Since Crick and Watson’s historic discovery of DNA, our investigation into coding DNA has gone a long way towards unravelling the key to life—but coding DNA only makes up just a few percent of the human genome. The rest is termed “Junk DNA” or “Non-coding DNA” because it doesn’t appear to have any function. However, new research suggests that this Junk DNA might actually play an important role in evolutionary history. Huge “ultraconserved” sections of it have remained the same for millions of years and are identical in many organisms—when you hear that humans and chimps share 98% of DNA, it’s mostly due to this. Increasing evidence suggests that Junk DNA influences coding DNA by acting as a kind of genetic “switch” in gene regulation, and it may also play a role in inheritance, but our knowledge is incomplete. If Junk DNA were really junk, then its sequence of “syllables” should be completely random, but it’s not random—leading scientists to believe it contains some kind of coded information. It’s been suggested that specific repetitive patterns are associated with susceptibility to cancer and other diseases, so understanding Junk DNA might be the key to understanding, diagnosing and curing disease.