Scientists Finally Solved Where Ashkenazi Jews Came From — After Centuries Of Debate

[00:00:00]In 2013, construction crews breaking ground for a parking garage in Erfurt, Germany, hit something their equipment was never meant to find.

[00:00:09]A medieval Jewish cemetery sealed beneath the city for close to 700 years, holding the remains of a community that had prayed, worked, raised children, and eventually died in that same stretch of German soil between the late 11th century and 1454.

[00:00:27]Some of them had lived through the First Crusade. Others had survived or failed to survive a massacre that swept through the city in 1349, when a wave of Black Death era violence destroyed much of Erfurt's Jewish community in a single catastrophic year.

[00:00:45]Nobody buried there could have imagined that their teeth would one day be drilled open by researchers in white coats nearly seven centuries later.

[00:00:53]Their genetic code read letter by letter on a laboratory screen, and their bones drafted as evidence in an argument about identity, ancestry, and belonging that would still be raging six centuries after the last of them died.

[00:01:10]That argument had been running for close to 200 years by the time the Erfurt skeletons were finally analyzed, and it had never stayed confined to academic journals.

[00:01:22]It has been cited in political speeches, weaponized in online forums, invoked by movements with radically opposed goals who somehow found common use for the exact same claim. At stake was a single, deceptively simple question.

[00:01:38]Where did the ancestors of today's roughly 12 million Ashkenazi Jews actually come from?

[00:01:45]Two sharply competing answers had circulated for generations, and only one of them could survive contact with real, physical, extractable evidence in 2022, and then again in a second even more precise study published in 2025, that evidence finally arrived and it did not arrive quietly.

[00:02:07]The Ashkenazi Jewish population represents one of the most intensively studied human groups in the entire field of population genetics and for good reason.

[00:02:17]Numbering somewhere between 11 and 12 million people worldwide today, Ashkenazi Jews make up roughly 80% of the global Jewish population.

[00:02:27]And their genetic history intersects with medical genetics, ancient migration studies and some of the most politically sensitive historical questions in modern scholarship.

[00:02:38]Three major bodies of research conducted across more than a decade by different teams using entirely different methods together form the evidentiary foundation this story rests on.

[00:02:51]The first is the 2022 study published in the journal Cell by a research team led by Shaman Waldman working alongside Shai Carmi at the Hebrew University of Jerusalem and David Reich, one of the most prominent population geneticists in the world based at Harvard Medical School.

[00:03:11]This team obtained genome-wide sequencing data from 33 individuals recovered from the Erfurt salvage excavation extracting genetic material directly from teeth that had survived buried underground for roughly six to seven centuries using laboratory protocols specifically developed to isolate degraded ancient DNA from modern contamination. The second is the 2025 study published in the journal Human Gene by researchers Joseph Livni and Karl Skorecki which developed an entirely new statistical method specifically designed to distinguish within the mitochondrial DNA of living Ashkenazi Jews today between genetic lineages that trace back to the populations original founders and lineages that were absorbed later through conversion or intermarriage with surrounding European populations.

[00:04:08]And underlying both of these more recent studies is a foundational 2013 paper published by Doron Behar and an international team of collaborators in the journal Genome Biology and Evolution which directly tested using genetic samples collected specifically from the Caucasus region whether Ashkenazi ancestry showed any meaningful connection to the historical population once native to that same territory.

[00:04:37]Together these three studies separated by nearly a decade and built on entirely different types of evidence ancient DNA extracted from medieval graves modern mitochondrial sequencing run through newly developed statistical models and direct comparative sampling of a specific regional population converge on findings precise enough to finally settle a debate that pure historical argument had never been able to resolve on its own.

[00:05:09]Each study alone would represent a meaningful contribution to the field.

