Certain families of single-stranded DNA virus are more than 40
to 50 million years old, according to investigators from the
Institute for Advanced Study, Princeton, NJ, and the Fox Chase
Cancer Center, Philadelphia. The investigators found remnants of
circoviruses and parvoviruses in the genomes of diverse
vertebrates from fishes to birds and mammals that had been
integrated into their genomes at different times from the recent
past to more than 50 million years ago. The research upends the
conventional wisdom that most virus families are of very recent
origin, and is published in the December Journal of Virology.
“Until recently, age estimates for all viruses except
retroviruses were in the thousands of years, and nobody expected
to be able to trace viruses beyond that time frame due to high
mutation rates of the most commonly circulating viruses,” says
Anna Marie Skalka of Fox Chase. “We showed that several families
have been around for tens of millions of years, and have barely
changed over that time frame