A technical defence of evolution is beyond the scope of this dissertation, but amongst the most persuasive arguments are Kimura and <!g>Ayala’s discovery of the ‘molecular clock’ and the ability to reconstruct the branching of species based on genetic change over time. A powerful argument for the existence of a common human/primate ancestor comes from genetic scarring left by ancient <!g>virus infections that can be found in both the simian and human <!g>genome.