Tick Tock Evolve a Clock: Selections for Oscillation in the Budding Yeast Director, Bauer Fellows Program
Tuesday, November 22, 2011 - 4:30pm to 5:30pm
Carl Icahn Lab 101
Home & Away Harvard-Princeton Series
Lewis-Sigler Institute

Director, Bauer Fellows Program
Professor of Molecular and Cellular Biology

Reception follows seminar

Abstract: We are investigating the genetic and molecular mechanisms that produce evolutionary novelty.  Using the budding yeast Saccharomyces cerevisiae, we set out to experimentally evolve a circadian oscillator.  Circadian oscillators are found in all phyla. They appear to have evolved numerous times in parallel and there is no evidence that yeast possesses such an oscillator. Through multiple rounds of selection for alternating high and low fluorescence of a strain expressing YFP from the FLO1 promoter, we have evolved a clonal yeast strain that exhibits oscillations in its ability to flocculate over a 24-hour period.  Sequencing a pool of spores that exhibits the selected phenotype has identified candidate causal mutations, and sequencing RNA during a complete oscillation has revealed genes that show cyclical changes in expression. We hope that determining the changes that give rise to this oscillator will provide insights into how novel phenotypes evolve.