Once considered unimportant "junk DNA," scientists have learned that non-coding RNA (ncRNA) -- RNA molecules that do not translate into proteins -- play a crucial role in cellular function. Scientists at Tel Aviv University's Sackler Faculty of Medicine have discovered that when infected with a virus, ncRNA gives off biological signals that indicate the presence of the infectious agent. Not only does this finding give researchers a more complete picture of the interactions between pathogens and the body, but it provides scientists with a new avenue for fighting off infections. The researchers conducted a blind study in which some cells were infected with the HIV virus. Using a deep sequencer, which can read tens of millions of sequences per experiment, they analyzed the ncRNA. The researchers were able to identify with 100 percent accuracy both infected and non-infected cells -- all because the ncRNA was giving off significant signals.