Ratios of radical to conservative amino acid replacement are affected by mutational and compositional factors and may not be indicative of positive Darwinian selection.

Dagan T, Talmor Y, Graur D (2002); Mol Biol Evol., 19(7):1022-5. doi: 10.1093/oxfordjournals.molbev.a004161

Phenotypic variation in Pseudomonas sp. CM10 determines microcolony formation and survival under protozoan grazing Identification of diacylated ureas as a novel family of fungus-specific leukocyte-activating pathogen-associated molecules.