A cautionary note on the application of limited genetics studies to whole populations

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"Unraveling the origins of the sogdians: Evidence of genetic admixture between ancient central and East Asians", Jiashuo Zhang, Yongdi Wang, Naifan Zhang, Jiawei Li, Youyang Qu, Cunshi Zhu, Fan Zhang, Dawei Cai, and Chao Ning, Journal of Archaeological Science: Reports (Volume 61, February 2025, 104957)

Highlights

  • Genome-wide data was generated for two individuals from a joint burial in the Guyuan cemetery dating to the Tang Dynasty.
  • The female individual exhibits local ancestry, while the male individual carries both local ancestry and additional genetic components.
  • The integration of genomic data with archaeological evidence suggests that the two individuals were likely husband and wife.
  • The Sogdians, who travelled to China and intermarried with local populations, played a significant role in the Silk Road trade.

Fair enough, but:

Abstract

The Silk Road, an ancient trade route connecting China with the West, facilitated the exchanges of goods, ideas, and cultural practices among diverse civilizations. The Sogdians were prominent merchants along the Silk Road, renowned for their roles as traders, artisans, and entertainers. They migrated to China, forming enduring communities that produced multiple generations of descendants. Despite their historical importance, primary written records detailing the origins of the Sogdians and their interactions with local populations are limited. In this study, we generated genome-wide data for two ancient individuals from a joint burial (M1401) in the Guyuan cemetery dating to the Tang Dynasty (618–907 CE). To our knowledge, this represents the first ancient genomic data obtained from the Sogdian population. Our results reveal that the female individual exhibits local ancestry, while the male carries both local ancestry and additional genetic components linked to the Bactria-Margiana Archaeological Complex (BMAC) in Central Asia. This was introduced into the local gene pool approximately 18 generations ago. Combining historical, archaeological, and genetic analyses, we conclude that the two individuals were likely husband and wife. Our findings suggest that Sogdians, who initially traveled to China for trade, settled, intermarried with local populations, and played a significant role as intermediaries in Silk Road commerce. This study highlights the importance of Sogdiana at the end of the first millennium BCE in fostering connections between the Hellenistic world and the Qin/Han dynasties, emphasizing early Sogdian identity traits that preceded their later prominence as key merchants of the Silk Road.

Again, the bulk of these observations are sound and safe, but the last sentence is garbled and overreaching, hence admonition is advised.

The Introduction of the paper consists of three paragraphs giving basic information about the history of the Silk Road, who the Sogdians were, and how the Sogdians settled in China.  The main sections of the paper are:

Archaeological context of Guyuan Tang dynasty tomb (M1401)
Ancient genome data overview and ancient DNA authentication
Discussion and conclusion

As one would expect from a paper on ancient DNA, the overwhelming emphasis is on the description of the human remains in  Tomb M1401, together with the extraction and analysis of their DNA.  These findings have caused quite a sensation among scholars and laypersons from various fields.  However, if one does a google search on — guyuan tomb M1401 — (no quotation marks or dashes) one will get a very different picture of the male occupant of the tomb from that offered in the paper under discussion here, namely the European aspects of his physical remains.  In contrast, the current study emphasizes his local affinities.

Strictly speaking, this study applies only to the two individuals whose ancient DNA remains were the subject of the analysis.  Similar interpretations have been applied to ancient DNA studies of specimens from the Tarim Basin, Mongolia, and elsewhere in Central and Inner Asia.  From these limited data, large claims about entire populations are made, giving precedence and weight to genetics, highlighting the "local admixture" of available specimens.

I believe that the balance has swung too far in favor of genetic material, which, after all, require extensive chemical, mathematical, and statistical manipulation to make sense of.  In my estimation, we should pay more attention to the larger panorama provided by history, archeology, language, and art history, e.g., "Sogdians on the Silk Road" (5/22/25).  Indeed,we need to take a very close look at the Guyuan Sarcophagus itself, including the massive volumes of Rosalind E. Bradford (2009), whose research has uncovered motifs from across Asia and even North Africa, while not overlooking the Chinese facets of this extraordinary coffin.

 

Selected readings

[h.t. Hiroshi Kimamoto}



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