Population genomics: a bridge from evolutionary history to genetic medicine

Studies of human genetic variation are making contributions in several key areas. Evolutionary genetic studies yield critical clues about the historie s of human populations, and they provide substantial support for an African origin of modern humans. The analysis of genetic variation has formed a fo undation for DNA-based forensic applications. And, as attention is focused on locating genes underlying complex diseases, it is becoming clear that a better understanding of genetic variation will help to guide gene-mapping e fforts. Population genomics, the large-scale comparison of DNA sequences, i s now beginning to provide new insights in these areas. We review some of t he general patterns of human genetic variation, and we show how our knowled ge of these patterns can aid in the mapping and cloning of disease-causing genes.