomic study shows that first Beaker expansion was one of cultural diffusion

Prehistoric Iberians 'exported' their culture throughout Europe, reaching Great Britain, Sicily, Poland and all over central Europe in general. However, they did not export their genes. The Beaker culture, which probably originated in Iberia, left remains in those parts of the continent.

Iberian beakers [Credit: Museo de Almeria]

However, that diffusion was not due to large migrations of populations that took this culture with them. These are the conclusions of an international study in which the Spanish National Research Council (CSIC) was involved. Its findings, published in the journal Nature, indicate no evidence of any genetic outflow from Iberia to those areas has been discovered.

"Therefore, the diffusion of the Beaker culture from Iberia is the first example of a culture being transmitted as an idea, basically due to a question of social prestige (since it was associated with the virtues of being virile and of being warriors), which is why it is adopted by other populations," indicates researcher Carles Lalueza-Fox, from the Institute of Evolutionary Biology, a mixed research centre run by CSIC and the Pompeu Fabra University, in Barcelona, Spain.

Between 4,700 and 4,400 years ago, a new type of bell-shaped beaker pottery was introduced throughout western and central Europe. For more than a century, archaeologists have been trying to determine whether the spread of this beaker pottery -- and the (Beaker) culture associated with it -- represented a large-scale migration or whether it was due simply to the exchange of new ideas.

Now, this new study, which includes DNA data from 400 prehistoric skeletons collected from sites across Europe, resolves the debate of whether the spread was due to migrations or ideas, indicating that both arguments are correct. The findings show that the culture which produced these bell-shaped beakers extended from Iberia to central Europe without a significant movement of populations, although the Beaker culture would spread to other places through migrations at a later date.

The study, whose first author is the Spanish researcher Inigo Olalde, a geneticist at Harvard Medical School, shows that once the (Bell) Beaker culture reaches the centre of Europe (around Germany and its surrounding area), it expands backwards to other places, notably to the British Isles. Yet, in this case, it does represent a migration, replacing around 90% of the population with it.

"That is to say, the Neolithic people who built Stonehenge (and who had a greater genetic similarity with Neolithic Iberians than with those from Central Europe) almost disappear and are replaced by the populations from the Beaker culture from the Netherlands and Germany. This replacement is almost absolute in terms of the Y chromosome, which is transmitted by the paternal line, indicating an extreme reproductive bias, and therefore a previously unheard of social dominance. The backward flow also reaches other places such as Italy (at least in the north) and Iberia. I believe it is possible that this is also associated with the expansion of the Celtic or Proto-Celtic languages," Mr. Lalueza-Fox points out.

Coordinated by researcher David Reich from Harvard University, the study was developed by an international team of 144 archaeologists and geneticists from institutions in Europe and the United States.

Source: Spanish National Research Council [February 21, 2018]