Roman rule reshaped Iberia's gene pool more than later migrations, a study finds

A study of 243 ancient genomes

A study published in the journal Cell on 21 October 2026 analyses 243 ancient genomes from 31 archaeological sites on the Iberian Peninsula, covering the period between the 1st and 8th centuries. The research is led by the Institute of Evolutionary Biology (IBE, CSIC-UPF), with participation from Iphes-Cerca, the Natural Sciences Museum of Barcelona, Harvard University and the University of the Basque Country (EHU). Researchers extracted DNA from bones and teeth, compared its genetic variants with those of ancient populations from other regions, and carried out 35 new radiocarbon dates to refine the age of some remains. The team describes it as the first systematic, large-scale genetic analysis of the peninsula's population across that span.

Rome reshaped the gene pool

Before the Roman expansion, Iron Age populations were relatively homogeneous genetically. From the 1st to the 4th centuries, the genomes show far greater diversity, with significant ancestry from the eastern Mediterranean and North Africa. Of 66 individuals from the imperial era, 55, or 83%, carried some ancestry linked to the eastern Mediterranean, especially Anatolia in present-day Turkey. The Italian-linked footprint was much smaller, with only 8 of 269 individuals from the Roman and late antique periods carrying ancestry associated with Italy or the central Mediterranean. The study does not conclude that only eight Italians arrived, nor that the other individuals migrated directly from Italy.

Later migrations left a smaller imprint

After the Roman period, migrant groups contributed between 12% and 22% of the ancestry, depending on region and social context. The authors conclude that great political and cultural changes were not always accompanied by demographic changes of the same scale. From the 5th century, Suevi, Vandals, Alans and Visigoths arrived and reshaped power, language and culture, but they did not replace the population. Study co-author Carles Lalueza-Fox, who now directs the Natural Sciences Museum of Barcelona, put the Roman impact in these terms:

Our data show that romanization also brought an important demographic transformation, connecting local populations with human movements from across the Mediterranean.

He added that future studies of medieval and post-medieval genomes are needed to connect the ancient inhabitants with present-day populations.

Two siblings, 725 km apart

Two siblings were buried about 725 km apart. One was laid to rest in Augusta Emerita, modern Mérida, and the other at Ildum, a former staging post beside the Vía Augusta in Castellón province. Both had entirely Central European ancestry, and the researchers describe both as first-generation immigrants. The richness of their graves and of the adjacent burials points to elite status. ABC reports that the Mérida burial lies alongside the nine women's tombs from the 5th century presented in 2021 as the Suevic princesses of Mérida, who may have belonged to the entourage of King Requila. Lalueza said the researchers do not know who the siblings were or why they were buried so far apart, and he suggested they may represent an unknown chapter of the Suevic expansion.

Other family links

The genomes also revealed family ties at several sites. At Els Masos in Cambrils, Tarragona, three individuals were identified as a mother, a father and their daughter. At La Mineta, two individuals were found to be siblings, and at Castellets, two individuals share a first-degree relationship compatible with parent and child. At Cova Simanya in Barcelona, three individuals dated between the 4th and 5th centuries came from the upper levels of the cave, which the team says was used as a burial space.