RUI: Gene Flow and Hybridization in Milkweeds (Asclepias L.) A Comparison of Two Sympatric Species

WPC 2 B V P Z快递10cpi？X，Z x 6 X@8；X@HP DeskJet 500 HPDES500.PRS x@x X，，0 FX@Courier 10cpi 2@V P Z#|x？X，Z x 6 X@8；X@HP DeskJet500HPDES500.prs x@x X，，0 Fx@9317476 Broyles杂交和花粉远距离移动(即基因流)是负责引入和维持植物种群内遗传多样性的重要过程。在拟议的研究中，我将研究两种常见的北美乳草(Poke Milkidus，Asclepias exaltata L.；普通乳草，Asclepias syriaca L.)之间的花粉传播、基因流动和有效杂交。这些物种出现在相同的地区，开花时间重叠，共享传粉者，形成可行的杂种，保持较高的遗传变异水平，并拥有几个独特的遗传标记。综合起来，这些特征使它们成为检测基因流动和杂交的理想候选者。然而，A。Exaltata和A.叙利亚菊在几个生殖特征(例如，无性繁殖、对花粉产生结构的投资和花序大小)上存在差异，这使得我们能够检查这些生活史特征对基因流动和杂交的影响。具体地说，基因流动和杂交将通过鉴定种子的花粉亲本来量化，以检查(1)花粉传播，(2)远距离花粉介导的基因流动水平，以及(3)这些物种之间的有效杂交。这项研究的结果将有助于我们理解基因流动和杂交在维持植物种群遗传多样性方面的作用。这些过程值得研究，因为遗传变异为适应和长期物种保护提供了必要的材料。我将研究直接影响这些进化过程的潜在授粉机制和植物传粉者之间的相互作用。此外，本研究还将为更全面地研究花粉在自然种群中远距离传播和杂交的过程和进化后果奠定基础。

WPC 2 B V P Z Courier 10cpi ? x x x , Z x 6 X @ 8 ; X @ HP DeskJet 500 HPDES500.PRS x @ x X , , 0 FX @Courier 10cpi 2 @ V P Z #| x ? x x x , Z x 6 X @ 8 ; X @ HP DeskJet 500 HPDES500.PRS x @ x X , , 0 FX @ 9317476 Broyles Hybridization and long distance pollen movement (i.e. gene flow) are important processes that are responsible for introducing and maintaining genetic diversity within plant populations. In the proposed study, I will examine pollen dispersal, gene flow, and effective hybridization between two common North American milkweeds (Poke Milkweed, Asclepias exaltata L.; Common Milkweed, Asclepias syriaca L.). These species occur in the same areas and overlap in flowering time, share pollinators, form viable hybrids, maintain high levels of genetic variation, and possess several unique genetic markers. Together these features make them ideal candidates for examining gene flow and hybridization. Nevertheless, A . exaltata and A . syriaca differ in several reproductive features (e.g., asexual reproduction, investment in pollen producing structures, and inflorescence size) which permits us to examine the effects of these life history traits on gene flow and hybridization. Specifically, gene flow and hybridization will be quantified by identifying pollen parents of seed to examine (1) pollen dispersal, (2) levels of long distance pollen mediated gene flow, and (3) effective hybridization between these species. The results of this study will contribute to our understanding of gene flow and hybridization in the maintenance of genetic diversity in plant populations. These processes are important to study because genetic var iation provides the necessary material for adaptation and long term species conservation. I will examine the underlying pollination mechanisms and plant pollinator interactions that directly affect these evolutionary processes. In addition, this study should lay the foundation for more comprehensive studies on the processes and evolutionary consequences of long distance pollen dispersal and hybridization in natural populations.