Dissertation Research: Origin and Adaptive Significance of Polyploidy in Achillea millefolium (Asteraceae)

大多数动物有两组染色体，但许多植物是多倍体的，有四个或更多的染色体互补。本研究探讨了乡土野生花卉百合多倍体的起源及其生态意义。实验室、温室和田间实验相结合，将研究(1)多倍体形成的频率和原因，(2)染色体数量对不同环境中生态特征和繁殖成功的影响，以及(3)多倍体在创造和维持生态和遗传多样性方面的作用。这项研究的一个新方面是使用第一代“新多倍体”来区分倍性本身和其他遗传因素的影响。多倍体在自然界中很常见，经常占据独特的生态位。大多数杂草和农作物都是多倍体的。尽管多倍体很重要，但人们对它们的起源知之甚少，就像它们在生态上成功的原因和经济上的重要性一样。这项研究在一种本土野花中解决了这些问题，但也与其他生物相关。DNA测序项目的最新数据表明，包括人类在内的许多动物都是神秘的多倍体，每个基因都有三到四个拷贝，分散在基因组中。因此，多倍体研究可能提供对一系列高等生物遗传系统的洞察。

Schemske9902294Most animals possess two sets of chromosomes, but many plants are polyploid and have four or more chromosome complements. This research investigates the origins and ecological significance of polyploidy in the native wildflower Achillea millefolium. A combination of laboratory, greenhouse and field experiments will examine (1) the frequency and causes of polyploid formation, (2) the effects of chromosome number on ecological characteristics and reproductive success in different environments, and (3) the role of polyploidy in creating and maintaining ecological and genetic diversity. A novel aspect of the research is the use of first-generation "neopolyploids" to distinguish the effects of ploidy per se from other genetic factors.Polyploids are common in nature, and often occupy unique ecological niches. Most weeds and crop plants are polyploid. In spite of their importance, the origins of polyploids are poorly known, as are the reasons for their ecological success and economic importance. This study addresses these issues in a native wildflower, but is also relevant to other organisms. Recent data from DNA sequencing projects suggest that many animals, including humans, are cryptic polyploids possessing three or four copies of each gene scattered through the genome. Thus, polyploid research may provide insight into the genetic systems of a wide array of higher organisms.