[00:05:13]Together examined side by side they close off nearly every avenue the older more speculative theories once relied on leaving remarkably little room for the kind of loosely sourced historical speculation that had dominated this question for generations before genetic evidence became available at this level of resolution. The older and more traditional of the two competing explanations is known as the Rhineland hypothesis. According to this account Ashkenazi Jews descend in essentially direct line from Jewish communities of the ancient Near East, communities dispersed westward across the Mediterranean world following the destruction of the Second Temple in Jerusalem in 70 CE, gradually settling along the Rhine River Valley in what is now Germany by around the turn of the first millennium before migrating further eastward into Poland, Lithuania, and the Russian Empire over the centuries that followed. This account matched the historical self-understanding most Jewish communities had preserved through generations of religious tradition and oral history.

[00:06:23]And it fit comfortably alongside a substantial body of documentary evidence tracing Jewish settlement patterns steadily moving north and east across medieval Europe. Evidence including tax records, rabbinic correspondence, and municipal charters documenting specific Jewish communities in cities including Mainz, Worms, and Speyer by the 10th and 11th centuries. The second theory offered something considerably more disruptive.

[00:06:52]Known as the Khazar hypothesis, it proposed that the primary ancestral source of Ashkenazi Jewry was not the ancient Levant at all, but rather the Khazar Khaganate, a powerful Turkic empire that had controlled a vast territory north of the Caucasus Mountains between roughly 650 and 950 CE, stretching across parts of what is now Southern Russia, Ukraine, and Kazakhstan. Historical sources indicate that at some point during the 8th or 9th century, the Khazar ruling elite converted to Judaism, and proponents of this theory argued that when the Khazar state eventually collapsed under pressure from surrounding powers, descendants of these Khazar converts migrated westward into Eastern Europe, becoming the demographic core of what would later be recognized as Ashkenazi Jewry.

[00:07:46]Under this model, the connection between modern Ashkenazi Jews and the ancient land of Israel would be religious rather than ancestral, a matter of shared faith rather than shared bloodline.

[00:07:58]The stakes attached to that distinction were never purely academic, and understanding why requires understanding exactly what the theory implied if true.

[00:08:09]If Ashkenazi ancestry traced primarily to Turkic converts rather than ancient Israelites, it would hand a powerful rhetorical weapon to anyone seeking to argue that the modern Jewish connection to the land of Israel rested on constructed narrative rather than demonstrated ancestry. That is precisely how the theory came to be used, adopted simultaneously and for opposite purposes by two very different groups. By certain anti-Zionist activists arguing that Jewish historical claims to the region lacked genuine ancestral grounding, and from an entirely different direction by anti-Semitic movements arguing that Jews possessed no legitimate historical roots anywhere in Europe either, framing Ashkenazi communities as perpetual outsiders wherever they happen to live.

[00:09:02]The same claim deployed by ideologically opposed camps toward the same practical end, severing a population from any deep defensible connection to a specific place, whether that place was the ancient Levant or the European countries Ashkenazi communities had by then called home for the better part of a millennium. Understanding that dual weaponization matters for grasping why the eventual genetic findings landed with the intensity they did, arriving not into a quiet academic backwater, but into a debate that had already spent decades absorbing political weight from multiple directions at once.

[00:09:43]The theory found its most influential popular champion in the writer Arthur Koestler, whose 1976 book on Khazar history brought the hypothesis to a wide general readership. It received a dramatic boost in the years that followed, gaining renewed academic attention as genetic testing technology became more widely accessible during the early 2000s, at exactly the moment when population geneticists first gained the tools necessary to test historical migration claims against real biological data, rather than documentary inference alone. This convergence of timing, a politically charged historical claim arriving just as the science needed to test it properly was finally becoming available, set the stage for the specific sequence of studies and counter-studies that would define the following decade and a half of research. It gained further more direct scientific backing in 2012 when Israeli geneticist Eran Elhaik published a study using genetic samples from modern Armenian and Georgian populations as statistical proxies for the historical Khazar population, concluding that Ashkenazi genomes showed a genuine Caucasus-related signal consistent with Khazar descent. The paper generated significant international attention and was widely cited in media coverage and in political commentary alike as a scientific confirmation of a theory that had until then rested primarily on historical argument rather than genetic data.

