Mating, Self-Fertility, and Meiosis in Yeast

Brown University, Providence RI

Investigators

Abstract

Intellectual Merit: Sexual reproduction is the predominant mode of reproduction in eukaryotic systems, from single-celled yeast cells to mammalian organisms. The goal of this project is to understand the diversity of mechanisms that regulate sexual reproduction in yeast, and to determine how changes in these mechanisms can lead to distinct modes of sexual reproduction. Much of our understanding of sexual biology has been derived from work on the model yeast, Saccharomcyes cerevisiae. However, it is now apparent that other hemiascomycete yeast exhibit elemental differences in their sexual lifestyles to that of S. cerevisiae. This project will analyze these differences by comparing mechanisms of sexual reproduction in multiple species from the Candida clade of hemiascomycetes. These represent a diverse collection of yeast species, including those with traditional sexual programs (mating occurs between two partners of opposite sex), those that are able to undergo self-fertilization, and those that may be completely asexual. This project will examine how signaling via sexual pheromones regulates self-fertilization (inbreeding) as well as outbreeding in different species of yeast. In addition, the mechanism of meiosis will be addressed in Candida lusitaniae. This species undergoes an efficient program of meiotic chromosome reduction but is lacking many of the key genes regulating meiosis in S. cerevisiae. Completion of this research will reveal how sexual lifestyles can be modified or re-programmed to promote alternative lifestyles amongst closely related species of yeast. Broader Impacts: This project will introduce approaches that foster integration of science in education and research using two broad themes. First, high school students from underrepresented minorities will be given Microbiology Fellowships to come to Brown University and participate in pre-college summer classes as well as full-time research projects in the project leader's laboratory. The project leader will also follow-up these fellowships by attending the fellows' high school to meet and encourage other students with a general interest in research in the biological sciences. The second approach will be to further the research opportunities for undergraduate students at Brown. Summer fellowships will be used to stimulate undergraduate interest in microbiology and genetics, and in particular to mentor students from underrepresented minorities.