Before revision:  Here we propose an active target search mechanism based on " epiphoresis ", the dynamics of DNA-binding proteins up or down gradients in the density of epigenetic marks  (biochemical tags on the genome).
After revision:  Here we propose an active target search mechanism based on " epiphoresis ", the dynamics of DNA-binding proteins up or down gradients in the density of epigenetic marks , or colours (biochemical tags on the genome).