A new study of chickens overturns the popular assumption that evolution is only visible over long time scales. By studying individual chickens that were part of a long-term pedigree, the scientists led by Professor Greger Larson at Oxford University's Research Laboratory for Archaeology, found two mutations that had occurred in the mitochondrial genomes of the birds in only 50 years. For a long time scientists have believed that the rate of change in the mitochondrial genome was never faster than about 2% per million years. The identification of these mutations shows that the rate of evolution in this pedigree is in fact 15 times faster. In addition, by determining the genetic sequences along the pedigree, the team also discovered a single instance of mitochondrial DNA being passed down from a father. This is a surprising discovery, showing that so-called 'paternal leakage' is not as rare as previously believed.