Mating, Self-Fertility, and Meiosis in Yeast

智力优势：有性生殖是真核生物系统中主要的生殖模式，从单细胞酵母细胞到哺乳动物有机体。该项目的目标是了解酵母有性生殖调节机制的多样性，并确定这些机制的变化如何导致不同的有性生殖模式。我们对性生物学的理解大部分来自于对酿酒酵母的研究。然而，现在很明显，其他半真菌酵母在性生活方式上表现出与酿酒酵母的基本差异。本项目将通过比较多种半球菌念珠菌分支的有性生殖机制来分析这些差异。这些酵母代表了各种各样的酵母物种，包括那些具有传统的性程序（交配发生在两个异性伴侣之间）的酵母，那些能够进行自我受精的酵母，以及那些可能完全无性的酵母。本项目将研究如何通过性信息素信号调节不同种类酵母的自交受精（近交）和远交。此外，还对卢西塔念珠菌减数分裂的机制进行了探讨。该物种经历了一个有效的减数分裂染色体减少程序，但缺乏许多在酿酒酵母中调节减数分裂的关键基因。这项研究的完成将揭示如何修改或重新编程性生活方式，以促进密切相关的酵母菌种之间的替代生活方式。更广泛的影响：该项目将采用两大主题，引入促进科学在教育和研究中的整合的方法。首先，来自未被充分代表的少数族裔的高中生将获得微生物学奖学金，来到布朗大学，参加大学预科的暑期课程，以及项目负责人实验室的全职研究项目。项目负责人还将跟进这些奖学金，前往研究员所在的高中，与其他对生物科学研究有普遍兴趣的学生会面并鼓励他们。第二种方法是为布朗大学的本科生提供进一步的研究机会。夏季奖学金将用于激发本科生对微生物学和遗传学的兴趣，特别是指导来自代表性不足的少数民族的学生。

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.