Viral interference-dominance of mutant viruses over wild-type virus in mixed infections

Abstract

It is generally accepted that a detrimental mutation in a gene results phenotypically in loss of the encoded activity and a recessive phenotype. However, there is considerable evidence that viruses with mutant alleles that produce temperature-sensitive, host range, small plaque, or nonsense mutants behave in a dominant manner and inhibit the growth of the standard wild-type virus in mixed infections. This review brings together and analyzes the information available concerning interference produced by mutants of a wide variety of ribonucleic and deoxyribonucleic acid viruses. In addition, possible mechanisms are proposed that would explain the dominance of conditionally defective viruses. The significance of the dominance of defective viruses is also discussed with emphasis on interference as a complication in genetic analysis, the role of interference in persistent infections, and interference as a factor in vaccinations with live viruses.