One of the largest DNA analyses ever conducted in the Middle East points to the origin of an ancient culture that settled in the area thousands of millennia ago. Publishing their work in Nature Communications, a multinational team of researchers believes it could resolve a long-standing debate on where the ancient people from an important evolutionary period came from.

Around 6,000 to 7,000 years ago, an ancient civilization in modern-day Iran began to undergo cultural, social, political, and economic transitions in what is now known as the Chalcolithic period between the first farming societies of the Neolithic era and the urban and literate societies of the Bronze Age. During this time, humans began establishing permanent village settlements and producing food at an agricultural scale. But where these people came from and what sparked these changes has long mystified archaeologists – until now.

According to scientists, the research is one of the largest ancient DNA studies conducted from one archaeological site and is the largest ever reported in the area.

First discovered in 1995, Israel’s Peqi’in Cave houses more than 600 people buried in its stalactite walls. Among the remains are a wide variety of jars, ancient ceramic containers filled with bones of the dead known as ossuaries, and other burial gifts meant to help transition the deceased to the next world. Some of these items are typical of the region, while others come from remote areas suggesting an exchange of ideas and culture between different regions.

Archaeologists examined 22 individuals exhumed from the mass burial site whose DNA had been well preserved in bones likely due to the cool conditions in the cave and the limestone crust covering them.

"The genetic analysis provided an answer to the central question we set out to address," said David Reich of Harvard University in a statement. "It showed that the Peqi'in people had substantial ancestry from northerners – similar to those living in Iran and Turkey – that was not present in earlier Levantine (area) farmers."

Genetic analyses from the Peqi’in Cave showed different characteristics from human remains found in the area, such as genetic mutations that could contribute to blue eye color. Because other Chalcolithic sites in the region had similarly decorated artifacts, it is suggested they could have been part of a unique population that had migrated from nearby areas.

“These ancient DNA results reveal a relatively genetically homogeneous population in Peqi’in,” write the authors. “We show that the movements of people within the region of the southern Levant were remarkably dynamic, with some populations, such as the one buried at Peqi’in, being formed in part by exogenous influences.”

Archaeological evidence suggests there were dramatic changes in how people settled and that an abandonment of sites around 6,000 years ago created a “profound cultural upheaval” that ultimately led to the extinction of Chalcolithic culture in this region.  

"Indeed, these findings suggest that the rise and falls of the Chalcolithic culture are probably due to demographic changes in the region," said study author Hila May.