Collins Conference Room
  US Mountain Time
Andreas Wagner (University of Zürich; SFI)

Our campus is closed to the public for this event.

Abstract:  How natural selection affects evolvability – the ability of organisms to evolve adaptive and novel traits – is poorly understood. For example, during evolution on a rugged adaptive landscape, strong selection may hinder the traversal of fitness valleys that is essential to reach high adaptive peaks. However, little experimental evidence supports this and other proposals for the role of selection in evolvability. To provide such evidence, we performed experimental evolution on light-emitting yellow fluorescent proteins. We first subjected these proteins to several generations of mutation and selection (strong or weak) for their native yellow color. We then selected for the new color of green fluorescence. We found that strong selection for the old, yellow color enhanced evolvability of the new green color. To find out why, we subjected the evolving populations to high-throughput DNA sequencing and studied their evolutionary dynamics. Strong selection does not hinder but enhances evolvability. It does so by increasing both mutational robustness and protein foldability. Our experiments not only demonstrate a positive role for natural selection in enhancing evolvability. They also prove that natural selection can enhance the robustness of biological systems to mutations. In doing so, selection can help a population circumnavigate rather than traverse fitness valleys, and thus create the conditions necessary for its own success.


Research Collaboration
SFI Host: 
Jennifer Dunne