Scientists have identified a new virus that has become the largest ever studied. The virus, dubbed Pandoravirus, is nearly ten times larger than other viruses, and only 6% of its genome is similar to genes found in other organisms on Earth.
In this regard, French researchers have suggested that the virus either survived from very ancient times, or came to Earth from another planet, for example from Mars.
The giant virus can only be found underwater and scientists believe that it does not pose a serious danger to humans. Still, the researchers, who published their findings in the journal Science, believe the virus opens up a number of questions about the history of life on Earth.
Dr. Jean-Michel Clavieri, of Aix-Marseille University in France, who found the virus, told NPR: "We believe that the Pandoravirus we discovered was formed from cellular structures that no longer exist."
Most terrestrial viruses range in size from 10 to 500 nanometers (nm). The dimensions of the Pandoravirus are over 1000 nm. This means that the virus is large enough to be seen under a normal school microscope.
Clavieri explained that the virus is very large and has an irregular shape, which is usually unusual for viruses. Because of this, he initially thought it was a small bacterium, not a virus.
A team of researchers went on a hunt for the giant virus after traces of it were identified in seawater. Scientists took sediment samples off the coast of Chile and from a pond in Australia. In the laboratory, they added antibiotics to the water to kill the bacteria present. Then, amoebas were added to the samples in which no bacteria remained. When the single-celled organisms died, the researchers became convinced that there was something non-bacterial in the samples. Thus, scientists were able to detect Pandoravirus.
After examining it, the team of researchers found that the genetic code of the virus was twice the size of the Megavirus, which was previously considered the largest ever found. However, scientists were even more shocked by the fact that only six percent of the genes of the new virus resemble genes found in other organisms on Earth.
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According to expert scientists, the virus is probably of extraterrestrial origin. Researchers still don't know why this cellular form became a virus.