Imitation Without Citation
I’ve seen this happen enough times that I can’t just shrug it off anymore. I publish on these topics not only on Substack, but in peer-reviewed journals, and then later I watch more prestigious people cover the same ground as if my work had never existed. Their papers get vastly more circulation on X, and once that happens, most people understandably assume they are seeing the first serious work on the topic. If my papers are not cited, then for the public they may as well not exist.
At first I told myself it was probably just an oversight. The literature is big, and these things happen. But after seeing my work replicated without citation more than once, I got tired of pretending that was a satisfying explanation. This latest case was the last straw.
That is why I am writing this post.
I said it more bluntly on X: “I love how Akbari and Reich keep replicating my results without bothering to cite my papers!” This post is my attempt to document it carefully, because too many readers, and some hostile commenters, seem unaware that I had already published in peer-reviewed journals on these questions before these later papers appeared.
This isn't just about my ego. There's a real scientific problem here. Credit and replication are two pillars of science, but they belong to different sides of it. Giving credit is part of the ethical structure of science: it is how the record stays honest about who contributed what. Replication is part of the methodological structure of science: it is how findings become more reliable. Both are damaged when later researchers reproduce an earlier result while presenting it as if it emerged for the first time in their hands.
Replication should strengthen science. But it only does so when it is acknowledged as replication, confirmation, or extension of earlier work. When prior work is omitted, replication is turned into apparent novelty, and the scientific record becomes distorted.
The Timeline
The sequence of events matters for the record:
In 2024, I published a paper on temporal trends in polygenic scores in ancient European populations. The abstract reported “positive directional selection for EA, IQ, and SES traits,” but the paper’s main findings went beyond that. In the discussion, I wrote that my results “indicated a decrease in PGS for traits such as neuroticism, depression and schizophrenia,” and I added that I had “observed an elevated schizophrenia PGS in ancient samples,” implying a decline toward the present.
Later that same year, Akbari et al. posted their West Eurasia preprint. In their abstract, they wrote that they identify combinations of alleles associated with “lower risk for schizophrenia and bipolar disease” and “increased measures related to cognitive performance,” including “scores on intelligence tests, household income, and years of schooling.”
Then, in early 2025, I published a second paper extending this same framework to Eastern Eurasia. I was explicit about what I was doing: “This article aims to replicate these findings,” referring back to my earlier European paper. The results were clear. In the abstract I reported “positive selection for cognitive-related traits such as IQ, EA and autism spectrum disorder (ASD), alongside negative selection for anxiety and depression.” In the discussion I made the pattern even more concrete: “EA, IQ, and ASD displayed negative correlations with sample age, indicating increases over time likely driven by positive directional selection,” while “anxiety, depression, and (dark) skin color PGSs showed positive correlations with Years BP, consistent with decreases over time.” I then stated plainly: “These results replicate findings from prior research on ancient West Eurasian genomes.” In other words, before Barton et al. published their East Eurasia paper, I had already put into print the basic claim that Eastern Eurasia showed the same kind of long-term polygenic shifts I had previously reported for Europe. Barton et al. later framed their paper around “highly correlated signals of adaptation” in East and West Eurasia and “convergent evolution in response to parallel transitions to food producing economies.” This is the same broad comparative argument, presented later and without citation.
Skin pigmentation makes the same point in a slightly different way. In my East Eurasia paper, I did not just discuss cognition and psychiatric traits; I also reported that “anxiety, depression, and (dark) skin color PGSs showed positive correlations with Years BP, consistent with decreases over time,” and added that the East Asian light-skin score “confirmed evidence of negative selection for darker skin (or positive selection for lighter skin).” Barton et al. also treated skin pigmentation as a major East Eurasian result, but as an exception: in their abstract they wrote that “most skin lightening in East Asians arose prior to the Holocene,” and later said they “failed to observe strong selection at skin pigmentation in the East Eurasian cohort.” We were addressing the same trait in the same region. The difference is that they presented a different conclusion. But that only strengthens the case for citation, not weakens it. When a later paper revisits the same trait and reaches a different or narrower conclusion, the earlier paper should be part of the conversation, not erased from it.
