Researchers analyzed ancient animal DNA to trace the evolution of an ancient group of retroviruses. Photo by xrender/Shutterstock

BOSTON, March 8 (UPI) -- A new study, published in the journal eLife, offers insight into the origins of a group of ancient retroviruses.

DNA analysis suggests a group of viruses called ERV-Fc infected 28 ancestors of modern mammals between 15 and 30 million years ago, when ERV-Fc viruses made their way to every continent except Australia and Antarctica.


Genetic remnants of the ancient retroviruses -- related to modern viruses like HIV and human T-cell leukemia -- were found in DNA recovered from fossilized ancestors of carnivores, rodents and primates.

"Viruses have been with us for billions of years, and exist everywhere that life is found. They therefore have a significant impact on the ecology and evolution of all organisms, from bacteria to humans," study co-author Welkin Johnson, a professor of biology at Boston College, said in a news release.

"Unfortunately, viruses do not leave fossils behind, meaning we know very little about how they originate and evolve," Johnson said. "Over the course of millions of years, however, viral genetic sequences accumulate in the DNA genomes of living organisms, including humans, and can serve as molecular 'fossils' for exploring the natural history of viruses and their hosts."

While tracing the path of these ancient viruses, researchers were able to pinpoint their genetic adaptations as they moved from species to species.

The key moving forward, researchers say, will be extracting lessons from the research for the study of modern viruses. What does the movement and evolution of ERV-Fc viruses have to say about viruses of today and tomorrow?