Education


PhD candidate Ecology, Evolution and Population Biology
    Washington University in St. Louis
    Advisor: Justin Fay M.S. Microbiology and Molecular Genetics, Michigan State University. 2004
 B.S. Microbiology and Molecular Genetics, Michigan State University. 2004

Current Research


Genetic evidence suggests that strains of Saccharomyces cerevisiae used to make wine may be domesticated. Although S. cerevisiae has been isolated from trees, soil, indigenous fermentations and clinical sources as well as vineyards and wine fermentations, the genetic variation that exists within the vineyard and grape must strains is a subset of the genetic variation that exists within the species as a whole. While a bottleneck pattern is consistent with domestication, it could also be the consequence of a complex population history rather than adaptation to wine making. To distinguish between these hypothesis I am investigating genetic and phenotypic variation between vineyard and non-vineyard strains of S. cerevisiae.
If vineyard strains are locally adapted we expect selection to limit gene flow between sympatric vineyard and arboreal isolates. To address this question, I have collected and am characterizing yeast from grapes, trees and soil at vineyard and non-vineyard locations during the grape harvest season.
Domestication is typically characterized by a suite of adaptive traits referred to as the 'domestication syndrome.' Potential domestication traits in S. cerevisiae could include growth and fermentation phenotypes that lead to fitness differences, as well as differential production of metabolic products that affect wine aroma and flavor. I have measured growth rate as a proxy for fitness over varying environments. I have also completed a sensory analysis using wines fermented from vineyard strains, oak tree strains, and other Saccharomyces species.