Despite a few individuals of eastern Mediterranean, northern African, and central European origins, the Etruscan-related gene pool remained stable for at least 800 years, spanning the Iron Age and Roman Republic period. The study finds, however, that during the subsequent Roman Imperial period, central Italy experienced a large scale genetic shift, resulting from admixture with eastern Mediterranean populations, which likely included slaves and soldiers relocated across the Roman Empire.

“This genetic shift clearly depicts the role of the Roman Empire in the large-scale displacement of people in a time of enhanced upward or downward socioeconomic and geographic mobility,” says Johannes Krause, Director at the Max Planck Institute for Evolutionary Anthropology.

Looking at the more recent Early Middle Ages, the researchers identified northern European ancestries spreading across the Italian peninsula following the collapse of the Western Roman Empire. These results suggest that Germanic migrants, including individuals associated with the newly established Longobard Kingdom, might have left a traceable impact on the genetic landscape of central Italy.

In the regions of Tuscany, Lazio, and Basilicata the population’s ancestry remained largely continuous between the Early Medieval times and today, suggesting that the main gene pool of present-day people from central and southern Italy was largely formed at least 1000 years ago.

Although more ancient DNA from across Italy is needed to support the above conclusions, ancestry shifts in Tuscany and northern Lazio similar to those reported for the city of Rome and its surroundings suggests that historical events during the first millennium CE had a major impact on the genetic transformations over much of the Italian peninsula.

“The Roman Empire appears to have left a long-lasting contribution to the genetic profile of southern Europeans, bridging the gap between European and eastern Mediterranean populations on the genetic map of western Eurasia,” says Cosimo Posth, Professor at the University of Tübingen and Senckenberg Centre for Human Evolution and Palaeoenvironment.