Genetics for all: the business of DNA tests   For around 100 euros and a sample of your saliva, a laboratory can tell you where your ancestors came from and your percentage of Scandinavian or Indian blood. Companies can even analyse your genetic predisposition to certain diseases. But do we really want to know all about our chromosomes? Guests: Rola Tarsissi, film director; Laurent Alexandre, chairman of DNA Vision. Presented by: Jacques Cardoze.