Dissertation Research: The Effect of Breeding System on the Level and Pattern of Molecular Variation in Plant Populations

小行星9532071 这项研究将检验最近的理论，即高度自交的物种应该在中性变异中分离。从理论上讲，植物种群遗传变异的模式和数量受交配系统的影响很大，而交配系统又受自花受精率的影响很大。 将在一组具有已知的自花受精率差异的植物（Leavenoclavia;菊科）中定量核苷酸序列变异。由此产生的数据将允许在不同的育种系统类群之间的核苷酸水平的中性和健身相关的变化的水平进行比较。了解近交对中性和适合度相关基因座遗传变异的影响，以及居群间各种遗传多样性差异的原因，对植物遗传学的各个方面都很重要。 自然居群遗传变异的发现也将对植物遗传保护具有重要价值。 保护生物学家认为，近亲繁殖的类群对环境退化非常敏感，因为它们在影响适应性的性状中的遗传变异性很低。资助的研究解决了这一假设的有效性，量化健身相关的遗传变异，这种高度近亲繁殖的人口。核苷酸序列数据可以进一步用于推断所研究的组的同源性。这将为了解该属的育种系统性状和生活史性状的进化历史提供一个有价值的框架。

9532071 CHARLESWORTH This research will test recent theories that highly selfing species should be depauperate in neutral variation. Theoretically, the pattern and amount of genetic variation in plant populations are greatly influenced by the mating system which, in turn, is strongly influenced by the self-fertilization rate. Nucleotide sequence variation will be quantified in a group of plants with known differences in self-fertilization rates (Leavenworthia ; Brassicaceae). The resulting data will allow the comparison of levels of neutral and fitness-related variation at the nucleotide level among taxa with diverse breeding systems. Understanding the influence of inbreeding on genetic variability at neutral and fitness related loci, and the causes of differences in each kind of genetic diversity among populations, is important in relation to all aspects of plant genetics. Findings on genetic variation from natural populations will also be of value for plant genetic conservation. Conservation biologists assume that inbreeding taxa are highly susceptible to environmental degradation, because of their low reservoir of genetic variability in traits affecting fitness. The funded research addresses the validity of this assumption by quantifying fitness-related genetic variation for such highly inbred populations. The nucleotide sequence data can be further utilized for inferring the phylogeny of the group studied. This will, in turn, ppovide a valuable framework for understanding the evolutionary history of breeding system traits and life history characters in the genus.