Evolutionary Ecology of Genetic Systems

我的研究项目是探索野生和驯化植物种群的生态学和遗传学。生物的这些属性是理解生物丰度变化和遗传多样性的基础，也是建立可持续食物来源、管理入侵物种影响和保护濒危物种的必要条件。我的研究团队通过关注生殖系统来实现这一目标，生殖系统控制着精子和卵子的数量和质量、交配模式，并最终控制着遗传变异从一代传递到下一代。在这个提议中，我将重点关注生殖的一个方面，即全基因组复制，通过这个过程，生物体产生的后代的染色体数量是原来的两倍，从而导致每个细胞中每条染色体有多达86个副本的新物种（称为多倍体）。这种现象在野生动植物（甚至人类！）中普遍存在。它也是一些癌症组织的特征，并被用作培育更大更好的作物（西瓜、草莓、土豆、杨树）和观赏植物的遗传工具。不幸的是，我们对全基因组重复的原因和影响的了解有限，这使我们无法充分了解调节生物多样性和管理多倍体对健康和粮食安全的影响的因素。为了解决这一知识缺口，我们建议研究新的多倍体形成和建立的机制，探索为什么多倍体在某些生物体中出现而不是在其他生物体中出现，并预测全基因组复制对生物体功能的影响及其与其他物种的相互作用。我们的研究最初将集中在未减少配子的生产上，配子形成中的错误会产生染色体数量是正常数量两倍的精子和卵子。利用几个物种，我们将沿着环境梯度（海拔）和生长室调查未减少的配子产量，以确定环境变化和压力在导致这些错误（产生多倍体后代）中的作用。我们还将通过在野生物种中鉴定独立的多倍体起源，在实验室中从不同的遗传背景合成新的多倍体，并在形态、生理和遗传水平上评价它们的表现，来研究全基因组复制的影响。利用苹果，我们将研究在倍性水平不同的相关家养和野生物种之间潜在的相互作用。在这一物种中，杂交和基因从国产苹果逃逸到本地苹果的可能性就是与这些相互作用相关的风险的一个例子。通过这项研究，我希望推进我们研究全基因组复制的方法——使用流式细胞术和遗传标记——并提高我们理解这一过程对生物多样性的重要性和管理它以造福社会的能力。

My research program explores the ecology and genetics of plant populations, both wild and domesticated. These attributes of living things are fundamental to understanding changes in abundance and genetic diversity in organisms, and necessary for building sustainable food sources, managing impacts of invasive species, and conserving species at risk. My research team pursues this goal by focusing on reproductive systems, which control the quantity and quality of sperm and eggs, patterns of mating, and ultimately the transmission of genetic variation from one generation to the next. In this proposal, I focus on one aspect of reproduction, whole genome duplication, a process by which organisms produce offspring with double the chromosome number, which leads to new species (called polyploids) with as many as 86 copies of every chromosome in each cell. This phenomenon is widespread in wild plants and animals (even humans!). It is also a feature of some cancer tissues and is used as a genetic tool for breeding bigger and better crops (watermelon, strawberries, potatoes, poplar) and ornamental plants. Unfortunately, our understanding of the causes and impacts of whole genome duplication are limited, which prevents us from fully understanding factors regulating biological diversity and managing the effects of polyploidy on health and food security. To address this knowledge gap, we propose to study the mechanisms by which new polyploids form and establish, explore why polyploids arise in some organisms and not others, and predict the effects of whole genome duplication on the function of organisms and their interaction with other species. Our research will initially focus on production of unreduced gametes, whereby errors in gamete formation give rise to sperm and eggs with twice the normal number of chromosomes. Using several species, we will investigate unreduced gamete production along environmental gradients (elevation) and in growth chambers to determine the role that environmental change and stress can play in causing these errors, which give rise to polyploid offspring. We will also study the impacts of whole genome duplication by identifying independent polyploid origins in wild species and synthesizing new polyploids from a variety of genetic backgrounds in the lab, and then evaluating their performance at morphological, physiological and genetic levels. Using apples, we will then examine the potential interactions between related domestic and wild species that differ in their ploidy levels. In this species, the potential for hybridization and gene escape from domestic apple into native apples is an example of the risks associated with these interactions. Through this research, I expect to advance the methods by which we study whole genome duplication - using flow cytometry and genetic markers - and improve our ability to both understand the importance of this process to biological diversity and manage it for the benefit of society.