The remains found in the well have since been reburied in the city's Jewish cemetery. Image © Rob Farrow, licensed under CC BY-SA 2.0 via Geograph.
Human remains discovered in Norwich could contain the oldest Jewish genomes ever sequenced.
Researchers investigating skeletons found at the bottom of a medieval well in Norwich discovered they likely represented Ashkenazi Jews. The scientists were able to extract ancient DNA (aDNA) from six of the individuals, and found that they shared the closest genetic affinity with modern Ashkenazi Jewish populations.
Radiocarbon dating carried out on the skeletons revealed that they date to the late twelfth century, which coincides with anti-Semitic riots that occurred at the beginning of the Third Crusade.
"I'm delighted and relieved that 12 years after we first started analyzing the remains of these individuals, technology has caught up and helped us to understand this historical cold case of who these people were and why we think they were murdered," said Selina Brace, a specialist in aDNA at the Natural History Museum (UK) and who is lead author on a paper documenting the research.
Analysis of the genomes also revealed that the genetic makeup of the Ashkenazi Jews was shaped before the 12th century, centuries earlier than had previously been thought.
"It was quite surprising that the initially unidentified remains filled the historical gap about when certain Jewish communities first formed, and the origins of some genetic disorders," said co-author Mark Thomas from University College London. "Nobody had analyzed Jewish ancient DNA before because of prohibitions on the disturbance of Jewish graves. However, we did not know they were likely Jewish until after doing the genetic analyses."
The study is published in Current Biology.
Who were the individuals found in a Norwich well?
The Norwich skeletons were first discovered in 2004 during construction work on the Chapelfield shopping centre – now known as Chantry Place. A subsequent archaeological dig discovered a medieval well with the remains of at least 17 people inside including adults, children and infants who have since been reburied.
The remains were initially thought to have been those of plague victims, with the range of ages suggesting a catastrophe such as a disease outbreak or famine. However, subsequent analysis in 2011 for the TV series History Cold Case raised the possibility they could instead have belonged to the city's Jewish diaspora.
Radiocarbon dating of the bones had suggested they were from some point in the eleventh or twelfth century, which is supported by the age of pottery fragments also found in the well.
This date has been used to suggest that the skeletons were from victims of an antisemitic riot that took place in Norwich on Feb. 6, 1190, when individuals heading on the Third Crusade massacred the city's Jewish community.
The position of the remains also added credence that these people were murdered. Unlike other medieval mass graves, the skeletons were generally complete but co-mingled, suggesting that bodies had been thrown down the well shortly after death.
"Our study shows how effective archaeology, and particularly new scientific techniques such as ancient DNA, can be in providing new perspectives on historical events," said co-author Tom Booth. "Ralph de Diceto's account of the 1190 AD attacks is evocative, but a deep well containing the bodies of Jewish men, women, and especially children forces us to confront the real horror of what happened."
What does ancient DNA reveal about the individuals?
Radiocarbon dating of the individuals suggests that they died between 1161 and 1216. This gave the researchers a strong indication these could be the remains of some of the victims of the 1190 antisemitic riots.
The DNA of six of the individuals was sufficiently well-preserved that whole genomes could be sequenced, revealing that three of them were sisters.
Researchers were also able to look further into the genetic history of the individuals by comparing them to those of current Ashkenazi Jewish populations and inferred that modern Ashkenazi ancestry was best explained if they had the same ancestors as the Norwich individuals.
The medieval individuals share many of the genetic markers associated with modern Ashkenazi populations, including certain genetic variants that are associated with genetic disorders.
Genetic disorders that are particularly common in certain populations can arise during bottleneck events, where a rapid reduction of the population size can lead to big jumps in the number of people carrying otherwise rare genetic mutations.
It had previously been thought that these bottlenecks happened around 500-700 years ago for Ashkenazi Jews. But, as the number of disease mutations in the medieval Ashkenazi is similar to that of modern populations, the study shows that the bottlenecks occurred before the twelfth century.
The researchers hope their work offers a greater insight into the historical development of human populations, while shedding light on the darkest moments of our past.
"When you study ancient DNA from people who've died several hundreds to thousands of years ago, you don't often get to work with the living community at the same time," said Barnes. "It's been really satisfying to work with the community on a story that's important to them."
Republished courtesy of Natural History Museum (UK).