Gene family sizes for homologous protein-coding genes in different species of the same genus. (a) Pseudomonas spp; (b) Bacillus spp. (c) Difference in the size of equivalent gene families between E. coli K12 and S. typhimurium LT2. Positive values indicate larger families in E. coli; negative values indicate larger families in S. typhymurium. The potG gene family is indicated.
Pushker et al. Genome Biology 2004 5:R27