Scientists have pieced together more than 6,000 years of human migration in southern South America using ancient DNA, offering a clearer picture of how early populations lived, moved, and interacted. The research suggests that prehistoric communities in the region were far more diverse and mobile than previously believed, based on archaeological evidence alone.
The study, led by Kim-Louise Krettek of the University of Tübingen in Germany and published in Current Biology, examined genome-wide data from 52 individuals. These individuals were buried across 31 archaeological sites in modern-day Argentina and Uruguay. The remains date from roughly 6,000 years ago to just 150 years ago, covering key regions such as the Pampas, Northwest Patagonia, the Paraná River Delta, and eastern Uruguay.
Findings reveal that populations in these areas did not follow a simple or uniform pattern of development. Instead, genetic data shows a dynamic history marked by multiple migrations, overlapping ancestries, and long-distance connections.
Multiple ancestries reshape understanding of early Pampas populations
One of the most significant discoveries centers on the Middle Holocene Pampas. Earlier theories suggested a single, continuous genetic group inhabited the region. However, the new evidence points to at least three distinct ancestries coexisting over time.
Two of the oldest groups, dating back around 7,700 and 6,800 years, share a common genetic foundation. A third group, identified from remains about 6,000 years old, shows strong links to populations from southeastern Patagonia, located hundreds of miles to the south. This suggests early long-distance movement across the region.
Researchers also identified a separate ancestry that entered the southern Pampas approximately 5,500 years ago. This group expanded rapidly and became the dominant genetic presence by around 4,000 years ago. Over time, this lineage spread into neighboring regions, reaching the Lower Uruguay River roughly 1,500 years ago and Northwest Patagonia by at least 600 years ago.
Long-lasting Andean links and regional cultural divides
In Northwest Patagonia, genetic ties to Andean populations appeared as early as 4,400 years ago and persisted for thousands of years, including into the colonial period. One individual from the Aquihueco site showed particularly strong Andean ancestry, indicating possible recent migration from the Andes at that time.
Meanwhile, in the Paraná River Delta, researchers identified a clear genetic distinction between populations in the upper and lower areas around 600 years ago. This division aligns with known differences in pottery styles, suggesting the presence of separate cultural groups despite their close geographic proximity.
Coastal migration signals broader regional connections
Another notable finding comes from eastern Uruguay, where a 730-year-old individual showed genetic links to coastal communities in southern Brazil. These groups, known for building Sambaqui shell mounds, were associated with the spread of Kaingang ancestry and Je language speakers.
Researchers believe this points to a coastal migration route that carried populations and cultural traits southward into Uruguay. Overall, the study highlights how migration and interaction played a key role in shaping the region’s cultural and genetic diversity over thousands of years.