Scientists claim that our Universe is some 13.8 billion years old, our Sun and our Earth are both some 4.5 billion years old and that microbes (e.g., bacteria) existed before (!) 3.5 billion years ago based on the dating of fossils in Australia and Greenland. Scientist now recognise viruses as ancient and as having origins that pre-date the divergence of life (see April 7 blog).
In 2013, the French scientists Jean-Michel Claverie and Chantal Abergel published their discovery of the so called Pandora virus in Science Magazine. They reported “the isolation of two giant viruses, one off the coast of central Chile, the other from a freshwater pond near Melbourne (Australia), without morphological or genomic resemblance to any previously defined virus families”. “These viruses are the first members of the proposed “Pandoravirus” genus, a term reflecting their lack of similarity with previously described microorganisms and the surprises expected from their future study.” And also: “Because more than 93% of Pandoraviruses genes resemble nothing known, their origin cannot be traced back to any known cellular lineage. However, their DNA polymerase does cluster with those of other giant DNA viruses, suggesting the controversial existence of a fourth domain of life”.
Adding viruses to the Tree of Life may actually be a little more than just controversial as it would come close to redefining our entire concept of Life.
Scientists debate whether viruses are alive at all. For something to be alive it must eat, grow, make waste, and reproduce. When a virus is floating around in the air or sitting undisturbed in soil, it is no more alive than a rock. But if that same virus comes in contact with a suitable animal, plant, or bacterium cell, it suddenly becomes active. A virus does not eat, but it gets its energy from the host cell it infects. It does not grow in the sense that it gets larger, but it does reproduce. In fact, a virus’s sole purpose seems to be reproduction, and it cannot do that without the help of a living cell. (Source)
I feel that we largely underestimate the purpose or role of viruses. Indeed they bring death like poison does. Yet the Chinese were already well aware that any poison may be a cure for another disease. Hence, poison as medicine. A woman readying for death from Lyme disease found herself cured after being attacked by a hoard of bees. Scorpion venom is used in Chinese medicine to treat everything from eczema to epilepsy. Now researchers are hoping to use bee venom to fight HIV, cancer, arthritis and multiple sclerosis. See: Food for Thought in FT First of 27 March 2015 and Mosaic Science.
Viruses may well play a vital role in death AND life. Viruses may perform the pivotal role in the survival of the fittest, in Evolution, and in Life. Please also see this article which I just found.
Some scientists suggested that the 93% unknown DNA in the Pandora virus may be extraterrestrial. “At this point we cannot actually disprove or disregard this type of extreme scenario,” Claverie added, referring to the possibility the virus is extraterrestrial in origin. I would suggest that the 93% represents extinct species (early humans, animals, plants, etc.) rather than anything extraterrestrial.