I am a theoretical evolutionary biologist who uses mathematical modeling as my chief research tool. I have background and interests in mathematical and statistical modeling within a wide range of topics including population genetics, population dynamics, and phylogenetic analysis. Most of my current research is focused at the interface between evolutionary genetics and trait adaptation. Evolutionary theory contains a sophisticated and detailed account of how adaptations are produced and maintained by natural selection, but selection is based on available genetic variation and the 'variational' properties of organisms are less well understood. A major challenge for evolutionary biology is to understand the laws of organismal variation and how they relate to evolutionary change.