DISSERTATION RESEARCH: The Genetic Structure and Phylogeographic History of African Populations of Drosophila melanogaster

本研究将记录非洲果蝇种群遗传多样性的地理结构。在扩展到几乎全世界的分布之前，这个物种被认为起源于热带非洲。然而，人们对非洲人口的进化史和遗传结构知之甚少。本研究将利用DNA序列和重复序列长度变化来：(1)评估非洲种群之间的遗传关系，(2)确定哪些种群似乎是最古老的，(3)推断黑腹龙从撒哈拉以南非洲向北非和欧亚大陆扩张的最可能的地理路线。这项工作将使人们更好地理解像种群历史和自然选择这样的进化力量是如何塑造遗传变异的，特别是在物种殖民新环境时。黑腹龙的历史与许多入侵物种和作物植物的历史相似，因此该项目具有指导未来研究生态和经济重要物种遗传多样性的潜力。通过提高我们对遗传学模式生物的进化理解，本研究将促进生物学学科之间的联系。这项研究将有助于研究生和本科生的培养。研究结果将在科学会议、印刷品、网络和高中课堂上进行交流。将与非洲的研究人员建立新的科学联系，并将获得和自由分享新的黑腹龙标本。

This study will document the geographic structure of genetic diversity in African populations of the fruit fly Drosophila melanogaster. Before expanding to a nearly worldwide distribution, this species is thought to have originated in tropical Africa. Yet, very little is known about the evolutionary history and genetic structure of African populations. This study will use DNA sequence and repeat length variation to: (1) evaluate genetic relationships among African populations, (2) identify which populations appear to be the most ancestral, and (3) infer the most likely geographic route for the expansion of D. melanogaster from sub-Saharan Africa into north Africa and Eurasia. This work will lead to an improved understanding of how evolutionary forces like population history and natural selection shape genetic variation, particularly in species colonizing new environments. The history of D. melanogaster is similar to that of many invasive species and crop plants, so this project has the potential to guide future studies that examine genetic diversity in ecologically and economically important species. By improving our evolutionary understanding of a model organism in genetics, this study will facilitate connections between biological disciplines. This research will contribute to graduate and undergraduate training. Findings will be communicated at scientific meetings, in print, online, and in the high school classroom. New scientific contacts will be made with researchers in Africa, and new collections of D. melanogaster will be obtained and shared freely.