Figure 5.

Pattern recognition with DNA-only circuits. (a) Summation. The concentrations of inputs are summed by translation gates. (b) Competitive amplification. Outputs are amplified by a mechanism based on toehold exchange. During amplification, outputs compete for a limited and global fuel. (c) Sequestration. Outputs Y_j are also irreversibly sequestered by threshold gates Th_j. When there is just enough fuel to saturate one but not all thresholds, amplification becomes competitive. It is expected that the output (or outputs) with the highest initial concentration (or concentrations) survive(s).