In 1986, US scientists held a conference at Santa Fe, New Mexico, where they outlined plans to sequence the entire human genome. There were initially two reasons for this massive undertaking. First, they thought it was the best way to understand the genetic changes that cause cancer. Second, the US Department of Energy needed an efficient way of studying long-term DNA damage caused by radiation - in particular, from the atom bombs dropped on Japan in 1945. The result was the international Human Genome Project, which started in 1990.