Stanford scientists have synthesized a molecule of DNA that is capable of shutting off specific genes in living bacteria. Dubbed the “nanocircle,” the new nanometer-size molecule might one day give researchers the ability to target harmful genes that cause cancer and other diseases in humans.
The technique — known as “rolling circle amplification” — is now one of the hottest fields in biotechnology because it offers the potential to produce and detect more copies of a specific DNA sequence faster and cheaper than other methods.

To target a specific gene in E.coli, the researchers designed a DNA nanocircle that could duplicate large numbers of ribozymes — enzymes found in all living cells that are capable of altering the function of individual genes in the organism’s DNA.