The appeal of sudoku has spread to the prokaryotic world. A strain of Escherichia coli bacteria can now solve the logic puzzles – with some help from a group of students at the University of Tokyo, Japan.
“Because sudoku has simple rules, we felt that maybe bacteria could solve it for us, as long as we designed a circuit for them to follow,” says team leader Ryo Taniuchi.
The team begin with 16 types of E. coli, each colony assigned a distinct genetic identity depending on which square it occupied within a four-by-four sudoku grid. The bacteria can also express one of four colours to represent the numerical value of their square. As with any sudoku puzzle, a small number of the grid squares are given a value from the beginning by encouraging the bacteria in these squares to differentiate and take on one of the four colours.