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G3 (Bethesda). 2016 Apr 7;6(4):939-55. doi: 10.1534/g3.115.024075.

Genetically Determined Variation in Lysis Time Variance in the Bacteriophage φX174.

Author information

1
Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island 02912 baker03@g.harvard.edu.
2
Department of Mathematics, University of Idaho, Moscow, Idaho 83844 Department of Biological Sciences, University of Idaho, Moscow, Idaho 83844 Center for Modeling Complex Interactions, University of Idaho, Moscow, Idaho 83844.
3
Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island 02912.
4
Department of Mathematics, University of Idaho, Moscow, Idaho 83844.
5
Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island 02912 Center for Computational Molecular Biology, Brown University, Providence, Rhode Island 02912.

Abstract

Researchers in evolutionary genetics recently have recognized an exciting opportunity in decomposing beneficial mutations into their proximal, mechanistic determinants. The application of methods and concepts from molecular biology and life history theory to studies of lytic bacteriophages (phages) has allowed them to understand how natural selection sees mutations influencing life history. This work motivated the research presented here, in which we explored whether, under consistent experimental conditions, small differences in the genome of bacteriophage φX174 could lead to altered life history phenotypes among a panel of eight genetically distinct clones. We assessed the clones' phenotypes by applying a novel statistical framework to the results of a serially sampled parallel infection assay, in which we simultaneously inoculated each of a large number of replicate host volumes with ∼1 phage particle. We sequentially plated the volumes over the course of infection and counted the plaques that formed after incubation. These counts served as a proxy for the number of phage particles in a single volume as a function of time. From repeated assays, we inferred significant, genetically determined heterogeneity in lysis time and burst size, including lysis time variance. These findings are interesting in light of the genetic and phenotypic constraints on the single-protein lysis mechanism of φX174. We speculate briefly on the mechanisms underlying our results, and we discuss the potential importance of lysis time variance in viral evolution.

KEYWORDS:

evolutionary theory; genetics of adaptation; life history; lysis time; variance

PMID:
26921293
PMCID:
PMC4825663
DOI:
10.1534/g3.115.024075
[Indexed for MEDLINE]
Free PMC Article

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