PS 101-89 - Power spectrum of environmental variability affects evolution in Escherichia coli.

Friday, August 6, 2010
Exhibit Hall A, David L Lawrence Convention Center
Joel E. Cohen1, Owen L. Petchey2, M. Henry. H. Stevens3, Michael Wiser4, Angela M. Wong4, Jaqueline F. Rivera4 and Steven E. Finkel4, (1)Rockefeller University and Columbia University, New York, NY, (2)1. Department of Evolutionary Ecology and Environmental Studies, University of Zurich, Zurich, Switzerland, (3)Department of Botany, Miami University, Oxford, OH, (4)Molecular & Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles, CA
Background/Question/Methods

The power spectrum of environmental variability is likely to affect evolution by means of natural selection. We quantified the evolution of the Growth Advantage in Stationary Phase (GASP) phenotype in E. coli populations incubated at a constant temperature or under varying temperatures with different red and white power spectra. In all incubations with changing temperatures, the bacteria experienced identical sets of temperatures; the time-series differed only in temporal order and power spectrum. We assayed growth advantage using pairwise competition trials. 

Results/Conclusions

After 5 weeks, bacteria incubated at constant temperature outgrew bacteria incubated in either a white-noise or a red-noise temperature environment. Bacteria incubated in a white-noise environment outgrew bacteria incubated in a red-noise temperature environment. E. coli cultivated at a constant temperature and under fluctuating temperature regimes with white power spectra or red power spectra evolved significantly differently, depending on the environmental temperature regime. These experiments demonstrate that the temporal structure of environmental variation reaches into the genome.

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