Example Tricarballylate Utilization Subsystem. A) The subsystem is comprised of 4 functional roles. B) The Subsystem Spreadsheet is populated with genes from 5 organisms (simplified from the original subsystem) where each row represents one organism and each column one functional role. Genes performing the specific functional role in the respective organism populate the respective cell. Gray shading of cells indicates proximity of the respective genes on the chromosomes. There are two distinct variants of the subsystem: variant 1, with all 4 functional roles and variant 2 where the 3rd functional role is missing.
Aziz et al. BMC Genomics 2008 9:75 doi:10.1186/1471-2164-9-75