Download A global analysis of nuclear genetic haplotype variation among

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.