Towards an integrative view of virus phenotypes

Linking genotype to phenotype is particularly challenging for viruses because of their small size, sparse phenotypic data and interlinked viral, host and environmental factors. In this Review, DeLong and colleagues discuss traits of virions and virocells and phenotypic plasticity. Understanding how phenotypes emerge from genotypes is a foundational goal in biology. As challenging as this task is when considering cellular life, it is further complicated in the case of viruses. During replication, a virus as a discrete entity (the virion) disappears and manifests itself as a metabolic amalgam between the virus and the host (the virocell). Identifying traits that unambiguously constitute a virus's phenotype is straightforward for the virion, less so for the virocell. Here, we present a framework for categorizing virus phenotypes that encompasses both virion and virocell stages and considers functional and performance traits of viruses in the context of fitness. Such an integrated view of virus phenotype is necessary for comprehensive interpretation of viral genome sequences and will advance our understanding of viral evolution and ecology.

Automated summary

This review discusses the traits of viral cells and viral particles, as well as how to categorize virus phenotypes; the foundational goal in biology is understanding how phenotypes emerge from genotypes; identifying the features that constitute a virus's phenotype is crucial for comprehensive interpretation of viral genome sequences and for advancing our understanding of viral evolution and ecology.