ADAPTIVE LANDSCAPES IN EVOLVING POPULATIONS OF PSEUDOMONAS FLUORESCENS
Version of Record online: 23 MAY 2011
© 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.
Volume 65, Issue 11, pages 3048–3059, November 2011
How to Cite
Melnyk, A. H. and Kassen, R. (2011), ADAPTIVE LANDSCAPES IN EVOLVING POPULATIONS OF PSEUDOMONAS FLUORESCENS. Evolution, 65: 3048–3059. doi: 10.1111/j.1558-5646.2011.01333.x
- Issue online: 24 OCT 2011
- Version of Record online: 23 MAY 2011
- Received July 15, 2010, Accepted April 16, 2011
- experimental selection;
The repeatability of adaptive evolution depends on the ruggedness of the underlying adaptive landscape. We contrasted the relative ruggedness of two adaptive landscapes by measuring the variance in fitness and metabolic phenotype within and among genetically distinct strains of Pseudomonas fluorescens in two environments differing only in the carbon source provided (glucose vs. xylose). Fitness increased in all lines, plateauing in one environment but not the other. The pattern of variance in fitness among replicate lines was unique to the selection environment; it increased over the course of the experiment in xylose but not in glucose. Metabolic phenotypes displayed two results: (1) populations adapted via changes that were distinctive to their selection environment, and (2) endpoint phenotypes were less variable in glucose than in xylose. These results indicate that although the response to selection is highly repeatable at the level of fitness, the underlying genetic routes taken were different for each environment and more variable in xylose. We suggest that this reflects a more rugged adaptive landscape in xylose compared to glucose. Our study demonstrates the utility of using replicate selection lines with different evolutionary starting points to try and quantify the relative ruggedness of adaptive landscapes.