European Jews are all related, scientists say, and a new study reported by LiveScience gives a sense of just how closely. "Everyone is a 30th cousin"—or more closely related—in the Ashkenazi Jewish population, says researcher Itsik Pe'er. "They have a stretch of the genome that is identical." Most US Jews are descended from the Ashkenazi Jews of Central and Eastern Europe; about 80% of today's Jews are of Ashkenazi descent, Maine News reports. The findings suggest, as NBC News notes, that if you're an Ashkenazi Jew, you can say Albert Einstein was your 30th cousin—at the furthest.
Pe'er's team made its find by comparing 128 Ashkenazi Jews' genomes to 26 Belgian Flemish genomes, identifying markers seen only among Ashkenazi Jews. The process pointed to a small ancestral "bottleneck" population of some 350, a founding group that lived about 600 to 800 years—or 30 to 32 generations—ago. They themselves were descended from European and Middle Eastern people, the study suggests. The findings could also help today's Ashkenazi population healthwise: Diseases like Tay-Sachs and breast cancer are relatively common among them, and the genome analysis could make it easier for doctors to spot risk. (Reports earlier this year suggested that Adolf Hitler's wife, Eva Braun, may have been descended from Ashkenazi Jews.)