The Biological Role of a Virus

This book answers the question “What is it that viruses do?” by presenting three aspects of viral ecology.

The  first aspect explains how viruses affect the population diversity and  energetics of their host communities. Perhaps the most notable example  of this concept is our understanding that primary production within  ecosystems often depends upon those viruses which serve as controllers  of nutrient recycling, connecting the aquatic and terrestrial realms in  ways that can be assessed locally and globally.

The second  aspect describes genetic partnerships which exist between hosts and  their viruses. These include processes termed endogeny and lysogeny by  which the host carries at least a partial genomic copy of the  virus. Fluidity of these collective genomes is expressed on an  evolutionary time scale and the mutual life cycles which they produce  represent a forging of shared genomic fate that obligates partnership of  the virus and its host. The viral sequences represent a source of  potential benefit as well as potential peril for the host and can  implement phenotypic changes in the host. Hosts often use those changes  as tools. As humans, the most notable example would be that mammals rely  upon temporary activation of their endogenous viral genes in order to  successfully develop a placenta.

The third aspect is defending  the health of a host, which relies upon activity in two directions.  Hosts often use their captured viral genes to identify and subsequently  direct battle against invading viruses. This natural concept has been  engineered for combating cancer, is useful for suppressing the  detrimental consequences of genetic diseases, and has been developed to  create targeted antiviral vaccines. But, the defense has to work in two  directions and the host can use other symbiotic microorganisms as  protection against its viruses.

This book will appeal to a wide  readership by providing a broad perspective of viral ecology, and all  scientists will find it helpful for gaining a view of fields beyond  their specialization.