A common, non-optimal phenotypic endpoint in experimental adaptations of bacteriophage lysis time

dc.creatorChantranupong, Lynneen
dc.creatorHeineman, Richard H.en
dc.descriptionLynne Chantranupong is with the Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA and the Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, USA -- Richard H Heineman is with the Institute for Molecular Virology, University of Minnesota, 18-242 Moos Tower 515 Delaware St. SE, Minneapolis, MN 55455, USA and the Section of Integrative Biology, University of Texas at Austin, Austin, Texas 78712, USAen
dc.description.abstractBackground: Optimality models of evolution, which ignore genetic details and focus on natural selection, are widely used but sometimes criticized as oversimplifications. Their utility for quantitatively predicting phenotypic evolution can be tested experimentally. One such model predicts optimal bacteriophage lysis interval, how long a virus should produce progeny before lysing its host bacterium to release them. The genetic basis of this life history trait is well studied in many easily propagated phages, making it possible to test the model across a variety of environments and taxa. Results: We adapted two related small single-stranded DNA phages, ΦX174 and ST-1, to various conditions. The model predicted the evolution of the lysis interval in response to host density and other environmental factors. In all cases the initial phages lysed later than predicted. The ΦX174 lysis interval did not evolve detectably when the phage was adapted to normal hosts, indicating complete failure of optimality predictions. ΦX174 grown on slyD-defective hosts which initially entirely prevented lysis readily recovered to a lysis interval similar to that attained on normal hosts. Finally, the lysis interval still evolved to the same endpoint when the environment was altered to delay optimal lysis interval. ST-1 lysis interval evolved to be ~2 min shorter, qualitatively in accord with predictions. However, there were no changes in the single known lysis gene. Part of ST-1's total lysis time evolution consisted of an earlier start to progeny production, an unpredicted phenotypic response outside the boundaries of the optimality model. Conclusions: The consistent failure of the optimality model suggests that constraint and genetic details affect quantitative and even qualitative success of optimality predictions. Several features of ST-1 adaptation show that lysis time is best understood as an output of multiple traits, rather than in isolation.en
dc.description.departmentChemical Engineeringen
dc.description.departmentIntegrative Biologyen
dc.identifier.citationChantranupong, Lynne, and Richard H. Heineman. “A Common, Non-Optimal Phenotypic Endpoint in Experimental Adaptations of Bacteriophage Lysis Time.” BMC Evolutionary Biology 12, no. 1 (March 19, 2012): 37. doi:10.1186/1471-2148-12-37.en
dc.publisherBMC Evolutionary Biologyen
dc.rightsAdministrative deposit of works to UT Digital Repository: This works author(s) is or was a University faculty member, student or staff member; this article is already available through open access at http://www.biomedcentral.com. The public license is specified as CC-BY: http://creativecommons.org/licenses/by/4.0/. The library makes the deposit as a matter of fair use (for scholarly, educational, and research purposes), and to preserve the work and further secure public access to the works of the University.en
dc.subjectexperimental evolutionen
dc.subjectLife History evolustionen
dc.subjectgenetic constrainten
dc.subjectmolecular evolutionen
dc.subjectphenotype predictionen
dc.titleA common, non-optimal phenotypic endpoint in experimental adaptations of bacteriophage lysis timeen
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