Were there already viruses on Earth when the first living cells appeared billions of years ago? – Aayush A., age 16, India ...

Archaea form one of the three domains of life; the others are bacteria and eukaryotes. A metagenomic CRISPR screening approach identifies an expansive diversity of viruses and mobile genetic ...

Bacteria and archaea are single-celled creatures that ... Some scientists consider viruses to be microbes made of genetic material enclosed in a protein coat. They are unable to replicate on ...

Another popular theory states that viruses evolved from degenerated bacteria or archaea that lost most of the genetic instructions for carrying out metabolism and forming cells. There are many ...

“The evolutionary history of RNA viruses is at least as long, if not longer, than that of the cellular organisms,” wrote the authors. Often ignored is the third branch of life, archaea. Evolved during ...