CommonCore-5 is the set of 2150 E. coli K-12 genes currently annotated in EcoGene representing the 2158 core genes common to five E. coli genomes identified by Davids (2008). They also identified a 1053 horizontally transmitted (HT) gene set (mapped to 1006 EcoGene genes) and a 1044 non-core gene set (mapped to 971 EcoGene genes), all defined so as to be non-overlapping gene sets, collected in subTopics and identified in GenePages.
The five E. coli organism codes and strains and the NCBI RefSeq accession numbers of the genome sequences used by Davids (2008) to define the common core of genes represented in CommonCore2150-5 are:
ECOLI: K-12 MG1655
ECOSA: O157:H7 Sakai
ECOED: O157:H7 EDL933
ECOUT: UTI89 (UPEC)
Please see Davids (2008) for their methods.
The 2158 core genes identified by Davids (2008) now map to 2150 genes in EcoGene due to sequence corrections and annotation changes.