Evolutionary adaptation of dense microbial populations to range expansion

密集微生物种群对范围扩张的进化适应

• 批准号: 10751361
• 负责人: Katie Elaine Randolph
• 金额: $ 4.77万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10751361
• 关键词: 3-Dimensional; Affect; Agar; Alleles; Biological; Biological Models; Biophysics; Biotechnology; Birth; Cell Communication; Cell Density; Cell Shape; Cells; Cicatrix; Collaborations; Communication; Dissection; Educational process of instructing; Ensure; Environment; Evolution; Feedback; Fellowship; Gene Frequency; Genes; Genetic; Genetic Drift; Goals; Grant; Growth; Haploidy; Health; Height; Human; Human Microbiome; Liquid substance; Measurement; Mechanics; Mentorship; Microbe; Microbial Biofilms; Modeling; Mutate; Mutation; Natural Selections; Nature; Neoplasms in Vascular Tissue; Pattern; Phenotype; Population; Property; Research; Resources; Saccharomyces cerevisiae; Saccharomycetales; Site; Speed; Structure; Surface; Surface Tension; System; Technology; Time; Training; Viscosity; Visual; Work; antagonist; cell growth; daughter cell; experimental study; genetic analysis; genome sequencing; insight; microbial; microbial colonization; microbial community; model organism; mutant; mutualism; nutrition; oral microbiome; physical model; physical property; reconstruction; research facility; simulation; theories; trait; whole genome

PROJECT SUMMARY Surface-associated microbial populations are ubiquitous in nature and display evolutionary dynamics that are not yet well characterized, despite their importance to human health and technology. Genetic drift, the change in allele abundances due to chance alone, is known to be much more important in the surface-associated scenario than for microbes in well-mixed liquid media, but it is unknown which properties of cells and populations modulate this effect. I performed an evolutionary range expansion experiment with the budding yeast, Saccharomyces cerevisiae, to investigate how cells evolve when selected for more efficient surface-associated growth. We found that cells selected for faster expansion on surfaces evolved an elongated cell shape and a bipolar budding pattern, in which daughter cells bud at the pole opposite to the birth scar. Additionally, preliminary results suggest that evolved colonies display increased genetic drift compared to the ancestor. This proposal aims to understand the genetic changes that caused these phenotypes, and how these phenotypes modify the physical parameters of the system to enable faster expansion. Further, I will use this information to understand how properties of single cells affect the relative strength of natural selection and genetic drift in dense cellular aggregates. I hypothesize that the faster expansion is the result of evolved changes in physical properties of the colony that modify the way cells interact with each other and the agar surface. Additionally, I hypothesize that an elongated cell shape contributes to an increased strength of genetic drift in surface-associated growth. I will address this hypothesis by identifying the genes that cause each evolved phenotype, characterizing the physical properties of colonies and cells that affect expansion dynamics and three-dimensional colony structure, and finally use this information to assess the effect of each phenotypic change on the relative strength of genetic drift in expanding colonies. Completion of these goals will ensure I have developed expertise in both theoretical and experimental approaches pivotal to independent biophysical research with health-related applications, a major goal of my fellowship training plan. My training plan also includes training in scientific communication and inclusive teaching and mentorship. I will benefit from the significant resources granted to me by Cornell in the way of on-site, state-of-the-art research facilities, collaboration with experts specific to all fields represented in my research, and a wonderfully supportive research advisor, the sponsor of this work.

项目概要 与表面相关的微生物种群在自然界中普遍存在，并表现出进化特征 尽管它们对人类健康和健康很重要，但尚未得到很好的表征 技术。众所周知，遗传漂变是指仅因偶然而引起的等位基因丰度的变化。 在与表面相关的场景中比在充分混合的液体中的微生物重要得多 媒体，但尚不清楚细胞和群体的哪些特性调节这种效应。我 用芽殖酵母进行了进化范围扩展实验，酵母 酿酒酵母，研究细胞在选择更有效的表面关联时如何进化 生长。我们发现，选择在表面上更快扩张的细胞进化出了细长的细胞 形状和双极出芽模式，其中子细胞在与出生相对的极上出芽 瘢痕。此外，初步结果表明，进化的菌落表现出增加的遗传漂变 与祖先相比。该提案旨在了解导致的基因变化 这些表型，以及这些表型如何修改系统的物理参数 实现更快的扩展。此外，我将使用这些信息来了解单个的属性如何 细胞影响致密细胞聚集体中自然选择和遗传漂变的相对强度。 我假设更快的扩张是物理进化变化的结果 集落的特性改变了细胞彼此以及琼脂相互作用的方式 表面。此外，我假设细长的细胞形状有助于 表面相关生长中遗传漂变的强度增加。我会解决这个问题 通过识别导致每种进化表型的基因，表征 影响扩张动力学和三维的集落和细胞的物理特性 菌落结构，最后使用这些信息来评估每个表型变化的影响 关于扩张群体中遗传漂变的相对强度。完成这些目标将 确保我在理论和实验方法方面都积累了专业知识，这对于 具有健康相关应用的独立生物物理研究，这是我奖学金的主要目标 培训计划。我的培训计划还包括科学传播和包容性方面的培训 教学和指导。我将受益于康奈尔大学授予我的重要资源 现场、最先进的研究设施以及与各领域专家的合作 代表我的研究，以及一位大力支持的研究顾问，该项目的赞助商 工作。