Improving our understanding of genetic differences between species allows us to better interpret genetic risk in people.|We are all at risk of developing a wide range of diseases, some very common, including heart disease, diabetes, dementia and cancer. But such risks differ hugely between individuals, and are to a large degree influenced by the sequence of DNA in our cells.|The big question is which of the many thousands of DNA differences between individuals are responsible for increasing or decreasing their risk of developing a given disease. The historic record of evolution can provide some answers. We can read it as the differences in DNA between species, for example human versus mouse. The pattern of differences between species can reveal functionally important regions of DNA. Contrasting the between species pattern with the differences between people can point to the critically important changes that influence disease risk.|More broadly, we compare how DNA has changed between species with the differences between people. This allows us to study why and where DNA changes (mutations) arise, and what the functional consequences of those changes are. We are applying these methods to understand the genetic basis of many rare and common diseases.