Sep 23, 2008

Genomic evolution in a virus under specific selection for host recognition

Infection, Genetics and Evolution : Journal of Molecular Epidemiology and Evolutionary Genetics in Infectious Diseases
Kim M PepinRobert McKenna


Genetic variation in viral structural proteins is often explained by evolutionary escape of strong host defenses through processes such as immune evasion, host switching, and tissue tropism. An understanding of the mechanisms driving evolutionary change in virus surface proteins is key to designing effective intervention strategies to disease emergence. This study investigated the predictability of virus genomic evolution in response to highly specific differences in host receptor structure. The bacteriophage PhiX174 was evolved on three E. coli mutant hosts, each differing only by a single sugar group in the lipopolysaccharides, used for phage attachment. Large phage populations were used in order to maximize the amount of sequence space explored by mutation, and thus the potential for parallel evolution. Repeatability was assessed by genome sequencing of multiple isolates from endpoint populations and by fitness of the endpoint population relative to its ancestor. Evolutionary lines showed similar magnitudes of fitness increase between treatments. Only one mutation, occurring in the internal DNA pilot protein H, was completely repeatable, and it appeared to be a necessary stepping stone toward further adaptive change. Substit...Continue Reading

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Mentioned in this Paper

Pathologic Cytolysis
Immune Evasion
Gait, Drop Foot
Alkalescens-Dispar Group
SLC25A29 gene
Amino Acids, I.V. solution additive
Viral Proteins
Biological Adaptation

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