Analysis reveals medieval genetic diversity, illuminates founder event
By THE HEBREW UNIVERSITY OF JERUSALEM COMMUNICATIONS Research
5 min read
The Old Synagogue of the medieval Jewish community of Erfurt. It is one of the oldest intact synagogues in Europe and now serves as a museum documenting Jewish life in the city. Image: Stadtverwaltung Erfurt
The largest study to date of ancient DNA from Jewish individuals reveals unexpected genetic subgroups in medieval German Ashkenazi Jews and sheds light on the “founder event” in which a small population gave rise to most present-day Ashkenazi Jews.
The findings, spearheaded by geneticists from The Hebrew University of Jerusalem and Harvard Medical School, were published Nov. 30 in Cell.
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About half of Jewish people around the world today identify as Ashkenazi, meaning that they descend from Jews who lived in Central or Eastern Europe. The term was initially used to define a distinct cultural group of Jews who settled in the 10th century in the Rhineland in western Germany.
Despite much speculation, many gaps exist in our understanding of the origin of Ashkenazi Jews and the demographic upheavals they experienced during the second millennium.
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To answer some of these pressing questions, the 30-person team — led by Shai Carmi at The Hebrew University and David Reich at HMS — analyzed DNA from the remains of 33 individuals buried in a medieval Jewish cemetery in Erfurt, Germany.
Erfurt’s medieval Jewish community existed between the 11th and 15th centuries, with a short gap following a massacre in 1349. At times, it thrived and was one of the largest Jewish communities in Germany. Following the expulsion of all Jews in 1454, the city built a granary on top of the Jewish cemetery.
In 2013, the granary stood empty and the city permitted its conversion into a parking lot. This required additional construction and an archaeological rescue excavation.The genetics team received a special permit from the local Jewish community, which allowed the researchers to retrieve DNA from detached teeth that had already been collected as part of the rescue excavation.
The analysis revealed two distinct subgroups within the remains: one with greater Middle Eastern ancestry, which may represent Jews with origins in Western Germany, and another with greater Eastern and Central European ancestry. The modern Ashkenazi population formed as a mix of these groups and absorbed little to no outside genetic influences over the 600 years that followed, the authors said.
Some disease-causing mutations that are widespread in modern Ashkenazi Jews are suspected to have been introduced by members of the founding group long ago. The team found some of these mutations in Erfurt as well, indicating that the medieval Ashkenazi population indeed originated from an extremely small set of founders.
Further evidence came from mitochondrial DNA, which is part of the genome transmitted only from mothers. Analyses showed that one third of the Erfurt individuals descended in their maternal line from a single ancestral woman, again highlighting how small the founding population must have been, the authors said.
Despite the insights it provides, the study was limited to one cemetery and one time period. The researchers hope it will pave the way for future analyses of samples from other sites, including those from antiquity, to continue unraveling the complexities of Jewish history.
- A Deeper Dive Co-senior author Shai Carmi offers further perspective on the work.
What is still unknown about the history of Ashkenazi Jews?
Current studies are still ambiguous regarding the founder event. When exactly did it happen? Was it a single catastrophic event or a continuous decline over centuries? Where did the founders live? Information on the origin of Ashkenazi Jews is also lacking. Where did the Ashkenazi Jewish founders and their ancestors come from? Did early Ashkenazi Jews descend from Judean Jews, or were they converts from other areas in the Mediterranean?
Finally, the Ashkenazi population is genetically homogeneous today. Was it equally uniform in the past? Were Jews from different communities in Northern Europe related only culturally or also genetically? Did the Ashkenazi Jewish gene pool change over the years due to intermarriage with Jews from other communities or with non-Jews?
What was the purpose of the study?
DNA from present-day individuals encodes information on past demographic events. However, DNA from people who lived during the events, or ancient DNA, can be orders of magnitude more informative. Ancient DNA can document migrations as they occur or demonstrate the continuity of populations. It can also tell us about the size of a population, marriage patterns, or ancestry differences between relatives.
