Reverse genetics, the genetic manipulation of RNA viruses to create a wild-type or modified virus, has led to important advances in our understanding of viral gene function and interaction with host cells. Since many severe viral human and animal pathogens are RNA viruses, including those responsible for polio, measles, rotaviral diarrhoea and influenza infections, it is also an extremely powerful technique with important potential application for the prevention and control of a range of human...