Dissertation Research: Seed Dispersal and Population GeneticStructure

种子传播对遗传结构的影响是多方面的 比花粉传播的研究要少。 广泛 分类学上的比较并没有最终证明 扩散方式与种群遗传的关系 结构 这项研究将比较三个同域的 伞形科的种类，主要区别在于 种子传播的形态学适应 动物，以隔离种子传播性状的影响， 遗传结构 内部和内部的遗传多样性15-18 人口，从0.5至100公里，将是 从同工酶数据评价。 两个人口将更多 通过对数百个基因进行定位和基因分型， 个体，以及收集种子进行异交 分析。 这些空间和基因数据，结合观测 在人口统计学上，开花和结果将被用来调查 微地理遗传分化和交配模式 系统. 现场和实验室研究将用于估计 种子去除率和附着和分离概率 水果在扩散。 遗传和空间相关性 生殖植物与种子作物或幼苗之间的距离 将被用来评估花粉的相对重要性， 种子传播对两个作图种群内基因流的影响。 这项研究将有助于了解种子如何 扩散机制影响种群遗传结构， 分配数量和质量的差异 不同空间尺度下的遗传变异，以及 种子传播与花粉传播的影响对 植物种群分化模式。 因为这些 物种出现在相对不受干扰的“栖息地岛屿” 森林在自然保护区，这项研究将提供信息 来研究栖息地大小和隔离的影响 基因流动和遗传多样性的维持。

The effects of seed dispersal on genetic structure are much less well studied than those of pollen dispersal. Broad taxonomic comparisons have failed to demonstrate conclusively the relationship between mode of dispersal and population genetic structure. The proposed research will compare three sympatric species in the family Umbelliferae, which differ mainly in morphological adaptations for seed dispersal by attachment to animals, to isolate the effects of seed dispersal traits on genetic structure. Genetic diversity within and among 15-18 populations, ranging from 0.5 to 100 km apart, will be evaluated from isozyme data. Two populations will be more intensively studied by mapping and genotyping several hundred individuals, as well as collecting seeds for outcrossing analyses. These spatial and genetic data, combined with observations on demography, flowering and fruiting will be used to investigate patterns of microgeographic genetic differentiation and mating systems. Field and laboratory studies will be used to estimate seed removal rates and attachment and detachment probabilities of fruits on dispersers. Correlations of genetic and spatial distances between reproductive plants and seed crops or seedlings will be used to evaluate the relative importance of pollen and seed dispersal on gene flow within the two mapped populations. This study will contribute to understanding how seed dispersal mechanisms affect population genetic structure, quantitative and qualitative difference in the apportionment of genetic variation at different spatial scales, and the relative importance of the effects of seed versus pollen dispersal on patterns of plant population differentiation. Because these species occur in "habitat islands" of relatively undisturbed forest in nature preserves, this study will provide information with which to examine the effects of habitat size and isolation on gene flow and the maintenance of genetic diversity.