Genetic History of East Africa

非洲被认为是现代人的故乡。最近的证据突出了东非(包括坦桑尼亚、肯尼亚、埃塞俄比亚和苏丹)作为现代人类在非洲内外扩散的来源地的重要性。尽管该区域在人类进化史上扮演着重要的角色，但以前很少有人研究过该区域的遗传变异。在国家科学基金会的支持下，Sarah Tishkoff博士和一个国际同事团队将在埃塞俄比亚南部进行一个野外季节，从20个不同种族的人群中收集从血液中获得的约600个DNA样本。这些样本将被添加到来自非洲80个民族的5000个DNA样本中，其中包括来自坦桑尼亚、肯尼亚和苏丹的2000个样本。这些新收集的DNA样本，以及以前收集的大约500个东非样本，将被分析线粒体基因组(母系遗传)、Y染色体(父系遗传)和核基因组(通过双亲遗传)的遗传变异。这些数据将与以前在其他非洲和非非洲人口中为这些相同标记收集或公布的数据进行比较，以便重建东非人口彼此之间以及与其他非洲人口之间的历史关系，重建人类人口历史(长期有效人口规模、历史人口扩张或收缩的时间和程度、人口之间的遗传交流水平)、遗传变异和语言变异之间的相关性，并检验现代人类起源的假设。智力价值：目前，人们对整个非洲，特别是东非的遗传多样性知之甚少。该项目的一个重要贡献将是从语言和种族多样化的东非人口中收集大量DNA，并开发一个大型遗传数据库，这将是检验关于现代人类起源和扩散事件的假说的关键资源。DNA样本将是未来许多年遗传学研究人员的重要资源。其次，Tishkoff将收集新的数据，这些数据将扩大对非洲人口历史的了解，特别是对一般人类进化史的了解。这些结果将对理解现代人在非洲内外的起源和传播、人口扩散事件的动态以及这些事件如何与气候变化相关联具有重要意义。第三，该项目收集的数据将公之于众，并将成为遗传学家对其他非洲和非非洲人口进行研究的重要比较数据库。最后，对非洲人口基本结构的了解将有助于生物医学研究，这些研究依赖于人口历史知识来适当设计和解释疾病图谱方法。广泛影响：该项目将为本科生和研究生以及博士后研究人员提供重要的培训机会，特别是来自对研究非洲人口历史感兴趣的代表性不足的少数民族群体。该项目的另一个目标是培训和支持非洲合作者和学生，使他们能够发起和开展独立的研究项目。所有收集的DNA样本都将与非洲同事共享。这将使非洲科学家能够利用收集到的样本开展独立的研究项目。其次，非洲合作者将分担产生基因分型数据的责任。第三，Tishkoff将参与培训非洲科学家在非洲和美国的基因研究技术。

Africa is thought to be the homeland of modern humans. Recent evidence has highlighted the importance of Eastern Africa (including Tanzania, Kenya, Ethiopia, and the Sudan) as a source region of modern human dispersals both within and out of Africa. Despite the important role of this region in human evolutionary history, very few populations have previously been studied for genetic variation. With National Science Foundation support, Dr. Sarah Tishkoff and an international team of colleagues will conduct one field season in southern Ethiopia to collect ~600 DNA samples obtained from blood, from 20 ethnically diverse populations. These will be added to a large collection of 5000 DNA samples from 80 ethnic groups throughout Africa, including 2000 samples from Tanzania, Kenya, and the Sudan. These newly collected DNA samples, together with ~500 previously collected East African samples, will be analyzed for genetic variation in the mitochondrial genome (inherited maternally), the Y chromosome (inherited paternally), and the nuclear genome (inherited through both parents). These data will be compared to data previously collected or published for these same markers in other African and non-African populations, in order to reconstruct the historical relationships of East African populations to each other and to other African populations, to reconstruct human demographic history (long-term effective population sizes, timing and extent of historic population expansions or contractions, levels of genetic exchange between populations), correlations between genetic and linguistic variation, and to test hypotheses of modern human origins. Intellectual merit: Currently, very little is known about genetic diversity in Africa as a whole, and in East Africa, in particular. An important contribution of this project will be the collection of large quantities of DNA from linguistically and ethnically diverse East African populations and the development of a large genetic database that will be a critical resource to test hypotheses about modern human origins and dispersal events. The DNA samples will be an important resource for genetics researchers for many years to come. Secondly, Tishkoff will be collecting novel data that will expand knowledge of African population history, in particular, and human evolutionary history, in general. The results will have important implications for understanding the origin and spread of modern humans within and out of Africa, the dynamics of population dispersal events and how these events are correlated with climatic changes. Thirdly, the data collected from this project will be made publicly available and will act as an important comparative database for geneticists doing research on other African, as well as non-African, populations. Lastly, knowledge of African population substructure will benefit biomedical studies that rely on knowledge of population demographic history for proper design and interpretation of disease mapping approaches.Broader impact: This project will provide important training opportunities for undergraduate and graduate students, as well as postdoctoral researchers, particularly from under-represented minority groups who are interested in studying African population history . An additional goal of this project is to train and support African collaborators and students so that they can initiate and conduct independent research projects. All collected DNA samples will be shared with African colleagues. This will allow African scientists to develop independent research projects using the collected samples. Second, African collaborators will share responsibility for generation of genetic typing data. Third, Tishkoff will participate in training African scientists in genetic research techniques both in Africa and in the U.S.