Collaborative Research: Mobile Elements and Primate Evolution

可移动元件是一种DNA片段，它可以自我复制，然后插入基因组的其他地方。这些元素可以影响许多重要的进化过程，包括染色体的突变和重排。它们也可能在新物种的发展中发挥重要作用。尽管可移动元件占人类基因组的近30%，但人们对它们的起源以及它们的复制和插入机制知之甚少。这项研究的主要目标是了解更多关于移动元素及其在人类和灵长类动物进化中所扮演的角色。一些可移动的元件，特别是那些被称为Alus和L1s的元件，在染色体的特定位置要么存在，要么不存在。由于在特定位置出现的可移动元素是最近的或派生的状态，并且由于这些元素在插入后不会被删除，因此这些多态性是进化分析的理想选择。在这个合作项目中，将在至少16种灵长类动物的不同集合中确定一系列至少100个Alu和L1元件，以便为灵长类动物的进化研究提供资源。由于一些移动元素在关键的进化过程中扮演着重要的角色，将人类与其他灵长类动物进行比较将有助于定义我们物种独特的遗传属性。伴随人类物种形成的关键变化可能会被确定。这样，就可以获得关于人类起源的重要信息。将对300人的不同集合进行100个L1插入元素的分型（这将添加到在同一个体中分型的100个Alu插入多态性的现有集合中）。这将为解决有关人类人口历史的问题提供强大的资源。解剖学上的现代人在历史上是否经历过人口瓶颈？如果是，瓶颈有多严重，什么时候发生的，在哪里发生的？这项研究将有助于进一步验证现代人起源于非洲的假设，后来一小部分人从非洲迁徙到旧大陆的其他地区。除了解决有关人类起源的问题外，该项目还将为任何对灵长类遗传学感兴趣的研究者提供新发现和特征化的移动元素资源。这个项目的一个重要方面是培训研究生和本科生以及代表性不足的少数民族成员。

Mobile elements are DNA segments that make copies of themselves that are then inserted elsewhere in the genome. These elements can influence many important evolutionary processes, including mutation and rearrangement of chromosomes. They may also play an important role in the development of new species. Although mobile elements make up nearly 30% of the human genome, little is known about their origins and their mechanisms of replication and insertion. The major goal of this research is to learn more about mobile elements and the roles they have played in human and primate evolution. Some mobile elements, particularly those termed Alus and L1s, are either present or absent at a specific chromosome location. Because the presence of a mobile element at a specific location is the more recent, or derived, state, and because these elements are not deleted after they are inserted, these polymorphisms are ideal for evolutionary analysis. In this collaborative project, a series of at least 100 Alu and L1 elements will be ascertained in a diverse collection of at least 16 primate species in order to provide a resource for primate evolutionary studies. Because of the role that some mobile elements play in key evolutionary processes, a comparison of humans with other primate species will help to define unique genetic attributes of our species. Key changes that accompanied human speciation may be identified. Thus, important information about the origins of our species will be obtained. A diverse collection of 300 humans will be typed for 100 L1 insertion elements (this will be added to an existing collection of 100 Alu insertion polymorphisms typed in the same individuals). This will produce a powerful resource for addressing questions about the demographic history of our species. Did anatomically modern humans experience a population bottleneck in their history? If so, how severe was this bottleneck, when did it occur, and where did it occur? This research will help to further test the hypothesis that modern humans originated in Africa, with a small subset of individuals later migrating out of Africa to other parts of the Old World. In addition to addressing questions about human origins, this project will provide a resource of newly identified and characterized mobile elements that can be used by any investigator interested in primate genetics. An important aspect of this project is the training of graduate and undergraduate students and of members of under-represented minority populations.