Prior to joining UC Davis, he did his PhD with Bob Griffiths in the mathematical genetics group of the Statistics Department at the University of Oxford, and was a post-doc in Jonathan Pritchard's group in the Department of Human Genetics at the University of Chicago, where he also worked closely with Molly Przeworski. His lab at UC Davis works on various topics in population genetics, including the role of geography in adaptation, the impact of natural selection on linked polymorphism, the causes and consequences of variation in recombination rates and the inference of demographic history from population genetic data.