In genetic terms, there is relatively little variation between humans. The differences between any two individuals, regardless of how diverse their origins, count for only a small fraction of the total genetic content stored in the DNA of either one. But the variation that does exist is important: some of it affects not only physical characteristics like size or shape, but also differences in disease susceptibility or the risk of genetic disorders. Until recently, it has only been feasible to study genetic variation at very short length scales within the DNA sequence. Now a new technology is becoming available for reading DNA much more quickly and at much less cost than before. This has made it possible to begin a comprehensive study of all types of variation amongst hundreds of individuals from all around the world. Analysing the data produced in this study will require powerful and sophisticated computing techniques. Our research will develop and refine these techniques, and will use them to make discoveries about some of the factors that have shaped human evolution. We will investigate how the human DNA sequence has been affected in different ways by the environments we inhabit, the threats we face, and the ancestors we share.