As a part of iGEM2006, a combined team from Davidson College and Missouri Western State University reconstituted a hin/hix DNA recombination mechanism which exists in nature in Salmonella as standard biobricks for use in E. coli. The purpose of the 2006 combined team was to provide a proof of concept for a bacterial computer in using this mechanism to solve a variation of The Pancake Problem from Computer Science. This task utilized both biology and mathematics students and faculty from the two institutions.

For 2007, we successfully continued our collaboration and our efforts to manipulate E. coli into mathematics problem solvers as we refine our efforts with the hin/hix mechanism to explore another mathematics problem, the Hamiltonian Path Problem. This problem was the subject of a groundbreaking paper by Adleman in 1994 (see citations) where a unique Hamiltonian path was found in vitro for a particular directed graph on seven nodes. We were able to use bacterial computers to solve the Hamiltonian path problem in vivo. (Why use a bacterial computer?)

The Adleman graph.

For the graph used in Adleman's paper (shown above), the Hamiltonian Path Problem would ask: can you find a path along the directed edges that travels from node 1 (green) to node 5 (red) and visits each node on the graph exactly once?