Meeting the ancestors: History of Ashkenazi Jews revealed in medieval DNA

The Jewish community of Erfurt was destroyed in a pogrom. The ringleaders of the pogrom were tried by the archbishop of Mainz, who granted Jews the right to live and work in the city. The others were exiled. The city's Christian population had to pay back money.

There was a new Jewish community five years later. New houses and a synagogue were funded by the city in the 13th century. It must have convinced them that it wouldn't happen again.

The Jews of Erfurt flourished for a century. They buried their dead in a large cemetery just outside the city walls after bathing in a ritual bath on the banks of the Gera River. Then it all ended again. The town council revoked the rights of Erfurt's Jews in 1441. The city destroyed hundreds of graves and built a granary on top of them.

A decade ago, Sczech and other archaeologists excavated a 192- square-meter plot on the grounds of the former cemetery. With a municipal construction project about to start, their goal was to save, study, and rebury any human remains found. The Jewish community wanted to do as little excavation as possible.

In the shadow of the 500-year-old granary, the team found the remains of more than 60 people, most of them with their legs pointing east. The skeletons were well-preserved.

The Ashkenazim, the major Jewish population that emerged in Germany in the Middle Ages and later expanded into central and Eastern Europe, received a gift before the remains were reburied. The Erfurt analysis offered clues to where the Ashkenazim came from, and what happened along the way. According to the studies, the Ashkenazi Jewish population, which numbers more than 10 million people spread around the world, has roots in a band of no more than a few hundred who lived in Europe more than 1000 years ago.

The Erfurt study is the first major study of a medieval Jewish population from a genetics perspective. Elisheva Baumgarten is a historian at the Hebrew University of Jerusalem who was not involved in the study. Cumulative evidence can tell us more than we know.

A rabbinical ruling that may establish a precedent for future studies of ancient Jewish remains is perhaps equally important.

Archaeology has found evidence of Jewish communities in the Germanic provinces of the Roman Empire as early as the 300s C.E. The cradle of Ashkenazi culture was a trio of German cities known asWorms, Mainz, and Speyer.

The period in between isn't known. The Jews of Erfurt and other medieval cities may have held onto their cities from the Roman era. They may have been descendants of the pioneers who crossed the Alps around 800 C.E. Leonard Rutgers is a historian and co-author on the Cell paper. Where were they from if they came from somewhere else?

Geneticists have tried to work in a different direction. Ashkenazi populations have high rates of certain genetic diseases due to the fact that many people carry the same genes. There are clues to an early population bottleneck that reduced Jewish genetics. The Ashkenazi population today is genetically homogeneity, according to Hebrew University geneticist.

Some ultra-Orthodox Ashkenazi communities give genetic compatibility tests to limit the risk that children will inherit genetic diseases. Modern Ashkenazi genomes can only give a partial picture of events 1000 or more years ago. Carmi says it's helpful to have data from the past.

Carmi met with a geneticist. If Reich could find an ethical way to do ancient DNA sampling, he would encourage him to do it. Reich said that although he is Jewish, he had avoided studying Ashkenazi genetics before Carmi reached out. He says it is difficult to study one's own community. You have biases when working on yourself.

Carmi didn't feel optimistic about studying ancient Jews' genes. He thought it would be difficult because there wouldn't be permission to sample. Tiny bits of bone would need to be grinded for the analysis. Sampling for radiocarbon dating is necessary. Alexander Nachama is the chief rabbi of the Jewish Community of Thuringia and the head of the modern-day Jewish community in Erfurt.

Carmi contacted historians and archaeologists in Europe to find out if there were suitable samples. Carmi said the historians thought she was crazy. Sczech, who received rabbinical permission to measure bones from the Erfurt cemetery, got back to him.

Carmi talked to a rabbi in Israel. The rabbi studied centuries-old interpretations of Jewish law and listened to Carmi explain the science. Stray teeth are not the same as a skull or rib because they fall out naturally. If loose teeth turned up during a rescue excavation, researchers could sample them without violating Jewish beliefs.

The chief rabbi of Erfurt was contacted by Carmi with a rabbinical ruling. They were a bit uneasy. Carmi says that they didn't want to be the first to allow an ancient DNA study. Carmi was able to sample the loose teeth of 38 people from the cemetery before they were reburied.

