Link between herpesviruses and giant viruses no longer missing
Enlarge / Electron micrograph of herpesviruses. (credit: Callista Images)
Double-stranded DNA viruses come in two main flavors, classified by their shapes. One contains large and giant DNA viruses that attack complex cells but also includes some viruses that are much smaller and infect bacteria. These viruses are shaped like soccer balls. The other flavor has tails and primarily infects bacteria and archaea but also contains the herpesvirus family, which infects animals.
The disparate properties of these viruses have raised some questions that have been plaguing virologists: Where did herpesviruses come from? And how are the large and giant DNA viruses related to the smaller viruses within their realm?
Tara Oceans is an international, multidisciplinary project to assess the complexity of ocean life across comprehensive taxonomic and spatial scales." Researchers with the project sail around all five oceans and two seas (the Red and the Mediterranean), sampling plankton to try to understand the ocean ecosystem. In new work reported in Nature, a team pulled plankton from the sunlit oceans (it's a technical term: only down to 200 meters below the surface, where light penetrates and photosynthesis happens). They surveyed all the planktonic DNA viruses by comparing a single hallmark gene among them.