The Evolution of Two-Component Systems in Bacteria Reveals Different Strategies for Niche Adaptation
Figure 5
Proximity of Different Classes of HPKs to RRs
Shown is the cumulative percentage of HPKs of each type that have RRs within the distance on the chromosome specified by the x-axis. The different gene types shown are: old HPKs—black squares (Old); HGT genes without recent paralogs—blue triangles (HGT); and HPKs with recent paralogs—red diamonds (LSE). In the bottom right panel, an average over all genomes is shown. In general, and for most specific cases (excepting Streptomyces), horizontally transferred genes are observed to have a much higher fraction of RRs in close genomic proximity. “Hybrid” HPKs, which have RRs in the same ORF as the HPK, were excluded from this analysis. Only genes that are not believed to have undergone duplication within a lineage are used in the HGT group. Lines stop when cumulative percentage equals 100%.