Archaeologists have made a groundbreaking discovery in Argentina, unearthing a previously unknown ancient lineage of humans that sheds new light on how our species populated one of the last places on Earth to be inhabited by modern humans.
The research, published in the prestigious journal Nature, reveals that this newly identified group of people developed in remarkable isolation, rarely intermingling with other populations while establishing diverse cultures and languages across the region.
A Continent's Hidden History
While modern humans first emerged in Africa before migrating worldwide, the southern tip of South America represented one of the final frontiers for human settlement. Until this discovery, the oldest evidence of human presence in Argentina dated back approximately 14,000 years to the Arroyo Seco archaeological site in the Pampas region.
Study author Javier Maravall López from Harvard University expressed the significance of their findings, stating: "We found this new lineage, a new group of people we didn't know about before, that has persisted as the main ancestry component for at least the last 8,000 years up to the present day."
Dr López described the discovery as "a major episode of the history of the continent that we just weren't aware of", highlighting how much remains unknown about the first populations to establish settlements in this part of the world.
Revolutionary Genetic Analysis
The international research team conducted an extensive analysis of ancient human DNA, examining samples from bones and teeth of 238 indigenous individuals up to 10,000 years old. This effort increased the number of genetic samples from the central Southern Cone region – encompassing modern-day Argentina, Chile and Uruguay – by more than tenfold.
Scientists compared this data with existing ancient DNA from 588 other indigenous people from across the Americas who lived between 12,000 years ago and the period of European contact.
The research focused on specific sections of the human genome known as single-nucleotide polymorphisms (SNPs), which vary between individuals. This approach enabled researchers to make detailed inferences about genetic relationships, identifying which individuals shared common ancestry and which were more distantly related.
Eight Millennia of Isolation and Diversity
The investigation revealed that this newly discovered human lineage appeared in the region by approximately 8,500 years ago and endured on the continent for over eight millennia. Remarkably, this group became the core ancestral component of central Argentina while developing what researchers describe as a "surprisingly diverse mix of indigenous cultures."
"People with the same ancestry, in an archipelago-like fashion, were developing distinctive cultures and languages while being biologically isolated," Dr López explained.
The study found that this central Argentina lineage eventually expanded southward around 3,300 years ago or earlier, mixing with the Pampas population and eventually becoming the dominant ancestry in that region.
Previous DNA studies had suggested that by 9,000 years ago, Native Americans began differentiating into three identifiable lineages: one in the central Andes, another in Amazonia's tropical lowlands, and a third in the southern regions including the Pampas, Chile and Patagonia. This new discovery adds a fourth, previously unknown branch to this family tree.
Researchers noted that while the newly found group did intermingle with others to some extent, they "mostly kept to themselves", maintaining biological separation despite developing rich cultural diversity. The scientific team hopes future studies will help explain this puzzling lack of migration and mixing between ancient groups in the region.
