Ancient graves reveal unexpected link to modern Andean people
The findings also reveal that while people in other regions resorted to violence, inhabitants of the Uspallata Valley lived peacefully with migrants during a time of crisis.
In the past, archaeologists have often claimed that the original inhabitants of the scenic Uspallata Valley in Argentina are extinct. But a recent study in Nature tells a different story: the people living in the wider region today are related not just to the farmers buried in the valley hundreds of years ago, but also to the hunter-gatherers that lived in the area even earlier.
Human remains found in several burial places across the valley tell a story of struggle with famine and disease and of collaboration in the face of crisis.
“In many places in the Andes, we see evidence of violence in this period not just on the bones, but in the architecture too,” says National Geographic Explorer Ramiro Barberena, who led the research team. “In Uspallata, there is almost none.”
Instead of violent clashes over dwindling resources, the study reveals a story of social resilience and solidarity, and of a society in which women may have led the way in seeking help in times of need. It also reinforces the Indigenous Huarpe view that their people have lived in the valley all along.
Famine and disease
Barberena, who is an archaeologist at the Interdisciplinary Institute of Basic Science in Mendoza, Argentina, had long been fascinated by a 700-year-old burial site called Potrero las Colonias. In the 1930s, archaeologists digging there found the remains of more than a hundred people. In 2018, Barberena finally had a chance to examine the chemical signatures in the old bones and teeth to figure out who these people were and where they had come from. The results, he says, were surprising.
“From 130 people, we initially sampled seven,” he says, “and all seven were migrants.”
His team drew that conclusion based on the levels of various kinds of strontium embedded in the bones and teeth, which differ depending on where someone grew up. Yet the biggest revelation came when the team analyzed DNA from the remains of 36 people buried there.
When the researchers compared this DNA to that of people buried at several other locations, they found a clear link with hunter-gatherers found at another site in the area who lived more than 2,000 years ago. This shows these earlier inhabitants were not replaced by farmers, as is often expected, but started farming themselves, which allowed them to settle down and support a larger population. The same analysis also revealed that people living in the wider region whose DNA was analyzed earlier are still related to the hunter-gatherers and ancient farmers.
The carbon in later teeth shows people ate a lot of corn, which may also explain some of the tooth decay. Stripes in the tooth enamel and spongy bone in some of the skulls–both indicators of famine–suggest the transition to farming may also have been a bit of a trap, however. When drought struck the region and irrigation channels ran dry, the ever-thirsty corn plants they relied upon may have withered away.
This also made people more vulnerable to disease: the DNA analysis revealed some people were infected with a lineage of tuberculosis bacteria that was first found in seals, according to Nicolás Rascovan, a paleogeneticist at the Pasteur Institute in Paris and an author of the paper, which was published last month.
“How it got into humans we don’t know yet,” he says.
The fact that it did make its way to Uspallata suggests that even these relatively remote mountain valleys may have been in contact with the rest of the world, he adds, and the cramped quarters where exhausted mountain travelers were likely seeking shelter at night may have been hotbeds of disease.
Neither famine nor disease appears to have kept people in the valley from welcoming migrants, however. DNA from several burial sites revealed immigrants buried alongside the locals. They also did not find signs of conflict-related trauma on the bones, further suggesting the migrants joined their neighbors peacefully.
A sense of community
Many of the migrants were women and children, including a grandmother, a mother, and a daughter, at Potrero las Colonias. To the researchers, this suggests entire families migrated together, and that women may often have led the way, perhaps because they played a prominent role in maintaining relationships between settlements, as they do among the Huarpe people living in the valley today.
“A particularly thought-provoking aspect of this study is how the combination of multiple lines of evidence sheds light on the social dimensions of migration,” says Josefina Motti, an anthropologist from the Universidad Nacional del Centro de la Provincia de Buenos Aires in Argentina, who has been involved in several studies of the genetic history of the wider region, but not this one. She also highlights the “apparent lack of conflict in the integration of migrants into local communities” and what the study reveals about women's role in maintaining social cohesion.
“We believe it shows people in the region felt connected to each other even if they grew up miles apart,” says Barberena, “which is an attitude that continues until today.”
Ever since he started working in the valley, Barberena has been collaborating with the Indigenous Huarpe people living there. Three community leaders are among the coauthors of the new study. They provided their own perspective and shared their community’s oral traditions to help the research team better understand the new findings.
“My first feeling was one of distrust,” says Claudia Herrera, leader of the Huarpe community called Guaytamari. “For years, we have been treated as just an object of science, and our identity was denied. But we understood that we are in different times, and that this dialogue was an opportunity.”
Genetic evidence should be treated very carefully in this context, cautions Rascovan. “The identity and rights of any inhabitant of a region or member of a community is rather defined by social and cultural bonds than by genetic makeup, whatever it may be,” he says.
But for those who have always felt they belong there, the long presence of people in the region, revealed by the findings, resonates deeply.
“My community has a long and difficult history of enslaved labor in foundries in the past and unhealthy wage labor on fields sprayed with agrochemicals today,” says Graciela Coz of the Huarpe community known as Llahué Xumec. “There are many people with disabilities in my community, including my own three kids. It was interesting to learn about the illnesses our ancestors struggled with.”
The Huarpe community and researchers alike hope that the new findings may help ward off extractive mining projects in the area that would threaten the livelihoods of local people and the survival of some valuable archaeological sites yet to be discovered and explored.
“Today we also live in a Western system that sets the general policies in the territory,” says Guaytamari community representative Matías Candito. “Science can be a tool to help us defend our identity.”
