Gene Network Homology in Prokaryotes Using a Similarity Search Approach: Queries of Quorum Sensing Signal Transduction
Figure 3
Lac operon LMNAST hits overlaid onto phylogenetic distributions of different scopes.
The larger, bolded leaves represent species that contain lac operon homologs, whereas the grayed italicized leaves were completely bereft. A. An E. coli specific phylogenetic tree as adapted from [4], wherein all genes from the core E. coli were used to construct a consensus tree. Among the species/strains represented here, lac system homologs were absent from certain Shigella. Additionally, BW2952, SE11, IAI1, HS, E243227A, CFT073, K-12 DH10B, and 11 of 18 O:H serotyped strains contained truncated systems. Uniquely, CFT073 retains lacA, while missing lacI in an otherwise preserved lac system structure. B. The phylogenetic dispersion of the lac system is mostly limited to Escherichia and proximal species, as seen in the 16s based tree adapted from [5]. Bolded leaves indicate the presence of the lac system in at least one strain.