In search of human variation.

There is widespread interest in documenting the amount and geographic distribution of genetic variation in the human species. This information is desired by the biomedical community, who want a densely packed map of SNP (single nucleotide polymorphism) sites to be used to identify genes associated with disease by linkage disequilibrium between sets of adjacent markers and the occurence of disease in populations, and to characterize disease-related variation among populations. Anthropologists use genetic variation to reconstruct our species' history, and to understand the role of culture and geography in the global distribution of human variation. The requirements for these two perspectives seem to be converging on a need for an accessible, representative DNA bank and statistical database of human variation. However, both fields have been using conceptual models that are oversimplified, and this may lead to unrealistic expectations of the questions that can be answered from genetic data.