RUI: Collaborative Research: Understanding the Roles of Natural Selection and Evolutionary Constraint in the Maintenance of Invariant Floral Traits.

9904164Karoly生物多样性的一个显著特性是当比较生物体的特征时观察到的模式。 虽然有些特征显示出相当大的变异，可以在种群中唯一地识别个体，但其他特征的变异较小，并且为大群相关物种所共有。 虽然生物学家早就认识到变异作为未来进化的原材料的重要性，但有时缺乏变异的原因却很少被研究。 这种缺乏变异可能是由于进化的限制，由缺乏遗传变异或与其他性状的遗传相关性引起的。 或者，缺乏变异可能是由于自然选择消除了不合适的变异，并保持了一个很好地适应环境的小范围的性状。 在这项研究中，一种新的组合，在温室中的人工选择和自然选择的研究领域将被用来确定是否限制或选择导致低水平的变化，发现在两套花性状。本研究以野生萝卜为材料，从花药形态、长短花丝长度比和长花丝伸出花冠的程度两个方面进行研究。 这项研究产生的限制和选择的基本理解可能适用于理解各种应用进化问题，例如作物和野生物种是否能够快速适应全球气候变化，濒危物种的保护（通常缺乏遗传变异），以及病原体和害虫对抗生素，杀虫剂和除草剂的抗性的进化。

9904164KarolyA remarkable property of biological diversity is the patterning that is observed when characteristics of organisms are compared. While some features show considerable variation and can uniquely identify individuals within a population, other traits are less variable and are shared by large groups of related species. Although biologists have long recognized the importance of variation as the raw material for future evolution, the reasons why variation may sometimes be lacking are less often studied. This lack of variation could be due to constraints on evolution, caused by a lack of genetic variation or by genetic correlations with other traits. Alternatively, the lack of variation could result from natural selection eliminating unfit variants and maintaining a narrow range of traits that are well-adapted to the environment. In this research, a novel combination of artificial selection in the greenhouse and studies of natural selection in the field will be used to determine whether constraints or selection cause the low levels of variation found in two sets of floral traits. The research will be done using the wild radish (Raphanus raphanistrum Brassicaeae) and two aspects of anther morphology, the ratio of long- and short-filament lengths and the extent of long-filament exertion beyond the corolla. The basic understanding of constraints and selection generated by this research may be applicable to understanding a variety of applied evolutionary problems, such as whether crops and wild species can adapt rapidly to global climate change, conservation of endangered species (which often lack genetic variation), and the evolution of resistance to antibiotics, pesticides, and herbicides by pathogens and pests.