Researchers reconstruct Balkan genomic history

The site of the imperial Roman city of Viminacium, now in Serbia, contains the m
The site of the imperial Roman city of Viminacium, now in Serbia, contains the mausoleum of third-century CE Roman Emperor Herennius Etruscus and his mother Herennia. (Miodrag Grbic photo)

A new multidisciplinary study reconstructs the genomic history of the Balkan Peninsula during the first millennium of the common era, a time and place of profound demographic, cultural and linguistic change.

The Balkan Peninsula is broadly defined as the region surrounded by the Adriatic, Aegean and Black Seas. Historically, this region was a bridge between Europe and Asia and the main migration and cultural exchange route that took place in the Danube valley in present-day Serbia.

The region is significant because of the tremendous ethnolinguistic diversity of its residents, and the resulting political complexities affecting the modern countries in the region, including those emerging from the former Yugoslavia. However, the genetic history of this region before this study was little understood.

The study was led by an international team including researchers at Western University, the Institute of Evolutionary Biology (Spain), the University of Belgrade (Serbia), and Harvard University. The team recovered and analyzed whole genome data from the remains of 146 ancient people excavated primarily from Serbia and Croatia, more than a third of which came from the Roman military frontier at the massive archaeological site of Viminacium in Serbia, which they co-analyzed with data from the rest of the Balkans and nearby regions.

The new research, published today in the journal Cell , highlights the cosmopolitanism of the Roman frontier and the long-term consequences of migrations that accompanied the breakdown of Roman control, including the arrival of people speaking Slavic languages. Archaeological DNA reveals that despite nation-state boundaries that divide them, populations in the Balkans have been shaped by shared demographic processes.

Anthropology laboratory at Viminacium, one of the richest archeological sites in terms of human remains in the Roman Empire, containing approximately 18,000 human skeletons. Note the perfect teeth of Roman soldiers, as a possible consequence of the lack of refined sugars. (Miodrag Grbic photo) The study involved an interdisciplinary collaboration of more than 70 researchers, including archaeologists who excavated the sites, anthropologists, historians and geneticists.

Western biology professor Miodrag (Mike) Grbic, members of his lab and collaborator Dusan Keckarevic at the University of Belgrade generated genomic data from diverse present-day Serbs that could be compared with ancient genomes and other present-day groups from the region.

Miodrag Grbic "We found there was no genomic database of modern Serbs. We therefore sampled people who self-identified as Serbian based on shared cultural traits, even if they lived in different countries such as Serbia, Croatia, Montenegro or North Macedonia," said Grbic, one of the senior authors of the study. "Co-analyzing the data with that of other modern people in the region, as well as the ancient individuals, shows that the genomes of the Croats and Serbs are very similar, reflecting shared heritage with similar proportions of Slavic and local Balkan ancestry."

Grbic was born in Novi Sad, Yugoslavia (now Serbia), just 30 km from the site of the Roman imperial city of Sirmium where he often spent his days as a child digging up ancient bricks in his grandmother’s garden.

"Ancient DNA analysis can contribute, when analyzed together with archaeological data and historical records, to a richer understanding of the Balkans’ history," said Grbic, also a visiting professor at the University of Belgrade. "The picture that emerges is not of division, but of shared history. The people of the Iron Age throughout the Balkans were similarly impacted by migration during the time of the Roman Empire, and by Slavic migration later. Together, these influences resulted in the genetic profile of the modern Balkans, regardless of national boundaries."

The Balkans formed a strategically important part of the Roman Empire. (PANONIAN/Wikipedia)