Where History Meets Genetics: Uncovering the Origins of Ashkenazi and Sephardic Jews

Where did Europe’s Jewish communities come from, and how did they evolve over time? This class delves into groundbreaking genetic research on Ashkenazi and Sephardic Jews, analyzing genome-wide data from over 300 individuals across medieval Europe (7th–18th centuries). By studying Identical-By-Descent (IBD) segments—stretches of DNA shared by individuals due to recent common ancestry—scientists have revealed a close genetic relationship between these groups, suggesting a shared population bottleneck in their past. The data also highlight regional genetic variations, including unexpected links between some Ashkenazi ancestors and medieval Slavic and Avar populations. Through the lens of ancient DNA, we’ll explore how genetics is reshaping our understanding of Jewish history, migration, and cultural interactions in Europe.

David Emil Reich is an American geneticist renowned for his pioneering work in human population genetics. A professor at Harvard Medical School’s Department of Genetics and an associate of the Broad Institute, Reich has significantly advanced our understanding of ancient human migrations and interbreeding events through genome-wide analysis. His notable research includes insights into the split between chimpanzees and humans, the genetic structure of Indian populations, and evidence of interbreeding between Neanderthals and modern humans. Reich’s contributions have been recognized with several prestigious awards, including the Dan David Prize (2017), the NAS Award in Molecular Biology (2019), and the Massry Prize (2021). In 2018, he authored the book Who We Are and How We Got Here, which delves into the new science of ancient DNA and its implications for understanding human history.