Are viruses alive? The replicator paradigm sheds decisive light on an old but misguided question

Abstract

The question whether or not “viruses are alive” has caused considerable debate over many years. Yet, the question is effectively without substance because the answer depends entirely on the definition of life or the state of “being alive” that is bound to be arbitrary. In contrast, the status of viruses among biological entities is readily defined within the replicator paradigm. All biological replicators form a continuum along the selfishness-cooperativity axis, from the completely selfish to fully cooperative forms. Within this range, typical, lytic viruses represent the selfish extreme whereas temperate viruses and various mobile elements occupy positions closer to the middle of the range. Selfish replicators not only belong to the biological realm but are intrinsic to any evolving system of replicators. No such system can evolve without the emergence of parasites, and moreover, parasites drive the evolution of biological complexity at multiple levels. The history of life is a story of parasite-host coevolution that includes both the incessant arms race and various forms of cooperation. All organisms are communities of interacting, coevolving replicators of different classes. A complete theory of replicator coevolution remains to be developed, but it appears likely that not only the differentiation between selfish and cooperative replicators but the emergence of the entire range of replication strategies, from selfish to cooperative, is intrinsic to biological evolution.

Genetic conflicts: the usual suspects and beyond

“…Natural selection acts on all replicators -any autonomous or partially autonomous replicating entity (Koonin and Starokadomskyy, 2016), whether it be a specific allele of a gene, a chromosome, a genome or even a group of genomes. In this context, transposable elements represent the ultimate (and perhaps original) selfish DNA elements (Doolittle and Sapienza, 1980; Fig.…”

Standing on the Shoulders of Giant Viruses: Five Lessons Learned about Large Viruses Infecting Small Eukaryotes and the Opportunities They Create

“…In recent months, we have seen a series of researchers working to redefine “What is a virus?” [19] and even “What is life?” [20]. Apparent, but not always on the forefront of this debate, is how these viruses have changed life as we understand it.…”

Viruses

“…Are viruses living organisms, or are they simply sequences of nucleic acid that have the wherewithal to move from cell to cell. Much of the debate focuses around the definition of life [1,26]. How we define life is somewhat arbitrary, and we can certainly produce a definition of life that includes the viruses, if that is what we choose.…”