What Black Death Survivors DNA Revealed About Us Is Extremely Disturbing

👇Decode your DNA results 👇 https://theorigindna.com/ Save 15% with code OriginYT Why do so many people today live with immune systems that attack their own bodies? Part of the answer may lie in the bones of people who died in the Black Death. Researchers from McMaster University, the University of Chicago and the Institut Pasteur pulled ancient DNA from more than 500 skeletons. They came from London and Denmark, from people who died before, during and after the plague. Only 206 samples were good enough to read, and they pointed to a startling idea: the Black Death may have acted as a powerful filter on human immunity. THE DISCOVERY The key site was East Smithfield, an emergency London cemetery used only in 1348–49. It gave scientists a precisely dated snapshot of the plague's victims, and in 2011 it had already yielded the first reconstructed genome of the plague bacterium. Comparing generations on either side of the pandemic, the team found a variant near the gene ERAP2 that became more common after the plague. People with two working copies were estimated to be about 40% more likely to survive. In lab tests, immune cells carrying that version were better at destroying the plague bacteria. THE HIDDEN COST The same ERAP2 version is a known risk factor for Crohn's disease. Scientists call this balancing selection: a gene that protects in one setting and harms in another, much like the sickle cell variant and malaria. It offers one possible piece of a modern puzzle. Around one in ten people in the UK now lives with an autoimmune condition. ALSO EXPLORED • Bioarchaeological evidence that the Black Death hit the frail hardest, and that Londoners after the plague lived longer • Similar immune-gene signals in plague victims from Ellwangen, Germany, and in Roma and Romanian populations • The 2025 scientific dispute over whether the statistics hold up, and the original team's response • How the plague bacterium lost copies of a virulence gene, became less lethal, and kept circulating longer • A modern parallel: Neanderthal-inherited DNA that raised the risk of severe COVID-19 Curious what your own genetic results reveal about your ancestry? The Origin DNA three-volume PDF guide bundle teaches you to read your raw data and go beyond your Ancestry or 23andMe reports: [YOUR LINK HERE] Key References & Sources The core study and the debate • Klunk, Vilgalys et al. (2022). Evolution of immune genes is associated with the Black Death. Nature. • Barton, Santander, Skoglund, Moltke, Reich & Mathieson (2025). Insufficient evidence for natural selection associated with the Black Death. Nature. • Vilgalys et al. (2025). Reply to Barton et al. Nature. Evidence from the plague pits • Bos et al. (2011). A draft genome of Yersinia pestis from victims of the Black Death. Nature. • DeWitte & Wood (2008). Selectivity of Black Death mortality with respect to preexisting health. PNAS. • DeWitte (2014). Mortality risk and survival in the aftermath of the medieval Black Death. PLOS ONE. Echoes in other populations • Immel et al. (2021). Molecular Biology and Evolution. Plague victims from Ellwangen, Germany, compared with modern residents. • Laayouni et al. (2014). PNAS. Convergent immune-gene evolution in Roma and Romanian populations. The pathogen's own evolution • Sidhu et al. (2025). Attenuation of virulence in Yersinia pestis across three plague pandemics. Science. Modern health connections • Conrad et al. (2023). The Lancet. Autoimmune disorders across 22 million people in the UK. • Zeberg & Pääbo (2020). The major genetic risk factor for severe COVID-19 is inherited from Neanderthals. Nature. Eyewitness account • Chronicle of Agnolo di Tura, Siena, 1348. Know someone who thinks the Black Death is just old history? Send them this video. Turn on notifications so you don't miss the next story written in human DNA, and share in the comments which discovery surprised you most. #AncientDNA #PlagueHistory #HumanEvolution #ImmuneSystem #medievalhistory