Researchers have now discovered a new kind of giant virus and have named it the "Pandoravirus" after the mythical Greek figure "Pandora" who opened a box and released evil into the world.
The viruses, however, don't seem to pose any threat to human health, npr.org reported. Instead, they may help researchers understand the origin of life on Earth. The viruses can be seen via a light microscope.
Jean-Michel Claverie, a virologist at the French National Research Agency at Aix-Marseille University and colleagues described their latest discovery in the journal Science.
Pandoraviruses range from 50 nanometers to 100 nanometers. The newly found viruses also have a large genome of about 2,500 genes when compared to about 10 genes in a normal virus, reports the National Geographic.
"Finding such a new type of virus that is so different happens once every 50 years-it's a major discovery," said the research team.
The new virus discovery suggests that they may have developed from an ancestor that was unique and different from the ancestor of the bacteria. Thus the "tree of life" for primitive cellular life may require some re-drawing to accommodate these massive viruses.
One of the giant viruses called Pandoravirus salinus was found just off the coast in Chile, while the other virus Pandoravirus dulcis was collected from a freshwater pond in Australia, reports Fox News. Megavirus chilensis, which has a genome of 1.18 million bases long, was earlier considered to be the largest virus. The newly discovered viruses: P. salinus is 1.91 million DNA bases long, while P. dulcis is 2.47 million DNA bases.
According to researchers, many people have assumed that viruses are extremely small which has led to these giant viruses remaining undiscovered for such a long time.
"When people look into cells and when they see things that don't have the right dimension or don't have regular assets or geometries, they don't think of viruses-they think its some kind of bacteria," Claverie and Chantal Abergel, another co-author of the study, reported The National Geographic
Over 90 percent of genes of these viruses haven't been studied yet, making it difficult for researchers to know how this kind of virus originated.
"It indicates that our knowledge of the microbial biodiversity on this planet is still very limited, and that huge discoveries remain to be made at the most fundamental level. These may change our present understanding about the origin of life and its evolution," researchers said, reports abc.net.au.