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.
