Viruses and Life: Can There Be One Without the Other?

Abstract

Viruses are omnipresent, genetically replicating parasites in our biosphere that affect and drive the evolution of life in various ways. Are viruses an inevitable feature of all naturally emerged (although hypothetical) living systems in the Universe or are they only a specialty of our life on Earth? We argue in this discussion that viruses indeed might be present in extraterrestrial, independently emerged biospheres, at least if the process of the origin of life was similar to that on Earth. Viruses are likely to have played important roles in the evolution of early life and thus their presence or absence could dictate the direction of the evolution of life in all living systems.