I had even written a Substack essay asking whether the same SNPs move through time in similar directions in Europe and East Asia. But the buildup to that comparative angle did not begin on Substack. Before that, I had already published a paper on Chinese provinces showing that European-derived polygenic scores could meaningfully track variation inside an East Asian population. In my Chinese provinces paper, I explicitly cited that study and wrote that it showed European-derived PGSs “predict differences in mean phenotypic traits across contemporary Chinese provinces,” and that these findings “support the utility of European-derived PGSs for predicting variation within East Asian populations.” So by the time Barton et al. framed their East Eurasia paper around “highly correlated signals of adaptation” and “convergent evolution” across East and West Eurasia, I had already laid out that broader Europe–East Asia comparative logic in both a published paper and a public essay.
Prestige is not an excuse
Sure, two groups can land on the same question independently. That happens. But when that happens, you cite the earlier work instead of pretending the conversation began with you. Science is not weakened by replication; it depends on it. If another group revisits a question I have already explored and finds similar results, that should be a good thing. Replication is one of the ways science corrects itself and gains confidence in a finding.
The problem begins when replication is framed as novelty. A later paper may have a larger sample, more funding, and a more prestigious author list, but that does not erase the work that came before it. On the contrary, it creates a greater responsibility to distinguish clearly between what is genuinely new and what is confirming, extending, or repackaging earlier results. Otherwise the scientific record is distorted. Readers come away with the impression that the idea originated with the most powerful lab rather than with the person who first published it.
The Choice of Silence
The authors were contacted over a year ago and given the opportunity to respond or amend the record.
They did not reply.
I have now contacted the authors again by email and am waiting for their response. If they reply in a substantive way, I will update this post accordingly.
Conclusion
I'm posting this because I have no other option. I'm not at a major institution. I can't call in a favor or apply quiet pressure. The usual advice is to stay polite and let it go — which is easy advice to give when your name isn't the one getting dropped. We contacted them. They didn't respond. So here we are.
The record should be clear:
I published on temporal polygenic trends in ancient Europe before the Akbari West Eurasia paper appeared.
I published on these same questions in Eastern Eurasia before their East Eurasia paper appeared.
I used the same methodologies to address the East-West comparative angle before their convergence paper appeared.
A healthy scientific culture shouldn’t allow “Big Science” to quietly overwrite the work of smaller researchers simply because they have more resources. Citation is the bare minimum we should expect.
References
Akbari, A., Barton, A. R., Gazal, S., Li, Z., Kariminejad, M., Perry, A., Zeng, Y., Mittnik, A., Patterson, N., Mah, M., Zhou, X., Price, A. L., Lander, E. S., Pinhasi, R., Rohland, N., Mallick, S., & Reich, D. (2024, September 15). Pervasive findings of directional selection realize the promise of ancient DNA to elucidate human adaptation [Preprint]. bioRxiv. https://doi.org/10.1101/2024.09.14.613021
Barton, A. R., Rohland, N., Mallick, S., Pinhasi, R., Akbari, A., & Reich, D. (2026, April 4). Convergent natural selection at both ends of Eurasia during parallel radical lifestyle shifts in the last ten millennia [Preprint]. bioRxiv. https://doi.org/10.64898/2026.04.03.716344
Piffer, D. (2025). Directional selection and evolution of polygenic traits in Eastern Eurasia: Insights from ancient DNA. Twin Research and Human Genetics, 28, 1–20. https://doi.org/10.1017/thg.2024.49
Piffer, D., & Kirkegaard, E. O. W. (2024). Evolutionary trends of polygenic scores in European populations from the Paleolithic to modern times. Twin Research and Human Genetics, 27(1), 30–49. https://doi.org/10.1017/thg.2024.8
Piffer, D., & Kirkegaard, E. O. W. (2024). Predictive accuracy of polygenic scores from European GWAS among Chinese provinces. Mankind Quarterly, 65(1), 58–71. https://doi.org/10.46469/mq.2024.65.1.6
I am sorry this is happening to you. I don't know what you can do. It is bullshit!