Fig. 3

Double homologous recombination was used to generate the markerless deletion. a Schematic of the double homologous recombination event that results in deletion of nblA from the chromosome is shown. Black arrows indicate primers, yellow rectangles indicate homology arms, and the blue arrow represents the nblA gene. b PCR was used to confirm the deletion of nblA. Colony PCR using Primer A and Primer B of mutant Synechococcus 2973 yielded a product that is 180 base pairs lower in molecular weight than the band produced by wild type culture