Saccharomyces Yeast Diversity

Saccharomyces cerevisiae is the dominant model organism of eukaryotic microbiology. My research exploits the natural diversity of S. cerevisae to expand the genetic and phenotypic tools already available in this species to address evolutionary questions that can't be answered in other systems. I also use related Saccharomyces species to explore the evolution of novel functions across longer evolutionary timescales.


Evolution of Gene Regulation

Having the correct molecular tools is useless to an organism unless those tools are employed in the appropriate amounts and at the appropriate times. As a model for the evolution of novel molecular function, my research dissects changes in gene expression and regulation. I use high-throughput flow cytometry and next generation RNA sequencing to identify both the molecular basis for specific changes in regulation and genome wide patterns of regulatory divergence.

The Role of New Mutations

New mutations are the ultimate source of novel phenotypes and the raw material of evolution, determining the magnitude and frequency at which new phenotypic diversity is available to evolution.  By comparing the effects of new mutations to the effects of variants found in natural populations, a powerful test for the action of natural selection can be formed. My research pioneers this approach for the study of regulatory evolution, identifying both the relative contributions of mutation, selection, and drift to patterns of variation across regulatory elements and the targets of natural selection.

Replaying the Tape of Life

The evolution of most molecular functions occurs but a single time in history. As such, we know very little about the mechanisms necessary for the emergence of new functions. Using ancestral state reconstruction, single-locus experimental evolution, and statistical genetics, my research explores alternative paths by which historically novel functions may have evolved if given a second chance. Combined with genetic and biochemical dissection of these paths, this research reveals the molecular basis by which novel functions can evolve.