[00:11:24]That claim did not hold up under closer examination.

[00:11:28]Doron Behar's 2013 study directly addressed the central methodological weakness in Elhaik's approach. Modern Armenians and Georgians, whatever their geographic proximity to the historical Khazar territory, are not themselves descendants of the Khazars, a Turkic-speaking population culturally and linguistically distinct from either group, and using them as a genetic stand-in risked detecting a broader Caucasus region signal rather than anything specifically Khazar in origin.

[00:12:04]Behar's team instead assembled genetic samples drawn from populations more directly situated within and around the actual historical territory of the Khazar Khaganate, and compared Ashkenazi genomes against this more carefully constructed reference set.

[00:12:22]The Caucasus-specific signal Elhaik's study had reported did not reappear.

[00:12:28]It's worth being precise about how this scientific disagreement actually stands today, rather than overstating it in either direction, since intellectual honesty matters more here than a clean, dramatic verdict. Behar's larger, more carefully constructed study represents the position held by the overwhelming majority of population geneticists currently working on this question, and it has become the standard reference point cited in subsequent literature examining Ashkenazi origins.

[00:13:01]Elhaik has continued to defend his original methodology and conclusions in later publications, meaning a small minority position within the field persists, even though it has not gained significant additional traction among researchers working independently on the same question using their own data sets and their own reference populations.

[00:13:23]That distinction between a settled scientific consensus and a literally unanimous one matters because science rarely produces the latter on any genuinely contested historical question.

[00:13:37]And claiming otherwise would misrepresent exactly the kind of evidence-based caution this entire investigation is built on.

[00:13:47]The Erfurt excavation gave researchers something genuinely new to work with, not modern DNA requiring statistical reconstruction of ancient events, but the literal physical genetic material of people who lived during the medieval period the debate was actually about.

[00:14:05]The genome-wide analysis of the 33 sequenced individuals found that their overall genetic profile closely resembled that of modern Ashkenazi Jews, sharing recognizable founder mitochondrial lineages still common in the population today, with roughly a third of the sampled individuals carrying one of these lineages directly.

[00:14:28]This alone represented a significant finding.

[00:14:32]Whatever genetic architecture defines Ashkenazi identity today was already substantially in place by the 14th century, centuries earlier than some previous models had assumed, meaning the core genetic story this entire debate revolves around cannot be a purely modern invention or a recent statistical artifact of living population sampling.

[00:14:56]The Erfurt data revealed something more specific still.

[00:15:01]Rather than reflecting a single uniform founding population, the genetic profile split cleanly into two distinguishable subgroups, one showing a somewhat greater proportion of Middle Eastern ancestry, plausibly reflecting Jewish communities with roots further west in Germany, and a second showing a greater proportion of ancestry connected to Eastern and Central Europe. The modern Ashkenazi population, the researchers concluded, formed through the merging of these two streams, absorbing little additional outside genetic influence during the roughly six centuries that followed.

[00:15:38]The study's authors also identified genuine evidence of a severe demographic bottleneck.

[00:15:44]A full third of the Erfurt individuals shared a single common mitochondrial ancestor.

[00:15:50]And at least eight of them carried genetic variants still associated with disease conditions elevated in Ashkenazi populations today, including the mutations linked to Tay-Sachs disease and certain hereditary cancer risks.

[00:16:06]A population that would eventually grow into the millions had, at some earlier point, narrowed down to a genuinely small founding group, plausibly numbering only in the low hundreds of families based on demographic modeling researchers have applied to this kind of genetic bottleneck signature.

[00:16:24]Separate research places a second, earlier bottleneck around the 1st century CE, coinciding with the period following the destruction of the Second Temple and the beginning of the wider Jewish diaspora, suggesting the population passed through at least two distinct demographic constrictions across the following 13 centuries before the genetic profile captured at Erfurt fully stabilized. What the Erfurt genomes could not fully resolve, because they only captured a single 14th-century snapshot, was the deeper question of geographic origin.

