Programmed mutagenesis is a DNA computing system that uses cycles of DNA annealing, ligation, and polymerization to implement programatic rewriting of DNA sequences. We report that programmed mutagenesis is theoretically universal by showing how Minsky's 4-symbol 7-state Universal Turing Machine [11] can be implemented using a programmed mutagenesis system. Each step of the Universal Turing Machine is implemented by four cycles of programmed mutagenesis, and progress is guaranteed by the use of alternate sense strands for each rewriting cycle. The measured efficiency of an in vitro programmed mutagenesis system suggests that segregating the products of DNA replication into separate compartments would be an efficient way to implement molecular computation.
Julia Khodor, David K. Gifford