Research Overview

Our research aims to understand the genetic basis of evolutionary change, and specifically how adaptation and constraints shape divergence between species. To achieve this goal we employ computational analyses, field research and wetlab experiments. While our primary experimental system is yeast, we also work on other systems through collaborations. Ultimately, we hope to generate new insights into how species adapt and become different from one another from the molecular to an organism level.

Domestication and diversification of yeast

Saccharomyces yeast species have evolved the amazing ability to ferment sugar in the presence of oxygen, providing us with beer, bread and wine. While this fermentative lifestyle is not unique to Saccharomyces species, S. cerevisiae is the predominate species used for the production of fermented foods and beverages. One characteristic unique to S. cerevisiae is its competitive advantage over other microbes during wine fermentations. Our research investigates the genetic factors and mutations responsible for S. cerevisiae’s distinctive characteristics and its widespread use for fermentation. Currently, we are working on thermal tolerance and resistance to copper and sulfite.

Genetic basis of thermal divergence

Organisms have evolved the ability to tolerate and even thrive across a wide range of temperatures. Yet, the genetic basis and mechanisms of thermal tolerance have been difficult to dissect, in part due to reproductive isolation of thermally divergence species. We are using a variety of genetic and biochemical approaches to understand thermal divergence across the Saccharomyces species. We have found very limited cis-regulatory divergence in relation to temperature, but that changes in mitochondrial genes are required for S. cerevisiae‘s thermotolerance. We are currently testing whether models of polygenic adaptation explain thermal divergence caused by the nuclear genome.

Copper and sulfite resistance

Vineyard strains of S. cerevisiae have evolved resistance to both copper and sulfite, which have been extensively used in vineyards and in wine making. In contrast, S. paradoxus has not evolved resistance despite often being present in vineyards and largely sympatric with S. cerevisiae. We are currently investigating genetic constraints present in wild S. cerevisiae and S. paradoxus populations with the goal of understanding how evolutionary outcomes can differ between species.