In the past year, scientists came to a shocking discovery when they found a virus larger than any found before: a Pandora virus. Discovered in Chile’s Tunquen River, Pandora viruses average a length of about a micrometer—0.3 micrometers larger than any virus found before—and contain an astonishing 2,500 genes. This is surprising considering an average virus can contain as few as 10 genes. Amoeba are the host for the Pandora viruses
With such a large relative size, one may begin to ask how these relatively enormous viruses went unnoticed for so long. The authors of the study admit that it is entirely possible that they had in fact been discovered before, but were never identified. In addition, other researchers most likely weren’t screening for something that large when looking for viruses. The study authors note that another reason why the Pandora virus had not been found before could be because ocean bacteria are extremely difficult to grow in a laboratory setting; only 10% are able to grow.
Although these new viruses have similar structures to normal viruses, they have a lot less in common than the study’s researchers would have anticipated. One of the key differences that the researchers immediately noticed was that they don’t infect people, or any microbes for that matter. In fact, they haven’t been found to have any harmful impact on humans, which is a stark contrast from standard viruses. In addition, they have been found to be helpful to the ecosystem by playing an important role in the ocean’s food chain.
Perhaps one of the most shocking findings of this research was that 93% of the Pandora virus’s genes could be traced back to any known lineage in nature. Additionally, they reproduce in a fashion that is unlike anything seen before. While typical viruses build the cell first and then fill it with DNA, Pandora viruses instead do each of these processes simultaneously. This suggests that these microbes are more foreign to us than we would have anticipated initially.
These significant differences in this so-called virus lead the researchers to suspect that there’s more to the story than meets the eye; they suspect that it could lead to the creation of an entirely new domain of life along with bacteria, archaea, and eukarya. Though this may be an extreme conclusion, there’s one thing that most scientists will agree on: discoveries like these truly showcase how much there is still yet to discover about microbiology on Earth.