Ancient DNA reveals how a chicken virus evolved to become more deadly

Electron Microscopy image of Marek’s disease virus particles replicating in the nucleus of an infected cell. Based on the ancient genetic sequences, they were also able to resurrect ancient biological processes using cellular assays, demonstrating that ancient strains were significantly milder than their modern counterparts. As chicken consumption dramatically increased in the 1950s and 1960s, MDV has continued to evolve and has become increasingly aggressive despite the development of several vaccines. Being able to watch this process take place by sequencing ancient virus genomes shows just how dramatically the virulence of MDV has increased in the past century.' The study Ancient chicken remains reveal the origins of virulence in Marek’s disease virus has been published in Science.