Ancient chicken remains reveal the origins of virulence in Marek’s 2 disease virus

Steven Fiddaman, Evangelos Dimopoulos, Ophélie Lebrasseur, Louis du Plessis, Bram Vrancken, Sophy Jessica Laura Charlton, Ashleigh Haruda, Kristina Tabbada, Patrik Flammer, Stefan Dascalu, Nemanja Marković, Hannah Li, Gabrielle Franklin, Robert Symmons, Henriette Baron, László Daróczi-Szabó, Dilyara Shaymuratova, Igor Askeyev, Olivier Putelat, Maria SanaHossein Davoudi, Homa Fathi, Amir Saed Mucheshi, Ali Akbar Vahdati, Liangren Zhang, Alison Foster, Naomi Sykes, Gabrielle Baumberg, Jelena Bulatović, Arthur Askeyev, Oleg Askeyev, Marjan Mashkour, Oliver Pybus, Venugopal Nair, Greger Larson, Adrian Smith, Laurent Frantz

Research output: Contribution to journalArticlepeer-review


The dramatic growth in livestock populations since the 1950s has altered the epidemiological and evolutionary trajectory of their associated pathogens. For example, Marek’s disease virus (MDV), which causes lymphoid tumors in chickens, has experienced a marked increase in virulence over the last century. Today, MDV infections kill >90% of unvaccinated birds and controlling it costs >US$1bn annually. By sequencing MDV genomes derived from archeological chickens, we demonstrate that it has been circulating for at least 1000 years. We functionally tested the Meq oncogene, one of 49 viral genes positively selected in modern strains, demonstrating that ancient MDV was likely incapable of driving tumor formation. Our results demonstrate the power of ancient DNA approaches to trace the molecular basis of virulence in economically relevant pathogens.
Original languageEnglish
Pages (from-to)1276-1281
Publication statusPublished - 14 Dec 2023

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