Recent research findings indicate that many of the plant pathogens affecting agriculture today originated during an earlier era than originally believed. Analysis performed by an international team of scientists found that viruses classified as tymoviruses most likely emerged before the last Ice Age. Evidence indicates that these viruses may have been present in some form among wild plants in Eurasia long before human agricultural practices were developed. In a study published in Plant Disease, researchers reconstructed the evolutionary history of the tymovirus family by comparing the genetic structures of over 100 viral genomes. The results indicate that the origins of the earliest tymoviruses may be traced back approximately 23,000 years, around the time when glaciers were still present in the Northern Hemisphere. Evolution of Viruses in The Tymovirus Family Tymoviruses are known to infect flowering dicots, most commonly brassicaceous plants (e.g., cabbage, radish) and solanaceous plants (e.g., pepper, tomato, eggplant). Many tymoviruses are transmitted to new hosts by leaf-chewing beetles. Others can be spread by seed or through direct contact with infected plants. Patristic distance …