Patterns of human genetic diversity: Implications for human evolution and disease.
Sarah Tishkoff, Dept. of Biology, University of Maryland, College Park.
A rough draft sequence of the human genome was completed in 2001. This sequence was assembled based on analysis of the genomes of only a handful of individuals. The next major phase of the human genome project will be to characterize levels and patterns of genetic variation among a broad range of globally diverse individuals. Such knowledge will be important both for reconstructing our evolutionary history and for understanding genetic susceptibility towards disease.
The origin of modern humans continues to be a subject of considerable debate.
We know little about the population structure, population size, or genetic diversity of archaic humans at the time of emergence of modern human form. Africa has been recognized as a key geographical region for the evolution of modern humans. And yet,
Africa has been greatly underrepresented in human genetic studies. My laboratory focuses on characterization of levels and patterns of genetic diversity in African populations. Our studies indicate very high levels of genetic diversity both within and between African populations. These data suggest that non-African populations originated recently in East Africa and that African populations have maintained a large effective population size and a subdivided population structure. The high level of genetic variation observed among African populations also has important implications for medical genetic studies, particularly for the design of linkage disequilibrium studies to identify human disease genes and for the treatment of diseases prevalent among people of recent African descent. The study of genetic diversity in Africa will also play a key role in the identification of genes that provide resistance against infectious agents such as malaria and HIV which are thought to have originated in Africa.