A study of skeletons from a medieval Jewish cemetery in Germany has shown a surprising genetic split among Ashkenazi Jews of the Middle Ages.
The first of its kind from a Jewish burial ground, the analysis shows that Ashkenazim have become more similar over the past seven centuries. Two Jews walking the cobblestone streets of Germany in the 14th century were more distinct than any other Ashkenazi Jews.
The co-author of the study said that it was wild. The population became more heterogeneous despite the rapid growth of the Ashkenazi Jews.
In a study published in the journal Cell, 33 men, women and children were compared with hundreds of modern Jews from around the world to see if they had the same genetic makeup. Modern communities are a genetic mélange with Ashkenazim the world over carrying the same collection of genes.
There is a different story to be told. European Jews came from two different genes.
Each group had the same genetic ancestry that dates back to a small founder population that most likely migrated from Southern Europe at the beginning of the first millennium. The genetics of the skeletons could have several explanations. Both groups came from the same place. The other branch went east to modern-day Poland, Czech Republic, Austria and eastern Germany.
Alternatively, Eastern Europe could have been settled by a different population of Jews who lived in the west of the country.
The two groups were isolated from each other for a long time due to their genetics. They got back together in places like Erfurt, the central German city that is home to the cemetery where the remains were taken, because of massacres, expulsions and economic opportunities.
Itsik Pe'er is a computational geneticist at Columbia University who was not involved in the research. There is a way to take you to places where you don't know anything.
Detailed accounts of a violent pogrom on March 21, 1349 are included in the historical record. The local synagogue was attacked by angry mobs in the middle of prayer. Few, if any, did not survive.
Property and belongings were taken after the massacre. They were able to collect on the debts of the murdered Jews. The need for lost tax revenue led to the city inviting Jews back.
They were from all over the place. Tax records show names from all over Europe, including some that had experienced antisemitic upheavals. Maria Strzebecher is the curator of the Old Synagogue Museum in Erfurt. When Jews were forced out again in 1433, that was the last time that happened.
The excavated teeth showed the same migration patterns.
Many people who had grown up in other countries were found to have high levels of radioactive particles in their teeth. The Erfurtian Jews came from multiple places and were genetically distinct.
Elisheva Baumgarten is a social historian at the Hebrew University of Jerusalem who was not involved in the study.
Maike Lmmerhirt is a historian at the University of Erfurt and a co-author of the study. Both groups prayed in the same place. They all took a bath. They all lie in the same cemetery.
Many of the same disease-causing genes were found in the Erfurt skeletons. It's possible that a population problem occurred before the Erfurtians were born, leading to genetic similarities and the amplification of some genes.
The scientists had calculated that the Ashkenazi Jewish population had a problem about 800 years ago. The British study that examined six 12th-century skeletons in England suggests it could have been even further back.
Mark Thomas is an evolutionary geneticist at University College London who led the British study.
Ron Pinhasi, an anthropologist and geneticist at the University of Vienna in Austria, was not involved in either study.
Out of concern for the dignity of the dead, rabbinic law frowns on exhumations. Scientists can't dig gravesites out of academic interest.
What happened in Erfurt wasn't related to the scientists.
The storehouse on top of the cemetery was converted into a parking garage. The state preservation office knew that some ancient Jewish remains might be disturbed by the construction.
The contractor had already broken ground when Dr. Sczech came to the site a day before the excavation was supposed to start. A small child's bones were found inside the bucket of an excavator.
Dr. Sczech said, "I yelled at the driver and said'stop,'"
There are 47 graves in an area the size of a volleyball court. Archaeologists removed the skeletons and brought them back to the local archives.
The bones were sitting there for a long time. Once scientists had a chance to look at the remains, the plan was to bury the bodies quickly. A long delay was caused by the anthropologist who became tied up.
It was lucky for genetics that he did it. The geneticists who led the new study, David Reich of Harvard and Shai Carmi of the Hebrew University of Jerusalem, were unaware of the existence of the skeletons.
In order to get a sample for genetic testing, the researchers set out to find an ancient Jewish cemetery.
The leader was Dr. Carmi. He asked the advice of a historian. Dr. Shoham-Steiner said that he wanted it to be in Erfurt.
The rabbi in Erfurt initially rejected the idea. Families of Yemenite children who disappeared in the early years of Israel's establishment can request graves be opened for forensic identification, if there is a situation that allows for DNA testing.
Concrete benefits to the deceased were the main reason for those cases. Scientific research done on anonymous bodies is not the same as scientific research done in the public eye.
The founder of the Simanim Institute in Jerusalem consulted a rabbinical court judge in Israel who said that it would be permissible to take saliva from teeth.
The rabbi in Erfurt decided to change his mind. There was a project going on. There were 38 skeletons with at least one tooth missing.
Dr. Reich was going back to Boston with zip-top bags full of medieval teeth. Dr. Reich and his team used techniques that won this year's Nobel Prize for Medicine or Physiology to extract genetic material from 33 teeth.
The scientists hope their approach to community engagement will provide a road map for others who want to look at the ancient remains of Jews. It's a prototype for what can be done in similar studies.
There are differing views among authorities on Jewish law about whether or not to get a sample of a Jew's genetic material during an archaeological dig.
Rabbi Myron Geller, a scholar of Jewish burial practices and a former member of the Committee on Jewish Law and Standards for the Conservative movement, described the rationale adopted by RabbiLitke and the study authors as the "firmest Halakhic perspective possible."
Some questioned if the benefits of scientific knowledge were enough to merit the killing of a loved one. The chief justice of the Rabbinical Court of Massachusetts said it gave him pause.
The Valley of the Communities was visited by Dr. Carmi on a recent trip to Jerusalem. He found the name Erfurt in this huge monument. Hundreds of Jews were murdered in Erfurt during the Nazi era.
The pieces of lost history that Dr. Carmi reflected on were the result of his genetics. He said it was a pleasure to bring their story to life.