Genetic studies of temperature-sensitive and nonsense mutants of bacteriophage φ6

Mindich, Leonard; Sinclair, Jacqueline F.; Levine, D.; Cohen, Jeffrey Jerome

doi:10.1016/0042-6822(76)90020-9

Cited by 50 publications

(29 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The bacterium Pseudomonas syringae pathovar phaseolicola strain HB10Y [13] served as the standard host. Novel host strains included P. syringae pathovar atrofaciens 2231, P. syringae pathovar glycinea 171 (obtained from Greg Martin, Cornell University) and P. pseudoalcaligenes pathovar ERA [13]. Culture conditions are described in the electronic supplementary material.…”

Section: Materials and Methods (A) Strains And Culture Conditionsmentioning

confidence: 99%

Competition and the origins of novelty: experimental evolution of niche-width expansion in a virus

et al. 2013

View full text Add to dashboard Cite

Competition for resources has long been viewed as a key agent of divergent selection. Theory holds that populations facing severe intraspecific competition will tend to use a wider range of resources, possibly even using entirely novel resources that are less in demand. Yet, there have been few experimental tests of these ideas. Using the bacterial virus (bacteriophage) f6 as a model system, we examined whether competition for host resources promotes the evolution of novel resource use. In the laboratory, f6 exhibits a narrow host range but readily produces mutants capable of infecting novel bacterial hosts. Here, we show that when f6 populations were subjected to intense intraspecific competition for their standard laboratory host, they rapidly evolved new generalist morphs that infect novel hosts. Our results therefore suggest that competition for host resources may drive the evolution of host range expansion in viruses. More generally, our findings demonstrate that intraspecific resource competition can indeed promote the evolution of novel resource-use phenotypes.

show abstract

Section: Materials and Methods (A) Strains And Culture Conditionsmentioning

confidence: 99%

Competition and the origins of novelty: experimental evolution of niche-width expansion in a virus

et al. 2013

View full text Add to dashboard Cite

show abstract

“…21781). Details of diluting, filtering, culture, and storage of phage and bacteria are published (Mindich et al 1976;Chao and Tran 1997). All phage and bacteria were grown in LC medium (5 g/liter yeast extract, 10 g/liter bactotryptone, 5 g/liter NaCl) at 25°.…”

Section: Strains and Culture Conditionsmentioning

confidence: 99%

Experimental Estimate of the Abundance and Effects of Nearly Neutral Mutations in the RNA Virus ϕ6

Burch¹,

Guyader²,

Samarov

et al. 2007

Genetics

View full text Add to dashboard Cite

Although the frequency and effects of neutral and nearly neutral mutations are critical to evolutionary patterns and processes governed by genetic drift, the small effects of such mutations make them difficult to study empirically. Here we present the results of a mutation-accumulation experiment designed to assess the frequencies of deleterious mutations with undetectable effects. We promoted the accumulation of spontaneous mutations by subjecting independent lineages of the RNA virus f6 to repeated population bottlenecks of a single individual. We measured fitness following every bottleneck to obtain a complete picture of the timing and effects of the accumulated mutations with detectable effects and sequenced complete genomes to determine the number of mutations that were undetected by the fitness assays. To estimate the effects of the undetected mutations, we implemented a likelihood model developed for quantitative trait locus (QTL) data (Otto and Jones 2000) to estimate the number and effects of the undetected mutations from the measured number and effects of the detected mutations. Using this method we estimated a deleterious mutation rate of U ¼ 0.03 and a gamma effects distribution with mean s ¼ 0:093 and coefficient of variation ¼ 0.204. Although our estimates of U and s fall within the range of recent mutation rate and effect estimates in eukaryotes, the fraction of mutations with detectable effects on laboratory fitness (39%) appears to be far higher in f6 than in eukaryotes.

show abstract

“…A. Fane (Department of Veterinary Science and Microbiology University of Arizona). Overnight cultures of C122 in liquid LC media (a modified Luria broth; Mindich et al 1976) were inoculated by single colonies obtained from plates of solid LC media (1.5% w/v agarose) streaked from a frozen bacterial stock. These cultures were subsequently incubated at 33ЊC for about 16 h on a shaking table to obtain stationary phase.…”

Section: Culturing and Infection Conditionsmentioning

confidence: 99%

Functional Origins of Fitness Effect-Sizes of Compensatory Mutations in the Dna Bacteriophage Øx174

Poon

Chao

2006

Evolution

View full text Add to dashboard Cite

Abstract. Epistasis is an important and poorly understood aspect of mutations and strongly influences the evolutionary impact of genetic variation on adaptation and fitness. Although recent studies have begun to characterize the distribution of epistatic effects between mutations affecting fitness, there is currently a lack of empirical information on the underlying biological causes of these epistatic interactions. What are the functional constraints that determine the effectiveness of a compensatory mutation at restoring fitness? We have measured the effect-sizes of 52 compensatory mutations affecting nine different deleterious mutations in the major capsid and spike proteins of the DNA bacteriophage X174. On average, an experimentally detectable compensatory mutation recovers about two-thirds of the fitness cost of the preceding deleterious mutation. Variation in fitness effect-sizes is only weakly associated with measures of the distance separating the deleterious and compensatory mutations in the amino acid sequence or the folded protein structure. However, there is a strong association of fitness effect-size with the correlation in the effects of the mutations on the biochemical properties of amino acids. A compensatory mutation has the largest effect-size, on average, when both the compensatory and deleterious mutations have radical effects on the overall biochemical make-up of the amino acids. By examining the relative contributions of specific biochemical properties to variation in fitness effect-size, we find that the area and charge of amino acids have a major influence, which suggests that the complexity of the amino acid phenotype is simplified by selection into a reduced number of phenotypic components.

show abstract

Genetic studies of temperature-sensitive and nonsense mutants of bacteriophage φ6

Cited by 50 publications

References 13 publications

Competition and the origins of novelty: experimental evolution of niche-width expansion in a virus

Competition and the origins of novelty: experimental evolution of niche-width expansion in a virus

Experimental Estimate of the Abundance and Effects of Nearly Neutral Mutations in the RNA Virus ϕ6

Functional Origins of Fitness Effect-Sizes of Compensatory Mutations in the Dna Bacteriophage Øx174

Contact Info

Product

Resources

About