Given that no DNA sequences existed for historical Ashkenazi Jews, we sought to generate ancient DNA data for this population. Our hope was to fill the gaps in our understanding of Ashkenazi Jewish early history. Naturally, we do not expect a single dataset to address each and every open question. Nevertheless, we hoped to illuminate some aspects of Ashkenazi Jewish demography during the Middle Ages.
What are the main points we learned about Ashkenazi history?
Put together, our work generated several new insights:
- Ashkenazi Jews had already acquired their main sources of genetic ancestry by the 14th century, including from Eastern Europe. There was little change in those ancestry components in the 600 years that followed.
- In contrast, the internal genetic structure of Ashkenazi Jews has changed over the years. Medieval Ashkenazi Jews are best viewed not as a single homogeneous community (as it came to be at present), but as an archipelago of communities, differentially affected by founder events and mixture with local populations.
- Specifically, we identified a division between one medieval group genetically similar to present-day Ashkenazi Jews from Western Europe, who may represent the descendants of the Rhineland Ashkenazi Jews, and another group with additional Eastern European ancestry, who may represent medieval Ashkenazi Jews from Central and Eastern Europe, who were at the time culturally and linguistically distinct from Western Ashkenazi Jews.
- A key source of pre-medieval Ashkenazi Jewish ancestry is related to people living today in Mediterranean Southern Europe.
- The Ashkenazi Jewish population was characterized by a very small population size during the first centuries of the second millennium. Consequently, late medieval Ashkenazi Jews already carried disease-causing and other variants that have drifted to higher frequencies in Ashkenazi Jews compared to neighboring populations.
First author Shamam Waldman performed most of the data analysis as a doctoral student in Carmi’s group. She is now starting a postdoctoral research position in the Reich lab. Reich is professor of genetics in the Blavatnik Institute at HMS and professor of human evolutionary biology at Harvard University.
The study was funded by the Israel Science Foundation (grant 407/17), United States–Israel Binational Science Foundation (grant 2017024), U.S. National Science Foundation (grants 1912776 and 0922374), U.S. National Institutes of Health (grants GM100233 and HG012287), the Allen Discovery Center program (a Paul G. Allen Frontiers Group advised program of the Paul G. Allen Family Foundation), John Templeton Foundation (grant 61220), a private gift from Jean-François Clin, and the Howard Hughes Medical Institute.
Adapted from a news release by The Hebrew University.
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(ASH-keh-NAH-zee jooz) One of two major ancestral groups of Jewish people whose ancestors lived in France and Central and Eastern Europe, including Germany, Poland, and Russia. The other group is called Sephardic Jews and includes those whose ancestors lived in Spain, Portugal, North Africa, and the Middle East.Do Ashkenazi Jews have different DNA? ›
Y-DNA of Ashkenazi Jews. The Y chromosome of most Ashkenazi and Sephardi Jews contains mutations that are common among Middle Eastern peoples, but uncommon in the general European population, according to a study of haplotypes of the Y chromosome by Michael Hammer, Harry Ostrer and others, published in 2000.Does Ashkenazi show up on ancestry DNA? ›
AncestryDNA offers an autosomal test and family finder tool. Their test can identify Ashkenazi/European Jewish ancestry, while other sorts of Jewish ancestries may appear as regional ethnicities.What does Ashkenazi Jewish mean on 23andme? ›
Ashkenazi Jewish genetic groups
This means that they share high genetic similarity with people in that genetic group. About 80 percent of our customers on the latest chip with more than 75 percent Ashkenazi ancestry will receive a match.
The Ashkenazi Jewish genetic panel can tell people if they have an increased chance of having a child with certain genetic diseases. This testing may be recommended for people with Ashkenazi Jewish heritage who plan to have children or are pregnant.Have Ashkenazi Jews become more genetically similar over time? ›
The analysis, the first of its kind from a Jewish burial ground and the product of yearslong negotiations among scientists, historians and religious leaders, shows that Ashkenazim have become more genetically similar over the past seven centuries.What is the most common genetic disorder in Ashkenazi Jews ancestry? ›
Type A is more common in the Ashkenazi Jewish population, with an estimated 1 in 90 carrier frequency. The gene is located on chromosome 11. Individuals with Niemann-Pick disease lack a substance called acid sphingomyelinase (ASM).
