The Influence of Hybridization and Polyploidy on Speciation in Houstonia

了解地球上物种多样性的起源仍然是一个难题。在植物中，很明显，这种多样性主要是由于物种染色体的加倍（多倍体）以及物种间的杂交。然而，这两个过程如何在新物种的进化中相互作用仍不清楚。本项目将以一组亲缘关系密切的本地植物物种（休斯顿属）为研究系统，验证多倍体相对于非多倍体增加物种间杂交率的假设。利用细胞学技术测定这些物种的自然种群的染色体数目。分子标记将被用来评估具有不同染色体数目的物种间杂交的历史比率。本研究结果将加深我们对植物多倍体和杂交这两种最重要的物种形成模式的认识。我们许多最重要的作物要么是多倍体，要么是杂交种，或者两者兼而有之，包括玉米、棉花和小麦，所以了解杂交和多倍体之间的相互作用也可以提高农业育种计划。这项研究将通过给本科生和研究生提供参与数据收集、管理和分析以及进行独立研究的机会，来训练他们在生物学研究方法方面的能力。

Understanding the origins of the diversity of species on earth remains a difficult question. In plants, it is apparent that much of this diversity is due to both doubling of the chromosomes of species (polyploidy) as well as hybridization among species. However, it remains unclear how these two processes interact in the evolution of new species. This project will test the hypothesis that polyploidy increases rates of hybridization among species relative to nonpolyploids using a group of closely related native plant species (Houstonia) as the study system. Chromosome numbers of natural populations of these species will be determined using cytological techniques. Molecular markers will then be used to assess the historical rate of hybridization among species with varying chromosome numbers. The results of this research will enhance our understanding of polyploidy and hybridization, two of the most important modes of speciation in plants. Many of our most important crop species are either polyploids or hybrids, or both, including corn, cotton, and wheat, so understanding the interaction between hybridization and polyploidy could enhance agricultural breeding programs as well. This research will train both undergraduate and graduate students in biological research methods by giving them an opportunity to participate in data collection, management, and analysis, and conducting independent research.