evidence: Made up of tiny loops of DNA, these genetic villains survive outside the chromosomes which are our cells' main repositories of genetic material.... "We have found that ecDNA act as cancer-causing genes that have somehow separated themselves from a person's chromosomes and have started to behave in ways that circumvent the normal rules of genetics," said Stanford university geneticist Howard Chang. "They behave like villains in a Bond film. At first, in a film, you see different explosions, killings and disasters occurring and you don't know why they are happening or who is responsible. Then, at some point, you finally meet the villain who is revealed to be the agent of all this mayhem."