The genetic landscape of northeastern Iberian communities from the early to late Iron Age

During the Iron Age (800-100 BCE), the Iberian Peninsula was home to diverse cultural groups. Indigenous Iberians in the eastern coastal regions and Celtic-speaking populations in central and western regions interacted with Mediterranean civilizations, including the Phoenicians and Greeks during the Early Iron Age, and later Punics/Carthaginians and Romans. Iberian culture developed along the Mediterranean coast around the 6th century BCE, flourishing between 450-200 BCE. While archaeological evidence is abundant, genetic studies remain scarce due to predominant cremation practices. However, the tradition of burying newborns beneath houses provides a unique opportunity for paleogenomic analysis. This study investigates the genetic profile of northeastern Iberians from the Early to Late Iron Age by analyzing 54 newborns from three sites: the fortress of Vilars (775–325 BCE), Sant Miquel d’Olèrdola (350–200 BCE), and El Camp de les Lloses (125 BCE–50 CE). More than 20k SNPs from the 1240k panel are reported for 22 individuals, and mitochondrial data for a further 9 individuals. Our findings support the archaeological hypothesis that Iberians emerged from local Bronze Age groups, evolving gradually through the Iron Age, with increased Mediterranean ancestry. This genetic continuity persisted until the Late Iron Age and the arrival of the Romans. From then on, the new genetic influences led to a more diverse Iberian-Roman population alongside significant social and political transformations. This study provides the first paleogenomic insights into the enduring genetic legacy of Iberian communities, highlighting the complex interplay between cultural and genetic continuity in the northeastern Iberian Peninsula.