[00:16:59]Whether the populations' earliest maternal ancestors, specifically, had come primarily from the ancient Near East, or whether a substantial proportion of Ashkenazi maternal lineage actually traced to European women who had joined Jewish communities through conversion as Jewish men migrated westward from the Levant.

[00:17:22]This question mattered enormously to the Khazar debate specifically, because mitochondrial DNA passed down exclusively through the maternal line represented exactly the kind of evidence that could most directly confirm or undermine a theory built around a specific geographic origin point. An earlier body of research, including a widely cited 2013 study led by Martin Richards, analyzing thousands of mitochondrial genomes, had in fact found that a substantial majority of Ashkenazi maternal lineages traced their deepest roots to prehistoric Europe rather than the Near East, a finding that seemed on its surface to support a scenario involving Near Eastern paternal ancestry combined with substantially European maternal ancestry, acquired through conversion during the communities' early centuries in the Mediterranean world.

[00:18:20]The 2025 study by Joseph Livni and Karl Skorecki approached this same question with a genuinely new methodological tool.

[00:18:30]And it is here that the most recent chapter of this story becomes both more precise and more actively contested within the scientific literature itself, in exactly the way real, ongoing research often is. Livni and Skorecki developed a statistical method capable of distinguishing within a population sample between mitochondrial lineages that represent original founding ancestry and lineages that were absorbed into the population more recently.

[00:19:02]Reasoning that true founder lineages, having had many centuries and many generations to multiply within an endogamous population, should appear repeatedly across multiple unrelated modern individuals, while more recently absorbed lineages arriving through occasional conversion or intermarriage in more recent centuries should appear as much rarer, largely singular occurrences within the same data set.

[00:19:31]Applying this method, the researchers concluded that the founding generation of the Ashkenazi population likely numbered around 150 families.

[00:19:41]And that only a comparatively small proportion in the range of 13 to 15% of the maternal mitochondrial lineages present in the population today actually trace to later absorbed sources rather than the original founding group. This finding directly challenged the earlier interpretation built on the 2013 Richards study suggesting instead that the deep European associated signal detected in Ashkenazi mitochondrial DNA more likely reflects ancient European ancestry that had already entered the founding population before it ever reached Europe as a distinct Jewish community or reflects Near Eastern lineages carrying genetic markers that happen to resemble broader Eurasian patterns rather than large-scale conversion of European women after Jewish communities were already established. It's worth being transparent about exactly how settled this particular actually is because presenting cutting-edge 2025 research as beyond any further scientific discussion would misrepresent how science genuinely works even in cases where the broader conclusion holds up well.

[00:20:56]The Livni and Skorecki study received a direct published commentary later in 2025 from researcher Joseph Faith who raised methodological questions about the approach and applying an alternative combination of identity by descent analysis and lineage extinction modeling arrived at a different estimate of approximately 54 distinct founder matrilineal lineages, a noticeably different figure than Livni and Skorecki's own framework had produced.

[00:21:28]Livni and Skorecki published a formal response later that same year, defending their core methodology while engaging directly and respectfully with the alternative approach and the resulting exchange playing out across three separate publications within a single calendar year represents exactly the kind of genuine ongoing scientific back and forth that characterizes an active unresolved corner of a research field rather than a single study that instantly and permanently closed the book on the question the moment it was published. What both sides of that specific technical disagreement do agree on, however, is the larger conclusion that matters most for the Khazar debate.

[00:22:13]Neither analysis found support for a Central Asian or Caucasus-derived maternal founding population and both approaches converge on a founding maternal lineage best explained by Near Eastern origin consistent with the existing body of Y chromosome research which has separately and consistently pointed toward Near Eastern paternal ancestry across multiple independent studies conducted since the early 2000s.

[00:22:39]Genome-wide autosomal studies examining genetic markers inherited from both parents rather than a single maternal or paternal lineage add a further layer of confirmation to this picture and represent yet another entirely independent line of evidence separate from either the mitochondrial or Y chromosome analyses already discussed.

