Blue-eyed, fair-skinned settlers inhabited the Levant some 6,500 years ago, according to an international interdisciplinary team of scientists. An article released Monday in the peer-reviewed journal Nature Communications solves the mystery of how Chalcolithic culture got to the Galilee: via population migration.

When they mapped the genomes of bones from 22 of the 600 individual skeletons discovered in a massive necropolis near Peki’in in the north of the country, the scientists found a genetic mix quite unlike that of previous and successive settlers of the region.

The findings address the decades-long arguments over the origins of this distinctive Late Chalcolithic culture, the artifacts of which “have few stylistic links to the earlier or later material cultures of the region,” write the authors.

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The highly artistic, bubble-in-time relics have “led to extensive debate about the origins of the people who made this material culture.” Did it come about by local populations adopting and implementing practices found in existent cultures in the north, or through migration?

In the article, “Ancient DNA from Chalcolithic Israel reveals the role of population mixture in cultural transformation,” the scientists concluded that the homogeneous community found in the cave could source ~57% of its ancestry from groups related to those of the local Levant Neolithic, ~26% from groups related to those of the Anatolian Neolithic, and ~17% from groups related to those of the Iran Chalcolithic.

The study was led by Tel Aviv University researchers Dr. Hila May and Prof. Israel Hershkovitz of the Department of Anatomy and Anthropology, Dan David Center for Human Evolution and Biohistory Research; Dr. Dina Shalem of the Institute for Galilean Archaeology at Kinneret College and the Israel Antiquities Authority, who was one of the original archaeologists who excavated the cave in 1995; and Harvard University’s Éadaoin Harney and Prof. David Reich.

“The genetic analysis provided an answer to the central question we set out to address,” said Harvard’s Reich. “It showed that the Peki’in people had substantial ancestry from northerners – similar to those living in Iran and Turkey – that was not present in earlier Levantine farmers.”

Archaeologist Shalem said the natural stalactite cave, 17 meters long and 5-8 meters wide, is unique both for the number of those buried in it and the “outstanding motifs” — geometrical and anthropomorphic designs — depicted on the ossuaries and jars holding the skeletal remains.

“Some of the findings in the cave are typical to the region, but others suggest cultural exchange with remote regions. The study resolves a long debate about the origin of the unique culture of the Chalcolithic people,” said Shalem. “Did the cultural change in the region follow waves of migration; the infiltration of ideas due to trade relations and/or cultural exchange; or local invention? We now know that the answer is migration.”

Added Harvard’s Harney, who led the statistical analysis for the study: “We also find that the Peqi’in population experienced abrupt demographic change 6,000 years ago.”

The Chalcolithic era, also dubbed the Copper Age, follows the Stone Age and precedes the Bronze Age. There are already several DNA analyses for Bronze Age settlement in the Levant, including last summer’s publication of research from Bronze Age burials that shows that 93 percent of the ancestry of modern Lebanese ancestry comes from the Canaanites. Now, the new Peki’in genome mapping fills in a void of 3,000 years of DNA analysis.

The DNA research gives an answer to questions asked by archaeologists throughout Israel who have unearthed remains of copper and other metalworking technologies that were not local to Israel but rather to Turkey. Discovered in 1961, the Cave of the Treasure near Ein Gedi housed a hoard of 429 objects hidden 6,500 years ago, some of which were created from copper thought to have been imported from eastern Turkey or the Caucasus. Likewise, the Negev’s Ashalim Cave, found in 2012, contained a lead object created by foreign Anatolian technology.

With the new study’s conclusion that some half of the indigenous Chalcolithic people’s genome derived from ancient Turkey and Iran, it appears that these artifacts may have arrived during migration, and were not merely as the byproducts of a trade route as previously suggested.

A chance find of huge import

The Peki’in burial cave, the largest burial site ever identified from the Late Chalcolithic period in the Levant, was discovered by chance in 1995 during roadworks. Then, a tractor caused a portion of the roof of the cave to collapse, unveiling hundreds of ossuaries and a multi-tiered, paved system of burial platforms.

In a 1998 Archaeology Odyssey article on the dig, the original archaeologists hypothesized that the cave was an important and prestigious burial site, calling it “the hub of a wheel, with its spokes radiating in all directions.”

The archaeologists saw indications that bodies were taken to the cave from all directions for internment — as far as the Jordan Valley, the Judean and Negev deserts, and the coast of Lebanon. “Clearly, great efforts were made to transport the bones of the dead to this revered site,” they write.

The artifacts discovered in the cave are “a veritable museum of Chalcolithic art.”

“Its cultic objects and grave goods exhibit artistic styles of various Levantine subcultures,” which, state the archaeologists, suggest the cave served as “a regional mortuary center, where people from all over ancient Palestine converged to bury their dead.” According to the new study, radiocarbon dating finds the cave was in use throughout the Late Chalcolithic (4500–3900 BCE).

Unfortunately, although the cave itself was sealed for some 6,000 years, quite soon after its initial closure, grave robbers entered and caused mass destruction at the site. It it is assumed that they took most of the metal objects that would have been buried with the dead, as there is a disproportionately low number in relation to other sites of the same era.

Despite this rampant vandalism, the plethora of preserved human remains could still be used for genetic testing. According to the Nature Communications article, in a dedicated clean room facility at Harvard Medical School, the scientists “obtained bone powder from 48 skeletal remains, of which 37 were petrous bones known for excellent DNA preservation.”

The data extracted from the skeletal remains, taken from 22 individuals, “is of exceptional quality given the typically poor preservation of DNA in the warm Near East,” wrote the scientists.

According to Tel Aviv University’s Hershkovitz, “human DNA was preserved in the bones of the buried people in Peki’in cave, likely due to the cool conditions within the cave and the limestone crust that covered the bones and preserved the DNA.”

As a result, the researchers were able to do a whole genome analysis of 22 of the skeletons.

“This study of 22 individuals is one of the largest ancient DNA studies carried out from a single archaeological site, and by far the largest ever reported in the Near East,” said Tel Aviv University researcher May.

The scientists uncovered some recessive genetic traits not usually expected in human remains from the Levant.

“Certain characteristics, such as genetic mutations contributing to blue eye color, were not seen in the DNA test results of earlier Levantine human remains,” said May.

The blue-eyed, fair-skinned community didn’t continue, but at least now researchers have an idea why. “These findings suggest that the rise and fall of the Chalcolithic culture are probably due to demographic changes in the region,” said May.