I have hazel-green eyes—“Ashkenazi eyes,” people tell me. These eyes and light skin conceal my Iraqi-Indian heritage, rendering half of me invisible. Before speaking with me about my experience or background, most people presume I am Jewish, and by that they mean Ashkenazi or white.Are Ashkenazi Jews genetically European? ›
A number of recent studies have shown that Ashkenazi individuals have genetic ancestry intermediate between European (EU) and Middle-Eastern (ME) sources [4–8], consistent with the long-held theory of a Levantine origin followed by partial assimilation in Europe.What genetic traits do Ashkenazi Jews have? ›
Individuals of Ashkenazi Jewish descent may carry pathogenic variants for Bloom syndrome, Canavan disease, cystic fibrosis, familial dysautonomia, familial hyperinsulinism, Fanconi anemia C, Gaucher disease, glycogen storage disease type 1A, Joubert syndrome type 2, maple syrup urine disease type 1B, mucolipidosis IV, ...
Who are Ashkenazi Jews? The term Ashkenazi refers to a group of Jews who lived in the Rhineland valley and in neighbouring France before their migration eastward to Slavic lands (e.g., Poland, Lithuania, and Russia) after the Crusades (11th–13th century) and their descendants.How do you know if you are Ashkenazi? ›
What is Ashkenazi Jewish ancestry? Individuals whose Jewish relatives come from Eastern Europe are known as Ashkenazim. Until recently, for the purposes of determining who met criteria for coverage of genetic testing, Ashkenazi Jewish (AJ) ancestry was considered having four Jewish grandparents.Which DNA test is best for Ashkenazi? ›
- For general genealogical testing, AncestryDNA, and 23andMe provide the most detailed reports about Ashkenazi heritage at the best prices.
- For Y-DNA and mtDNA testing, FamilyTreeDNA is your best option, especially compared with the health-oriented testers, like EasyDNA.
- 3-Phosphoglycerate Dehydrogenase Deficiency.
- Alport Syndrome.
- Arthrogryposis, Mental Retardation and Seizures.
- Bardet-Biedl Syndrome.
- Bloom Syndrome.
- Canavan Disease.
- Carnitine Palmitoyltransferase ll Deficiency.
One in 40 Ashkenazi Jewish women has a BRCA gene mutation. Mutations in BRCA genes raise a person's risk for getting breast cancer at a young age, and also for getting ovarian and other cancers. That is why Ashkenazi Jewish women are at higher risk for breast cancer at a young age.What does the Bible say about Ashkenazi? ›
“Ashkenaz” is one of the most disputed Biblical placenames. It appears in the Hebrew Bible as the name of one of Noah's descendants (Genesis 10:3) and as a reference to the kingdom of Ashkenaz, prophesied to be called together with Ararat and Minnai to wage war against Babylon (Jeremiah 51:27).What are Ashkenazi Jews at risk for? ›
One in 40 Ashkenazi Jewish women has a BRCA gene mutation. Mutations in BRCA genes raise a person's risk for getting breast cancer at a young age, and also for getting ovarian and other cancers. That is why Ashkenazi Jewish women are at higher risk for breast cancer at a young age.What is special about Ashkenazi? ›
Most people with Ashkenazi ancestry trace their DNA to Eastern and Central Europe. But many also have Middle Eastern ancestry, which is just one reason for their genetic “uniqueness.” It's clear that people with European ancestry are genetically distinct from those of Asian or African descent.What genes do Ashkenazi Jews have? ›
The Genetic Structure of Ashkenazic Jews. AJs were localized to modern-day Turkey and found to be genetically closest to Turkic, southern Caucasian, and Iranian populations, suggesting a common origin in Iranian “Ashkenaz” lands (Das et al., 2016).