Mitochondrial Genes and Human Origins

这笔资金是华莱士博士和他的同事们将线粒体DNA技术应用于一系列人类学问题的三年资助中的第一笔。它将允许继续对新旧大陆的线粒体DNA类型进行分类，并提供关于新大陆美洲原住民的原始人口和随后的多样化的更多信息。华莱士博士将采集各种美洲原住民和亚洲人的血液样本。这些细胞将被分成不同的细胞类型和因EBV而永生化的淋巴细胞。每个个体的线粒体DNA类型将通过六种限制性内切酶的消化和Southern blotting检测的片段类型来确定。来自代表性个体的淋巴母细胞线粒体DNA将使用额外的限制性内切酶、mtDNA：RNA异源双链和mtDNA测序进行更详细的检查。因为每个个体都只从他们的母亲那里继承线粒体DNA，所以有丝分裂DNA以一种直接的基因简单的方式反映了血统。因为因为它的变异相对较快，所以它是一个很好的标记，可以追踪人口的移动，无论是人类还是非人类随着时间的推移。多年来，人类学家一直使用其他受基因控制的生理特征，如牙齿形状和大小，以类似的方式确定现有种群之间的关系，并追溯它们的历史。从理论上讲，线粒体DNA可以更有效地完成这一任务。一个极具人类学意义的问题是史前人类何时进入新大陆，他们可能来自哪里。虽然已经知道这些第一批居民是亚洲血统，并穿越了当时被曝光的白令大陆桥，但这一重大迁徙的细节仍然缺失。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强大的工具。因为最精通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是很重要的，这个项目将有助于实现这一点。此外，由于在某些情况下，考古学和语言学数据可以重建过去的人口迁徙，人类学可以提供分子生物学家可以利用的受控背景。

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.