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.
