Figure 2. Changing the genetic code for semantic containment.

Any change in the genetic code–sense-to-sense, sense-to-stop or triplet-to-quadruplet (see orthogonal translation as a containment strategy section)–leads to the incorporation of a different amino acid (Xxx) or protein synthesis termination (RF–release factor). As a result, the same messenger RNA (mRNA) message leads to two different proteins under the natural and engineered code. If the reassignment is sufficiently disruptive, such that under the natural code the resulting protein is not functional, then information cannot move from engineered to natural organism.