Can DNA solve the mystery of Europe’s pointy skulls?
A new genomic study tries to see if there’s a correlation between artificial cranial deformation and migration following the collapse of the Roman Empire.
Skull modification may have been an extreme way to declare one's identity during the Migration Period (ca. 300-700 A.D.), when so-called "barbarian" groups like the Goths and the Huns were vying for control of territory in Europe after the collapse of the Roman Empire. Could ancient DNA help archaeologists pinpoint what exactly those cultural alliances were?
At a site called Hermanov vinograd in eastern Croatia, archaeologists recently found a peculiar burial pit that contained the remains of three teenage boys. The teens were buried sometime between 415 and 560 A.D.
Two of the boys had artificially deformed skulls, and a DNA analysis, published today in the journal PLOS ONE, has now revealed another curious fact: The three boys buried together all had dramatically different genetic backgrounds. The one without any skull modifications had ancestry from western Eurasia, the teen who had a heightened but still rounded skull had ancestry from the Near East, and the boy who had a very elongated skull had ancestry mainly from East Asia.
"When we got the ancient DNA results we were quite surprised," says senior author Mario Novak of the Institute for Anthropological Research in Zagreb, Croatia. "It is obvious that different people were living in this part of Europe and interacting very closely with each other. Maybe they used artificial cranial deformation as a visual indicator of membership in a specific cultural group."
Artificial cranial deformation (ACD) involves binding a child's head from infancy to deform the skull, and is a form of body modification that has been practiced since at least the Neolithic period in cultures all over the world. In Europe, the practice of ACD appeared around the Black Sea in the second and third centuries A.D., reached a high-point in the fifth and sixth centuries and faded away at the end of the seventh century, says Susanne Hakenbeck, a University of Cambridge historical archaeologist who has studied skull modification in Europe (Hakenbeck was not involved in the study).
According to Novak, about a dozen ACD skulls have been found in Croatia outside of Hermanov vinograd, but to date scientific studies of these skulls have not been published.
Enter the Huns
Novak and his colleagues think their findings lend support to a long-standing theory that the Huns—a nomadic, horse-riding confederacy that some believe originated in East Asia—introduced ACD in Central Europe.
"For the first time now we have physical, biological evidence of the presence of East Asian people, probably the Huns, in this part of Europe, based on ancient DNA results," Novak says.
However, the exact homeland of the Huns is a matter of debate among archaeologists, and other scholars have suggested this group came not from East Asia but from north of the Black Sea.
Genetic data alone also can't prove that a specific individual from the past—such as the boy with the most elongated skull at Hermanov vinograd—would have identified as a Hun, which Novak is quick to acknowledge.
"I wouldn't say that we can say, based on ancient DNA, that this [person] is an Ostrogoth or this [person] is a Hun," Novak says. "It also depends on how people felt about themselves, which is quite subjective"—and fairly impossible to glean without written sources, which the Huns didn't leave.
After studying the spread of ACD skulls discovered in Europe and Eurasia, Hakenbeck doesn't think there's an exclusive link between Huns and the practice. "More likely the practice came to Europe through connections with the Eurasian steppes that aren't necessarily historically attested," she says. "It's possible that the Huns contributed to that, but they weren't the only ones."
More surprising stories
How the teens came to be buried in the pit together is also still a mystery. Hermanov vinograd is the site of a large Neolithic settlement but there is no Migration Period settlement in the immediate vicinity. The one-off burial wasn't part of any larger, established cemetery, and was perhaps linked to a community of nomads or a group of people who lived elsewhere, Novak says. The boys had similar diets in their final years, suggesting they had lived in the same place for some time. They were buried with horse and pig bones, and their cause of death is unclear. Though the incomplete skeletal remains show no signs of a violent death, the researchers think it's possible that the teens were killed in some sort of ritual, or that they may have died of plague or another quick-killing disease.
"The caveat is really that it's a small sample size—it's just one burial and we don't have much information about what it is," says Krishna Veeramah, a geneticist at Stony Brook University in New York, who was not involved in the study. "But even so, it's interesting that you'd have such diversity."
Last year, Veeramah and his colleagues published a study analyzing the DNA of women with artificial cranial deformation who had been buried in southern Germany during the Migration Period. Those women had very diverse genetic backgrounds, including possible components of East Asian ancestry, and one possible explanation for this pattern is that women with ACD skulls migrated westward by marriage. According to Hakenbeck, the majority of individuals with modified skulls in Europe and western Eurasia are female, at a ratio of about 2 to 1.
Novak says that with more samples, researchers could get a finer and more precise resolution on where people who practiced ACD came from and figure out if it really was a visual indicator of association with a certain cultural group.
There hasn't been much work studying the DNA of individuals with ACD skulls, and the Migration Period in Europe hasn't been very well covered in the plethora of ancient DNA studies that have been published in the last two decades, says Ron Pinhasi of the University of Vienna, another senior author of the new study.
In terms of genetic data, "we know a lot more about what happened 5,000 years ago in Europe than we know what happened 1,500 years ago in Europe," Pinhasi says. However, he thinks that's starting to change, and he expects to see more investigations on DNA samples from the last 2,000 years.
"I think we're going to find a lot more surprising stories," says Pinhasi. "And maybe when they're pieced together, we'll have a very different understanding of the Migration Period."