Genomics solves the mystery of a medieval mass burial
Genomic analysis suggests that human remains recovered from a medieval well in Norwich, UK, were probably those of Jews murdered in the twelfth century1.
Construction workers discovered human bones at the site in 2004, and further investigations found an ancient well that held the remains of 6 adults and 11 children. The burial was situated outside any consecrated ground, raising suspicions that the dead were victims of violence, disease or famine. But their identity had not been firmly established until now. The results of the analysis were published on 30 August in Current Biology.
“We didn’t know they were Jewish,” says study co-author Mark Thomas, an evolutionary geneticist at University College London. “Doing the analysis is a part of identifying that they were Jewish, partly so that they could be given appropriate burial in a Jewish cemetery.”
Young lives cut short
Radiocarbon dating established that the bodies had been deposited between 1161 and 1216 — a time frame encompassing a historically documented antisemitic massacre in Norwich in 1190. Analysis of the individuals’ DNA suggests that three were full sisters — one aged 5–10 years, one aged 10–15 years and one young adult. The genetic results also indicate that at least one of the individuals was descended from a recent union between two close relatives.
Researchers compared the DNA of six of the individuals with the genomes of more than a dozen modern western Eurasian groups. The assessment hinted that the six were more closely related to today's Ashkenazi Jewish populations — who have roots in northern and eastern Europe — than to modern non-Jewish ones in England.
Moreover, the ancient DNA showed that the Norwich victims were predisposed to some genetic conditions, such as primary ciliary dyskinesia, that are prevalent in modern Ashkenazi Jews. Using computer simulations, the researchers found that in the six individuals, the number of these genetic-disease variants was consistent with what would be expected if the diseases were as common in the population to which the Norwich individuals belonged, as they are in today's Ashkenazi Jewish populations.
Many scientists have speculated that an event between 500 and 800 years ago caused the Ashkenazi Jewish population to shrink sharply. Such a ‘population bottleneck’ can cause a jump in the frequency of rare genetic variants, such as those that cause genetic diseases. But if Ashkenazi Jews in the twelfth century were already predisposed to these diseases, the timeline changes.
“The bottleneck that drove up their frequency must be before the [Norwich individuals],” says Thomas. “That puts it back older than the vast majority of estimates of when that bottleneck occurred.”
The paper is “incredibly interesting and informative”, says Karl Skorecki, a human-population geneticist at Bar-Ilan University‘s Azrieli Faculty of Medicine in Safed, Israel. “You can see the convergence of computational biology, genetics, genomics, population genetics, history, ethical considerations.”
Not everyone is convinced, however. The authors did not test enough hypotheses for the Norwich individuals’ origins, says Eran Elhaik, a population, medical and evolutionary geneticist at Lund University in Sweden. He argues that the authors concluded that the people in the well were Ashkenazi Jews because that was the only population that they considered.
New light on a cold case
But Thomas contends that he and his colleagues tested various scenarios and that their genetic-disease analysis alone was sufficient evidence that the deceased people had Ashkenazi Jewish ancestry, rather than non-Jewish English. Furthermore, “when we spoke to archaeologists and historians, who knew the Norwich community pretty well, there were not very many options about other groups that might be in medieval Norwich at the time”, says study co-author Ian Barnes, an ancient-DNA specialist at the Natural History Museum in London. “The plausible alternatives are essentially covered by the analysis that [we] have explored.”
The study demonstrates how ancient DNA can help to solve “historical cold cases”, according to Barnes. He has worked to identify the origins of the mass burial for more than 12 years, and has been in touch with the Norwich Jewish community throughout the process. The community buried the remains in 2013 after an earlier, less conclusive DNA analysis, and the latest study provides more definitive results.
“They were correctly buried in the right graveyard and with the right religious rites,” says Barnes. “It took more than 800 years, but [they] got there in the end.”
doi: https://doi.org/10.1038/d41586-022-02356-w
References
Brace, S. et al. Curr. Biol. https://doi.org/10.1016/j.cub.2022.08.036 (2022).
