CAREER: Polyploid speciation in the Achillea millefolium aggregate

几乎所有的动物都是二倍体，即它们有两套染色体。相比之下，许多植物是多倍体的，有四组或更多组染色体，但多倍体在物种形成中的作用仍然存在激烈的争论。不能与二倍体植物杂交的多倍体植物很少被认为是不同的物种，这在很大程度上是因为不确定二倍体和多倍体是否在生态上是不同的。本项目结合野外观察和移栽实验，调查野生羊草(一种多年生野生花卉)二倍体和多倍体种群之间的生殖障碍，并严格测试多倍体物种形成的性质。该项目将使用自然产生的多倍体谱系和二倍体种群中自发产生的新的多倍体突变，以分离生态分歧和基于倍性的障碍对生殖隔离的影响。该项目对全球生物多样性格局的解释具有广泛的影响。多倍体在高纬度地区很常见，对多倍体的分类识别可能会使开花植物的数量翻一番，并从根本上改变对物种多样性的理解，这通常被认为是热带地区最大的物种多样性。该项目将使教师和研究生不仅参与实验室和实地研究，还将参与制定关于城市森林及其保护的公共教育和推广计划。城市森林为野生动物提供了重要的栖息地，也为城市和郊区居民提供了娱乐机会，但越来越多地受到栖息地碎片化和入侵生物的威胁。该项目将把城市森林发展为正规和非正规生物教育场所和公共资源。

Nearly all animals are diploid, i.e., they have two sets of chromosomes. In contrast, many plants are polyploid and have four or more sets of chromosomes, yet the role of polyploidy in speciation remains sharply debated. Polyploid plants that cannot interbreed with diploid plants are rarely recognized as different species, in large part because it is uncertain whether diploids and polyploids are ecologically distinct. This project combines field observations and transplant experiments to investigate reproductive barriers between diploid and polyploid populations of wild yarrow, a native perennial wildflower, and rigorously test the nature of polyploid speciation. The project will use naturally-occurring polyploid lineages and new polyploid mutants that arise spontaneously within diploid populations to separate the effects of ecological divergence and ploidy-based barriers on reproductive isolation. This project has broad implications for the interpretation of global biodiversity patterns. Taxonomic recognition of polyploids, which are common at high latitudes, could double the number of flowering plant species and fundamentally alter understanding of species diversity, which is generally thought to be greatest in tropical regions. This project will involve faculty and graduate students not only in the laboratory and field research, but also in development of a public education and outreach program on urban forests and their conservation. Urban forests provide critical habitat for wildlife as well as recreational opportunities for urban and suburban citizens, yet are increasingly threatened by habitat fragmentation and invasive organisms. The project will develop urban forests as sites of formal and informal biology education and as a public resource.