Introduction
Contemporary Jewish groups trace their roots to the Near East but have mixed over time with neighbors in Europe, North Africa, and the Middle East. It wasn’t clear whether they ever picked up genes from East Asia, even though Jewish merchants and communities traded and lived along the Silk Road and left behind letters, pottery, and synagogues in China.
To find out, scientists looked at mitochondrial DNA (mtDNA) from 55,595 people across Eurasia, including about 2,000 Jews and over 21,000 East Asians. They discovered that some Ashkenazi Jews carry haplogroups (A, N9a, M33c) typically found in eastern Eurasia. By reconstructing family trees of these mtDNA lines, they traced one founder lineage (M33c2) to roughly 1,400 years ago—right in the Silk Road era.
This shows that Ashkenazi Jews didn’t just trade goods and ideas with China; a small but real flow of genes also passed between them.
Summary of Results and Discussion
Key Findings
Our large-scale analysis of mitochondrial DNA (mtDNA) across 55,595 Eurasian samples—including 23,121 East Asians and Jews—reveals that Ashkenazi Jews carry rare eastern Eurasian lineages. Four individuals fall into haplogroups A and N9a, and 14 into haplogroup M33c, linking a subset of Ashkenazi maternal ancestry to East Asia and South Asia.
Eastern Eurasian Lineages in Ashkenazi Jews
- Four Ashkenazi individuals have mtDNA from haplogroups A and N9a, common in East Asia.
- Fourteen carry M33c, a sister group to M33a, M33b, and M33d, which are mostly found in South Asia.
Phylogeographic Distribution of M33c
To understand where M33c emerged, we screened an extra 32,474 Eurasian control-region sequences. We found:
- 38 additional M33c samples (most from China, plus Vietnam and Thailand).
- One sample likely European but with unclear origins.
All evidence points to an origin or early differentiation of M33c in East Asia, especially China.
Internal Structure and Age of M33c
Eleven representative M33c genomes were fully sequenced and combined with six previously reported genomes. The resulting phylogenetic tree shows:
- M33c is defined by specific mutations at positions 3316, 4079, 5894, 8227, 8848, 16111, and 16235.
- Five subclades (M33c1–M33c5) are identified, almost all found in China except M33c2.
- M33c2 carries three additional mutations (4182, 4577, 7364) and includes:
- Three Ashkenazi Jewish individuals (all sharing the same control-region motif).
- One Chinese individual.
- One likely Jewish or Ashkenazi European.
Age estimates place the origin of M33c around 10,000 years ago, with the M33c2 subclade forming about 1,400 years ago.
Historical Context: Silk Road and Ashkenazi Origins
- The timing of M33c2’s emergence (circa 640–1,400 AD) overlaps with medieval Silk Road activity.
- Jewish merchants, known as Radhanites, traded between east and west from as early as the ninth century.
- Archaeological records place a continuous Jewish presence in Cologne from 321 to 1424 AD, suggesting Ashkenazi roots in Roman-era Europe, possibly Italy.
- Genetic evidence and historical records indicate Ashkenazi communities in eastern Germany before expanding into Poland (1500–1650 AD).
Conclusions and Implications
- There was a maternal gene flow from East Asia into eastern European Ashkenazi Jews, likely via Silk Road contacts.
- Women as well as men participated in these ancient exchanges.
- Further analysis of Y-chromosome and autosomal data would clarify the full scope of pan-Eurasian interactions in Jewish history.
Methods
Ethical Approval and Consent
The study was approved by the Ethics Committee at Kunming Institute of Zoology, Chinese Academy of Sciences. Every participant received information about the project and gave written consent before providing a DNA sample.
Data Collection
- We gathered 23,121 mitochondrial DNA (mtDNA) control-region sequences from East Asian and Jewish individuals, using both published and our own unpublished data.
- To study the distribution of haplogroup M33c, we added another 32,474 Eurasian samples, bringing the total to 55,595 mtDNA sequences.
Haplogroup Assignment
- Each mtDNA sequence was initially grouped into a haplogroup based on characteristic patterns in the control region.
- We confirmed these assignments by checking key coding-region mutations against the PhyloTree Build 16 reference.
Whole Mitogenome Sequencing
- For detailed phylogeny, we selected 11 representative M33c samples.
- We amplified and sequenced their entire mitochondrial genomes following established protocols.
- Raw sequence data were edited and aligned using Lasergene software and compared to the revised Cambridge Reference Sequence.
Phylogenetic Analysis
- We manually constructed a median-joining network for haplogroup M33c.
- To validate our manual network, we ran the same data through Network 4.612 software.
