mrspoonsi writes: A project aiming to revolutionise medicine by unlocking the secrets of DNA is under way in centres across England. Prime Minister David Cameron has said it "will see the UK lead the world in genetic research within years". The first genetic codes of people with cancer or rare diseases, out of a target of 100,000, have been sequenced. Experts believe it will lead to targeted therapies and could make chemotherapy "a thing of the past". Just one human genome contains more than three billion base pairs — the building blocks of DNA. Prof Jeremy Farrar, director of the Wellcome Trust, said: "I can see a future where genetics is going to come into every bit of medicine from cardiology to oncology to infectious diseases." "Twenty years from now there's going to be a plethora of those, we will have a series of mutations which academics and industry will have developed therapies for, which will be targeted at you and specific for that cancer." He said chemotherapy, which attacks all dividing cells in the body, would be replaced with such therapies. "We will look back in 20 years' time and think of blockbuster chemotherapy [as] a thing of the past and we'll think 'Gosh, what an era that was'." David Cameron has announced a series of investments across government, industry and charities totalling £300m ($500m).