Virus “Fossils”

Genetic signatures representing viral codes are found in the chromosomal DNA of even the most primitive angiosperms. Plants evolving to survive changing environmental conditions rely on the acquisition of novel genes and sometimes viruses can supply them. In nature, during the normal DNA repair process when DNA is replicated, viral sequences may be slipped in and incorporated into a plant genome. The pace of plant evolution by this means is quickened considerably over the more familiar means of genetic change involving outcrossing seed production and random mutation. The study of genetic sequences found in Pinot Noir grapes reveals the ancient structure of viruses from millions of years ago. Virus particles themselves, independent of a plant host, would never be found as they disassemble and fall apart when the host dies. So not only can we appreciate viruses for contributing to our modern day grapes, we can also learn about the evolution of viruses by means of these molecular fossils.

Nature Communications 5, Article number: 5269