Evolving a 24-hour oscillator in budding yeast
We asked how a new, complex trait evolves by selecting for diurnal oscillations in the budding yeast, Saccharomyces cerevisiae. We expressed yellow fluorescent protein (YFP) from a yeast promoter and selected for a regular alternation between low and high fluorescence over 24-hour period. This selection produced changes in cell adhesion rather than YFP expression: clonal populations oscillated between single cells and multicellular clumps. The oscillations are not a response to environmental cues and continue for at least three cycles in a constant environment. We identified eight putative causative mutations in one clone and recreated the evolved phenotype in the ancestral strain. The mutated genes lack obvious relationships to each other, but multiple lineages change from the haploid to the diploid pattern of gene expression. We show that a novel, complex phenotype can evolve by small sets of mutations in genes whose molecular functions appear to be unrelated to each other.
Article and author information
- Michael Laub, Massachusetts Institute of Technology, United States
- Received: September 23, 2014
- Accepted: November 7, 2014
- Accepted Manuscript published: November 10, 2014 (version 1)
- Version of Record published: December 10, 2014 (version 2)
© 2014, Wildenberg & Murray
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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