Mitochondrial Genes and Human Origins

这笔拨款为华莱士博士和他的同事们提供了为期三年的第一笔支持，使他们能够将mtDNA技术应用于许多人类学问题。它将允许继续对旧世界和新世界的mtDNA类型进行分类，并提供关于新世界原始人口和随后美洲土著人口多样化的额外信息。华莱士医生将采集不同印第安人和亚洲人的血液样本。这些细胞将被分离成用EBV永生化的细胞类型和淋巴细胞。每个个体的mtDNA类型将通过六种限制性内切酶的酶切和Southern blotting检测到的片段类型来确定。来自代表性个体的淋巴母细胞mtDNA将使用附加的限制性内切酶、mtDNA:RNA异双链和mtDNA测序进行更详细的检查。因为每个个体只从母亲那里继承线粒体DNA，所以线粒体DNA以一种直接的、简单的遗传方式反映了谱系。因为因为它变异的速度相对较快它是一个很好的标记来追踪人口流动，无论是人类还是非人类。多年来，人类学家以类似的方式利用其他基因控制的身体特征，如牙齿形状和大小，来确定现存种群之间的关系和追踪它们的历史。理论上，mtDNA可以更有效地做到这一点。一个引起人类学极大兴趣的问题是史前人类何时进入新大陆，以及他们可能来自哪里。虽然我们知道这些第一批居民是亚洲人，他们穿越了当时暴露的白令海陆桥，但这次主要迁徙的细节却缺失了。华莱士博士的研究应该有助于回答这个问题。这项研究之所以重要，有几个原因。它为人类学和历史学研究提供了一种新的、极其有力的工具。因为最擅长这项技术的科学家不是人类学家，所以在这两个群体之间建立桥梁很重要，而这个项目将有助于实现这一目标。此外，因为在某些情况下，考古和语言学数据允许重建过去的人口流动，人类学可以提供可控的背景，分子生物学家可以利用这些背景。

This grant provides the first of an expected three years of support to permit Dr. Wallace and his colleagues to apply their mtDNA techniques to a number of anthropological problems. It will allow continued categorization of both Old and new World mtDNA types and provide additional information on the original peopling and subsequent diversification of Native American populations in the New World. Dr. Wallace will collect blood samples from various Native American and Asian groups. These will be fractionated into cell types and lymphocytes immortalized with EBV. The mtDNA type of each individual will then be determined by digestion with six restriction endonucleases and the fragment types detected by Southern blotting. Lymphoblast mtDNAs from representative individuals will be examined in greater detail using additional restriction endonucleases, mtDNA:RNA heteroduplexes and mtDNA sequencing. Because each individual inherits mtDNA only from their mother, mitocondrial DNA reflects lineage in a straightforward genetically simple way. Because because it mutates relatively rapidly it serves an an excellent marker to trace population movement, both human and non-human over time. For many years anthropologists have used other genetically controlled physical traits such as tooth shape and size in a similar way to determine both the relationships between extant populations and trace their history. mtDNA can, in theory, do this much more effectively. One question of great anthroplogical interest is when prehistoric humans entered the New World and where they may have come from. Although it is known that these first inhabitants are of Asian stock and crossed over a then-exposed Bering land bridge, the details of this major migration are missing. Dr. Wallace's research should help to answer this question. This research is important for several reasons. It provides a new and extremely powerful tool for anthropological and historical research. Because the scientists who are most expert with this technique are not anthropologists it is important to build bridges between these two communities and this project will help to accomplish that. Also, because, in some instances, archaeological and linguistic data allow reconstruction of past population movements, anthropology can provide controlled contexts which molecular biologists can use to advantage.