DNA is found on every level of the game except the boss levels. There are 10 non-boss levels. There are 5 per level. To advance to the boss levels you will need a specific amount of DNA. DNA is usually easy to spot and is scattered throughout the entire level. You can tell it is DNA if you see strands of colors: purple, blue, green, yellow, and red. The DNA appears in the same order throughout the level as it does in the menu. Example: If you collected all DNA except blue, when you reach where purple was then your not there yet, and if you reach where green was then you have gone to far.