Understanding the process of speciation is a major goal of evolutionary research; currently, most of our knowledge comes from plant and animal studies. Microbial species make up most of the world's biodiversity, but because many are hard to isolate and culture, little is known about how they interact. This research will investigate interactions among natural populations of the sexual yeast Saccharomyces paradoxus that may be undergoing speciation. Individual cells will be tested for preferences among potential mates from the same and other populations - a new approach in microbial ecology - to determine the mechanism underlying reproductive isolation between populations. The variants of genes responsible for a yeast cell's ability to identify and communicate with an appropriate mating partner will then be identified and studied.
This research may provide the first example in a microbial species of the evolution of differences that allow ecologically similar and closely related populations to co-exist. Furthermore, understanding cell-to-cell communication between microbial populations and species has implications for the spread of genetic material across species boundaries in important contexts such as the passage of virulence genes between pathogenic and non-pathogenic fungal species. Studying these basic processes in a risk-free system offers a valuable opportunity to understand them.
