Did the Black Death Shape the Human Genome? New Study Casts Doubt
Did the Black Death Shape the Human Genome? New Study Casts Doubt
Unraveling the Genetic Legacy of the Black Death: A Debate in Genomic Studies
The devastating Black Death of 1349, while taking a significant toll on medieval Cambridge, might not have left a lasting imprint on the genomes of its people, as suggested by a recent study published in Science Advances1. This challenges a high-profile 2022 Nature paper2 that claimed variants in immune genes enriched in Black Death survivors had a protective effect. The study emphasizes the complexity of linking specific genetic changes to historical disease outbreaks and raises questions about the impact of singular events versus repeated epidemics on human evolution.
The Genetic Scars of Ancient Disease Outbreaks
The human genome bears scars from ancient diseases, with certain gene variants reflecting survival advantages during infections. While the idea of connecting specific genetic changes to historical outbreaks is challenging due to the subtle influence of natural selection over generations, it's an area of active exploration in genomics.
Contradicting Claims from 2022
A 2022 study identified over 200 immune gene variants that changed in survivors of the Black Death. In contrast, the recent Cambridge study sequenced 275 genomes from medieval and post-medieval Cambridge, finding little evidence of natural selection after the Black Death. Out of 22 gene variants related to plague survival, no significant shifts were observed in their frequencies.
Debating the Impact of Black Death on Genomes
The debate extends to analytical issues, with some researchers pointing out flaws in the 2022 study. While the Cambridge study found no conclusive evidence of Black Death-induced genetic shifts, proponents of the 2022 findings argue that certain variants, notably in the ERAP2 gene, were under selection in the past 2,000 years, encompassing various plague epidemics.
Looking Ahead: Resolving the Debate
The debate underscores the need for more extensive genomic data and larger sample sizes to draw definitive conclusions about the impact of the Black Death or any historical disease outbreak on human genetics. As the field progresses, understanding whether singular events or repeated pandemics significantly influence our genetic makeup remains a central question for researchers.
In conclusion, while the Black Death remains a pivotal point in history, unraveling its genetic legacy demands more comprehensive studies and a nuanced consideration of the complex interplay between pathogens and human evolution.
Hui, R., Scheib, C. L., D’Atanasio, E., Inskip, S. A., Cessford, C., Biagini, S. A., Wohns, A. W., Ali, M. Q. A., Griffith, S. J., Solnik, A., Niinemäe, H., Ge, X. J., Rose, A. K., Beneker, O., O’Connell, T. C., Robb, J. E., & Kivisild, T. (2024). Genetic history of Cambridgeshire before and after the Black Death. Science Advances, 10(3). https://doi.org/10.1126/sciadv.adi5903
Klunk, J., Vilgalys, T. P., Demeure, C. E., Cheng, X., Shiratori, M., Madej, J., Beau, R., Elli, D., Patino, M. I., Redfern, R., DeWitte, S. N., Gamble, J. A., Boldsen, J. L., Carmichael, A., Varlik, N., Eaton, K., Grenier, J.-C., Golding, G. B., Devault, A., … Barreiro, L. B. (2022). Evolution of immune genes is associated with the Black Death. Nature, 611(7935), 312–319. https://doi.org/10.1038/s41586-022-05349-x