DNA from Early Europeans Sheds Light on Impact of Bronze Age
The Bronze Age was a significant era in Earth's early history, but how did it change Europe? New DNA analyses from the bones of early Europeans have attempted to answer just that question, showing that the demographic structure of present-day Europe and Asia is the result of widespread population migrations, and subsequent cultural changes that occurred during the Bronze Age.
Between 3000 BC and 1000 BC, new technologies and social tradition spread outward from the steppes between the Caspian Sea and the Black Sea into all of Europe and Central Asia (Eurasia), according to new findings published in the journal Nature.
The study was conducted to settle the long-standing debate about whether the cultural changes that led to modern Eurasia were born from a massive migration, or from a gradual evolution of ideas through pre-existing populations, researchers said.
"Both archaeologists and linguists have had theories about how cultures and languages have spread in our part of the world. We geneticists have now collaborated with them to publish an explanation based on a record amount of DNA-analyses of skeletons from the Bronze Age," Morten Allentoft, a geneticist from the Centre for GeoGenetics at the Natural History Museum of Denmark in Copenhagen, who led the research, said in a press release.
After analyzing more than 600 samples of Bronze Age (about 5,000-3,000 years ago) human remains, they found that the changes came about as a result of migrations.
"The driving force in our study was to understand the big economical and social changes that happened at the beginning of the third millennium BC, spanning the Urals to Scandinavia. The old Neolithic farming cultures were replaced by a completely new perception of family, property and personhood," explained researcher Kristian Kristiansen, of the University of Gothenburg in Sweden.
One of the main findings from the study is how these migrations resulted in huge changes to the European gene-pool, in particular conferring a large degree of admixture on the present populations. Genetically speaking, ancient Europeans living after these migrations took place are much more similar to modern Europeans than those alive prior the Bronze Age.
In one example, the researchers say they determined ancient members of the Yamnaya culture, a population of nomadic herders originating about 5,000 years ago in what is present-day southwestern Russia, are genetically indistinguishable from the peoples of the slightly younger Afanasievo culture, which inhabited a region thousands of miles further east.
Such migrations can also explain the origins of the language families of northern Europe, the researchers suggest.
Another interesting discovery from this study was the realization that, contrary to popular belief, lactose intolerance was prevalent among Europeans. Prior belief suggested that it evolved earlier in time, roughly between 5,000 and 7,000 years ago.
"Previously the common belief was that lactose tolerance developed in the Balkans or in the Middle East in connection with the introduction of farming during the Stone Age," explained co-author Martin Sikora from the Centre for GeoGenetics. "But now we can see that even late in the Bronze Age the mutation that gives rise to the tolerance is rare in Europe. We think that it may have been introduced into Europe with the Yamnaya herders from Caukasus but that the selection that has made most Europeans lactose tolerant has happened at a much later time."
This study not only gives us a new glimpse into the Bronze Age and how it influenced Europe, dairy related or otherwise, but also is the first time an actual population evolutionary study back in time has been made to this extent.
"The results show that the genetic composition and distribution of peoples in Europe and Asia today is a surprisingly late phenomenon - only a few thousand years old," geneticist Eske Willerslev concluded.
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