DISSERTATION RESEARCH: Mitochondrial Epistasis in Yeast

这个项目将研究线粒体基因之间的相互作用如何影响线粒体的功能和进化。线粒体产生了细胞所使用的大部分能量，而这种产生依赖于多个基因的精确相互作用。目前，线粒体基因之间的相互作用尚未得到证实，主要是因为这些基因通常是作为一个单一单位从母亲那里遗传的，这种单亲遗传使基因相互作用的研究变得困难。为了绕过这一挑战，研究人员将研究面包酵母(酿酒酵母)，它继承了父母双方的线粒体DNA。他们将首先从大量酵母群体中产生独特的线粒体基因组合，以评估这些基因如何影响能量生产。然后，他们将对单个线粒体基因组进行测序，以确定涉及的特定基因。该项目将促进我们对线粒体蛋白质相互作用的机制以及它们如何塑造进化的理解。此外，这项研究将被整合到遗传学实验室课程中，并让128名本科生参与实践研究。呼吸功能依赖于核和线粒体基因之间的兼容相互作用，这导致线粒体-核上位性，理论上，线粒体基因之间的相互作用(mt-mt上位性)。线粒体DNA的自然变异导致适应度的差异，但由于线粒体DNA通常是单亲遗传的，不会重组，因此很难从功能上剖析mtDNA多态的个体效应和上位性效应。酿酒酵母具有线粒体DNA的双亲遗传和重组。Mt-mt上位性的自然分布将通过核型相同但mtDNA不同的交配菌株进行评估，并对含有线粒体重组体的菌株进行功能筛选，以寻找mt-mt上位性的证据。将对单个线粒体重组基因组进行测序，并通过比较不同表型组之间等位基因对频率的差异来绘制相互作用的基因座图。这项研究将确定mt-mt上位性在自然种群中的作用，并在单个重组mtDNA单倍型的解析下提供有关酵母线粒体重组的信息。

This project will investigate how interactions among mitochondrial genes influence mitochondrial function and evolution. Mitochondria produce much of the energy used by cells, and this production depends upon precise interactions of multiple genes. Currently, interactions among mitochondrial genes have not been demonstrated, mainly because these genes are normally inherited as a single unit from the mother and such uniparental inheritance makes it difficult to study gene interactions. To get around this challenge, the researchers will study baker's yeast (Saccharomyces cerevisiae), which inherit mitochondrial DNA from both parents. They will first generate unique combinations of mitochondrial genes from a large yeast population to evaluate how these influence energy production. Then they will sequence single mitochondrial genomes to identify the specific genes involved. The project will advance our understanding of the mechanics of mitochondrial protein interactions and how they shape evolution. Additionally, the research will be integrated into a genetics laboratory course and engage 128 undergraduate students in hands-on research.Respiratory function relies on compatible interactions between nuclear and mitochondrial genes, which leads to mitochondrial-nuclear epistasis and, theoretically, interactions between mitochondrial genes (mt-mt epistasis). Natural variation in mtDNAs contributes to differences in fitness, but because mtDNAs are typically uniparentally inherited and do not recombine, it is difficult to functionally dissect individual vs. epistatic effects of mtDNA polymorphisms. The yeast Saccharomyces cerevisiae has bi-parental inheritance and recombination of mtDNAs. The natural distribution of mt-mt epistasis will be assessed by mating strains with identical nuclear genotypes but divergent mtDNAs, and the resulting strains containing mitochondrial recombinants will be functionally screened for evidence of mt-mt epistasis. Individual mitochondrial recombinant genomes will be sequenced and interacting loci mapped by comparing differences in allele pair frequencies between phenotypically distinct groups. This research will determine the role mt-mt epistasis plays in natural populations and provide information on mitochondrial recombination in yeast at the resolution of individual recombinant mtDNA haplotypes.