The ruling represents a religiously acceptable way of applying scientific techniques to date Jewish remains and study their ancestry and diet. Carmi says it could be used to analyze mass graves from World War II. The use of teeth seems to be an excellent compromise according to an Archeologist who was not involved with the study. The results of the first study will show what is at stake and what benefits each side can expect.

It was only after an initial analysis in 2011 that the researchers realized the 17 people whose remains were found during construction may have been killed in a pogrom. One clue was the presence of genetic material in Ashkenazi Jews. Ian Barnes, an evolutionary geneticist at London's Natural History Museum, says that when they first tested the DNA, they got a few hundred base pairs. They were compatible with Jewish origin.

The bones were reburied in a church. They were moved to a quieter spot after five years. After they were reburied a second time, the authors were given permission to analyze them again, and this time they were able to show that they were related to modern Ashkenazi populations. The town's Jews were massacred in 1190 on the eve of the First Crusade and the bones were found to be 800 years old. Barnes thinks it's reasonable to think it could be an antisemitic event. Everything contributed to the case.

Modern Ashkenazim are descended from a small founding population. The founder group emerged from a population crunch in the 13th and 14th century when the religious fervor of the Crusades and false accusations that Jews spread the Black Death sparked violent pogroms. The new data points to a different scenario.

The 14th century teeth from Erfurt have clear evidence of that roadblock. The medieval genetic code showed disease and long stretches of the same code. One type of mitochondrial genetic material that is passed through the maternal line was identical in one-third of the people in the excavated plot.

The disease markers seen in modern Ashkenazi populations were found at about the same frequencies in the Norwich individuals. Barnes says that the bottleneck happened before these people died. This is an example of the power of the data.

Small differences between the dozens of Erfurt genomes suggested medieval Ashkenazi communities weren't completely homogeneity. The University of Erfurt's Maike Lmmerhirt found clues to that in the city archives. Some of the names of 14th century Jewish residents suggest family roots in southern and western Germany. The ancestry of some prominent Erfurt Jews, such as Jacob of Bohemia, was traced far to the east, in one instance as far away as Kaliningrad, now in Russia.

The medieval Ashkenazim apparently mixed back together in places like Erfurt generations after branching out from a single, small founding population into small communities across Europe.

There were signals in the teeth. The parents with distant birthplaces were buried near their children in the Erfurt cemetery. Sczech says that it is a hint that we have the founding fathers. This is the first time we have all these results together.

By comparing the Erfurt genomes with modern and ancient DNA data from many different populations, the researchers were able to peer even further back. The Ashkenazi circa 1350 had a mix of ancestry that looked like it came from southern Italy or Sicily, with components found in modern Eastern Europe and the Middle East. Krishna Veeramah is a geneticist who was not involved in the work.

A group of Jews crossed the Alps at the invitation of the first Holy Roman emperor to arrive in Germany around 800 C.E., and settled in the Rhineland.

The Erfurt results show a glimpse into medieval Jewish culture. The burials of the postpogrom community are the same as they were when they were drawn from all over Europe. Carmi says that they were all Ashkenazi Jews.

There was a genetic similarity between the Erfurt community and the modern Ashkenazim. Reich says that an intermarriage rate with outsiders of more than one in 500 per generation would have changed Ashkenazi ancestry. That didn't occur. New information.

The Jewish community has a central position in European life. The Jews would have been in constant contact with their Christian neighbors if they were bankers. In Erfurt, synagogues, ritual baths, and Jewish houses were located in the center of the town at the intersection of two major roads. Christians served as wet-nurses to Jewish children, according to archival records. Jews and Christians lived in close proximity. It seems like they didn't have children together. Modern people don't have words to describe their sense of belonging

The Jews of Erfurt are back in the center of the city as part of an effort to make it a UNESCO World Heritage site. It is often overshadowed by the horrors of the Holocaust and the pogroms that occurred centuries ago. She says that making it only into a dark story would be a mistake. The truth is that the Jews of medieval Germany were welcomed when they came and were integrated into medieval German space, even though they were a religious and sometimes persecution.

The story of all Ashkenazim, including its formative event, is being told by their genomes. No one knows why it happened. Disasters such as massacres or discrimination that prevent people from marrying outside their community are calls to mind by bottlenecks. According to Rutgers, Jewish history is a big sequence of problems.

According to the Erfurt data, a few dozen people flourished in Europe before the Erfurt Jews were laid to rest, passing their genes and culture to millions of people. Reich thinks that it could be the legacy of a small town with a tradition of large families. Sometimes a group that has been successful is thought of as a crisis.