DISSERTATION RESEARCH: Mitochondrial Epistasis in Yeast

该项目将研究线粒体基因之间的相互作用如何影响线粒体功能和进化。线粒体产生细胞所需的大部分能量，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作为一个单一的单位从母亲遗传，这种单亲遗传使得研究基因相互作用变得困难。为了克服这一挑战，研究人员将研究面包酵母（酿酒酵母），它从父母双方继承线粒体DNA。他们将首先从大量酵母菌群中产生线粒体基因的独特组合，以评估这些基因如何影响能量产生。然后，他们将对单个线粒体基因组进行测序，以确定所涉及的特定基因。该项目将推进我们对线粒体蛋白质相互作用机制以及它们如何塑造进化的理解。此外，该研究将被整合到遗传学实验室课程中，并吸引128名本科生参与实践研究。呼吸功能依赖于核基因和线粒体基因之间的相容相互作用，这导致了线粒体-核上位性，理论上，线粒体基因之间的相互作用（mt-mt上位性）。mtDNA的自然变异导致了适应性的差异，但由于mtDNA通常是单亲遗传的，不会重组，因此很难从功能上分析mtDNA多态性的个体效应与上位效应。酿酒酵母具有双亲遗传和线粒体DNA重组的特点。mt-mt上位性的自然分布将通过使具有相同核基因型但不同mtDNA的菌株交配来评估，并且将对含有线粒体重组体的所得菌株进行功能筛选以获得mt-mt上位性的证据。将对个体线粒体重组基因组进行测序，并通过比较表型不同组之间等位基因对频率的差异来绘制相互作用的基因座。这项研究将确定线粒体-线粒体上位性在自然群体中的作用，并提供有关酵母中线粒体重组的信息，以解决单个重组mtDNA单倍型。

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.