NEW YORK – A team from Croatia's Institute for Anthropological Research, the University of Vienna, Harvard University, and elsewhere has used genetic sequencing to investigate a massacre that took place some 6,200 years ago in present-day Croatia.
Using targeted enrichment sequencing methods, the researchers profiled mitochondrial and nuclear genome sequences in dozens of samples from the site in Potocani, Croatia. Their findings, appearing in PLOS One on Wednesday, suggested that the massacre included male and female victims across a wide age range from multiple families. Most of those killed had Neolithic Anatolian ancestry, though a small subset carried ancestry resembling Western European Mesolithic hunter-gatherers.
Together, the findings are consistent with a "systematic indiscriminate mass killing (slaughter) that was not aimed at a specific sex or age group or even family," co-first author Mario Novak, a researcher at the Institute for Anthropological Research's Centre for Applied Bioanthropology, explained in an email.
"Since this event occurred over 6,000 years ago, we don't have any written sources talking about this dreadful act," he added. Instead, he and his colleagues relied on relatively scarce archeological clues, along with genetic and bioanthropological data on the skeletons, to try to untangle the events that left dozens of corpses in a mass grave. Past studies suggested the remains represented victims of a massacre, since more than a dozen individuals buried there showed signs of head trauma.
"A comprehensive bioanthropological analysis of the skeletal remains from the Potocani mass burial showed perimortem cranial injuries in 13 individuals (six children, three adult males, and four females) located mostly on the side or the back of the head," the authors noted. "The injuries caused by different weapons, in combination with [the] archaeological context and absolute dates, point to a single episode of execution."
To dig into the event with the tools at hand, the investigators isolated DNA from 38 of the 41 individuals found at a mass burial site in the Croatian village of Potocani, which included children under five years old and adults as old as about 50.
They found that 93 percent of the individuals shared ancestry from a seemingly homogenous population. Much of the ancestry resembled Neolithic Anatolians, with around 9 percent ancestry from Western European hunter-gatherers. The individuals fell into a cluster that was genetically distinct from the present-day population in Croatia.
Based on mitochondrial sequences and genome-wide SNP patterns, the team determined that 11 of the victims had relatives in the same grave, falling into four family pedigrees. That suggested that the massacre did not target one specific family, the authors explained, while the age, sex, and ancestry also lined up with an event that was relatively unselective.
"We find no sign of population turnover around the time of the massacre, contrasting with the pattern at massacres in the Early Neolithic Pyrenees or in the Globular Amphora culture where the arrival of new people likely played an important role," the authors wrote, suggesting that "organized violence in this period could be indiscriminate just as indiscriminate killings have been an important feature of life in historic and modern times."