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.

项目总结 与表面相关的微生物种群在自然界中无处不在，并表现出进化的特征 动力学尚未得到很好的描述，尽管它们对人类健康和 技术基因漂移，即仅由偶然引起的等位基因丰度的变化，已知是 在与表面相关的情况下，比充分混合的液体中的微生物重要得多 介质，但尚不清楚细胞和群体的哪些特性调节了这种效应。我 对发芽酵母进行了进化范围扩展实验 Cerevisiae，研究细胞如何进化，当选择更有效的表面相关时 成长。我们发现，被选为在表面更快扩张的细胞进化成了细长的细胞 形状和两极发芽模式，其中子细胞在与出生相反的极处发芽 刀疤。此外，初步结果表明，进化的群体表现出更大的遗传漂移。 与祖先相比。这项提议旨在了解导致基因变化的原因 这些表型，以及这些表型如何修改系统的物理参数以 实现更快的扩展。此外，我将使用这些信息来了解Single的属性 细胞影响自然选择的相对强度和密集细胞聚集体中的遗传漂移。 我假设，更快的扩张是物理上进化变化的结果 改变细胞相互作用方式和琼脂的菌落特性 浮出水面。此外，我假设一个细长的细胞形状有助于 表面相关生长中遗传漂移的强度增加。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菌落和细胞的物理性质 菌落结构，并最终使用这些信息来评估每个表型变化的影响 在不断扩大的群体中遗传漂移的相对强度。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 独立的生物物理研究和与健康相关的应用，这是我的主要目标 训练计划。我的培训计划还包括科学交流和包容性培训 教学和辅导。我将受益于康奈尔大学在年授予我的大量资源 现场最先进的研究设施，与所有领域的专家合作 代表了我的研究，是一位非常支持我的研究顾问，这项研究的发起人 工作。