Figure 3
From: Gene duplications in prokaryotes can be associated with environmental adaptation
Distribution of COG categories. The figure shows distribution of paralogs and persistent singletons according to COG categories, as well as the general distribution of the COG database. '-' is used where no COG group could be identified. The different categories are A: RNA processing and modification, B: chromatin structure and dynamics, C: energy production and conversion, D: cell-cycle control and mitosis, E: amino acid metabolism and transport, F: nucleotide metabolism and transport, G: carbohydrate metabolism and transport, H: coenzyme metabolism, I: lipid metabolism, J: translation, K: transcription, L: replication and repair, M: cell wall/membrane/envelope biogenesis, N: cell motility, O: post-translational modification, protein turnover, chaperone functions, P: inorganic ion transport and metabolism, Q: secondary metabolites biosynthesis, transport and catabolism, R: general functional prediction only, S: function unknown, T: signal transduction, U: intracellular trafficking and secretion, V: defence mechanisms, W: extracellular structures, Y: nuclear structure, Z: cytoskeleton. COG classification A, Y, and Z are not used for prokaryotic COGs.