Viruses have been thought to be poisons, then life-forms, then chemicals – and today scientists are yet unsure if they are living or nonliving. The notion that viruses are largely nonliving has caused scientists to ignore viruses in the study of evolution – but viruses play a huge role in the evolution of life.
Wendell Stanley at Rockefeller U. in NY, 1935, crystallized a virus, revealing that it was made of a bunch of complex biochemicals, and lacked essential metabolic systems. This showed the world that viruses were not alive, which was believed, but only for a time. It was later discovered that viruses have their own nucleic acids, and upon entering a living cell, induce the cell to produce more viruses based on its own DNA. This act makes a virus seem very alive.
Perhaps the reason nobody can say for sure if viruses are dead or alive is that nobody can say for sure what life is. A definition is difficult to come up with: Something that can replicate, is born, dies, metabolic autonomy, etc. Viruses, however, depend on a living host to carry out many of these functions. Rocks are deader than viruses, though, it would seem. So maybe viruses resemble seeds, with potential, but requiring something else to “live.” Viruses are more than inert matter…
Recently in Marseille, France, the genome of the largest known virus, Mimivirus, was sequenced. The Mimivirus is about the size of a small bacterium. The virus’s DNA contained code for many genes previously thought to only be in bacteria, and the enormous complexity of the virus’s genome challenges previous borders between living cells and viruses.
The author then explains how considering viruses as un-alive negatively impacts evolutionary research. He points out that scientists classify viruses in the same category as climate change, and don’t seriously consider the role viruses might have played in evolution. For example, viruses can permanently add their DNA to the host, effectively changing the DNA of the host’s descendents. This means viruses potentially have a much greater and quicker role in evolution that accumulated mutations.
The huge number of viruses with their rapid replication and mutation make viruses the world’s utmost source of evolution in genetics. Not only can a virus affect the evolution of other living things, but they themselves evolve. New viruses can be witnessed as they come into being, such as the HIV-1 virus. What animal can a scientist watch come into existence?
This article rose many points that I have not previously thought about. I did not know that viruses can implant their DNA into the host…that especially raises so many possibilities for applications of viruses in medicine, etc. I also enjoyed reading this article because viruses have always interested me, and the question of what life is interests everyone…I think! Perhaps I will have to drop the pharmacy thing and pursue viral research…eh, I still have time. Anyway, I’m sure the debate about whether viruses are alive or dead will be a heated argument for much time to come, but it’s always an interesting question to consider, and the author certainly brought up decent points regarding viruses role in evolution.
This was in response to an article, which I have no record of.