Mysterious human group lived in Argentina for thousands of years

Ancient genetic data from central Argentina reveal a previously unknown human population that endured there for millennia.

The finding shows that one long-lasting group stayed rooted in its homeland while cultures, languages, and technologies shifted around it.

Researchers read this story in DNA taken from human remains representing hunters, fishers, and farmers who once lived across the region.

The study turns a blank spot on South America’s genetic map into one of its best documented chapters.

A new look at an overlooked region

The research was led by Javier Maravall López, a geneticist at Harvard University. He uses DNA to study the long term history of Indigenous peoples throughout the Americas.

The researchers relied on ancient DNA, genetic material preserved in old bones and teeth, to probe deep history.

The analysis focused on central and northern Argentina, a region that earlier genetic work had mostly skipped.

Filling a gap in the genetic map

Earlier studies of South American genetics identified three main ancestry patterns in the Andes, Amazonia, and the far south. Central Argentina sat between those zones, which made it a key test case for how different ancestries might meet.

Archaeological finds suggest that the central Southern Cone was among the last parts of Earth settled by modern humans.

That late occupation, combined with limited DNA sampling, left this region as a blind spot in reconstructions of population history.

What ancient genetic clues reveal

To build a detailed timeline, the team studied bones and teeth from hundreds of individuals recovered across central and northern Argentina.

From this material, the researchers produced genome-wide data, genetic information covering almost every chromosome, for 238 ancient people.

The scientists enriched each sample for over a million single nucleotide polymorphisms (SNPs), tiny one letter DNA changes that are particularly informative about ancestry. 

Comparing these markers with data from other ancient and present day Native Americans revealed which groups were related and where their ancestors had mixed.

Samples that span human history

Ages for the remains came from radiocarbon dating, a method that estimates how long it has been since bone or charcoal stopped absorbing carbon. 

Because the samples stretch from the first burials in the region to people living just before European contact, they span human history here.

Using mathematical tools, the team reconstructed population structure and estimated past community sizes. 

The experts also searched for close relatives in the data, which reveals marriage practices and social rules that archaeology alone cannot show.

Tracing a lineage that stayed put

One striking result was a deep lineage, a long-lasting branch of related people found in central Argentina. Its earliest known member lived about 8,500 years ago in the same region.

Most later individuals from this area inherited much of their DNA from that lineage, which points to unusually strong continuity through time. Even a long period of severe drought between roughly 6,000 and 4,000 years ago did not erase this ancestry from the record.

Mapping ancestry across the landscape showed that central Argentina ancestry blended gradually into neighbors along two clines, gradual genetic shifts over distance. 

“We found that the central Argentina lineage is geographically structured along two clines, a new group of people we didn’t know about before,” said López.

Ancient humans in Argentina

Although the genetic signal looks relatively simple, archaeological records show a patchwork of languages and cultural traditions across central Argentina. 

The new results suggest that much of that diversity arose locally within a population that shared common ancestry, not from large waves of newcomers.

Within the study area, the northwest shows elevated rates of close-kin unions, marriages between relatives such as cousins. 

A separate study of ancient individuals in the Andes found similar increases in close kin marriages during the centuries just before European contact.

Kin-based social organizations

Spanish colonial accounts and modern anthropology describe the ayllu system, a kin-based social unit that links households through shared ancestry. 

Anthropologists describe ayllus as extensive social groups bound by kinship, reciprocity, land claims, and remembered ancestors. 

The pattern of genetic homogeneity within communities and close relative marriages in northwest Argentina fits with kin-based social organizations similar to ayllus. 

At the same time, DNA from the study shows contacts between central Argentina ancestry and Andean related groups in the northwest.

Why this history matters today

Those links hint at long standing regional ties that did not erase local identities. Among the ancient individuals, one woman who lived about 10,000 years ago in the Pampas represents an early population in the region.

Her DNA connects more strongly to later peoples in the Southern Cone than to ancient groups farther north. Together with the central Argentina lineage, this pattern supports a picture of rapid spread into South America.

After that initial expansion, many populations appear to have remained in the same broad regions for very long periods. The findings show that major shifts in tools, farming, or language do not always come with incoming populations.

In central Argentina many cultural changes happened while core ancestry stayed largely the same. For descendant communities, this genetic record offers another line of evidence that deep roots in the region stretch back many thousands of years.

Questions for future research

The research also highlights histories that written documents barely touch, since most of the people behind these genomes never appeared in official records.

Future work will need more densely sampled time series, especially from regions such as the Gran Chaco and parts of the Pampas.

Those links could show how individual communities responded to droughts, new crops, and contacts with neighbors. For now, the story from central Argentina shows that human history includes long stretches of continuity as well as episodes of migration.

The newly uncovered lineage from the Pampas and nearby regions adds a missing chapter to American history and highlights the power of genetic tools.

The study is published in the journal Nature.

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