The genomic portrait of the Picene culture provides new insights into the Italic Iron Age and the legacy of the Roman Empire in Central Italy

Abstract

Background: The Italic Iron Age is characterized by the presence of various ethnic groups partially examined from a genomic perspective. To explore the evolution of Iron Age Italic populations and the genetic impact of Romanization, we focus on the Picenes, one of the most fascinating pre-Roman civilizations, who flourished on the Middle Adriatic side of Central Italy between the 9^th and the 3^rd century BCE, until the Roman colonization.

Results: More than 50 samples are reported, spanning more than 1000 years of history from the Iron Age to Late Antiquity. Despite cultural diversity, our analysis reveals no major differences between the Picenes and other coeval populations, suggesting a shared genetic history of the Central Italian Iron Age ethnic groups. Nevertheless, a slight genetic differentiation between populations along the Adriatic and Tyrrhenian coasts can be observed, possibly due to different population dynamics in the two sides of Italy and/or genetic contacts across the Adriatic Sea. Additionally, we identify several individuals with ancestries deviating from their general population. Lastly, in our Late Antiquity site, we observe a drastic change in the genetic landscape of the Middle Adriatic region, indicating a relevant influx from the Near East, possibly as a consequence of Romanization.

Conclusions: Our findings, consistently with archeological hypotheses, suggest genetic interactions across the Adriatic Sea during the Bronze/Iron Age and a high level of individual mobility typical of cosmopolitan societies. Finally, we highlight the role of the Roman Empire in shaping genetic and phenotypic changes that greatly impact the Italian peninsula.

Keywords: Adriatic cultures; Ancient DNA; Ancient Italy; Archaeogenomics; Iron Age; Late Antiquity; Novilara necropolis; Picenes; Proto-history; Roman Empire.

Fig. 1

Location of the sites analyzed in this study. On the left, map of Italy with the Picene area highlighted in red. On the right, the magnification of Central Italy showing the location, the period, and the number of samples for each necropolis analyzed in this study. Symbols associated with necropolises are the same as in PCA (Fig. 2A)

Fig. 2

Population structure of the Italic IA and LA period. A PCA with the newly reported samples and a relevant subset of modern and ancient individuals from the literature (see also Additional file 3: Fig. S1). Modern samples are pictured in gray. B Unsupervised Admixture analysis at k = 4. Above, a subset of samples representing the four ancestral components that contributed to the European gene pool since the Bronze Age: Serbia Iron Gates Mesolithic (blue), Anatolian Neolithic (orange), Caucasus Hunter-Gatherers (CHG)/Iran Neolithic (purple), and Eastern Hunter-Gatherers (EHG)/Yamnaya (green); below, genetic make-up of the newly reported individuals

Fig. 3

Genetic affinity and modeling of the Italic IA populations. A D-statistics in the form D(X,Y; Italy_BA_EBA; YRI.SG), where X and Y are Italic IA groups. If D > 0, the Italian BA individuals (Italy_BA_EBA) are more closely related to population X, while if D < 0, Italy_BA_EBA is more closely related to population Y. In the first two tests, comparisons between Italic groups on the same side of the peninsula (Italy_IA_Apulia vs Picenes; Etruscans vs Italy_IA_Romans) are represented; the third test shows the comparison between all the Tyrrhenian vs all the Adriatic IA populations. B qpAdm with 3 source populations for the Italic IA groups. Above, Italic IA ethnic groups analyzed so far. Below, Italic IA Adriatic and Tyrrhenian populations grouped together. For each model, p-values are reported

Fig. 4

Proposed scenarios for the genetic evolution of the Italic IA. The differences observed between Italic IA Adriatic and Tyrrhenian populations, mainly represented by different proportions in the Yamnaya-related ancestry (blue color in the pie charts) could be explained by two scenarios: (1) differential arrival of the Yamanaya-related ancestry (blue arrows); (2) trans-Adriatic genetic connection represented (red arrows). Green gradients indicate the putative area of origin of individuals with different genetic ancestry identified among the Central Italic IA (based on Antonio et al. (2019), Posth et al. (2021), and the putative outliers here identified)