A tautomer can bond in the following pairs (defined by their molecular geometries): A*-C, A-C*, G*-T and G-T*. Due to the geometric similarity between purine-pyrimidine bonding within both canonical and tautomeric pairings, the tautomer will not disrupt the replication process. The tautomeric mismatch can evade correction by the replisome fidelity checks, and a genetic error can be established in two DNA double helices, propagating through subsequent generations of DNA replication. It is also possible for the zwitterionic products of single proton transfer to bond in an anti-syn mismatch (where a base bonds in a flipped orientation) to form non-standard base pair configurations. However, these anti-syn products are energetically unfavourable and cannot be incorporated into a full DNA sequence due to sterical repulsion. Therefore, a single proton transfer cannot propagate as a genetic mutation since it will interrupt the process of mitosis and be corrected.