Genomic variation at the citrate fermentation gene locus. Divergence of the 13-kb genomic region in 19 K. pneumoniae strains was detected by CGH analysis using the NimbleGen chips. Hybridization signals of each probes placed in the order of the MGH 78578 genome were compared with those of the reference strain, NTUH-K2044. The probes covering the cit genes and the oad genes of the 13-kb region were shown together with that of the adjacent orfs. The normalized CGH signals for each probe are plotted as black dots. The dot position above or under the baseline represents higher or lower copy of specific genomic sequence in comparison to the reference. The scores in vertical axis are log2 values of test/reference signal intensity obtained from image scanning of hybridization results. The detection of elevated scores in the cit genes (citA-B, citS~citG2) in the last 10 strains (from NK3 to MGH 78278) is marked by solid triangles. Variations in the oad region are marked by open triangles.