Tracing the Genomic History of the Balkans

[seqadmin]

A comprehensive study, led by international institutions including the Institute of Evolutionary Biology in Spain, the University of Belgrade, the University of Western Ontario, and Harvard University, has successfully reconstructed the genomic history of the Balkan Peninsula during the first millennium CE. Published in the journal Cell, this research utilized whole genome sequencing data from 146 ancient individuals to explore the demographic, cultural, and linguistic transformations in this region. The majority of the excavated samples were taken from Serbia and Croatia, with over a third that came from the Roman military frontier at the archaeological site of Viminacium.

The Roman Influence and Beyond
The analysis revealed significant demographic influxes into the Balkans during the Roman Empire, particularly from the eastern Mediterranean and East Africa. Notably, individuals of Anatolian descent contributed significantly to the genetic makeup of the Balkans, a finding similar to previous studies on ancient Rome. "During the Imperial period, we detect an influx of Anatolian ancestry in the Balkans and not that of populations descending from the people of Italy," states Íñigo Olalde, a co-lead author of the study.

The research also uncovered unique cases of long-distance mobility, including an adolescent boy with genetic links to Sudan. "The genetic analysis of his burial reveals that he probably spent his early years in the region of present-day Sudan, outside the limits of the Empire, and then followed a long journey that ended with his death at Viminacium," explains Carles Lalueza-Fox, a principal investigator of the study.

Early Integrations and Migrations
Interestingly, the study identified individuals in the Balkans with mixed Northern European and Pontic steppe descent from the 3rd century, highlighting the integration of people from beyond the Danube into Balkan society well before the fall of the Roman Empire.

"The borders of the Roman Empire differed from the borders of today's nation-states," comments Michael McCormick, a co-author from Harvard University. “The Danube served as the geographic and military boundary of the Empire. But it also acted as a crucial communication corridor that was permeable to the movement of people attracted by the wealth Rome invested in its frontier zone."

The Arrival of Slavic Populations
The collapse of Roman control in the sixth century marked the beginning of significant demographic shifts, with the arrival of Slavic-speaking populations. "According to our ancient DNA analysis, this arrival of Slavic-speaking populations in the Balkans took place over several generations and involved entire family groups including both men and women,” says Pablo Carrión, another co-lead author. This migration left a substantial genetic imprint on modern Balkan populations, with varying degrees across different regions.

Interdisciplinary Approach
This study stands out for its interdisciplinary collaboration, bringing together over 70 researchers from fields such as archaeology, anthropology, history, and genetics. "Ancient DNA analysis can contribute, when analyzed together with archaeological data and historical records, to a richer understanding of the history of Balkans history,” notes Miodrag Grbic, a coauthor from the University of Western Ontario. The genomic data from this research offer a nuanced perspective on the shared historical and genetic heritage of the Balkan populations, transcending modern national boundaries.

Original publication: Olalde & Carrión et al., 2023, *Cell* 186, 1-14; December 7, 2023; DOI: https://doi.org/10.1016/j.cell.2023.10.018