Dissertation Research: Comparing Prezygotic Isolating Mechanisms in Unimodal and Bimodal Plant Hybrid Zones.

这项研究评估了限制植物自然杂交的生态和遗传机制的相对重要性。两种关系密切的Ipomopsis植物在美国西部山区的几个地点非常接近地生长。通过比较杂交种常见的接触点和相同的两个物种没有成功杂交而形成双峰形态分布的接触点，可以研究不同分离机制对杂交率的重要性。杂交种频率低和频率高的地点将使用分子方法根据基因的导入程度进行比较。将在每个地点检查鸟类和昆虫传粉者的行为，以测试传粉者行为选择或传粉能力引起的基因流的差异。实验授粉将测试来自其他物种的花粉竞争能力的差异。杂交比率在不同的分类群中差异巨大。了解原因将有助于理解如何维持物种差异和生物多样性这一根本问题。它还可以帮助预测与转基因作物或入侵植物物种杂交的影响。

This study assesses the relative importance of ecological and genetic mechanisms that restrict natural hybridization in plants. Two closely related species of Ipomopsis plants grow in close proximity in several sites in the mountains of the western U.S. By comparing contact sites where hybrids are common with a contact site where the same two species do not hybridize successfully and instead form a bimodal distribution of morphologies, it is possible to investigate the importance of different isolating mechanisms to the rate of hybridization. Sites with low versus high frequencies of hybrids will be compared with respect to the degree of introgression of genes using molecular methods. Behavior of bird and insect pollinators will be examined at each site to test for differences in gene flow induced by behavioral choices or ability of pollinators to transfer pollen. Experimental pollinations will test for differences in the competitive ability of pollen from another species.Hybridization rates vary tremendously across different taxonomic groups. Understanding the reasons why will contribute to an understanding of the fundamental problem of how species differences and biological diversity are maintained. It could also help in predicting impacts of hybridization with genetically engineered crops or with invasive plant species.