Double-stranded DNA viruses have two main characteristics that are classified according to their shape. One contains large, giant DNA viruses that attack complex cells, but also several viruses that are much smaller and infect bacteria. Another flavor is the tail, which mainly infects bacteria and archaea, but also includes the herpes virus family, which infects animals.
The different properties of these viruses have given rise to several questions that have puzzled virologists: where did the herpes virus come from? How are they related?
Cod Ocean “An international, interdisciplinary project to assess the complexity of marine organisms across comprehensive taxonomic and spatial scales”. Researchers in this project will sail through all five seas and he two seas (the Red Sea and the Mediterranean) to sample plankton and try to understand the ocean ecosystem. In a new study reported in Nature, the team pulled up plankton from a sunlit ocean (that’s the technical term, up to 200 meters below the surface where light penetrates and photosynthesis occurs). They surveyed all planktonic DNA viruses by comparing single, characteristic genes.
This analysis reveals a new phylum of DNA viruses that have a herpesvirus-like shape and infect eukaryotes but share key enzymes with large and giant viruses.Scientists have named the phylum myrusvirus, after the Latin word Milsmeans amazing or strange.
They identified seven different clades of myrusviruses and found them worldwide. Three of them were found only in the Arctic Ocean, and only one was endemic to temperate waters. As recently discovered, the myrus virus appears to be one of the most abundant eukaryotic viruses in the sunlit sea. They are also very active within infected plankton, indicating that they likely play an important role in marine ecosystems.
The two regions of DNA viruses bridged by the myrus virus, one containing the giant virus and the other containing the herpes virus, are of ancient lineage. So it’s still unclear how they got to where they are today. The similar shapes of myrusviruses and herpesviruses suggest that these eukaryotic viruses share a common ancestor. The authors speculate that a common enzyme was transmitted between giant viruses and this common ancestor, but they do not know which lineage had it first or how it was transmitted. Hmm. After that, the herpes virus lost its genes through reductive evolution. He then acquired the ability to infect animals along the way. lucky.
Nature, 2023. DOIs: 10.1038/s41586-023-05962-4
