RUI: The Effects of Natural Selection on Molecular Variation in Structured Populations

在过去的十年里，人们已经清楚地认识到，自然选择对果蝇、小鼠、人类和番茄等多种生物体的整个染色体上的DNA序列变异模式有着重要影响。 然而，分子变异的水平和模式在多大程度上反映了适应性达尔文进化与有害突变的净化选择仍然是一个谜。 这里提出的研究将利用东南亚果蝇种群的高度结构化的性质来估计有限的基因流、局部适应、遗传漂变和重组对基因组结构的影响程度。 将使用一组密集的分子标记来扫描基因组，以寻找与沿着代表东南亚不同气候区域的纬度渐变群的种群中的当地适应有关的基因。 遗传和物理图谱将提供一种手段来检查自然选择在广泛的基因组中的作用。 本研究还将对D. ananassae从物种的祖先范围来估计自然选择对DNA序列变异的地理边界。这些研究探索了结构化果蝇种群中基因组变异和多样性的基本机制，为构建具有结构化种群的其他生物（如人类）的基因组多样性提供了深入了解。 这项研究涉及美国和德国之间的国际合作，以及为本科生提供培训机会。

During the past decade it has become clear that natural selection has major effects on patterns of DNA sequence variation across entire chromosomes of organisms as diverse as Drosophila, mice, humans, and tomato. However, the extent to which the levels and patterns of molecular variation reflect adaptive Darwinian evolution versus purifying selection of deleterious mutations remains a mystery. The studies proposed here will take advantage of the highly structured nature of Drosophila ananassae populations in Southeast Asia to estimate the extent to which limited gene flow, local adaptation, genetic drift, and recombination influence the architecture of the genome. A dense set of molecular markers will be used to scan the genome for genes involved in local adaptation in populations along a latitudinal cline representing different climatic regions in Southeast Asia. Genetic and physical maps will provide a means to examine the effect of natural selection across broad expanses of the genome. Studies will also be performed to examine the patterns of polymorphism at genes in population samples of D. ananassae from the ancestral range of the species to estimate the geographic boundaries of natural selection on DNA sequence variation.These studies explore the fundamental mechanisms shaping genome variation and diversity in structured Drosophila populations, providing insight into the processes responsible for molding genome diversity in other organisms with structured populations such as humans. The research involves international collaborations between the United States and Germany, and training opportunities for undergraduate students.