Evolutionary Ecology of Genetic Systems

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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.