2023-12-15 ミュンヘン大学(LMU)
With the increase in poultry farming, Marek’s disease virus evolved. | © IMAGO / imagebroker/Dieter Hopf
◆国際的な研究チームが、ヨーロッパと近東の考古学的な場所で最大1,000年前の鶏の骨から古代DNAを分離し、MDVの進化を解読しました。1907年に初めて記述される1,000年前には既にウイルスが広く分布していたことが判明し、1950年代以降の鶏肉生産の急増に伴い、ウイルスは進化して毒性が増しています。特に、腫瘍を引き起こすMeq遺伝子の変異が増加する傾向があり、これが毒性の増加に関与しています。
◆また、一部のワクチンの使用が毒性の進化を促進している可能性があります。この研究は、MDVの進化史を解き明かし、古代DNA技術と現代のゲノミクスを組み合わせて病原体の毒性を理解する基盤を提供しています。
<関連情報>
- https://www.lmu.de/en/newsroom/news-overview/news/deadly-chicken-disease-ancient-dna-reveals-evolution-of-virulence.html
- https://www.science.org/doi/10.1126/science.adg2238
古代のニワトリの死骸がマレック病ウイルスの病原性の起源を明らかにする Ancient chicken remains reveal the origins of virulence in Marek’s disease virus
Steven R. Fiddaman,Evangelos A. Dimopoulos,Ophélie Lebrasseur,Louis du Plessis,Bram Vrancken,Sophy Charlton,Ashleigh F. Haruda,Kristina Tabbada,Patrik G. Flammer,Stefan Dascalu,Nemanja Marković,Hannah Li,Gabrielle Franklin,Robert Symmons,Henriette Baron,László Daróczi-Szabó,Dilyara N. Shaymuratova,Igor V. Askeyev,Olivier Putelat,Maria Sana,Hossein Davoudi,Homa Fathi,Amir Saed Mucheshi,Ali Akbar Vahdati,Liangren Zhang,Alison Foster,Naomi Sykes,Gabrielle Cass Baumberg,Jelena Bulatović,Arthur O. Askeyev,Oleg V. Askeyev,Marjan Mashkour,Oliver G. Pybus,Venugopal Nair,Greger Larson,Adrian L. Smith,and Laurent A. F. Frantz
Science Published:14 Dec 2023
DOI:https://doi.org/10.1126/science.adg2238
Editor’s summary
Marek’s disease virus (MDV) causes tumors in chickens and has increased in virulence over the past century. Fiddaman et al. studied ancient DNA from chickens to reveal the evolutionary history of this once mild disease (see the Perspective by Duchene). They sequenced MDV DNA from 15 ancient chickens, finding that these strains were basal to modern ones and identifying multiple fixed genetic changes. Testing the ancient version of the gene Meq, a regulator of tumor formation, the authors found that virulence was greatly reduced compared with modern versions. These results shed light on the evolution of virulence in a major disease in modern agriculture. —Corinne Simonti
Abstract
The pronounced 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 past century. Today, MDV infections kill >90% of unvaccinated birds, and controlling it costs more than US$1 billion 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.
