Dissertation Research: Integrating Biosystematics and Phylogenetics: Floral Diversity, Polyploidy, and Serpentine Endemism in the Recently Resurrected Plant Family Themidaceae

整合生物系统学（生物变异、多样性和多样化的生物学方面的实验研究）和系统遗传学（生物系谱关系的研究）已经成为进化和生态研究的一个有前途的途径，因为系谱学为进行生物比较提供了有意义的历史背景。菊科是一个最近复活的植物家族，来自北美西部的洋葱状草本植物。这个科是一个理想的模式系统，因为几个属（例如，Brodiaea）在花的特征、染色体数目和栖息地偏好方面具有令人难以置信的多样性。多倍体——当一个生物体包含两组或更多的染色体——似乎很常见，而且相当多的物种是只在加利福尼亚岛屿、蛇形土壤或其他不寻常的基质上发现的特有物种。族谱史将使用分子和形态数据推导。这一历史背景将与新的染色体绘画技术相结合，以确定多倍体的类型以及与家族内物种形成和地方性有关的染色体变化种类。染色体绘制还可以帮助确定哪些dna序列应该在家谱研究中进行比较。初步的研究结果已经揭示了菊科在不同分类水平上的形态学、细胞学和生态学的新见解。

Sytsma and Pires 9902169Integrating biosystematics (the experimental study of biological aspects of organismal variation, diversity and diversification) and phylogenetics (the study of genealogical relationships of organisms) has been a promising avenue for evolutionary and ecological investigations because genealogies provide a meaningful historical context for making biological comparisons. Themidaceae is a recently resurrected plant family of onion-like herbs from western North America. The family is an ideal model system because several genera (e.g., Brodiaea) are incredibly diverse with respect to floral features, chromosome number, and habitat preference. Polyploidy - when an organism contains two or more sets of chromosomes -appears common, and a significant number of species are endemics found only on California islands, serpentine soils, or other unusual substrates. Genealogical histories will be derived using both molecular and morphological data. This historical context will be integrated with newchromosome painting techniques to determine the types of polyploidy andkinds of chromosomal change involved in speciation and endemism within thefamily. Chromosome painting can also assist in determining which DNAsequences should be compared for genealogical studies. Preliminary resultshave already revealed new morphological, cytological, and ecological insights at various taxonomic levels within the Themidaceae.