[00:23:00]These studies consistently cluster Ashkenazi Jews together with other global Jewish populations and with broader Near Eastern reference populations in analyses of genetic relatedness rather than clustering them with Turkic-speaking or Central Asian populations a pattern that has held up across multiple independent research teams working with different sample sets over more than a decade.

[00:23:28]The most methodologically refined of these genome-wide analyses estimate that Ashkenazi ancestry overall splits roughly evenly between a Near Eastern component and a European component, typically in a range close to 50% each.

[00:23:44]A pattern entirely consistent with a population that originated in the ancient Levant and subsequently spent many centuries moving through and settling within the Mediterranean and European world, gradually absorbing a real but bounded degree of local genetic influence along the way.

[00:24:03]Exactly the genetic signature diaspora history would be expected to leave behind and entirely distinct from the genetic signature a large-scale Turkic conversion event would have produced.

[00:24:16]What emerges from this accumulated body of research, ancient genomes pulled from beneath a German parking garage, a newly developed statistical method applied to modern mitochondrial DNA, and a direct genetic test of the specific Caucasus population the Khazar theory required, is a history considerably more precise and considerably more resistant to political reinterpretation than either side of the two-century-old argument fully anticipated.

[00:24:46]Ashkenazi Jewish ancestry does not trace primarily to a medieval Turkic conversion event disconnected from the ancient Near East, a claim the genetic evidence has now tested directly and repeatedly failed to support across multiple independent research teams working with different data and different methods. It traces instead to a genuinely small founding population, quite possibly numbering only a few hundred families at its narrowest point, carrying ancestry from the ancient Levant on both its paternal and, according to the most recent analysis, predominantly its maternal lines as well, passing through at least two severe demographic bottlenecks across roughly 13 centuries of documented history.

[00:25:33]And somehow, despite catastrophic losses at nearly every turn, arriving at the genetic profile carried by more than 11 million people alive today.

[00:25:45]There is something worth sitting with in the fact that the people buried beneath that 14th century Erfurt cemetery had no way of knowing their remains would eventually become evidence in an argument about identity that would still be unresolved and still politically weaponized more than 600 years after their deaths.

[00:26:07]They were not making a scientific statement.

[00:26:10]They were simply living, praying, and eventually dying in the specific genetic and religious tradition they had inherited from their own parents, the same tradition their descendants would carry forward through further centuries of expulsion, persecution, and in the 20th century near total catastrophe without that tradition's underlying genetic signature ever fully disappearing. A third of them, the 2022 study found, shared a single common maternal ancestor.

[00:26:43]Somewhere in that detail sits the quiet outline of an entire community survival, narrowed at points to a thread never fully broken, carried forward not by any single dramatic event, but by the accumulated unglamorous persistence of ordinary families generation after generation across a continent that was rarely kind to them. If a question this old, this politically charged, and this thoroughly contested for nearly two centuries could ultimately be tested against real physical evidence extracted tooth by tooth from the ground and cross-examined against newly developed statistical methods as recently as 2025, it raises a genuinely worthwhile question to sit with. How many other origin stories still repeated as settled political fact in arguments far removed from any laboratory are still waiting for someone to finally go back and read what the evidence itself actually says?

[00:27:47]Genetics did not settle this question by handing either side of the old debate a clean, uncomplicated victory. It settled it by replacing speculation with something considerably more durable.

[00:28:00]Evidence drawn from the actual physical remains of the people the argument was supposedly about all along cross-checked repeatedly by independent teams who did not always agree with each other on every technical detail, but who converged again and again on the same basic historical outline. A small founding population rooted in the ancient Near East, carried forward across roughly 2,000 years of displacement, bottleneck, and catastrophe without ever fully losing the thread connecting it back to where the story actually began.

[00:28:38]If you found this as fascinating as we did, subscribe to DNA Origins for more documentaries uncovering the genetic history hidden inside the world's peoples.

[00:28:49]Next week, we're returning to West Africa to trace what modern genetic studies have revealed about the deep, surprising origins of the Yoruba people.

[00:28:59]That video is already on the channel.