Scientists Discovered Ancient Viruses that Existed 30 Million Years Ago

Scientists have discovered the history of ancient viruses 30 million years ago. This new study could help researchers better understand how these viruses evolve and will open new knowledge about existing viruses.

Retroviruses, which include immunodeficiency viruses that are present in HIV-1 and -2 and T-cell leukemia viruses, are abundant in nature. In the new study, the researchers focus on ERV-Fc, a group of viruses that affect a wide range of hosts, HNGN reported.

Welkin Johnson of Boston College, co-author of the new study said that viruses have existed for billions of years. They have an important contribution on the ecology and the evolution of all organisms, from bacteria to humans.

"Unfortunately, viruses do not leave fossils behind, meaning we know very little about how they originate and evolve. 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," Johnson said.

Researchers focused on discovering the natural history of ERV-Fc using the said "fossil" remains. They looked for mammalian genome sequence databases for ERV-Fc loci and compared the recovered sequences.

For each genome with enough ERV-Fc sequence, they performed a sequence reconstruction of the proteins that represent the virus that colonized the ancestors of specific species. It was then used to conclude the natural history and evolutionary connections of ERV-Fc-related viruses, as reported by EurekAlert.

Through the study, the researchers were able to point out the patterns of evolutionary change in the viruses' genes that showed how they adapt to different kinds of mammalian hosts. However, what caught the researchers' interest is when they found out that viruses can exchange genes with each other and with other kinds of viruses, and shows that genetic recombination played an important role in their evolutionary success.